The World of Insects Movies
Endorsed by Sioux Falls Zoologists
Sioux Falls Zoologists recommends the following documentaries that describe the world of insects and their behavior.
Insects have been around for 400 million years. They also were once quite large. Dragonflies once had a wingspan of over 2 feet. Their individual intelligence isn't much to speak of, but they do exhibit swarm intelligence (see Gathering Swarms ) which has obviously been incorporated in their genetics.
Bees seem to be on the high end of insect intelligence. They communicate locations using fairly complicated "waggle" dances and seem to "vote" on where to locate new hives. It's amazing what 40 million years of evolution (or more) can incorporate in a species' genetics.
The movies are all available from Amazon.com but you are free to obtain them from many other sources. Amazon offers them on their website along with many alternate sources, often less expensive. Many are probably also available on NetFlix.com and elsewhere for online viewing. You are free to choose whatever source you please. The movie links provided on the following pages point to the movie location at Amazon.
Documentaries on Insect behavior, including Butterfly and Bee behavior, are described on the following 7 pages:
10-28-21 Assassin bugs tap spiders to distract them before a lethal strike
The strange behavior seems to lull the arachnids into fatal complacency. The strange Assassin bugs live up to their name. The insects expertly stalk and feed upon other small invertebrates, jabbing them with a venomous proboscis. Some species even hunt spiders and use a strange trick to gain the upper hand. Using their antennae, assassin bugs tap spiders, which appears to discombobulate the arachnids long enough to let the bugs make a toxic strike, researchers report September 29 in the Biological Journal of the Linnean Society. The findings provide insight into some of the sophisticated hunting tactics that predators evolve when targeting dangerous prey (SN: 8/4/21). Thread-legged bugs are a subfamily of particularly gangly assassin bugs, and some species spend their lives in a place most insects avoid: spider webs. The bugs silently creep along the spider’s silk, taking care to make their vibrations seem benign before violently dispatching the web’s architect, seizing the spiders with their front legs and injecting them with venom. While watching two species of Stenolemus assassin bugs hunt spiders, ecologists Anne Wignall and Fernando Soley took note of the bugs’ habit of lightly knocking their antennae on spiders once the bugs were within striking distance. “It struck us early on that tapping prey was a really strange thing to do,” says Wignall, of Massey University in Albany, New Zealand. Spiders could easily defend themselves in a lethal fashion. “Watching [the bugs] spend so much time and effort on stealth, only to essentially tap [the spiders] on the shoulder was absolutely fascinating.” To figure out why the bugs tap, Wignall and Soley, of the Organization for Tropical Studies in San José, Costa Rica, tested the behavior of 30 web-building cellar spiders (Pholcus phalangioides) in the laboratory. The researchers replicated the bugs’ antennae tapping by gently brushing the spiders’ leg with a dog hair. After the tapping, the team measured the spiders’ responses to a vibrating tuning fork placed on the web, mimicking a struggling insect.
10-25-21 Jumping spiders’ remarkable senses capture a world beyond our perception
Scientists are catching glimpses of the surreal sensory landscape these spiders navigate. Imagine that the world is shades of gray and a little blurry, almost as if your lousy peripheral vision has taken over. This fuzzy field of view extends so far that you can make out dim shapes and motion behind you as well; no need to turn your head. The one bright spot is an X-shaped splash of color that moves with your gaze. At the center of this splash, everything is crisp and clear — a small window of sharp, colorful detail in a gauzy grayscape. Add some blades of grass the size of redwood trees, and you’ve got an inkling of what the world looks like through the eight eyes of a jumping spider. It might be a bit like watching a poorly focused black-and-white movie on a 3-D IMAX screen that wraps around the room, while you hold a spotlight shining high-definition color wherever you point it. In other words, it’s really, really strange, at least compared with our two-eyed human perspective. Jumping spiders, which are the family Salticidae, are best known for their hilariously flamboyant mating dances, their large front eyes that make for adorable close-ups and their itty-bitty size — some of the more than 6,000 known species of jumping spiders are smaller than a sesame seed. But scientists are discovering that there’s much more to these diminutive arachnids. Researchers are getting a sense of what it’s like to be another animal by doing innovative experiments to go deeper into these spiders’ lives, probing their ability to see, feel and taste. “Part of why I study insects and spiders is this act of imagination that is required to really try to get into the completely alien world and mind and perceptual reality of these animals,” says visual ecologist Nathan Morehouse of the University of Cincinnati.
10-19-21 Danish children trap 19,000 ants to study impact of climate change
Important information about how ant populations are evolving in the face of global warming, forest farming and urbanisation has come from a citizen science project involving hundreds of Danish children. The project involved youngsters and their families collectively trapping 19,000 ants near their homes or holiday sites across Denmark. Comparing the new catches with specimens dating back to 1900, an international research team has detected major population shifts in these “hugely important, but vastly underappreciated” insects, says team member Julie Sheard at the University of Copenhagen. Most population studies have focused on “charismatic” insects like butterflies, dragonflies, grasshoppers and bees, she says. “But ants pollinate plants, spread seeds and aerate the soil, so they’re also extremely important.” Sheard and her colleagues provided 1500 families and schools with the Ant Hunt project ant-baiting kits. The kits explained to the children – aged from 3 to 18 years old – how to set the traps and leave them for 2 hours, and to then send them back to the research centre. In the laboratory, the scientists analysed the specimens and gave the children details about the species they found and sent them a diploma. Last year, DNA analyses revealed that the children had discovered an invasive species – the immigrant pavement ant (Tetramorium immigrans) – for the first time in Denmark. In their latest study, the team compared ant-baiting kit catches with historical specimens housed in Danish museums. Taking into consideration the year in which historical specimens were captured and the locality of capture, the researchers used modelling to estimate how the geographical range and population size of 29 ant species has changed across the years. They found that while half of the species have had stable populations since 1900, the other half have either declined, increased or fluctuated, Sheard says. Among those that have fluctuated, three are currently in decline – including two species that build mounds in sunny patches of forests. This is probably because tree-farming has made forests denser and less hospitable to insects, she says.
8-4-21 Amazing images show butterfly mouthparts up close
THESE colourful and startlingly detailed appendages may look otherworldly, but they are actually proboscises, straw-like butterfly mouthparts used for feeding. The images were taken by Jan Michels at the University of Kiel, Germany, co-author of a recent study on butterfly feeding (Functional Ecology, doi.org/gp7x). He created the picture by stitching together multiple images taken using confocal laser scanning microscopy, an optical imaging technique that reveals the tiny intricacies of the proboscis by using mirrors to direct a laser beam across the field of view. The research showed that flower-feeding butterflies have a smoother, more tapered and less bendable proboscis than species that don’t feed on flowers. This allows the flower-feeders to penetrate nearly twice as deep. Michels and his colleagues tested how well both types of butterfly could use their proboscis to enter funnel-shaped glass tubes filled with a sugar solution. They found that non-flower-feeding individuals, such as mourning cloaks (Nymphalis antiopa), tended to get their mouthparts stuck 90 per cent of the time, while flower-feeding species like the eastern tiger swallowtail (Papilio glaucus) never got them stuck. The work reveals how evolution shaped butterfly proboscises to allow some species to be able to feed via narrow floral tubes easily and efficiently.
8-4-21 Snake-eating spiders are surprisingly common
Spiders from at least 11 different families feed on serpents many times their size. A spider’s typical dinner menu might include insects, worms or even small lizards and frogs (SN: 2/3/21). But some arachnids have more adventurous tastes — they can eat snakes up to 30 times their size. Take the Australian redback. Not including legs, a female of this species of spider is only about the size of an M&M candy. But she can take down relatively big prey such as juvenile eastern brown snakes, which are among the most venomous serpents in the world. A snake that gets trapped in a redback’s web — a messy tangle of long, sticky silk threads that dangle to the ground — is quickly set upon by the spider, which subdues the struggling victim with more sticky silk before delivering a toxic bite that eventually kills the snake. “I find it cool that tiny Australian redback spiders can kill brown snakes,” says spider biologist Martin Nyffeler of the University of Basel in Switzerland. “[It’s] very fascinating and a little frightening!” But redbacks are far from the only spiders with an appetite for snake. At least 11 different families of spiders feed on snakes, Nyffeler and herpetologist Whit Gibbons report May 11 in The Journal of Arachnology. Nyffeler and Gibbons, of the University of Georgia in Athens, searched for reports of snakes eating spiders in all sorts of places — from research journals and magazine articles to social media and YouTube videos. In all, the team analyzed 319 accounts from all over the world. Most reports came from Australia and the United States, but these spiders live on every continent except Antarctica. “I didn’t realize how common this was. I don’t think anybody did,” says evolutionary biologist Mercedes Burns of the University of Maryland, Baltimore County, who was not involved in the research.
8-3-21 Harvestman genome helps explain how arachnids got grasping legs
Some spider-like animals grow long legs that wrap and grasp like a monkey’s tail – and a genetic study has helped establish how they develop. Harvestmen, or daddy-long-legs, are arachnids, but they aren’t spiders: they instead belong to a closely related group called the Opiliones. They have eight extraordinarily long legs that can measure up to 28 times their body length, and they can bend the tips of them to wrap around and grasp objects. However, harvestmen – like spiders, ticks and scorpions – actually have 12 limb-like appendages in total. The four at the head end develop into short jaws or pincers, or short limbs called pedipalps, which are unique to arachnids and can often detect tastes. Fascinated by the way these appendages develop differently, Guilherme Gainett at the University of Wisconsin-Madison and his colleagues teamed up with genome specialists at the Smithsonian Institution in Washington DC to draft a sequence of the genome of a lab-raised harvestman (Phalangium opilio). After identifying three genes they thought might affect how the animal’s legs develop, they engineered dozens of harvestmen embryos with different combinations of modified ways of expressing those genes. Some of the harvestmen developed deformed legs that more closely resembled the first four appendages, says Gainett. And when the team interfered with specific genetic pathways, the legs lacked the kind of segmentation – similar to joints in vertebrates – that normally allows harvestmen to curl their legs around objects. “We’ve shown… how the combinations of these genes create a blueprint in the embryo to differentiate between what’s going to be a leg that is used for walking and what is going to be a pedipalp, which can be used to manipulate food and assess the surroundings,” says Gainett.
7-30-21 Viruses can kill wasp larvae that grow inside infected caterpillars
A new study is a take on the adage, “The enemy of my enemy is my friend.”. When parasitic wasps come calling, some caterpillars have a surprising ally: a viral infection. Insects called parasitoid wasps lay their eggs inside young moth larvae, turning the caterpillars into unwitting, destined-to-die incubators for possibly hundreds of wasp offspring. That’s bad news for viruses trying to use the caterpillars as replication factories. For the caterpillars, viral infections can be lethal, but their chances of survival are probably higher than if wasps choose them as a living nursery. Now, a study shows how certain viruses can help caterpillars stymie parasitoid wasps. A group of proteins dubbed parasitoid killing factor, or PKF, that are found in some insect viruses are incredibly toxic to young parasitoid wasps, researchers report in the July 30 Science. The new finding shows that viruses and caterpillars can come together to fight off a common wasp enemy, says study coauthor Madoka Nakai, an insect virologist at Tokyo University of Agriculture and Technology. A parasitoid wasp would kill a host that the virus needs to survive, so the virus fights for its home. “It’s very clever,” Nakai says. What’s more, some moth caterpillars make the wasp-killing proteins themselves, the team found. It’s possible that in the distant past, a few moths survived a viral infection and “got some presents” in the form of genetic instructions for how to make the proteins, says study coauthor Salvador Herrero, an insect pathologist and geneticist at the University of Valencia in Spain. Those insects could have then passed the ability down to offspring. In this case, “what doesn’t kill you makes you stronger,” Herrero says. Previous studies had shown that viruses and insects, including moths, can swap genes with each other. The new finding is one of the latest examples of this activity, says Michael Strand, an entomologist at the University of Georgia in Athens who was not involved in the work.
