On August 7th, 2017 we learned about

Honeybees can compare quantities from four down to zero

As bees fly through an area to look for nectar, they’re not just listening to their stomachs. Like a good explorer, they’re taking mental notes about where to find the best food supplies so that they can share the good news with the rest of the hive. Their assessments may be more than abstract judgments too, as honeybees have been found to be able to compare specific quantities between one and four. This allows bees to effectively count up to four flowers, on par with the capabilities of most dogs. New research has found that bees can take one big step further though, as they can also understand zero.

Selecting fewer shapes

To test how well bees could count, they were first trained to seek out smaller quantities. Images of different numbers of shapes were displayed at two feeding stations, with the lower number of shapes always being paired with a tasty sugar-solution. Higher numbers were paired with quinine to reinforce the pattern more quickly, and bees regularly flew to the correct, smaller quantity at least 80 percent of the time. What’s more, they were able to correctly compare quantities when the winning option showed no shapes. This may seem obvious, but understanding that “no shapes” is a quantity that can compared is a feat only seen in humans, chimpanzees and monkeys, all of whom have a lot more brain to work with than a tiny bee.

Few can make note of nothing

Understanding that zero is less than one may seem obvious, but that’s largely because you’re used to the idea that zero is a number. Zero wasn’t really recognized as a number until the fifth century A.D. in India, and managed to elude Europeans until the year 1200. Mayans also came up with zero in the first few centuries A.D., but it wasn’t innately part of human mathematics. This doesn’t mean that our honeybees are on the verge of working out multiplication or negative numbers (negative flower counts?), but it does shake our understanding of what kind of brain is necessary to handle a quantity of none.

At this point, it’s also not clear what bees might be counting. Keeping tabs on flower counts may be an option, although it may also be useful for tracking the dances bees perform to communicate their discoveries to each other. We know that bee brains can handle these operations, but figuring when they employ these math skills may be much harder.


My four-year-old asked: Why does zero matter?

This is a tough question to answer for someone still working on counting to 12. To start, it makes dealing with large numbers much easier, as we don’t need as many unique digits. We don’t need a character for ten because we can use 1 and a 0. Zero has also allowed us to deal with numbers less than one, including decimal fractions and negative numbers. It’s also critical for… oh wait, four-year-old.

Zero lets us keep track of amounts smaller than one, as well as work with much bigger numbers more easily. We’ll come back to this in a few years maybe…

Source: Bees are first insects shown to understand the concept of zero by Sam Wong, New Scientist

On July 12th, 2017 we learned about

Tomatoes infuse their leaves with toxins to turn insects against each other

Tomato plants do not want to be eaten. The 31 pounds of tomatoes each American gobbles per year is fine, because that helps with seed dispersal and gives us a reason to plant more tomatoes. The problem for the plants is that too many bugs bypass the red fruit and eat the leaves of the plant, leaving it with no way to produce its own food through photosynthesis. To defend themselves, the plants have found a way to control the bugs’ appetites and populations— they get the bugs to eat each other.

This pest-control concept is actually based on normal behavior in various pest herbivorous insects, like mottled willow moth caterpillars (Spodoptera exigua). When these bugs can’t get enough nutritious food, they don’t really have the means to travel to find something better, as they’re trying their best to hoard calories in preparation for metamorphosis. So when the leaves are scarce, or just low enough quality, the insects will start eating each other instead as the last local source of nutrients and calories.

Turning up the toxins

Tomato plants (Solanum lycopersicum) have evolved to exploit this quirk of pest ecology. Tomatoes in danger can start producing extra toxins in their leaves that make them less nutritious to eat. Manipulating leaf-quality like this then convinces caterpillars it’s time to switch to cannibalism. In experiments, caterpillars offered more toxic leaves started munching caterpillar corpses much sooner than their peers. From the tomato plant’s perspective, adjusting the chemistry of leaves may be energetically costly, so they don’t make their leaves less attractive all the time. When circumstances demand it, this strategy does work well enough to make a measurable difference in just how much each plant gets eaten.

The last layer of this defensive strategy is that a tomato plant doesn’t need to get bitten to start raise its defenses. Like a variety of other plants, tomato plants can warn each other about the arrival of herbivores. They emit a compound called methyl jasmonate (MeJA) that can be detected by nearby plants, giving them a chance to start toxifying their leaves before the insects begin their buffet. There is some interest in manipulating this warning system, since presumably farmers could release MeJA to warn crops whenever they wanted. However, it might be best to follow the tomato plants’ lead on this, since constant warnings and toxic leaves could stress the plants while selecting for only the hardiest, toughest insects around.

