Eastern Tent Caterpillars

Note: This show first aired June 11, 2016.

Early summer in Maine is astonishing. One moment the forest canopy is open, allowing glimpses of the newly arrived migrating warblers, a day or two later and the broad leaves have exploded from their buds, and any chance you had of seeing a tiny fast moving bird is gone. These rapidly growing fresh green leaves are not just a beautiful annoyance to bird watchers, but a nutritious salad bar for many of the insects that those warblers come here to eat. The young newly emerged leaves have a high water and nitrogen content to support their rapid growth, and generally lack the defensive chemicals that develop age, protecting the mature leaves. The high nutrient content combined with a lack of protection make them easy targets for developing insect larvae.
 

One type of larva that everyone has been freaking out about this year is the Eastern Tent Caterpillar, aka Malacosoma americanum. If you have been around any cherry or apple trees this spring, you have seen these. They are a remarkably social insect, emerging as tiny caterpillars in May, from a mass of eggs that overwintered glued to a branch on the host tree. The larvae congregate together and immediately start spinning a large three dimensional web in the crotch between two branches, that’s the tent. This web serves as home base for this community of caterpillars. As a native of north America, they especially like native cherry trees, but are also commonly seen in apple trees, though will occasionally end up on other species. The caterpillars emerge just as the new leaves are emerging on the host tree in the spring, perfectly timed to hatch just as their food source does. As they grow they continue to spin more and more silk, enlarging their tent as they themselves need more room. The tent provides a space to congregate when they are not feeding, and a temperature regulation mechanism. The tent is usually oriented to have maximum surface area towards the sun in the morning, so the caterpillars can warm up, become active and digest their food more efficiently. They go through a series of six instars, or caterpillar size classes, shedding their soft exoskeleton and expanding their body into a new larger skin. Generally they spend all of their time on their host tree, but at the end of their larval period, the group disbands, and individuals wander off, in search of good places to pupate on their own. When you see individuals wandering about over the landscape, this is what they are doing—looking for a good spot like a tree trunk or fence post on which to spin their cocoon and undergo the three week transformation into an adult.

One would think that these caterpillars would be sitting ducks for any and all predators—after all they live in big juicy groups in large easy to spot nests. As a result they have evolved several defensive mechanisms that keep them off the menu for most birds and parasitic insects, the organisms that would be their most likely predators. First they have a behavioral tic that causes them to thrash about wildly if threatened. This makes it especially hard for a parasitic wasp to successfully inject an egg into the caterpillar. Secondly, as is noted, they feed on cherry trees, and cherry tree tissue contains cyanide, so these caterpillars can sometimes release cyanide containing juices if threatened. Thirdly, and probably most obviously, the backs of these caterpillar are lined with hundreds of irritating hairs. Any animal that eats the caterpillar has to contend with the build up of these hairs in their throats and stomachs, the effects of which can range from uncomfortable to debilitating. The Black billed cuckoo is one local bird that has evolved the ability to eat these irritating caterpillars hair and all, the birds eat their fill and then cough up the lining of their stomach, growing a new one ready for the next meal of hairy tent caterpillars.

Seeing a tree, like the black cherry tree in my yard, totally stripped of leaves by hungry caterpillars is alarming, when all around lush green leaves are spilling out of twigs. The cherry tree looks dead, but trees are not that easy to kill, and it takes more than a denuding by tent caterpillars to do in a cherry tree. They, and many other broad leaf trees, have the ability to grow another set of leaves later in the summer, from buds that form in the spring (as opposed to the ones that over winter). Watch a tree attacked by tent caterpillars this summer, by August it should have sprouted new leaves, and not a tent caterpillar in sight. The caterpillars pupate in June and emerge as adults at the end of June or into July depending on location. The adult’s job, as is the job of so many adult lepidopterans, is simply to mate as soon as possible, lay eggs and die. Those eggs, once laid, wait many long months, until next spring, before the next round of tent caterpillars emerges, and we start all over again. 

References:

http://www.maine.gov/dacf/php/gotpests/bugs/factsheets2/tent-cater-wisc.pdf

https://entomology.ca.uky.edu/ef423

http://www.maine.gov/dacf/php/gotpests/bugs/tent-caterpillars.htm

http://web.cortland.edu/fitzgerald/Easterntent.htm

http://northernwoodlands.org/outside_story/article/of-cuckoos-and-caterpillars

http://www.nytimes.com/2016/05/15/nyregion/when-caterpillars-move-in-the-yellow-billed-cuckoo-feasts.html?login=email&_r=0

http://biologylabs.utah.edu/coley/ColeyPubs/2006Coley_cats_Oikos.pdf

https://extension.tennessee.edu/publications/Documents/W227.pdf

Bot Flies in Maine

Note: This program first aired on September 20, 2014.