7-23-21 Essential oils help to stop invasive beetles from eating palm trees
The red palm weevil, a beetle known for its devastating effect on palm trees, can be stopped in its tracks by clove and thyme oil – offering hope of new control options for growers hit hard by the insects’ damage to their crops. Researchers at Universiti Malaysia Terengganu tested the effect of eight chemicals derived from the two essential oils on feeding by larvae of the red palm weevil (Rhynchophorus ferrugineus), one of the world’s most invasive species which severely impacts the date, coconut and palm oil industries. In a study of 225 larvae over a two-week period, daily consumption of blocks ofsago palm (Cycas revoluta) soaked with both clove and thyme oil derivatives was at least 35 per cent lower than untreated blocks. Of the chemical compounds found in these oils, ethers reduced weevil feeding more than esters, and two stood out as particularly effective. These have the potential to be used as targeted bioinsecticides, says the research team. “Botanical biopesticides are seen as increasingly important crop protection tools. This stems, in part, from the reduced availability of synthetic pesticides,” says Tom Pope at Harper Adams University, UK, who was not involved in the work. He says such insecticides derived from natural materials such as plants reduce the risk that comes with conventional pesticides of resistance developing in pest populations, and they linger in the environment for less time. “Despite this, all biopesticides should be integrated within dynamic pest management programmes and not seen as ‘silver bullets’,” he says. While a number of products work against red palm weevil under lab conditions, the problem is how to deliver such deterrents, says Michel Ferry at the French National Institute for Agriculture, Food, and Environment, who was not involved in the research.
7-16-21 The Big Butterfly Count has just kicked off - here’s how to help
WITH summer truly under way in the northern hemisphere, now is a perfect time to spot butterflies and day-flying moths. If you live in the UK, you can help conservation scientists by participating in this year’s Big Butterfly Count. By simply counting the amount and type of butterflies and moths you see, and logging your results via the Big Butterfly Count app or website, you can help researchers investigate where different species in the UK are located and how they are responding to climate change. “You can’t conserve something unless you know where it’s found,” says Zoë Randle, senior surveys officer at the UK charity behind the count, Butterfly Conservation. This year’s Big Butterfly Count has now started and runs until 8 August, so there is still plenty of time to join in. Once you have chosen a place to spot butterflies and day-flying moths, wait and watch for 15 minutes and record which species you see out of 20 target species, and the highest number of individuals of that species you see at one time. Don’t worry if you don’t know your painted ladies from your commas – a handy ID chart is available on the Big Butterfly Count app or website, where you can also record your observations. Sunny weather is ideal for spotting butterflies, says Randle. “Butterflies are insects – they’re cold-blooded and they need the warmth from the sun,” she says. Data provided through the Big Butterfly Count and other research efforts indicate that while some species are expanding their range as the planet heats up, others are faring less well. “The ringlet butterfly is expanding its range due to climate change, [as are] the speckled wood and the comma,” says Randle. But the small tortoiseshell butterfly, often spotted in gardens in the UK, has fallen by 79 per cent since 1976, she says.
7-14-21 Climate change may rob male dragonfly wings of their dark spots
Shadowy areas are a heat-absorbing liability, but losing them may mess with the insects’ mating. Many dragonflies zip through the air with their translucent wings painted in an array of dark spots and bands. But — for males at least — those dapper decorations could soon fall out of style as a result of climate change. Males’ dark wing patches are smaller in dragonflies of a given species that live in warmer climates than in cooler regions, researchers report in the July 13 Proceedings of the National Academy of Sciences. That finding suggests that dragonfly populations over time may experience their spots shrinking as temperatures rise. The evolutionary change may not only dampen the male insects’ flair, but also their dating life. Understanding how organisms have adapted to warmer climates over the years is key to understanding how they may adapt to future climate conditions, says Michael Moore, an evolutionary ecologist at Washington University in St. Louis. Heavy wing pigmentation can help dragonflies stay warm in chillier regions, but could be dangerous in hotter weather. The dark spots absorb sunlight and can heat wings by as much as 2 degrees Celsius, which may cause tissue damage and interfere with flight, Moore says. Tossing or shrinking the spots is a way to beat the heat, and could result in a color shift response to climate change among dragonflies akin to owls (SN: 7/11/14) and hares (SN: 1/26/16). But the adaptation could also garble communication with mates. Male dragonflies use wing spots to attract mates and intimidate rivals, and females rely on those spots to recognize potential mates of the same species. The markings differ greatly among species, ranging from small speckles near the wing’s base to extensive bands or panels spread across the entire wing. Most organisms, Moore says, “don’t just need to survive in order to persist and perpetuate their species within the habitats they live in, they also have to be able to reproduce.”
7-14-21 Froghoppers are the super-suckers of the animal world
Tiny insects can produce negative pressures equivalent to people sucking a 100-meter-long straw. To tap an unlikely source of nutrition, insects small enough to sit on a pencil eraser have to suck harder than any known creature. Philaenus spumarius froghoppers pierce plants with their mouthparts to feed solely on xylem sap, a fluid made mostly of water that moves through plants’ internal plumbing. Not only is the substance largely bereft of nutrients, but it’s also under negative pressures, akin to a vacuum. Sucking the sap requires suction power equivalent to a person drinking water from a 100-meter-long straw. Such a feat seemed so unlikely for the tiny insects that some scientists questioned whether xylem sap truly could be under such negative pressures. But both biomechanical and metabolic evidence suggests that froghoppers can produce negative pressures greater than one megapascal, researchers report July 14 in Proceedings of the Royal Society B. “It’s incredibly impressive. [The scientists] used a range of techniques to tackle a long-standing problem,” says Jake Socha, a biomechanist at Virginia Tech in Blacksburg who wasn’t involved in the work. “These insects are really well-adapted for generating” extreme negative pressures. The problem is long-standing because measuring negative pressures is tricky. Within xylem, sap is pulled like a string, caught in a tug-of-war between spongy soil and airy leaves. Piercing the plant with pressure probes can easily break that internal tension, so scientists typically use a more indirect method. By cutting off part of a plant and sticking the leafy end in a pressure chamber with the stem sticking out, researchers can turn up the pressure exerted on the outside of the plant until it just exceeds the plant’s internal pressure and xylem sap oozes from the stem. This strategy suggests that the negative pressures of xylem sap can exceed one megapascal.
7-8-21 Nature: Backyard moth spotting rises during lockdown
Lockdown sparked a surge in interest in moths, with a rise in rare species spotted last year. Sightings were up by about a third - and many counties across the UK recorded species new to their area. Experts are heartened by a new found fascination for the insects, which they say are ecologically important but underappreciated and under threat. They say July is the perfect month to find moths - and are calling for the public to go in search of them. Mark Tunmore, editor of Atropos, the journal for butterfly, moth and dragonfly enthusiasts, said all the evidence points to a surge of interest during lockdown. "It's not surprising in many ways, because moth trapping is an ideal activity for the garden," he said. "All you need is a moth trap, which is something you can construct yourself or buy from specialist dealers, and once you've got that, you can run it in your garden and the moths come to you." Data from the National Moth Recording Scheme suggests there was a rise of around a third in the numbers of people submitting sightings of moth species in 2020, while sales of moth traps also rose. In Cheshire, seven species new to the county were recorded in 2020, including Light Feathered Rustic and Beautiful Marbled. Several species new to Cornwall were spotted in the county, and it was also a record year for numbers of some scarce migrant species such as Crimson Speckled, Slender Burnished Brass and Scar Bank Gem. In Yorkshire, the number of annual moth records submitted rose by around a quarter in 2020. There was also a surge in interest in moth hunting in Shetland, with four species new to the islands recorded last year. With many people desperate to find things to do in their own backyard during lockdown, moth trapping provided a distraction and interest, Mark Tunmore said. "It's a whole new world once people start looking at moths and they're amazed by what's in their garden," he explained. "Even in a very simple garden you can have dozens or hundreds of species, potentially, recorded over a long period of time."
7-5-21 Male dragonflies may become less colourful as the climate warms
Climate change may make the male dragonflies of North America less colourful – which might also make them less sexually attractive to females. Michael Moore at the Living Earth Collaborative and Washington University in Saint Louis, Missouri, and his colleagues examined hundreds of thousands of records of dragonflies representing 319 North American species and compared them with the animals’ home climates. They found that the cooler the region, the darker and more elaborate the wing colouration on males of each species. The team then focused on 10 dragonfly species with a particularly wide geographical range across North America, and examined 2700 photographs of these species uploaded to the iNaturalist community science platform. This revealed that, even within each dragonfly species, males had wings that were less colourful in warmer climates. This makes sense, because colourful wings absorb more sunlight – and become warmer – than colourless wings. In fact, coloured patterns can raise wing temperatures more than 2°C, damaging wing tissue, which can even lead to death by overheating. It also suggests that, as the climate warms, male dragonflies might stand a better chance of surviving if they have less colourful wings. “It’s very likely that dragonflies will lose a moderate amount of their wing colouration as they adapt to warmer temperatures associated with climate change,” says Moore. “It becomes a cost-benefit question.” Finally, the team took a closer look at how the 10 focus species have changed in the recent past. This revealed that male dragonflies photographed between 2005 and 2019 tended to have less colourful wings in warmer years and more colourful wings in cooler years. The implication is that, when it is hotter, only the less colourful male dragonflies survive. Female dragonflies have colourful wings too, but they are less likely to lose their colour in hotter years. This may be because females prefer to hide in the shade while males fly in the sunlight.
6-29-21 These beetles walk on water, upside down, underneath the surface
The insect’s inverted surface scurrying is a rare method for getting around. Being quite small, insects can have a very different relationship with the water-air interface than larger animals do. Surface tension allows for insects like water striders to skate along the top of still waters, for example. But new research reveals an unusual way to tread along this boundary: from the underside. A water-dwelling beetle can scuttle upside-down along the underside of the water’s surface, as if the water were a solid pane of glass, researchers report June 28 in Ethology. It’s the first detailed documentation of a beetle moving in this manner, which is known only in precious few animal groups. John Gould, a behavioral biologist at the University of Newcastle in Callaghan, Australia, hadn’t set out to look for beetles one night in the country’s Watagan Mountains, searching instead for tadpoles in ephemeral pools. In one of these pools, he spotted a black object smaller than a pinky nail. “At first, I just assumed it must have been a bug that had fallen into the water and was swimming across the surface,” Gould recounts, “but then realized the bug was upside-down and below the water’s surface.” As Gould quickly filmed the scene, the beetle walked under the water’s surface just as it would on a flat, solid surface, periodically resting and changing direction. Later, Gould mentioned the encounter to his colleague Jose Valdez, a wildlife ecologist at the German Centre for Integrative Biodiversity Research in Leipzig. Valdez thought the observations were interesting, but he’d seen insects walk upright under water before. “I didn’t fully grasp what he was describing until he showed me the video,” says Valdez. “Then I was floored.” Searching the scientific literature, the researchers found that some snails could slide along the underside of the water’s surface on a layer of mucus, but little documentation of beetles walking this way existed — just passing mentions in decades-old papers.
6-16-21 How gardeners can help plant-eating insects instead of killing them
AS MOST of the UK recovers from a frigid April and a soggy May, its gardens are starting to perk up. That means so are caterpillars, aphids such as greenflies, and other plant-feeding invertebrates generally seen as the gardener’s foes. A common reaction to seeing prized plants covered with bugs is to reach for the pesticide spray. But we should temper that instinct, says Andrew Salisbury, principal entomologist at the UK Royal Horticultural Society. Many invertebrate species in the UK and elsewhere are in decline, and gardens can be a haven – the UK’s home gardens collectively add up to an area larger than the country’s official nature reserves. You might think there is no shortage of aphids, but they are food for bigger insects, such as ladybirds, lacewings and wasps, not to mention blue tits. While gardens are a much understudied ecological resource, some work suggests they can support hundreds of invertebrate species, including at least two insects in decline in the UK: two-spot ladybirds and, in the south, stag beetles. Most synthetic pesticides kill aphids’ insect predators too – and aphids tend to bounce back faster than their predators, requiring repeated spraying. If you must spray, try to use organic, soap-based products, which tend to be less harmful to predators – though they aren’t completely non-toxic, says Salisbury. He doesn’t advise home-made soap solutions as they haven’t been tested for their effects on plants or wildlife. There are other ways you can encourage invertebrates into your garden, according to a four-year study by Salisbury and his team. These include denser planting (although spiders love bare spots between plants) and choosing British species. The researchers compared how many invertebrates could be supported by three types of typical garden planting scheme: native British plants, “near-native” plants (defined as those from the same genus found in the northern hemisphere) and exotics, or those from the southern hemisphere.