Source: Plants turn caterpillars into cannibals by Laura Castells, Nature

On July 4th, 2017 we learned about

Engineers look to Lepidoptera for lessons on manipulating light

Butterflies and moths are masters of light manipulation. Their bodies have evolved specialized structures that allow them to reshape light in ways we can, at this point, only envy. Researchers are doing their best to emulate them though, building new materials based on molecular structures found in these insects’ wings and eyes. With any luck, we’ll soon have new ways to bend and trap light, improving everything from the ways we cool our buildings and stare at our screens.

Skipper butterflies in the family Hesperiidae might not have the saturated oranges or blues of other species, but small flecks of white on their wings have been catching researchers’ eyes. As with blue, there’s no pigment that makes the wings white. To send white light to your eye, the butterfly’s wings are instead covered in tiny scales that are bent or twisted at different angles to control how the light is refracted. The angle of each scale then plays a role in the color produced, which can apparently be manipulated in a why a static pigment can not.

In the case of skipper butterflies, the white dots on the outside of their otherwise brown wings can display more than one color of white. Close examination found that these spots seem to be a key signal to other butterflies, and their wing scales can control just how reflective or dull the white appears. The degree of control can even very between being dependent or independent on the viewing angle of the wing.

This kind of control would be great to build into various technologies, starting with glass and paints. Since white light is made up of all the colors from the visible spectrum, reflecting white light is a good way to keep sunshine off an object. People in hot climates often paint roofs white to try to keep buildings cool, a strategy that could be greatly enhanced if the paint could incorporate some of butterfly scales’ light-bending properties.

Seeing more with less light

Sometimes reflecting light isn’t what you’re looking for. In those cases, moth eyes may provide a good model for how to bend light in order to trap it. Moths evolved specialized structures in their eyes to help keep them from reflecting ambient light at night, which might make them visible to predators. Human eyes really only experience this a problem when a camera flash goes off, but the underlying principles may be very helpful in the design of LCD screens, like those found on your phone.

When light hits the glass of your phone, some of it is reflected back at your eyes. When it’s coming from a source brighter than the screen, like direct sunlight, it can overpower the image the screen is trying to show you, leaving you nothing to see but glare. To compensate, devices crank up their screen brightness, but that takes a lot of power, draining your battery faster. With a moth-inspired film on the outside, the sunlight wouldn’t be reflected, and the screen could remain dimmer without a problem. Engineers are hopeful that this will be available to phone manufacturers soon, but some issues like durability are still being worked out. For all their subtle ways of controlling light, moths and butterflies aren’t the most rugged insects out there.

Source: Penn collaboration produces surprising insights into the properties of butterfly wings

On June 25th, 2017 we learned about

Pulsing lights can make mosquitoes miss their meal times

In a battlefield strewn with netting, pesticides and other deterrents, people’s fight against mosquitoes may soon be aided by some new lighting, and the mosquitoes’ own brains. As with many inter-species conflicts, there’s long been an arms race between humans and mosquitoes, with each new defense being challenged and possibly potentially defeated as one side makes small adjustments against the other. For humans, this has meant adding pesticides or repellents to mosquito netting over our beds, but in many parts Africa those tools are being undermined by hungry Anopheline mosquitoes that have learned to wait until we’re out of bed. Still, this attentiveness to a schedule has opened the door to another line of defense— the circadian rhythms that tell us when to sleep, and the mosquitoes when to eat.

Dining in the dark

Anopheline mosquitoes prefer to do their dirty work in the cover of night, getting a lot of their feeding done in the low-light of early morning and the late evenings. Mosquito netting helps keep the insects off sleepers, but if the female mosquitoes wait a person out by feeding in slightly brighter light, netting can only do so much. To develop a non-chemical way to keep the bugs away from people for other parts of the day, scientists started experimenting with resetting the mosquitoes’ internal clocks with carefully-timed lights. If successful, this would essentially confuse the insects enough to miss their optimal feeding times, making their survival much more difficult.

Two experiments were conducted in dark chambers full of mosquitoes. The control group was kept in the dark, while the experimental group was exposed to ten minutes of pulsing white light. When offered a volunteer’s arm to munch on, the insects that had seen some pulsing light were much less likely to feed or even attempt to fly. In a follow-up, the experimental group of mosquitoes was exposed to pulsing light every two hours over a 12-hour night, and their behavior remained altered for four hours afterwards, meaning they weren’t ready for a normal feeding schedule until well after they’d normally eat.