There are so many reasons I am grateful to live in Maine. One of those reasons is the list of things I just don’t need to worry about, like poisonous snakes. The historic and even then very rare reports of timber rattlers in the far western mountains never cross my mind when I am in the woods. Also on that list are poisonous spiders, both poisonous species that are occasionally found here are not native. Brown Recluses and Black Widow spiders make their way into Maine using the time honored tradition of non native species everywhere, they let us transport them, in this case on things like bunches of bananas or grapes, or shipments of used furniture. Our biting insects, though fierce, are typically not deadly. I don’t have to worry about getting malaria or dengue fever from a mosquito bite. Our long winters keep all kinds of tropical maladies and pests from becoming issues here in Maine.

Typically the host survives the bot fly. Not this time.

All of this got turned on its head after a conversation I had last week with Susan Hayward, naturalist extrordinaire and a founding co-director of the Maine Master Naturalist Program. She was commenting on my recent program about horn worms (aka hawk moth larvae) and the curse of the naturalist to be simultaneously fascinated and repulsed by something. She shared her own experience of recently watching a bot fly larva emerge from a meadow vole. Wait, what?? A bot fly larva? We have bot flies in Maine?

Bot flies are a pest that I typically associate with warmer places. The fly lays an egg that ends up contacting your skin, and the egg hatches stimulated by the heat of your body. The tiny larva then burrows below your skin, into your body and sets up shop. It feeds on your flesh and breaths through a hole it maintains at the surface of your skin.  It gets big. Once it is developed enough, it crawls out of your body, drops to the ground and pupates in the soil. Everything about this is simultaneously fascinating and revolting, but it was never something I thought I had to worry about here in Maine.

And it turns out, actually, I was right. We do indeed have bot flies in Maine, but there are lots of different kinds of bot flies, and as parasites, they tend to have good fidelity to their host species. The bot fly Susan saw was in the genus Cuterebra which tend to attack rodents. The flies lay eggs in the entrances to rodent burrows, and as the animal moves past, the eggs hatch and the larvae, well, you know what they do. Apparently, from the number of veterinary web sites out there, its not unheard of for pets to get a bot fly, perhaps from sniffing around rodent burrows. Horse and other live stock owners know about bot flies (other species) too. Apparently I was the only one who didn’t know. And if I had thought about it, all the books I’ve read about the arctic talk about caribou infested with warble flies, which is another name for bot fly, so they venture even further north than here.

It is apparently quite rare but not unheard of for humans to get parasitized by bot fly larvae in this part of the world, but if you need something to worry about, feel free. I am going to put the rodent parasitizing bot flies in the same box in my brain as timber rattlers and brown recluse spiders, the one labeled “cool, possible, but not worth worrying about”. I encourage you to do the same. And one more thing, if you want to know more about bot flies, my advice is, don’t google this while you are eating.

Photos courtesy of Susan Hayward.

References:

UMaine cooperative Extension site: http://umaine.edu/home-and-garden-ipm/frequent-specimens/frequentspiders/

Bug Guide to the rescue: http://bugguide.net/node/view/551729/bgpage

Images of Rodent and Rabbit adult bot flies http://bugguide.net/node/view/53511/bgpage

Rodent Bot fly fact sheet: http://bspm.agsci.colostate.edu/files/2013/03/Rodent-Bots.pdf

Hornworms

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Note: This program first aired on September 6, 2014.

I am a vegetable gardener and this year I went out of my way to pick a tomato variety that would yield large and plentiful fruits. I am lucky enough to have a green house, and though I don’t give my tomatoes all the attention they deserve, they thrive in the heat and grow to heights well above my head. My peppers do just as well, and year after year I am amazed that such large and productive plants can grow from such tiny seeds.

The end of summer is always a whirlwind of activity, and this year was no different. I walked into the green house last week after several days away and noticed some of my pepper plants seemed to be missing a lot of leaves. Then I noticed many dark green blobs and blotches on the soil under the plants, and it slowly dawned on me that something was eating my pepper plants, and I knew just what it was. With a search image in my head, I quickly found the unbelievably large caterpillars that were munching away, confirming my fears. The hornworms are back.

The hornworms in this case are Tobacco Hornworms, Manduca sexta . They and their closely related cousins Tomato Hornworms, are common garden pests, generally showing up on tomato plants in late summer, capable of defoliating a plant seemingly overnight. If you aren’t paying attention at just the right time, you can lose all of your tomato plants. We tend to find them on tomatoes, but they feed preferentially on most members of the Solanaceae including tomatoes, peppers, potatoes and tobacco.