6-5-21 ‘Hangry’ male fruit flies attack each other if they go without food
If you’ve ever been hangry – so hungry you become angry – you have a little something in common with fruit flies. When these insects don’t get enough to eat, they aggressively lash out at others and some even make a kind of fencing manouevre with their legs to fight with other fruit flies. “Male fruit flies display aggression that they direct towards other fruit flies. They don’t show these behaviours towards females,” says Jennifer Perry at the University of East Anglia in the UK. Perry and her colleagues separated virgin male fruit flies (Drosophila melanogaster) into five groups of between 58 and 74 insects. One group consisted of newly emerged adults that had not fed since their larval stage, while another was made up of flies that were allowed to feed throughout the experiment. The remaining groups were fed and then deprived for periods of 24, 48, or 72 hours. At six to seven days old, pairs of flies from each group were placed together with food and monitored over 5 hours. The team observed the pairs 16 or 32 times over 5 hours to record their behaviour. Flies deprived of food had became increasingly aggressive, which peaked at 24 hours without food. The aggressive flies would lunge at and chase each other or fence with their legs. “I think we can all relate to feeling hangry after periods of food deprivation, and what our study shows is that these feelings extend across even very distantly related animals,” says Perry. “They share lots of genes for their physiology and behaviour with vertebrates, including humans. They’re a good model [for aggression] in that way.” Even animals as seemingly simple as a fruit flies have complex social lives and respond to changes in their environment that affect the costs and benefits of social behaviour like aggression, she says.
6-2-21 Parasitic ants keep evolving to lose their smell and taste genes
To most ants, smell and taste are everything. But some parasitic ant species have lost the genes that drive these senses – a sensory shake-up that may be due to the way they outsource some tasks to host species. Interpreting subtle chemical cues through smell and taste help ants hold their societies together. This “chemoreception” is involved in everything from group foraging to recognising nest mates. But not all species of ant live or interact with each other in the same way. Some ants are social parasites that raid the nests of other, closely related ant species, steal their workers and eventually become dependent upon their captives’ labour. To unveil the evolutionary impacts of this parasitic lifestyle, Erich Bornberg-Bauer at the University of Münster in Germany and his colleagues delved into the insects’ genomes – their full genetic instructions. The researchers analysed the genomes of eight ant species: three parasites, their three host species and two non-host species. The team found that the parasitic ants – Harpagoxenus sublaevis, Temnothorax ravouxi and Temnothorax americanus – had half as many taste receptor genes compared with their hosts and the non-host ants. The parasites had also lost about a quarter of their olfactory genes, which are involved in smell. Greg Pask at Middlebury College in Vermont, who wasn’t involved with the work, says he expected some loss of these receptor genes, but not to the degree revealed in the study. In general, olfactory genes are massively multiplied in ants compared with other insects, implying that they are important for ant survival, he says. Relying on host ants for a range of tasks that involve heavy use of smell and taste may allow these chemoreceptor genes to wane over evolutionary time. “If you don’t have to forage and do a lot of the major work where you need chemosensory activity, then you have no pressure to maintain those genes as functional copies,” says Pask. “It turns out if [an olfactory] gene is broken you can get along fine with that, because the host species is able to take care of [the task].”
6-2-21 This smart shift in pesticide use could let insect populations recover
The world's insects are in trouble – if we start using pesticides to protect plants rather than killing insects it could make a big difference. INSECTS are disappearing. The world has 25 per cent fewer terrestrial insects now than in 1990. This includes those we rely on to pollinate our crops and clean our rivers. If we don’t solve this problem very soon, some species will disappear. There are many causes for the insect decline, but insecticides are a major part of the problem. Those used today are longer lasting and up to 10,000 times more toxic than some that were banned in the 1970s. Adding to the problem is that these pesticides are now applied to crops prophylactically and used whether pests are present or not. Overall, the amount of pesticide applied to the land is decreasing, but this is a grossly misleading statistic. A recent paper found that, between 2005 and 2015, there was a 40 per cent reduction in the amount of pesticide applied to crops measured by weight. But because modern insecticides are so much more toxic, the global toxicity of treated land to pollinating insects has more than doubled in the same period (Science, doi.org/f5vp). Governments and regulating agencies are aware of the problem, and some parts of the world have moved to ban the use of certain insecticides outdoors in an attempt to help bees survive. But the pesticides used instead are just as toxic. One often-touted approach is to use pesticide-free pest control methods. These varied techniques are gathered under the name of integrated pest management (IPM) and have been around for decades. They offer effective crop protection and include methods such as crop rotation and the use of natural predators. But their adoption has been incredibly slow, because spraying pesticides is viewed as an easier option. As a result, IPM methods are unfortunately seldom used today. Neither changing insecticides nor shifting to IPM is a quick fix. We argue instead that we need a subtle shift in focus, away from killing pests and towards protecting crops.
5-16-21 The essential fly
When entomologist Jonathan Finch turns his dust-caked car off the highway and onto the old wartime airstrip at Manbulloo, he knows what awaits him at the other end: 65,000 blooming mango trees, an indescribably horrible smell, and the unmistakable buzz of excited blowflies. These days, the old airstrip is the access road to the vast Manbulloo mango farm — 4 square kilometers of orchards near the town of Katherine in Australia's Northern Territory. "It's a beautiful place — remote, peaceful and blissfully shady beneath the trees," Finch says. "But the smell is unbelievable. You just can't get it off you." Although we are talking on the phone, I get the impression he's grinning. The loathsome odor, it turns out, is one he created himself. And it's vital to his research into the pollinating prowess of flies. Most of us don't much like flies. Finch, though, is a big fan. He's part of a team investigating the role that flies play in pollinating crops and whether, like honeybees, they might be managed to improve yields. He's traveled from Western Sydney University on the other side of the continent to test a widely held belief among mango growers: If you leave out rotting carcasses, flies will come, and more flies mean more mangoes. Mango growers realized way back that flies are important pollinators. "Some encourage flies by hanging large barrels from their trees and putting roadkill in them," Finch says. "Other guys bring in a ton of fish and dump it in a heap in the middle of the orchard." The farmers are convinced that the pungent bait makes a difference, and the biology of blowflies suggests that it might. Yet there's no scientific proof that it does. Blowflies are drawn to the smell of rotting flesh because they mate and lay their eggs on corpses and carcasses. They also forage among flowers to fill up on energy-boosting nectar and protein-rich pollen, transporting pollen from one flower to another in the process. So it seems fair to assume that extra flies will pollinate more flowers and the trees will bear more fruit. But do they? To find out, Finch and his colleagues have coopted the Manbulloo farmers' bait barrels and filled them with a mix of fish and chicken. With the temperature hovering around 30ºC (85ºF), the scent of decay soon wafts through the trees and the team can put the idea to the test. Flies generally get a bad rap. People associate them with dirt, disease and death. "No one except entomologists really likes flies," Finch says. Yet there's good reason why we should cherish, encourage, even nurture them: Our future food supply could depend on it. The past few years have seen growing recognition that flies make up a large proportion of wild pollinators — but also that we know little about that side of their lives. Which sorts of fly pollinate what? How effective are they at delivering pollen where it's needed? Which flies might we harness to boost future harvests — and how to go about it? With insect populations plummeting and honeybees under pressure from multiple threats, including varroa mites and colony collapse disorder, entomologists and pollination specialists are urgently trying to get some answers. Animals are responsible for pollinating around 76 percent of crop plants, including a large number of globally important ones. Birds, bats, and other small mammals do their bit, but insects do much more — pollinating flowers of many fruits, vegetables, and nuts, from almonds to avocados, mangoes and melons, cocoa and coconuts, as well as crops grown to provide seed for future vegetable harvests. In a recent analysis for the Annual Review of Entomology, Australia-based biologist Romina Rader and colleagues from Australia, New Zealand, and the U.S. calculated that the world's 105 most widely planted food crops that benefit from insect pollination are worth some $800 billion a year.
4-27-21 Male parasitic wasps can detect females inside an infected host fly
Males of a species of parasitic wasp can identify potential mates from chemicals they give off, even before the females have emerged from within their host fly. Jewel wasps (Nasonia vitripennis) are found across North America. Females deposit eggs inside the cocoon-like casings of developing flies, using their ovipositors to inject each fly with a venom that paralyses it. The developing wasps remain in the host as they mature from egg to adult, only eating their way out to mate. Males emerge first, hanging around on the hosts to wait for females to appear. “Males want to increase their mating success, so would benefit from finding hosts with females,” says Garima Prazapati at the Indian Institute of Science Education and Research (IISER) Mohali. It is possible for these wasps to up their chances. Males develop from unfertilised eggs and females from fertilised eggs, so some hosts hold all-male broods, while others house a mixture of males and females. Prazapati and her team collected jewel wasps from the wild and bred them. They isolated some females, keeping them from mating so their eggs would go on to create all-male broods. Next, they individually presented 26 male wasps with two Petri dishes: one holding a host containing male and female adult wasps, and one with a host containing only adult males. The researchers found that the males spent around four times longer on the host with the females inside. Analysing the chemical compositions of both hosts, the team found that the one containing female wasps had a higher abundance of nine cuticular hydrocarbons – compounds that cover the wasp exoskeleton – than the host with males inside. They then dipped adult wasps in a chemical solution that extracts these hydrocarbons and found that adult females also had a higher concentration of them than males.
4-14-21 Wasps with no social life may find it harder to recognise others
Paper wasps that live alone don’t see as much development of a part of their brain that seems to be important for facial recognition. The discovery shows how vital the social environment can be to brain development, even in biologically simple animals like insects. Northern paper wasps (Polistes fuscatus) usually live in groups of around a dozen, though these sometimes comprise up to 100 individuals. Group members all share umbrella-shaped nests, often built beneath roof hangings. The wasps can live their entire adult lives alone, but they rarely do. Within their social groups, these insects recognise that all nest-mates share the same odour – but they also learn to identify individual group members by the unique colour patterns on their faces. “These wasps use facial recognition to basically know who’s who and maintain hierarchies, similar to what we see in many primate systems,” says Christopher Jernigan at Cornell University, New York. “It’s really incredible.” To understand how the paper wasps are able to recognise the unique colour patterns on other individuals’ faces, Jernigan and his colleagues gathered several cocoon-filled nests from the natural environment and placed them in clear plastic containers in their laboratory. As soon as the new adults chewed their way out of their silk cocoons – and could see for the first time – the researchers isolated some in a separate container, while leaving others in their nests to lead a social life. They provided all of the wasps with plenty of coloured paper, which stimulates their brains. When the wasps were between 58 and 71 days old, the researchers analysed their brains under a microscope, comparing them with each other and with the brains of newly hatched wasps. They found that, even though the wasps’ bodies didn’t grow after emerging from their cocoons, their brains had increased by about 13 per cent in size during those first two months of adulthood.
4-12-21 The frequencies of a vibrating spider web have been made into music
Spiders are mostly blind, but their webs are sensitive to disturbances, which they detect with their legs. Now, scientists have created an audio-visual virtual reality take on this that converts a web’s vibrations to sounds we can hear, giving us an idea of what it might feel like to be a spider. “The spider web can be viewed as an extension of the body of the spider, in that it lives within it, but also uses it as a sensor,” says Markus Buehler at the Massachusetts Institute of Technology, who presented the work at a virtual meeting of the American Chemical Society. “When you go into the virtual reality world and you dive inside the web, being able to hear what’s going on allows you to understand what you see.” Because of differences in the length and tension of each strand of a spider’s web, they emit a different frequency when disturbed and can even be used to send out signals or communicate with other spiders when the web’s owner taps on the strands. Buehler’s team used laser imaging to create a 3D map of webs made by tropical tent-web spiders (Cyrtophora citricola). They identified each thread’s vibrating frequency through its size and elasticity, then converted those frequencies into ones that can be heard by humans. By piecing the visual and auditory layers together, users connect the sounds to the threads they see, mimicking a spider surveying its world, he says. The team made some artistic decisions, such as using a synthesiser with a harp-like sound. Threads that are closer to the listener or connected to many others sound louder than others. For Buehler, who has spent hours listening to the noises the virtual webs make, they no longer just sound dissonant, but begin to have identifiable structure. “We believe we have an accurate reflection of what the spider would ‘see’,” he says.