Sensing light to set a schedule

The idea that brief exposure to flashing lights can reshape one’s behavior has been established in other animals already, including humans. While our eyes and brains evolved around the gradual change in light from sunrise to sunset, it turns out that even brief flashes of light can change when we feel awake, hungry, sleepy, etc. These carefully-timed pulses stimulate special ganglion cells in the eye, which then inform our suprachiasmatic nucleus, which then helps govern things like melatonin production so that we feel sleepy at night. In people, adjusting our light intake can enable manipulations to your daily sleep schedule, but for the mosquitoes it means missing feeding hours entirely.

Knowing such a disruption is possible, researchers hope that lights could be used at night to stop mosquitoes from feeding on sleeping humans. While white light was used in these first experiments, other ranges of light are going to be tested, in case they’re still effective while being less disruptive to people. Either way, if flashing lights can reduce the number of mosquito bites people receive, it should help with the larger goal of slowing the spread of dangerous diseases, like malaria or the zika virus. This probably wouldn’t neutralize mosquitoes forever, but it would be a chemical-free way for a lot of people around the world to sleep easier each night.

Source: Researchers use light to manipulate mosquitoes by Jessica Sieff, Notre Dame News

On June 13th, 2017 we learned about

Assessing the imagined ferocity of several local insect species

According to my kids, our street is on the verge of being inundated in dangerous insects. My four year old has warned me that “if you step on a pincher bug, it will bite your foot!” which… well yeah, most animals try to defend themselves if you step on them. So what vicious mandibles were my kids and their friends uncovering? The pincher bugs turned out to be earwigs, with a few cameos from silverfish (or maybe a firebrat.) Since these creatures really only pose threats to aphids, cardboard and old book bindings, it seems that our suburban street is still as tame as you’d expect it to be.

Encountering earwigs

To be fair to my kids, earwigs (Forficula auricularia) are probably the most intimidating-looking insect in this group. Their abdomens carry curved appendages technically known as forceps, but that have the visual panache of a bug-sized antler crossed with a claw. Since they’re on the abdomen, these forceps can’t really deliver a bite, but a larger male earwig could possibly give you an uncomfortable pinch if you scared it (or stepped on it.) The forceps are more often used to fight with rivals over potential mates, like the hardware on stag or Hercules beetles, and as such are generally larger on male than females.

The name “earwig” of course confuses people’s understanding of these bugs’ ecology. Anecdotes of burrowing into ears aside, the name is most likely the result of a misunderstanding of the name “earwing.” This name would have been much more descriptive, since these aphid-munching creatures have little interest in ears, but do have unusually shaped wings. The only way these bugs do make themselves a problem for humans is when they can’t find their preferred food and attack plant roots in a garden rather than assaulting humans.

Spotting silverfish

A few members of the Zygentoma order have also been found around our house, more commonly known as silverfish (Ctenolepisma longicaudata). These ancient insects can scuttle around at impressive speeds, flattening their bodies out to squeeze through tight spaces where they prefer to stay out of sight. They’re not great at climbing though, which is part of why you find them stuck in smooth-sided containers like your bathtub or a certain kid’s toy bin. They lack any appreciable claws or spines, and, despite some rumors to the contrary, can’t cause harm to you (although your belongings might not be so lucky).

One of the neat things about a silverfish is that they can go months at a time without eating. However, in the average American household, they don’t have to worry much about that thanks to people stocking their houses with papers, glues, cardboard, pastas, as well as veggies and bits of mold. Eating mold probably won’t raise any complaints, but people do run into problems with silverfish eating the starch around the house, which can lead to damaged books, stolen dry food, or holes in clothing. If you have spiders around though, they’ll probably help keep your silverfish populations in check.

Finding firebrats

While silverfish appreciate moist locations, their firebrat relatives prefer heat. Firebrats (Thermobia domestica) basically copy a lot of the silverfish lifestyle, but do it closer to your hot water heater, furnace or other hot spots around the house. Looking like a striped version of a silverfish, they’re equally harmless to people, but also potentially hazardous to books, glues and other starchy objects.

So I think between this collection of creepy crawlies, plenty of craneflies, daddy long-legs, a few black widows plus wasps and bees, it’s probably still safe to let the kids play outside. If we can keep the mosquitoes at bay, we may even survive the summer.