If you have never seen one, they are amazing looking, and sort of freaky. They grow to a size larger in length and diameter than my finger, and according to one source, can actually bite when attacked. Some how I never seem to see one when they are small, but they do start out that way. They are the larvae of Sphinx moths, large nocturnal moths that lay eggs on the host plant in summer. After a few days the eggs hatch and the larvae emerge, feeding for three weeks, and apparently growing from a tiny hatchling, to a caterpillar larger than my finger. They then pupate in the soil, burrowing under the surface and remaining there for at least three weeks. In the first generation of the summer the adults emerge in three weeks. Those adults then mate and lay eggs, and that second generation pupates and overwinters in the soil, with the adults emerging in late spring or summer of the next year. And just like the larvae when they are small, I never seem to see the adult moths either.

The crux of the matter is this, my feelings about the hornworms are complicated. On one level, they are amazing. Huge puffy green caterpillars with beautiful markings and bizarre appendages, they are hard to draw your eyes away from. On another level they are pests, they destroy my tomatoes and are so well camouflaged you are never sure you found them all. When I do find one, I invoke the circle of life and feed it to my chickens. On a final, and more visceral level, I find them disgusting. Though I know better, when I see them I feel a distinct physical sensation in the pit of my stomach, it’s revulsion. Something in my animal brain reacts badly to these enormous grub like larvae, even when my human brain says “wow! Cool!” quickly followed by “darn those pests!”.  I take it to mean that there is something in my evolutionary history that is speaking up, something that is telling me not to eat these hornworms, and I don’t have any way to assure my animal brain not to worry, there is no chance of that. So I am left simply with this strange tension between the very old and the very new. If we pay close attention, I think we will find this tension in many parts of our lives. Whether or not we can rectify it, it is worth being aware of. It’s a window that allows us to look at where we came from, how we lived, and how far we have come from that today.

Beloved Summer Insects: Deerflies

Note: This program first aired on August 2, 2014.

This week’s show is dedicated to WERU’s own News Editor, Amy Browne. I happen to know, from social media, just how she feels about the animal we are going to talk about today, though I also know from experience, she’s not alone.

The animal, the bane of existence for so many people, and so many companion animals this time of year, is the deer fly. The common name Deer fly refers to a group of animals in the genus Chrysops, of which there are about 100 species in North America alone. Deer flies are in the insect order Diptera, with all the other flies, in this case their common name is not a trick. It is the females that cause us so much grief. They require a blood meal from a vertebrate to ensure viability of their eggs. Males sip nectar from flowers, (like male mosquitos) for their sustenance. Deer flies (and their closely related bretheren Horse flies) are universally referred to in the literature as having “knife like” mouth parts. They achieve the required blood meal by slashing away at the flesh of the victim, causing a generalized bleeding, which they then slop up with their “sponge like” mouth parts. This part of the story you know well, if you spend any time outside in Maine in the summer.

I wanted to know more about these extremely annoying creatures, so I dug in a bit to see what I could find. And it turns out it is much as I suspected. They are hydrobionts, meaning they need wet areas in which to breed. The females, after their blood meal, lay their eggs on the underside of leaves in the understory or in swamp areas, above damp or wet ground. When the eggs hatch the larvae that emerge drop into the wet ground below and burrow in, living on detritus or as predators of smaller insects and worms. The larvae are active all winter, below the frost line apparently, and after feeding all winter they apparently pupate in early spring for a few weeks. The adults emerge in summer and live from one to two months, tormenting me and Amy Browne and our dogs, and anyone else foolish enough to be outside in wet areas when the temperature is warm enough. One of the sources I found indicated a minimum temperature range of 72 degrees F, but I know that to be incorrect, at least for the deer flies here in Maine. If I can get out before the temperature hits 60 degrees I know I will miss most of them, but above that, they are good to go. They are also primarily visual predators, attracted first and foremost to dark objects that move. If I wear a light colored shirt on my morning run I am much less bothered. My large black thin coated dog however, has no such choice. Sources say that scent and other biological cues like carbon dioxide are also attractants, but my experience leads me to believe the idea that they are primarily visual. It seems that their job in this world is to bite, and bite well, much to our chagrin.

Isn’t that the job of every animal? Every organism? To do whatever it can to carry on and pass on its genes? It is easy to disparage a biting insect that bothers us for one to two months a year, but we have to remember that everything has a job in an ecosystem. The job of many of the deer fly eggs is to get parasitized by wasps. The job of many deer fly larvae is to get invaded by bacteria and fungus and other microbial parasites. The job of many an adult deer fly is to get eaten by swallows and flycatchers and predatory insects like dragon flies and hornets. The job of the ones that survive is to reproduce, and to do that, they need us, or our dogs, or our livestock, or more likely, the large vertebrates that populate the north woods.