3-3-21 Playing dead really works to help insects avoid being eaten by birds
Playing dead might help prey animals stay alive because the tactic leaves predators vulnerable to having their attention diverted elsewhere. Nigel R. Franks at the University of Bristol, UK, and his colleagues were running a study on how the beetle-like larvae of flying antlions (Euroleon nostras) use grains of sand to build pitfall traps to catch food. They noticed that when they dropped the 12-millimetre-long larvae onto a microbalance to weigh them, the insects would freeze. Fascinated, Franks and his colleagues observed the behaviour repeatedly, noting that the insects would stay immobile on the microbalance for anywhere from a few seconds to more than an hour. The researchers suspected this was a last-ditch survival mechanism for when various kinds of predatory birds, like dunnocks (Prunella modularis), accidentally drop antlions after grabbing them out of their sandpits. They modelled the behaviour using computers in the hope of understanding how playing dead – what the scientists called post-contact immobility (PCI) – keeps a prey animal alive. Their models considered various predator-prey factors like the number of pits in a given patch of sand, the distance between them, the time it takes birds to travel between pits, aspects of the birds’ behaviour – the likelihood that a bird will drop an antlion, for instance – and the amount of time that the antlion remains in PCI. The models were also informed by marginal value theorem, which describes the optimal way an animal should feed to maximise efficiency. This weighs the costs and benefits of an animal staying in one spot to eat every last morsel of food available there, or instead taking the time to move to another food-rich spot when supplies at the initial location begin to run low.
2-24-21 Moth species becomes more sexually active when bathed in red light
An Asian-Australian moth becomes more sexually active under red light than under another colour of light or in the dark. Dim red light appears to stimulate chemical changes in the antennae of male yellow peach moths (Conogethes punctiferalis), making them more sensitive to the smells emitted by nearby females. This increases their copulation rates, says Wei Xiao at Southwest University in Chongqing, China. Xiao and his colleagues made the accidental discovery while studying the general behaviour of the moths, which invade orchards and spice farms across Asia and Australia. To mimic natural light conditions in their laboratory, the scientists kept the lights on for 15 hours and turned them off for 9 hours per day. When they needed to work with the moths during the hours of darkness, they turned on red lights because scientists generally assume that insects can’t see red and react negligibly to it, says Xiao. However, his team realised that every time the red lights were on, the moths responded by laying more eggs. So the researchers decided to test the effects of red light on mating. They set up four cages, three of which were dimly lit by either red, white or blue light. The last was in complete darkness. Then they placed 30 male and 30 female moths in each cage. They found that the moths in the cage exposed to red light mated significantly more frequently and laid more eggs than the moths in the other cages, says Xiao. To understand why, the scientists analysed the antennae of male moths that they had raised in conditions with 15 hours of normal light and 9 hours of dim red light. They found that these moths had more odorant binding proteins (OBPs) in the smell receptors of antenna neurons, apparently making them hypersensitive to female sex pheromone odours.
2-17-21 A tiny spider can spin different types of web for land, air and water
An island spider decides which of its three kinds of webs to make depending on location and perhaps individual preferences. Spiders usually make only one kind of web, but the Wendilgarda galapagensis spider – which lives exclusively on Cocos Island, about 550 kilometres off the western coast of Central America – can make three different webs. High above ground it makes “aerial” webs attached to nearby stems and leaves. Nearer to the ground it makes “land” webs with long horizontal strands secured between branches and with a series of vertical strands anchored to the ground. Finally, over pools it makes “water” webs that are a bit like the land webs, but with the vertical strands attached to the water surface itself. Darko Cotoras at the California Academy of Sciences in San Francisco wondered whether this flexibility in web construction indicates the spider is undergoing speciation, splitting into three distinct species, each with unique behaviours and exploiting a different food source. So with his colleagues he ran genomic analyses on 142 of the spiders. To the team’s surprise, the results revealed that all of the spiders belonged to the same species, says Cotoras. This means they haven’t genetically diversified since arriving on the newly formed volcanic island perhaps as long as two million years ago, when their ancestors were probably carried in by air currents. The researchers then marked the 2-millimetre-long spiders with drops of fingernail polish and moved them to different locations on the island to track their behaviour. For example, they took water-web-making spiders away from water sources and placed them in high bushes nearby. Again, the researchers were surprised to see that the spiders often built a new web with the architecture suited to the new location.
2-10-21 Dragonflies do a backwards roll to fly upright – even when unconscious
When falling through the air in an upside-down position, dragonflies do backwards somersaults to return to an upright stance. They do this even when they are unconscious and – if their wings are propped open – when they are dead.Q These findings suggest that dragonflies are equipped with a potent mechanical design that keeps them right side up and airborne without any real effort. Such a passive flight-stabilisation mechanism could inspire better designs for small aircraft like drones, allowing for good stability and manoeuvrability “with less computational effort”, says Samuel Fabian at Imperial College London. “Passive stability lowers the effort requirements of flight, likely influencing the evolution of the dragonfly’s shape.” Fabian and his colleagues placed magnets and six motion-tracking markers on 20 male common darter dragonflies (Sympetrum striolatum) that they had trapped in the wild. They then placed the dragonflies, one by one, either right side up or upside down on platforms under magnets. By lifting the magnets, they dropped the dragonflies to study their falling technique using high-speed motion-capture cameras. Next, they chilled the dragonflies, essentially shutting them down into a torpor state, before dropping them again. “The animals were chilled on ice for 20 minutes, which effectively knocks them out and ceases much of their neural function for a while,” says Fabian. Finally, after each dragonfly died a natural death in the laboratory, they dropped it again, both with and without its wings propped up into the open, resting positions it used when it was alive. Reconstructed 3D models of the falling dragonflies showed that the alert ones somersaulted backwards when they were dropped upside down, says Fabian. Interestingly, the knocked-out dragonflies did the same thing, but more slowly.
1-21-21 Physicists find best way for insects to avoid collisions when jumping
A mathematical solution to a biological puzzle that may not really exist might prove useful for designing hopping rovers for space exploration. Alberto Vailati at the University of Milan, Italy, normally researches the physics of fluid dynamics. However, about 10 years ago, after noticing jumping insects on a holiday, he was intrigued to read some lab studies in which insects, including fruit fly larvae, gall midge larvae and froghoppers, had all been seen leaping with an average take-off angle of about 60 degrees. The idea that many different types of insects should have independently evolved to leap at this take-off angle seemed odd to Vailati: for insects wanting to escape predators, or simply move efficiently from A to B, a 45-degree take-off angle is the natural choice, as this maximises the range of a jump. For several years, Vailati mentioned the insects to his first-year students, in the hope that it would pique their curiosity too. After a recent lecture, one student, Samuele Spini, came back with two pages of hand calculations and the idea that a 60-degree take-off angle may help the insects avoid obstacles mid-jump. Vailati, Spini and their colleagues then built a mathematical model to investigate the idea. They considered the trajectory an insect would take depending on the take-off angle and explored which aerial path would give the insect the best chance of avoiding step-like or fence-like obstacles of random size and position lying ahead. The researchers also factored in wind and air resistance to make their calculations more applicable to the real world. Defining a successful jump as one in which the insect leaps over or lands on top of an obstacle, they found that a take-off angle of 60 degrees minimised the probability of striking the side of an obstacle, while maintaining a long jump range.
11-23-20 Bumblebees can fly sideways to fit through tight gaps
Bumblebees change their flight patterns differently when they have to pass through a tight space based on their size, indicating that they have some idea of their own size and shape despite their simple nervous systems. To test whether bees are aware of their size, Sridhar Ravi at the University of New South Wales in Sydney and his colleagues connected four hives to tunnels through which buff-tailed bumblebees (Bombus terrestris) had to fly in order to reach food. They then placed a wall in the middle of the tunnel, partially blocking it off but leaving a gap for the bees to slip through. As the bees flew up to the wall, they flitted back and forth to get a better look at the gap and then tilted themselves over to get through without smashing their wings into the wall. The researchers observed 400 flights by the bees and found the amount that they tilted depended on the relative sizes of the gap and the bees – large bees going through small gaps even flew through on their sides. “It’s not that they have a sense of self or would recognise themselves in the mirror, but they do seem to have a better sense of their own size and shape than we thought,” says Stacey Combes at the University of California, Davis. This is similar to how people and animals with more complex brains perceive the world, says William Warren at Brown University in Rhode Island. “When you look at a gap you need to walk through, you calibrate that information to your own body size. This emphasises that there’s a kind of universality in how we perceive the world, from insects to humans.” It may seem like a no-brainer, but this is actually a surprisingly complex calculation for a simple animal to be capable of, says Combes. “Kids are sometimes scared to be in the bathtub when you open up the drain because they’re scared to go down the drain,” she says. “If human toddlers don’t have that understanding of how big they are compared to the world around them, it’s surprising that bees do.”
11-12-20 'Murder hornets': More nests likely to be found in US
Washington is unlikely to have seen its last Asian giant hornets, the state's agricultural department has said, after scientists found 200 queens in one nest. The nest - the first in the US - of the so-called murder hornets was captured with a vacuum from a tree in October. Researchers believe more queens - which are responsible for establishing colonies - could remain at large. But they are confident the population can be brought under control. Asian giant hornets are an invasive species in the Pacific North-West. They target honeybees, which pollinate crops. The insect, which is native to Japan and South Korea, can slaughter a bee colony in a matter of hours. They can also spit venom and inflict numerous powerful stings on humans. "We believe there are additional nests. There is no way to be certain we got them all," Sven-Erik Spichiger, who researches insects with the Washington State Department of Agriculture, said in a press conference on Tuesday. The nest was extracted from a tree in the city of Blaine, close to the Canadian border, on 24 October. Scientists then quarantined the 22cm (9 in) diameter nest and after 24 hours were able to open it to examine the contents. Inside they found evidence of almost 500 insects at various stages of life including 112 worker hornets and close to 200 queens. "It's possible some [queens] emerged before we did the extraction. There is no way of knowing how many more," Mr Spichiger said, explaining that three queens were found in the local area after scientists had removed the nest. But he said they had arrived "in the nick of time" to prevent the majority of queens from leaving the nest and mating. "Frankly we are encouraged because of the number of queens we were able to count and kill," he said. Queen hornets go on to establish new colonies when they mate with a male and successfully hibernate over the winter season. When they wake up in spring, a small portion go on to establish nests. Mr Spichiger said it was likely that the insects arrived in the Pacific North-West as part of international commerce. "We will never know how they got here...but it could have been a vehicle, wood chips, hay bales," he explained.
11-12-20 Some male spiders tie up females before mating to avoid being eaten
Many male spiders engage in courtship rituals during mating, but some attack females instead and tie them up to avoid being eaten. “Spiders sometimes spend hours luring females to court them, but these guys just go and bite,” says Lenka Sentenská at the University of Toronto Scarborough, Canada. Running crab spiders, a group containing more than 600 species, are found widely across Europe, Asia and Africa. In April 2019, while working at Masaryk University in Brno, Czech Republic, Sentenská was studying the behaviour of one species – Thanatus fabricii – that is native to Israel. She realised males behaved oddly at mating time, but the action was so quick that it was difficult to observe. Sentenská and her colleagues chased down a number of the fast-moving spiders in the Negev desert in Israel and brought them to the lab for closer observation. Slow-motion recordings gave the researchers a clearer look at the reproduction of these spiders. “The male just rushed towards the female and it seemed more like an attack,” says Sentenská. The male spider would bite the female a handful of times, more so if she was larger and less so if she was missing limbs. In most cases, this seemed to startle the female spider, who would pull in her legs and play dead. At this point, the male spider would begin to lay down some strands of silk on the female’s body, binding her legs. The male spider then mated with the female for the next 19 minutes, on average, before running away. The behaviour is savage, but it may be the best way for males to come out of the mating process alive. The team observed that some males were eaten by the slightly larger females before they could begin biting. Even when tied up, the female spiders may be in control. Sentenská says it doesn’t take a female spider long to break free. “She would jerk several times, then spread her legs and she’s good to go.”