Source: Earwig invasion! Pest inundating gardens eats your fruit -- and those nasty aphids too by Jeff Spurrier, LA at Home

On May 31st, 2017 we learned about

Stingless bees employ specialized guards to stop other bees from stealing

One of the many things I’ve learned from cartoons is that if you try to steal honey from a beehive, the bees will swarm and chase you until you hide in a nearby pond. The threat of a barrage of bee stings is pretty motivating, even for a cartoon character, but of course this system doesn’t hold up in real live too well. For at least 500 species of stingless bees, a venom-filled poke isn’t even an option, leaving evolution to come up with another way to defend their hives: bee bouncers.

Beating back bad bees

Stingless bee species like the Brazilian Tetragonisca angustula have been found to have developed a sort of third caste of bee not normally seen among wider bee populations. In addition to queens and drones, T. angustula bees can grow up to be guards. The guard bees grow to be around 30 percent larger than their nectar-collecting kin, and in related species even have slightly different coloration on their bodies. Importantly, they don’t leave the hive to gather supplies for food. Instead, they hang out at the hive’s entrance all day, ready to brawl with thieves that might arrive to steal their honey.

Now, 30 percent larger than a bee isn’t going to be especially intimidating to a bear, even in a cartoon, but that’s fine because these guards are really looking out for other bees. The most likely thieves are species of robber bees, who live up to their names by only gathering honey from their pollinating brethren. For instance, all the species in the genus Lestrimelitta skip visiting flowers altogether, relying only on cleptobiosis, or the stealing of food from other animals. This kind of parasitic honey-gathering can pose a serious threat to other bees, and phylogenetic analysis of other stingless bees found that robber bees have pushed the evolution of larger guard bees at least five separate times in the last 20 million years.

From robbers to all-out raiders

The clashes between pollen-gathering Tetragonisca and honey-stealing Lestrimelitta bees have been developing over enough time for special guards to develop in threatened hives, but sometimes honey robbery can blindside a hive before defenses can be mounted. When food supplies are stressed, usually in late summer as flowers are less abundant, any normal Apis honeybee can apparently be pushed into a life of crime. Bees in search of food smell a hive’s honey, at which point they start by infiltrating in small numbers to grab as much honey as they can. They bring more of their own colony members, and may eventually swarm a target hive in such high numbers that they can wipe their rivals out entirely. Honeybees will try to defend things as best they can, but short of fortifying a hive’s entrance, even humans have a hard time stopping a swarm of looting bees once they get started.

Source: Stingless bees have specialized guards to defend their colonies, study reveals by Samuel Antenor, Scienmag

On May 21st, 2017 we learned about

Directional microphones may not be able to match the aural acuity of this parasitic fly

A very important feature of your ears is the space in between them. That’s because a lot of the information you gather about sounds in the world around you gleaned from comparing how they differ from one ear to the other. The 100 milliseconds it takes for a sound to travel past one ear to reach the other, known as the interaural time difference, is automatically processed by our brains to help us determine the spacial source of a sound. That way, you can find where a creak, beep or cry is coming from, or in the case of Ormia ochracea, a male cricket so you can deposit a lethal larva into it’s body.

Hearing potential hosts

Ormia ochracea is a yellow, nocturnal fly, no bigger than your fingernail. At night, females fly through the dark, navigating by their hearing to find male crickets chirping for mates. The female flies are interested in reproduction too, but they’re after the crickets as hosts for their larvae, which will eat their way out of the cricket a few days after being implanted. In broadcasting for a mate, the unwitting bachelors give away their location to the flies, although if you’ve ever had a cricket in your house you’ll know how hard it can be to really locate a hidden cricket, interaural time differences and all.

The flies can do it though, as they have some of the most sensitive directional hearing in the world. Instead of using ears on their head, they use sound-sensitive structures on their front legs (which is similar to the “ears” of a cricket.) A point of interest to researchers is that these membranes are so close together that sound hardly has time to be separated before it passes from ear to ear, so any kind of interaural time comparisons have to be made on a nanosecond timescale. This is of great interest to  engineers designing directional microphones for small spaces, such as hearing aids, but it has also revealed a considerable weakness in the fly’s hearing.