10-31-20 Great fox-spider rediscovered on MoD land in Surrey
One of Britain's most endangered spiders has been seen for the first time in a generation. The great fox-spider is listed as critically endangered and was feared extinct in the UK. It had only ever been found at three sites, in Dorset and Surrey, and had not been seen since the early 1990s. Mike Waite, who rediscovered the spiders on a Ministry of Defence (MoD) training area in Surrey, said he was "over the moon". The arachnid enthusiast initially found some unidentifiable immature spiderlings on the site, managed by the Amphibian and Reptile Conservation Trust, after "many hours of late night searching with a torch over the last two years". The discovery then led to several mature males and a female. The great fox-spider, Alopecosa fabrilis, lives on the ground and is largely nocturnal. It is one of the largest of the wolf spider, Lycosidae, family of spiders. According to the Surrey Wildlife Trust, it has excellent eyesight - with wrap-around vision provided by eight black eyes - and captures insects at speed by chasing them across sandy terrain, over gravel and rocks before pouncing. Mr Waite, of the Surrey Wildlife Trust, said: "I am naturally over the moon to have finally proved the continued existence of the great fox-spider in the UK. "Although I've always held a latent interest in spiders, as a bona-fide arachnologist, I am still a relative newbie, so am doubly pleased to have made this important contribution to our scientific knowledge." Nick Baker, naturalist, TV presenter and president of the British Arachnological Society, said the spider was "mega", adding: "It's about as handsome as a spider gets, it's big and now it's officially a member of the British fauna again."
10-25-20 'Murder hornet': First nest found in US eradicated with vacuum hose
The first nest of Asian giant hornets found in the US has successfully been destroyed by scientists. The nest, in the state of Washington, was found by putting tracker devices on the hornets and it was sucked out of a tree using a vacuum hose. The invasive species insects, known as "murder hornets", have a powerful sting and can spit venom. They target honeybees, which pollinate crops, and can destroy a colony in just a matter of hours. The nest in Washington was found when entomologists, scientists that study insects, used dental floss to tie tracking devices to three hornets. The nest of around 200 insects was then discovered in the city of Blaine close to the Canadian border. On Saturday, a crew of scientists wearing protective suits vacuumed the insects from the tree, which will now be cut down to remove any further nests. Asian giant hornets are the among the world's largest wasps - the queens can reach over 5cm (2in) long. Their venomous sting can penetrate humans' protective clothing but the number of people they kill each year is low - about 40 annually in Asia, according to the Smithsonian museum in Washington D.C. Normally their natural habitat is in areas of Asia from China to Japan, but in 2019 there were several sightings of single "murder hornets" in North America. A nest was destroyed in Vancouver Island in Canada in December last year. Globally, conservationists are deeply concerned about falling insect populations. But it can be permissible to kill some insects if they are an invasive species - one that is not native to an area and preys on other insects there. Honeybees are under threat due to loss of food after habitat destruction, pesticides, and disease. When an Asian giant hornet enters a honeybee colony, it begins a "slaughter phase" in which it kills bee after bee and can destroy the colony in a few hours.
10-20-20 Fire ants build little syphons out of sand to feed without drowning
To escape a watery death, the insects construct relatively sophisticated structures on the fly. The threat of death is no obstacle for some hungry fire ants. To escape drowning while feeding on sugary water, black imported fire ants built syphons out of sand that moved the water to a safer spot. A range of animals, including birds, dolphins, primates and even ants, use objects as tools (SN: 12/30/19; SN: 6/25/20; SN: 6/24/19). Ants often employ debris or sand grains to carry food. But this is the first time that the insects have been observed adjusting their tool use to build relatively complex structures in response to a problem, researchers report October 7 in Functional Ecology. In the wild, black imported fire ants (Solenopsis richteri) typically eat honeydew produced by aphids. In the lab, entomologist Jian Chen of the U.S. Department of Agriculture’s Agricultural Research Service in Stoneville, Miss., and colleagues provided the ants with containers of sugary water. The insects have a hard, water-repellent outer covering called a cuticle, and can typically float on a liquid — and sure enough, the insects floated and fed without a problem. The researchers then reduced the water’s surface tension with a surfactant to make it more difficult for the ants to float. While some ants drowned, most stopped entering the containers and instead used grains of sand placed nearby to build structures leading from the inside of a container to outside of it. Those structures acted like syphons. Within five minutes of building one, nearly half of the water was drawn out through the sand pathway, allowing the ants to feed safely. “The fact that ants are building little syphons is new and interesting,” says Valerie Banschbach of Gustavus Adolphus College in Saint Peter, Minn., who was not involved in the study. The insects’ “flexibility to act in a creative way responding to a situation suggests that they have higher cognitive abilities than what is traditionally believed.”
10-19-20 Heating deltamethrin may help it kill pesticide-resistant mosquitoes
The insecticide is used to control pests that spread life-threatening diseases like malaria. A few minutes in the microwave made a common insecticide about 10 times more lethal to mosquitoes in lab experiments. The toxin deltamethrin is used around the world in home sprays and bed nets to curb the spread of mosquito-borne diseases like malaria — which kills over 400,000 people each year, according to the World Health Organization. But “mosquitoes the world over are showing resistance to deltamethrin and [similar] compounds,” says Bart Kahr, a crystallographer at New York University who has helped develop a more potent form of deltamethrin by heating it. This form of deltamethrin may stand a better chance of killing insecticide-resistant pests, Kahr and colleagues report online October 12 in the Proceedings of the National Academy of Sciences. Malaria has been essentially eradicated in the United States, but more effective pesticides could be a boon for regions like sub-Saharan Africa, where the disease is a major public health problem. Kahr’s team increased the potency of commercial deltamethrin dust spray simply by melting a vial of it — either by heating it to 150° Celsius in an oil bath for five minutes or by popping it in a 700-watt microwave for the same amount of time. While the microscopic deltamethrin crystals in the original spray have a haphazard structure, which looks like a jumble of misaligned flakes, the melted deltamethrin crystals solidified into starburst shapes when they cooled to room temperature. Chemical bonds between deltamethrin molecules in the starburst-shaped crystals are not as strong as those in the original microcrystal structure. “The molecules are intrinsically less happy, or settled, in the arrangement,” Kahr says. So, when a mosquito lands on a dusting of starburst-shaped crystals, it should be easier for deltamethrin molecules to be absorbed into the insect’s body via its feet.
10-14-20 Leafcutter ants choose architecturally sound building materials
Ants that construct turrets for their nests choose what to build them with in an architecturally sound way, even when given unfamiliar materials. South American leafcutter ants (Acromyrmex fracticornis) carry plant clippings into underground chambers where they use them to cultivate fungus for food. To promote fungal growth, they build thatch-like turrets that keep rainwater from flooding their nests and that create the correct humidity level. In their natural environment, the ants select thick wooden sticks for the base of the turrets, overlapping them like a log cabin, and lightweight grass for the top, then plaster the interior with clay pellets. The whole process takes three days. “They try to keep [the nest] at about 25°C for the fungus and then really high humidity,” says Daniela Römer at the University of Würzburg, Germany. “Putting plant fibres on top prevents against humidity loss.” To test how the ants choose their building materials, Römer and her colleagues replaced their regular choice of twigs and fresh grass with slivers of processed smooth wood and dry grass. They found that the insects still made the same decisions with these new materials, selecting for thickness at the base and lighter vegetation, which promotes humidity, at the top. This illustrates how relatively simple animals can use social organisation to create complex structures, says Römer. “They just react to what is right in front of them,” she says. “They’re not thinking of what they’re building or how it’s supposed to look. But by organising their behaviour in the whole colony, reacting to each other’s cues and cues from their environment, they actually manage to build very complex structures that you wouldn’t expect such simple animals to be able to do.”
10-2-20 A new map shows where Asian giant hornets could thrive in the U.S.
Washington state officials are racing to find and kill ‘murder hornets’ before they can spread. The race is on to keep Asian giant hornets from spreading in the Pacific Northwest. Since 2019, 12 of the hornets — five trapped and dead, the rest photographed but escaped — have turned up in Washington state. That includes three recently reported in Whatcom County, Wash. Others have been found in British Columbia, Canada. “We’re pretty sure there’s at least one nest” somewhere near Birch Bay along the Washington coast, says Karla Salp, a spokesperson for the Washington State Department of Agriculture in Olympia. Efforts are under way to catch a live hornet, attach a radio tag and track it back to a nest, Salp says. The plan is to destroy the nest, hopefully before hornets that can start nests of their own hatch. That usually happens in mid to late October, she says. That eradication effort was already urgent thanks to the insects’ reputation: The world’s largest hornets (Vespa mandarinia) have been dubbed “murder hornets” in part for their deadly assaults on honeybees (SN: 5/29/20). Now a new study maps where the giant hornets could spread if left unchecked. Asian giant hornets thrive where it’s mild and rainy — and that makes large swaths of the Pacific Northwest prime real estate for them. Farther afield regions of the United States — including along the East Coast — could potentially support the hornets, but it’s unlikely the insects could fly that far on their own, researchers report online September 22 in the Proceedings of the National Academy of Sciences. The mapping efforts are important because “we really don’t know anything about how this species spreads,” says Chris Looney, an entomologist with Washington’s agriculture department. Details like how fast the hornets can fly and how their preference for underground nests affects their potential to spread are unknown, he explains. “That’s the kind of maddening lack of information that makes responding to this species so challenging.”
10-2-20 Cockroach species found to live like ants with workers and a queen
Cockroaches can team up. A South American species is the first cockroach known to live in group nests with workers and a queen, like honeybees or leaf-cutter ants. “All cockroaches are solitary,” says Peter Vršanský at the Slovak Academy of Sciences in Bratislava – or so everyone thought. “It’s unbelievable. It’s like discovering ants as a group.” Some animals, such as honeybees, are eusocial: not only do they live in large groups and work together to tend the young, but most individuals don’t themselves reproduce. Worker bees are sterile, for instance, and only the queen lays eggs. Vršanský’s colleagues spent 20 years looking for living specimens of the cockroach Melyroidea magnifica, which has barely been seen since it was identified in cloud forests around the Rio Bigal in Ecuador in 1912. Local conservationist Thierry Garcia at the Sumac Muyu Foundation in Ecuador finally found a nest in 2017. The cockroaches nested in bamboo or hardwood trees in groups of several hundred. They spend a lot of time inside the nests, which explains why they were so hard to find. “There was one week where not one cockroach was outside,” says Vršanský. The adult cockroaches had bright red heads and green abdomens. There were also tiny black larvae. The team found one individual that was 1.25 times larger than the others and had white wings. They have tentatively identified this as the queen, although Vršanský says they need more evidence to be sure. “We would need to prove that it is the only individual which lays eggs,” he says. But in two months of observations, they never saw the other cockroaches laying eggs, which suggests they are sterile workers. The finding highlights how little is known about cockroach behaviour, says Vršanský. “We know nearly nothing.”
9-11-20 This moth may outsmart smog by learning to like pollution-altered aromas
Scientists taught tobacco hawkmoths that an ozone-affected scent is from a favorite flower. Pollution can play havoc with pollinators’ favorite flower smells. But one kind of moth can learn how to take to an unfamiliar new scent like, well, a moth to a flame. Floral aromas help pollinators locate their favorite plants. Scientists have established that air pollutants scramble those fragrances, throwing off the tracking abilities of such beneficial insects as honeybees (SN: 4/24/08). But new lab experiments demonstrate that one pollinator, the tobacco hawkmoth (Manduca sexta), can quickly learn that a pollution-altered scent comes from the jasmine tobacco flower (Nicotiana alata) that the insect likes. That ability may imply that the moth can find food and pollinate plants, including crucial crops, despite some air pollution, researchers report September 2 in the Journal of Chemical Ecology. Scientists already knew that some pollinators can learn new smells, but this is the first study to demonstrate an insect overcoming pollution’s effects on odors. Chemical ecologist Markus Knaden and colleagues focused on one pollutant — ozone, the main ingredient in smog. Ozone reacts with flower aroma molecules, changing their chemical structure and therefore their fragrance. In Knaden’s lab at the Max Planck Institute for Chemical Ecology in Jena, Germany, his team blew an ozone-altered N. alata scent from a tiny tube into a refrigerator-sized plexiglass tunnel, with a moth awaiting at the far end of the tunnel. Usually, when the moth smells the unaltered floral fragrance, it flies upwind and uses its long, skinny mouthparts to probe the tube the way that it would a blossom. The researchers expected that the modified scent might throw the moth off a little. But the insect wasn’t attracted at all to a flower aroma exposed to levels of ozone that are typical on some hot, sunny days.