Linked, but more limited

To help calculate the direction of a sound, the fly’s ears two-part structures, coupled in the middle. That coupling means that comparisons between incoming sounds can be made instantly, as sound hitting one side mechanically triggers activity in the other. The fly’s brain gets a clearer one-two signal to process, letting it pick apart these minuscule differences in stimuli. However, that same solution makes the flies very vulnerable to louder, distracting noises. A loud noise in one ear can essentially knock out the second ear, as both end up vibrating. In lab tests, distracting sounds could pull flies off their path towards a cricket, apparently unavoidably.

Researchers now need to figure out how these O. ochracea handles loud noises in the wild, or if noise pollution poses more of a threat to their reproduction than was previously appreciated. Assuming they can somehow cope with distracting sounds, recreating that feat would enable better microphones, radar and other sound-sensitive technologies that we need to pack into spaces the size of fly legs. Until that can be determined, this supremely-accurate hearing remains on our biomimicry wishlist.

Source: This parasitic fly’s incredible hearing remains a curiosity to those trying to develop better hearing aids by Don Campbell, University of Toronto

On May 17th, 2017 we learned about

Measuring the anatomy of the most minuscule microinsects

In a world with tiny tardigrades, minute molluscs and shrimpy snails, it may seem like the only limit on how small an organism can be is the underlying size of a cell. Like all of these creatures, there’s more to it when you look closer, and scientists are studying the world’s more infinitesimal insects to see how nature scales down larger species. Many bugs used be bigger than we see them now, and some lineages seem to be evolving to be smaller and smaller. However, not every body part seems to shrink in exactly the same way.

There’s a whole range of so-called microinsects out there, and you’ve probably never noticed them. At the front of the line is Dicopomorpha echmepterygis, a member of the fairyfly family ( which means it’s actually a wasp). Their body length can be as small as 186 micrometers, which makes them close to the size of Roosevelt’s pupil on a dime. Surprisingly, even at that size they can pose a threat to other insects, as they lay their eggs inside other insects’ eggs so that the larvae can hatch and eat the host egg for it’s first meal. It’s not the most unusual strategy among wasps, but making it work does require special adaptations if you’re going to do anything at such a tiny size.

Assessing shrunken anatomy

Researchers in the Lomonosov Moscow State University in Russia have been scanning and comparing the anatomy of microinsects like fairyflies to see how evolution has miniaturized different systems to cram them into such small exoskeletons. One of the more obvious changes is the shape of these insects’ wings- rather than the flat, blade-like shape you see on a house fly or dragonfly, fairyflies and their minuscule brethren have wings that look more like a single feather, with fluffy bristles protruding from a single movable vein.

Inside the body, researchers are learning that not all anatomy can be reduced equally. Organs and structures that help with metabolic activity, like the trachea or stomach, can apparently be scaled down without a problem. No matter how small the insect gets, those guts grow in equally small proportions. On the other hand, some anatomy can only get so small, as the tiniest insects end up carrying proportionally oversized reproductive and nervous systems. These organs may end up creating a bit of a “floor” for insect miniaturization unless evolution really changes up how the body functions.

Models for other miniaturization

While fairyflies and other microinsects are not the smallest organisms, or even smallest arthropods, on Earth, they’re a good model for scientists and engineers who want to build smaller devices, or even robots. We can look at the differences between larger and smaller species to see what accommodations were made to make specific moving parts smaller, hopefully providing a good analog for taking a larger robot and updating it’s design to be as tiny as a fairyfly.

Source: How evolutionary miniaturization in insects influences their organs by Vladimir Koryagin, Scienmag

On May 9th, 2017 we learned about

The many ways that ants select and make new mothers

The first requisite for motherhood in vertebrates is to be female, but many bugs toss that rule out in favor of a more nuanced system. With most of their populations being female, social insects like wasps, bees and ants usually designate specific individuals to be everyone’s mom, a role usually referred to as the “queen.” Wasps can actually trade this role, bees can instigate it with food, but ants really make it hard to become a parent. Specifying exactly what’s needed to become an ant queen is hard, largely because it varies so much between the 12,000 types of ants in the world. Pheromones, genetics and more come into play, and even if a larvae seems destined for royalty, that honor isn’t always easy to hang onto.

Judging nobility with their noses

Indian jumping ants (Harpegnathos saltator) raise batches of would-be queens each year, although ideally they’ll mature around the time for summer rains. That way, the new “princesses” can take leave to start a new colony  when environmental conditions are most favorable.

As larvae, these princess ants will secrete a pheromone that communicates their probable destiny to their worker sisters in the colony. If the timing is right, these future-moms will be well taken care of so they can spread the colony’s DNA. If it’s not a good time for a mating flight, the workers block any coronation by biting the princess, stressing her body and causing her to mature into another worker instead. The pheromone signal is strong enough to even convince workers a male larvae might become a mom, as they don’t have time to learn biology when resources may be on the line.

This sense of maternal destiny has also been observed in a harvester ant species from the southwestern United States, Pogonomyrmex rugosus. In that case, specific pairings of current queens and males were more likely to produce new princess larvae than others. There are still likely environmental factors involved in this role selection, but studies with manipulated breeding in these ants make a strong case for caste determination, wherein parenting is not equally available to all members of the species.

Royal blood not required

On the opposite, more egalitarian end of the spectrum, some species are more like the wasps ants evolved from, and rely on gamergates. Gamergates are basically queens, but when they die, the colony can easily promote another worker to become the new mom for the colony. These working mothers only exist in species where queens don’t have significant anatomical differences from the rest of the population, such as larger bodies or wings.

More eggs from multiple moms

Finally, some ant species hedge their bets by allowing for more than one queen at a time. The unusually cooperative Argentine ant (Linepithema humile) will often have three to four queens laying eggs at a time, which allows their populations to expand very quickly. The queens are still queens from birth, but at the very least an individual queen’s survival isn’t as important for the colony to carry on.

That doesn’t mean that multiple queens guarantees a big, cooperative nursery. If a queen is laying fewer eggs than her fertile counterparts to save her own energy, she’s more likely to be attacked by the workers that tend to her. She might have more strength to fight back, but angry workers can also overwhelm and starve the reluctant queen. In some cases they do this until only one queen is left, but occasionally things get out of hand and the workers will wipe out all their queens. In this case, if a new queen isn’t growing up to replace the victims of regicide, the colony will likely collapse as their populations dwindle.

Source: Development of Ant Queens by Roberta Gibson, Wild About Ants

On May 2nd, 2017 we learned about

The biological mechanisms of metamorphosis that make butterflies and moths

It’s funny how many kids’ early exposure to biology involves the metamorphosis of caterpillars and butterflies, since the exact process of of these transformations is kind of a mysterious, black box of an event. We know the Hungry Hungry caterpillar eats a lot, then makes a coc- *ahem,* a chrysalis and then… poof! Magic! We’ve got a butterfly! Even after helping my second grader raise some butterflies from their larval stage, and seeing our neighborhood dotted with Tussock moth cocoons each spring, metamorphosis is just hard to relate to as a mammal. Fortunately, even knowing some of the nuts-and-bolts of what’s happening in a cocoon doesn’t really make it any less fantastic.

My kids apparently hadn’t dug into this process too much in their heads. My four-year-old explained that involved the caterpillar turning into “a black thing,” which somehow yielded a moth or butterfly. My second grader didn’t want to expose herself with a wrong answer, but she did note some similarities between the tube-shape of a caterpillar’s body and the shape of their adult abdomen and thorax. Maybe caterpillars just moved anatomy around, giving it small adjustments as needed, then adding wings?

Reblended bug-batter

The truth is a bit gloppier than that, although it’s obviously well managed enough to create amazing, delicate structures like the color-bending scales of a butterfly’s wings. Once inside a cocoon or chrysalis, the caterpillar essentially liquefies the bulk of its body so that the proteins can be recycled into new anatomy. Certain tissues, like muscle, are broken up but kept somewhat recognizable, where they can be reshaped or reallocated into something fit for an adult insect. Other anatomy is built upon structures called imaginal discs, which are a sort of scaffolding to anchor things like eyes and antennae onto.

Importantly, nerve tissue may be preserved enough that adult moths and butterflies can retain larval memories. Experiments with caterpillars conditioned to avoid certain smells found that those lessons were retained after metamorphosis. Some species of caterpillars even carry around the beginnings of anatomy like wings inside their exoskeletons as well, so it’s not like the entire bug is pureed in this process.

Peeking at the growth process

Knowing this isn’t just hard for amateur entomologists either. For a long time, the best data available was from cutting open cocoons and chrysalises. This not only interrupted the process, but also required matching progress and bodies of various specimens to infer how things were actually growing. More detailed data is now available thanks to micro-CT scans, which can create 3D models of a single specimen at different phases of development. The resulting views include detail and reveal patterns and trends, such as how tracheae bend and shift from meet the needs of the emerging butterfly. Which is basically what we were all thinking as kids, right?

Source: How Does a Caterpillar Turn into a Butterfly? by Ferris Jabr, Scientific American