8-23-20 Genetically modified mosquitoes have been OK’d for a first U.S. test flight
As dengue cases rise in the Florida Keys, a much-debated public health tool gets a nod for 2021. After a decade of fits and starts, officials in the Florida Keys have voted to allow the first test in the United States of free-flying, genetically modified mosquitoes as a way to fight the pests and the diseases they spread. The decision came after about two hours of contentious testimony in a virtual public hearing on August 18. Many speakers railed against uncertainties in releasing genetically engineered organisms. In the end, though, worries about mosquito-borne diseases proved more compelling. On the day of the vote, dengue fever cases in Monroe County, where the Keys are located, totaled 47 so far in 2020, the first surge in almost a decade. The same mosquitoes known for yellow fever (Aedes aegypti) also spread dengue as well as Zika and Chikungunya (SN: 6/2/15). The species is especially hard to control among about 45 kinds of mosquitoes that whine around the Keys. Even the powerhouse Florida Keys Mosquito Control District with six aircraft for spraying — Miami has zero — kills only an estimated 30 to 50 percent of the local yellow fever mosquito population with its best pesticide treatments, says district board chairman Phil Goodman. “We can’t rely on chemistry to spray our way out of this,” Goodman, a chemist himself, said as the commissioners conferred after the public’s comments. Then 4–1, the commissioners voted to go forward with a test of genetically modified males as pest control devices. Sometime after January 1, 2021, Florida workers will set out boxes of eggs of specially bred male yellow fever mosquitoes (a recent version called OX5034) in a stretch of Monroe County still to be chosen. The eggs, shipped from the biotech company Oxitec based in Abingdon, England, will grow into normal-looking males. Like other male mosquitoes, they drink flower nectar, not blood.
8-8-20 Lockdown: Label showing plants safe for bees and butterflies
A label scheme has been launched to protect bees and butterflies from plants containing insecticides. The National Botanic Garden of Wales said a "massive growth in gardening" during lockdown had seen people unwittingly buying plants with residues poisonous to pollinators. Its new labels will guarantee eligible plants have no synthetic insecticides and are grown in peat-free compost. Twenty-three growers and nurseries have already signed up. The Saving Pollinators logo scheme, set up with the Growing the Future Project, will also harness the botanic garden's DNA barcoding research, which has investigated which plants honeybees, solitary bees, bumblebees and hoverflies visit. Dr Natasha de Vere, of the garden, said: "Lockdown has seen a massive growth in gardening with many more people spending extra time and money buying plants to make their gardens more wildlife-friendly, without realising the plants could contain residues of synthetic insecticides that are extremely damaging to pollinators and to our environment." Those behind the project said it would be the first time gardeners could buy plants guaranteed to be good for bees and other pollinators. It also aims to benefit other wildlife such as hedgehogs, sparrows and frogs. Dr de Vere said pollinator decline would have an impact on the availability of many foods such as fruits, nuts, coffee and chocolates. Reports in the United States have suggested a lack of pollinators has reduced crop production. "The good thing about looking after pollinators is that it's essentially looking after ourselves," she added. The National Botanic Garden of Wales, located in Llanarthney, Carmarthenshire, said it hoped the label concept could be rolled out to other parts of the UK in the future, calling on the horticulture and garden retail industry to "take note".
8-3-20 Some spiders may spin poisonous webs laced with neurotoxins
Droplets on the silk strands contain proteins that subdue prey, a study suggests. Orb weaver spiders are known for their big, beautiful webs. Now, researchers suggest that these webs do more than just glue a spider’s meal in place — they may also swiftly paralyze their catch. Biochemical ecologist Mario Palma has long suspected that the webs of orb weavers — common garden spiders that build wheel-shaped webs — contain neurotoxins. “My colleagues told me, ‘You are nuts,’” says Palma, of São Paulo State University’s Institute of Biosciences in Rio Claro, Brazil. No one had found such toxins, and webs’ stickiness seemed more than sufficient for the purpose of ensnaring prey. The idea first came to him about 25 years ago, when Palma lived near a rice plantation where orb weavers were common. He says he often saw fresh prey, like bees or flies, in the spiders’ webs, and over time, noticed the hapless animals weren’t just glued — they convulsed and stuck out their tongues, as if they’d been poisoned. If he pulled the insects free, they struggled to walk or hold up their bodies, even if the web’s owner hadn’t injected venom. Palma had worked with neurotoxins for many years, and these odd behaviors immediately struck him as the effects of such toxins. Now, thanks in large part to the work of his Ph.D. student Franciele Esteves, Palma thinks he has found those prey-paralyzing toxins. The pair and their colleagues analyzed the active genes and proteins in the silk glands of banana spiders (Trichonephila clavipes) — a kind of orb weaver — and found proteins resembling known neurotoxins. The neurotoxins may make the webs paralytic traps, the team reports online June 15 in the Journal of Proteome Research. The prey-catching webs of other species probably have similar neurotoxins, Palma says.
7-26-20 Why are scientists creating genetically modified mosquitoes?
Creating these "Trojan horse" bugs could save human lives. But is it moral? Scientists plan to release altered mosquitoes designed to sabotage the species' ability to reproduce. Is this safe? Here's everything you need to know:
- Who's doing this? The federal Environmental Protection Agency has approved a plan by a British biotech company called Oxitec to release about 1 billion genetically modified (GM) mosquitoes in the Florida Keys and, next year, Texas. The mosquitoes (code-named OX5034) will only be male — the gender that does not bite humans — and will carry a new gene that will be passed on to their female offspring and cause them to die while they're still larvae.
- How does this technology work? Scientists first genetically modified an animal — a mouse — in 1974. But the process remained cumbersome and slow until the development of the CRISPR technique and other "gene-editing" technology this decade.
- Where do the plans stand? n May, the EPA greenlighted Oxitec's plans for both Florida and Texas, issuing the company an experimental use permit. Florida state authorities followed suit with their own approval.
- What could go wrong? Some geneticists, including Dr. Ricarda Steinbrecher of EcoNexus, a public-interest research organization, have raised alarms that Oxitec's altered mosquitoes haven't been adequately studied. The researcher said "the underlying mechanism(s) leading to cell death" in the larvae aren't "fully understood" and thus can't yield "precise and predictable results.
- What's the upside? Some see world-changing possibilities. Florida witnessed its first mosquito-to-human transmission of the Zika virus (which causes serious birth defects) in 2016, and West Nile is a perennial problem.
- Oxitec's modified moths: South Florida and Texas aren't the only places that Oxitec is testing its genetically modified insects. Earlier this year, Cornell University scientists announced the results of a project they had conducted with the company involving its genetically modified diamondback moths, or Plutella xylostella.
7-24-20 Spiderwebs gather DNA that can help us monitor insects in forests
Spiders may build their webs to catch prey, but trials in Slovenian forests have shown they can also moonlight as a way for humans to monitor the biodiversity of ecosystems. Recent years have seen a growing interest in detecting species by collecting the fragments of DNA they shed in an environment, an approach that is often less invasive and quicker than traditional surveying with nets, trays and other equipment. Matja? Gregoric at the Slovenian Academy of Sciences and Arts turned to an unusual tool to collect such environmental DNA: the orb webs of garden spiders (Araneus diadematus) and sheet webs of common hammock-weaving spiders (Linyphia triangularis). The webs act as a passive filter for the air, capturing DNA from insects, fungi and bacteria – and providing an elegant alternative to the air filtering machines ecologists use, which need to be powered by heavy generators. “The results are fantastic, much more than I hoped for. From 25 webs, I found [DNA from] 50 families of animals, from nematodes to butterflies, moths, wasps, bees, beetles and flies, everything. The richness of information surprised us a lot,” says Gregoric. He and his colleagues got the idea from a 2015 trial in the highly controlled environment of a zoo, but Gregoric says their research is the first proof of concept in the wild. The approach could complement traditional ways of surveying pollinators, which are suffering major declines, or be used for the early detection of pests and invasive species. The use of environmental DNA to monitor ecosystems is growing, with the technique being deployed by regulators in English rivers and lakes. The approach doesn’t require years of taxonomical knowledge to identify species, which instead have their DNA matched against databases. “You don’t have to be a spider expert to use spider webs,” says Gregoric.
5-13-19 Nature crisis: Moths have 'secret role' as crucial pollinators
Long seen as annoying creatures that can leave holes in your clothes, moths have been badly misjudged, say scientists. New research suggests they play a vital role as overnight pollinators of a wide range of flowers and plants. The study says that the moths' transport networks are larger and more complex than those of daytime pollinators like bees. The authors believe there is an urgent need to stem declines in moth numbers. Over the past decade, public anxiety about the role of our pollinators has focused squarely on bees. The fall-off in their numbers, linked to changes in land and widespread use of pesticides, has helped raise environmental awareness of the critical role these creatures play in the food chain. Moths, though, have not evoked similar sympathies. "There's this big misconception that all moths come and eat my clothes. That's not what happens at all," said Dr Richard Walton, from University College London (UCL), the lead author of the new study. "Some of them happen to be visiting flowers and can be an important part of the pollination process." To find out how vital a part the moths play, Dr Walton and colleagues monitored moth activity around ponds in agricultural areas of Norfolk. They found that 45% of the moths they tested were transporting pollen, which originated from 47 different plant species, including several that were rarely visited by bees, hoverflies and butterflies. The scientists found that while bumblebees and honeybees are critically important, they tended to target the most prolific nectar and pollen sources. Not so with moths. "From what we see from our work, moths tend to be generalists, meaning they're not specifically visiting a narrow group of flowers," said Dr Walton. "They're kind of visiting any type of flower that they can access. These tend to be the open cup-shaped flowers like bramble, they can access things from the legume family, the clover family was also very important."
4-24-20 Earthy funk lures tiny creatures to eat and spread bacterial spores
Master chemist soil bacteria can waft a scent appetizing to springtails. The master chemists known as Streptomyces bacteria have turned a compound rich with the tangy odor of moist soil into a hitchhiking scam. This group of bacteria, the inspiration for streptomycin and other antibiotics, can release a strong, earthy whiff of what’s called geosmin. It’s not just an everyday scent for them. Some bacterial genes that regulate spore-making also can trigger geosmin production, an international research team reports April 6 in Nature Microbiology. When bacteria start making spores, geosmin wafts into the soil and attracts hungry little arthropods called springtails. They feast on the bacteria, inadvertently picking up spores that hitchhike to new territory, says Klas Flärdh, a microbiologist at Lund University in Sweden. Geosmin floats off many environmental microbes, including virtually all Streptomyces. People as well as many other animals can detect low concentrations of it. For instance, the common Drosophila lab fruit fly dedicates a circuit in its sensory wiring just to detecting geosmin, which the flies find repellant. That kind of disgust might help animals avoid microbially contaminated food. Various springtails, however, flock to the smell. Springtails abound in soil (SN: 1/19/14). The “spring” part of their name comes from a prong latched against the body that snaps loose to smack the ground in a crisis, bouncing the springtail up and away from danger. Scuttling specks of springtails showed up in unusual numbers when coauthor Paul Becher set out bits of Streptomyces bacteria forming spores under shrubbery at the Swedish University of Agricultural Sciences in Alnarp. A springtail can smell the bacterial geosmin, Becher, Flärdh and colleagues say after testing the antenna sensitivity of a pale, all-female kind popular in labs, Folsomia candida.
4-24-20 The ‘insect apocalypse’ is more complicated than it sounds
Freshwater arthropods trended upward, while terrestrial ones declined, decades of data suggest. Taking a big view of the so-called Insect Apocalypse finds some possible winners among the losers, plus a lot of things we don’t know yet. Overheated end-times terms have popped up during the last few years conveying fear that the bounty of Earth’s butterflies, beetles, bees and many other insects has started slipping away. The worry is not just about species likely to go extinct. Even species that will probably survive might be shrinking in population so much that their skimpy numbers no can longer fill their current roles in ecosystems. Now a new look at insect abundance, slanted toward North America and Europe, hints that freshwater residents are overall increasing. Data mostly gathered since the 1960s suggests that beetles, mayflies, dragonflies and other creatures that spend a good part of their lives in water have increased about 11 percent per decade, says a study in Science April 24. In contrast, land-dwelling insects shrank in abundance by about 9 percent per decade, the study says. “Insects will not disappear,” says coauthor Roel van Klink, an entomologist at the German Center for Integrative Biodiversity Research in Leipzig. He and colleagues found, however, “a lot of reason for concern” overall, he says. Van Klink first started thinking about the project in 2017, when careful, long-term monitoring of the biomass of insects flying in 63 protected nature preserves in Germany had dropped more than 75 percent over 27 years. “I doubt that’s a general phenomenon,” van Klink remembers thinking. After two months without hearing about anybody else starting a worldwide search for data, he says he realized, “I’ve got do it.” Van Klink and colleagues found 166 surveys of abundance (numbers of individuals and/or the absolute mass of insects and occasionally spiders mixed in) that ran for at least 10 years at 1,676 sites around the world. The oldest data went back to 1928, but data are most abundant from the 1980s. Researchers compared how steeply or gently the populations were falling and rising. Many of the sites already were affected heavily by humans when surveys began. For instance, he speculates that the rise in freshwater arthropod abundance may reflect some recovery as environmental laws improved water quality in the United States.
4-23-20 Reports of an insect apocalypse are overblown but still concerning
Reports of the death of insects may have been greatly exaggerated. Research out today finds that while an alarming 9 per cent of land-dwelling insects are being lost each decade, the state of the world’s insects is much more nuanced than warnings of an “insect apocalypse”. The issue came to the fore in 2017, when a study found a 75 per cent decline in flying insects across parts of Germany due to environmental pressures such as intensive farming. But fears of an insect meltdown – and the impact on the food we all rely on – really took off last year with a study by Francisco Sánchez-Bayo at the University of Sydney and his colleagues that hit front pages suggesting 2.5 per cent of insect biomass is being lost each year. Without action, the team cautioned: “Insects as a whole will go down the path of extinction in a few decades.” A backlash ensued, with at least seven criticisms published in journals. A simple one was the authors had conducted keyword searches of literature for the “insect” and “decline”, but not for “increase”, which would bias their literature review. So what is the true state of the world’s insects? Entomologists say a new analysis published in the journal Science today gives a much more realistic, but no less concerning, picture. Roel van Klink at the German Centre for Integrative Biodiversity Research in Leipzig and his colleagues compiled data on the long-term abundance of thousands of insect species from 166 studies in 41 countries, covering declines and increases. Gergana Daskalova at the University of Edinburgh, UK, who was not involved in the study, says it is the most comprehensive to date. The analysis concluded that the number and biomass of insects is declining at 0.92 per cent a year. While much lower than the number in last year’s paper, van Klink notes that out over the course of a human generation, or 30 years, it is a decline of a quarter. “I find that quite severe and quite alarming,” he says. “The most important thing for people to realise is it’s not going bad for insects everywhere, that it’s variable.”
4-23-20 Nature crisis: 'Insect apocalypse' more complicated than thought
The global health of insect populations is far more complicated than previously thought, new data suggests. Previous research indicated an alarming decline in numbers in all parts of world, with losses of up to 25% per decade. This new study, the largest carried out to date, says the picture is more complex and varied. Land-dwelling insects are definitely declining the authors say, while bugs living in freshwater are increasing. Reports of the rapid and widespread decline of insects globally have caused great worry to scientists. The creatures are among the most abundant and diverse species on the planet and play key roles, from aerating the soil to pollination and recycling of nutrients. Case studies, such as one from nature reserves in western Germany, indicated a dramatic fall, with around a 75% decrease over 27 years. Many other, similar reports have followed. But many of these were specific to a region or a species. This new study, the largest on insect change to date, aims to give a more complete understanding of what's really happening to bugs worldwide. Drawing on data from 166 long-term surveys across 1,676 sites, it paints a highly nuanced and variable picture of the state of insect health. The compilation indicates that insects like butterflies, ants and grasshoppers are going down by 0.92% per year, which amounts to 9% per decade, lower than many published rates. This is not as bad as previous reports but the authors stress that it is still substantial. "That is extremely serious, over 30 years it means a quarter less insects," said lead author Dr Roel Van Klink, from the German Centre for Integrative Biodiversity Research. "And because it's a mean, there are places where it is much worse than that." Many people have an instinctive perception that insects are decreasing - often informed by the so-called "windscreen phenomenon", where you find fewer dead bugs splattered on cars. The researchers say it's real.
3-18-20 Wasps may benefit us as much as bees. Could we learn to love them?
We love to hate wasps, but they pollinate flowers, kill off pests and their venom might even help us treat cancer. EVERYBODY loves bees. They are celebrated for their glorious honey, cooperative work ethic and commercially valuable pollination services. In a 2019 survey, 55 per cent of respondents chose bees as the species they most wanted to save, above the likes of elephants and tigers. How differently we see wasps. These most unwelcome picnic guests have been reviled for millennia. Ancient Greek essayist Plutarch described wasps as degenerate bees. The very word “waspish” summons up ideas of irritability, implying they are quick to anger, spiteful and vindictive. And that’s just the regular wasp or yellow jacket. Our attitudes to the largest wasp species, hornets, are even more negative. The tabloids hawk horror stories about how the invasive Asian hornet, Vespa velutina, threatens honey production and native pollinators in the UK. Meanwhile, persecution of the huge but docile European hornet, Vespa crabro, continues, fuelled by fear and ignorance, even though its numbers are declining. Few people seem to care. But are we judging this diverse group of insects unfairly? Certainly, our perceptions are ill-informed. There are whole institutes dedicated to studying bees, while wasp research is in the doldrums. Limited funds attract few projects, the results of which are often misconstrued in the press, bolstering an already negative stereotype. In fact, what we have learned about wasps tells a different story. Far from being bothersome and vindictive, they make valuable contributions to ecosystems, the economy and even our health. Take ecosystem services – a buzz phrase of our time that means the quantifiable benefits nature provides for us. Honeybees may be the prime pollinators of many cultivated fruit crops, but wasps and other insects pollinate most wild flowers. Indeed, some plants rely exclusively on wasps. Among them are almost 100 species of orchids, including helleborines. These widespread but scarce plants of woodland edges have a cunning trick to entice pollinators. Their flowers produce the sort of volatile chemicals that other plants emit when under attack from caterpillars, which lure predatory wasps hoping to find prey. The wasps then sip the nectar in the orchid flowers, which contains soporific agents – possibly alcohol from fungal contaminants – that slow them down, increasing the likelihood they will pick up pollen. Without their tipsy wasp pollinators, these elegant plants would become extinct.
3-4-20 What if all the wasps disappeared?
Wasps are not exactly the most-loved creatures, but they are hugely important to the eco-system - and us all.
2-21-20 Bumblebees in dire trouble
Climate change is pushing the much-loved bumblebee to the brink of extinction, new research has found. The fuzzy, buzzy insects are among the most important pollinators in the Northern Hemisphere, helping to spread pollen and fertilize many wild plants, as well as important crops such as tomatoes, blueberries, and squash. But their numbers have been dropping for years, and to understand why, scientists looked at a database of 550,000 records detailing where the bees have been spotted since 1901. It showed that bumblebee populations had crashed by 46 percent in North America and by 17 percent across Europe in recent years when compared with the base period of 1901 to 1974. The biggest declines were in areas that have experienced the most extreme temperature swings, suggesting that climate change is a significant factor. High temperatures can cause bumblebees to overheat and can also kill the flowers on which they depend. Adding to the problem is that bees aren’t migrating to cooler areas. “They’re simply not able to colonize new regions at the same rate that they’re disappearing from old ones,” lead author Peter Soroye, from the University of Ottawa, tells NPR.org. The authors stress that climate change isn’t the only cause of the bees’ decline; pesticide use and habitat loss also play a role. They say people can help the troubled insects by planting native flowers in their gardens and leaving out leaf piles and fallen logs to create shade for the bees on scorching days.
9-25-19 Crypt-keeper wasps can control the minds of 7 other species of wasp
A recently discovered parasitic wasp appears to have extraordinary mind-controlling abilities – it can alter the behaviour of at least seven other species. Many parasites manipulate the behaviour of their victims in extraordinary ways. For instance, sacculina barnacles invade crabs and make them care for barnacle larvae as if they were their own offspring. If the host crab is male, the parasite turns them female. It was thought each species of parasite could manipulate the behaviour of only one host, or at least only very closely related species. But the crypt-keeper wasp Euderus set is more versatile. It was known to parasitise Bassettia pallida, a species of gall wasp. Gall wasps lay their eggs in plants, triggering abnormal growths – galls – inside which the wasp larvae feed and grow. Adult gall wasps chew their way out of the gall and fly off. The crypt-keeper wasp seeks out oak galls and lays an egg inside them. The crypt-keeper larva then attacks the gall wasp larva. Infected gall wasps still start chewing their way out of the gall, but they stop when the hole is small and then remain where they are with their head blocking the exit, thus protecting the larva growing inside them – “keeping the crypt”. How the crypt-keeper larva makes the gall wasp stop chewing at such a precise point isn’t clear. “I’d love to know how they do it,” says Anna Ward at the University of Iowa. When the crypt-keeper larva turns into an adult wasp after a few days, it then chews through the head of the gall wasp to get out of the gall.The crypt-keeper wasp, which was only described in 2017, was thought to parasitise just one species of gall wasp. But when Ward’s team collected 23,000 galls from 10 kinds of oak trees as part of a larger study, they found that at least 7 of the 100 species of gall wasp they collected were parasitised by the same crypt-keeper wasp. “What we found is that it is attacking different hosts that don’t seem to be closely related,” says Ward.
9-18-19 Radio waves from electric devices may affect the body clock of insects
Weak radio frequency fields seem to affect the body clocks of cockroaches. If the finding is confirmed, it could mean that weak radio waves – which are already known to disorient birds – are capable of affecting a wide range of animals. However, Martin Vacha of Masaryk University in the Czech Republic, who conducted the study, says he is “very cautious” about his team’s results. In normal conditions, there might not be any effect on insects, he says, and the team isn’t making any claims about possible effects on people. Other scientists are sceptical, and say the study needs to be independently confirmed. Many claims have been made about possible effects of electromagnetic fields on humans and other animals. In particular, it is been claimed that the radio waves from mobile phones could cause cancer. But radio waves are much less energetic than, say, X-rays and don’t cause the damage to DNA that leads to cancer. Nonetheless, some researchers think they could have more subtle effects on living tissue. A couple of recent studies, for instance, have suggested that static magnetic fields affect the body clock of fruit flies. Vacha and his colleagues decided to look at whether they affect cockroaches too. His team kept cockroaches in constant dim UV light, with no clues as to whether it was night or day, and measured the animals’ activity using image analysis software. From that they worked out what time their body clocks were keeping. When they exposed the animals to either static magnetic fields or weak radio frequency broadband noise, the cockroaches’ periods of activity became an hour or two longer. In other words, their body clocks were running more slowly. Vacha says the team tested frequencies much lower than those from mobile phones. But many electric devices, such as computers, produce this kind of broadband noise.
9-15-19 Wasps: If you can't love them, at least admire them
Want to know the best way to kill a cockroach? Well, first inject some powerful neurotoxins directly into its brain. This will make the bug compliant; it won't try to fly away and will bend to your will. Second, slice off one of its antennae and drink the goo that comes out. For snack purposes, you understand. And then lead it off to your lair by the stump, like a dog on a leash. You're going to bury this zombie in a hole in the ground. But just before you close up the tomb, lay an egg on the bug. Your progeny can have the joy of eating it alive. Dr Gavin Broad relishes these stories about how wasps will parasitise other critters. He's the principal curator in charge of insect collections at London's Natural History Museum, which means he's got plenty of material to work with. He has drawer after drawer of wasps, gathered from all corners of the globe. Ok, I can already hear you saying, "I hate wasps even if they kill roaches". But spend just a few minutes with Gavin and I promise you your views will evolve. You'll marvel at their skill and in quite a few cases you'll be stunned (not stung) by their beauty. That destroyer of cockroaches, for example - Ampulex compressa - has an extraordinary iridescent exoskeleton. You can see why they sometimes call it the jewel wasp. "But every wasp is glorious," says Gavin, as he urges you to move beyond the PR spin that's got us to prefer beetles and bees instead ("Bees are just furry wasps that turned vegetarian"). Wasps have their role in Nature and it's not to pester humans in the autumn. Ignore those "yellow jackets" getting drunk on cider in September orchards; they'll soon be gone. No, wasps have very useful functions, one of which is to keep other insects in check. Every insect you can think of probably has some wasp that will attack it. If that wasn't the case, we'd almost certainly be using more pesticides than we already do on our farms.
8-30-19 More aggressive spiders
Parts of the U.S. where hurricanes occur most frequently may have another problem to worry about: the evolution of more-aggressive spiders. During last year’s hurricane season, researchers examined more than 200 colonies of Anelosimus studiosus spiders before and after three big storms in the Southeast. Anelosimus studiosus colonies are either relatively docile, with mothers working together to rear offspring, or much more combative, with a higher ratio of aggressive females. The researchers found that about 75 percent of the colonies survived the storm—and that the more-aggressive ones were much more likely to do so, probably because they outcompeted other spiders for the food and resources made scarce by the storm. The obvious evolutionary implication is that over time spiders will adapt to harsher weather events by becoming more aggressive—and that other species may also evolve in the same way. “As sea levels rise, the incidence of tropical storms will only increase,” lead author Jonathan Pruitt, from McMaster University in Canada, tells CNN.com. “We need to contend with what the ecological and evolutionary impacts of these storms will be for nonhuman animals.”
8-9-19 The Mosquito: A Human History of Our Deadliest Predator
Never underestimate that tiny insect whining in your ear, said Keith Johnson in Foreign Policy. “The mosquito, far and away mankind’s deadliest enemy, has killed half of all the people who have ever lived.” Per the calculations of historian Timothy C. Winegard, 52 billion people in all have died of malaria, yellow fever, and other mosquito-borne diseases, making the tiny pest the malevolent Zelig to our own species’ long journey through the ages. Winegard “finds no shortage of pivotal events to pin on the little critter.” The rise of Rome into an empire was aided by the invader-proof malarial swamps that surrounded the city. Mosquitoes also ended Alexander the Great’s campaigns. And they were major contributors to the British defeat at Yorktown. Though Winegard’s book is sometimes florid and sometimes repetitive, it “serves up an eye-opening, deeply alarming, and absolutely engrossing view of humanity’s most tenacious foe.” “There is very little of human history mosquitoes have not touched,” said Brian Bethune in Maclean’s. Though we’ve only known for a century that it is the mosquito, not “bad air,” that spreads malaria, humans have been in a fierce battle with the disease since the dawn of agriculture. About 8,000 years ago, when Bantu farmers in West Central Africa expanded their territory, the malaria parasite was waiting for them, and it proved so deadly that our bodies developed emergency genetic defenses, including sickle-cell anemia, a disorder that defends blood cells against the parasite but regularly results in death at about age 23. Five centuries ago, mosquito-borne diseases carried from the Old World to the New helped wipe out 95 percent of the Americas’ indigenous population. And because Africans had greater immunity to the illnesses than white indentured servants, millions of Africans were enslaved to serve as the New World’s labor class. Winegard sometimes gives the mosquito too much credit, said Brooke Jarvis in The New Yorker. His case for the mosquito’s role in the drafting of the Magna Carta, for example, relies on “a cascade of contingencies” stretching back centuries. But we who live in rich, temperate corners of the world are foolish if we presume that the mosquito has had its day in the human story. Climate change is expanding the reach of the genus and the diseases it carries. Though we think we are in control of our future, “the entire time that humanity has been in existence, the mosquito has been proof that we are not.”
7-5-19 Toxic processionary caterpillar plague spreads across Europe
Germany and the Netherlands are battling many infestations of oak processionary caterpillars, whose tiny toxic hairs can trigger allergic reactions and skin irritation. The mild winter and warm spring this year boosted caterpillar numbers. In Louvain, Belgium, firefighters had to destroy nests of the invasive species before a rock concert. The caterpillars turn into pupae, then moths in late July, and the threat diminishes. Germany's western Ruhr region is densely populated and among the worst affected by the caterpillars. Some schools and parks have been closed to allow specialists to attack the nests in oak trees. The caterpillars - measuring 2-3cm (about one inch) - march in long processions to the treetops at night, and can wreak havoc in oak trees, as they feast on the young leaves. One mature caterpillar has up to 700,000 hairs, which can be spread by the wind. The Fredenbaumpark in Dortmund was closed for three weeks, as nearly 500 trees were found to be infested there, broadcaster Deutschlandfunk reported. "The oak processionary infestation this year is very intensive - much more than last year," said the park's manager Frank Dartsch. Special teams there and elsewhere have donned protective gear and used firefighters' lifts to reach the treetops, where they have attacked the caterpillar nests with blowtorches or big vacuum cleaners. In the Netherlands, the infestations have also increased compared with 2018, with the oak-rich provinces of Noord-Brabant, Drenthe and Overijssel especially affected. A video of an elderly woman attacking the caterpillars with a heat gun in the city of Enschede has gone viral, the nltimes.nl website reports. Broadcaster RTL says the caterpillars have spread all over Luxembourg, a heavily forested country. The Luxembourg City authorities have issued a health warning, as the caterpillars are in the city too.
6-27-18 Bumblebees in cities are healthier than those in the countryside
Cities provide a refuge for bumblebees, which have been found to grow bigger colonies and store more food in urban areas than they do in the countryside. City bumblebees have been found to grow healthier colonies than those in the surrounding suburbs and countryside. They may be taking advantage of humans’ preference for flowering plants around businesses and homes. “There are a few species that are really able to exploit the urban environment – pigeons, rats, foxes. It seems like bees belong to that group,” says Ash Samuelson at the Royal Holloway University of London. She and her team raised colonies from wild-caught bumblebee queens, and placed them in 38 spots in areas with different degrees of urbanisation – inner-city London, surrounding suburbs, and rural farmland in southeast England. They tracked the size of the eventual colony, and the amount of pollen and nectar the bees stored. Both the village and city colonies produced a significantly higher number of offspring than the countryside bees. Samuelson says this suggests that queen bees in the cities and villages lived longer and were able to build up a larger troupe of worker bees. “Cities can be very good resources for bees. There are gardens and parks that have a lot of flowers available all year round,” she says. “In agricultural areas, you have mass crops that provide flowers only for a short-lived period.” The bees that lived among the crops stored less food – an indicator of colony strength – than their city counterparts.
5-3-18 Flying beetle cyborgs guided with tiny battery-powered backpacks
Beetles have been turned into autonomous flying robots. They could one day swarm through disaster zones on search and rescue missions. Buzzing cyborg beetles are taking to the skies. Just when you thought big insects were creepy enough, electronic filled bug backpacks have been used to turn them into controllable flying bio-robots. Male M. torquata beetles had electrodes implanted into four of their flight muscles. Small electric pulses were then administered to steer them left or right. Their acceleration could be increased by upping the frequency of the pulses. A 3D motion capture system tracked their position during flight. The researchers found that when a continuous pulse was applied, the beetles would eventually adapt to the intervention. However, applying two short pulses lasting 150 milliseconds, with a 50 millisecond rest in between, was most effective for controlling their route, reaching a success rate of 79 percent when the beetle’s position was reassessed every 200 ms. “This is the first demonstration that insect motion can be steered in a desired direction in a consistent way,” says Sawyer Fuller from the University of Washington in Seattle, who is not involved with the research. “It shows that truly autonomous, bio-hybrid robots the size of insects are a real technical possibility.” The beetle cyborgs were created by Hirotaka Sato from Nanyang Technological Institute in Singapore, Malaysia and his colleagues. They were interested in building tiny flying robots and by using beetles as the starting point, Sato and his team could avoid the incredibly difficult task of making small robotic bodies.
2-6-18 Pollinators are usually safe from a Venus flytrap
Out of the hundreds of species of carnivorous plants found across the planet, none attract quite as much fascination as the Venus flytrap. The plants are native to just a small section of North Carolina and South Carolina, but these tiny plants can now be found around the world. They’re a favorite among gardeners, who grow them in homes and greenhouses. Scientists, too, have long been intrigued by the plants and have extensively studied the famous trap. But far less is known about the flower that blooms on a stalk 15 to 35 centimeters above — including what pollinates that flower. “The rest of the plant is so incredibly cool that most folks don’t get past looking at the active trap leaves,” says Clyde Sorenson, an entomologist at North Carolina State University in Raleigh. Plus, notes Sorenson’s NCSU colleague Elsa Youngsteadt, an insect ecologist, because flytraps are native to just a small part of North and South Carolina, field studies can be difficult. And most people who raise flytraps cut off the flowers so the plant can put more energy into making traps.
11-4-17 This robot was inspired by bees. And it can swim.
"What's better than a robot inspired by bees? A robot inspired by bees that can swim." "What's better than a robot inspired by bees? A robot inspired by bees that can swim," said Katherine Ellen Foley at Quartz. Researchers guided by a team of scientists from Harvard University have developed a tiny, bee-size bot, weighing the same as "about two feathers," to study the ocean. The robot has "insect-inspired wings that can both flap and rotate," allowing it to dive into water, swim, take off again, and land safely. It also comes equipped with its own "little chemical lab" to help it break the water's surface tension after it has taken a plunge. The bot converts water into oxygen and hydrogen, and once enough gas is generated, "a lighter sets it on fire, the force of which shoots the robot about 12 inches into the air." Scientists hope the robots will be able to "keep tabs on fish and algae populations," monitor water pollution, and even participate in search-and-rescue missions at sea.
8-3-17 Pollination threatened by artificial light
Pollination threatened by artificial light
Researchers have discovered a new global threat to pollination - artificial light at night, which was found to reduce visits of nocturnal pollinators to flowers by 62%. The impact of this is a significant reduction in fruit production. Pollinator numbers are declining worldwide so this is not good news for wild plants and crop production. Nocturnal insects are easily distracted from their pollination duties by the lure of bright lights. Fruit begins with a flower, but not every flower results in a fruit. A number of factors result in the remarkable transformation of flower to fruit and one of the most important is insect pollination. But insects are in rapid decline caused largely by an anthropogenic assault including habitat loss and disruption, pesticide use, invasive alien species and climate change. But in a new study reported in Nature, another threat is revealed - artificial light at night. Dr Eva Knop, University of Bern, Switzerland, who led the research said: "Our study suggests that it is quite common for plants to have both night and day pollinators. During night it is often the scent that attracts the nocturnal pollinators but also other cues can be important, such as visual cues as the nocturnal pollinators have often very sensitive eyes." We are all familiar with bees and butterflies pollinating flowers during the day but come sundown a parade of "night-shift" pollinators take over. "In our study, the most abundant night time pollinators were moths (Lepidoptera), followed by beetles (Coleoptera) and bugs (Hemiptera)", said Dr Eva Knop. But, owing to artificial light contamination, from street lamps for example, our nights are no longer properly dark. Artificial light at night is spreading globally at an estimated rate of 6% per year.
8-2-17 Light pollution can foil plant-insect hookups, and not just at night
Light pollution can foil plant-insect hookups, and not just at night
For cabbage thistles, daytime pollinators didn’t make up for missed after-hours seed-making. Artificial light at night upsets pollinating insects and plants, and that disruption may spread into daylight hours. For flowers, too much light at night could lead to a pollination hangover by day. Far from any urban street, researchers erected street lights in remote Swiss meadows to mimic the effects of artificial light pollution. In fields lit during the night, flowers had 62 percent fewer nocturnal visitors than flowers in dark meadows, researchers report August 2 in Nature. For one of the most common flowers, daytime pollination didn’t make up for nightly losses, says ecologist Eva Knop of the University of Bern in Switzerland. In a detailed accounting of the pollination life of cabbage thistles (Cirsium oleraceum), Knop and colleagues found that night-lit plants produced 13 percent fewer seeds overall than counterparts in naturally dark places.
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