No body likes hanging out with deer flies. But all the same, I prefer a world where they exist, a world as full as it can be with as many different kinds of organisms as possible, a world rich and damp and squirming with life. That is truly the point of it all, and we can’t do it without the biters and scratcher anymore than we can do without the cute furry babies and the fluffy little birds. They all count, every last knife like mouthpart wielding one.

References:

More good stuff from Bug Guide: http://bugguide.net/node/view/11387/bgpage

Here’s a whole bulletin about them from the Maine Forest Service: http://library.umaine.edu/MaineAES/TechnicalBulletin/tb160.pdf

Good photos: http://entnemdept.ifas.ufl.edu/creatures/livestock/deer_fly.htm

Butterfly Life Cycle, More Than Just Egg, Larva, Pupa and Adult

Note: This program first aired on July 26, 2014.

A few weeks ago, I mentioned some of the butterflies I’ve been seeing around; right now its all fritillaries and sulphurs, earlier this summer is was Swallowtails, the Mourning Cloaks were earlier still this spring. Later in the summer I hope to see some Monarchs. Have you ever wondered why some butterflies are around at certain times but not others? Why are the Mourning Cloaks the first ones here in the spring, and then they disappear? Why are we seeing the fritillaries in such abundance now? Have you even noticed that there is a pattern to the appearance of different butterflies? Believe it or not, it’s not random happenstance. The answer is due to the fact that although we’ve all watched the Discovery Channel and think we have the butterfly life cycle down pat, it’s much more complicated and interesting than egg, larva, pupa and adult.

The truth is, butterflies are short lived creatures that come in seasons based on their life histories. Though it is hard to remember now in the thick of the heat of summer, the main obstacle to all arthropods is the cold of winter. Being primarily ectothermic or at the mercy of the external environment for temperatures favorable for metabolism and activity means that most insects have a difficult time being active in the winter here in Maine. The question facing butterflies, and all arthropods, is how to deal with winter. There are two main choices, the same ones we humans face, you can stick it out here in some kind of overwintering dormancy, or you can get the heck out of Dodge and migrate to warmer climes. 

Migration is not the most common butterfly strategy for dealing with winter, and it’s easy to speculate on why. First, only the adults could possibly travel far enough, how much ground can a caterpillar really cover? Secondly adults don’t tend to live very long, we’re talking about live spans of days to weeks in most cases. Thirdly, and this is pure bias and subjectivity on my part, butterflies seem so fragile, so wispy. I can barely believe that tiny birds migrate successfully thousands of miles, but something as insubstantial as a butterfly? The best known of the migrating butterflies is of course the Monarch, and the details of just how they do it is still a huge mystery. What is known is that it takes multiple generations for them to complete the migration. The ones that leave here are not the same ones that return the next year. The ones that return are the great or great great grandchildren of last year’s butterflies.

So then, migration happens but is uncommon, and the timing of the return of the migrators depends on many factors, weather and conditions not only here but everywhere along their route, which can be thousands of miles. For those butterflies that stay here year round, the majority of them, they face a choice as well. We know that the basic butterfly life cycle includes an egg, a larval stage, a pupa stage and an adult stage. Which stage is the best one in which to wait out the winter? If you thought there was a clear cut answer to that, you haven’t spent much time studying evolution. The answer is of course, all of them. Different species have evolved different tactics for dealing with winter, mainly guided by coevolution with their host plant, the thing the larva or “eating stage” of the insect, lives on.

Mourning Cloaks are the first butterflies we see in the spring, and the reason for this is that they over winter as adults. They hide out under bark or in the leaf litter, emerge on the first warm days in early spring, mate and die. We see them again in the fall when the new generation emerges from a period of summer dormancy, fattens up on nectar and prepares to over winter. The Swallowtails we see in June by contrast, after the Mourning Cloaks are all gone, have over wintered as pupae, often attached to the trunks of trees. Their larvae spend the summer feeding on the leaves of various deciduous trees, and the last instar forms the chrystalis in time for winter’s cold. The fritillaries flying about now started out last year as an egg laid in late summer, near a patch of dead violets. The egg hatched and the tiny larva that emerged, the first instar, is what over wintered, without eating. This spring, when the violets emerged as a spring wild flower, the fritillary larvae were already there, ready to start feeding. Each of these butterfly species positions itself to be ready to make full use of its favorite larval food, and these plant foods in turn, have their own seasons, thus so do the butterflies.

Watch nature long enough and it becomes a giant game of connect the dots. The more you play, the more you learn, and the more you realize there is to learn. Play long enough, and you realize all the dots are connected.

References:

Canadian reference on Mourning Cloaks http://www.naturenorth.com/spring/bug/mcloak/Fmcloak.html

Butterflies

 Note: This program first aired on June 21, 2014.

Summer seems like it is finally here and I have been enjoying the good weather outside as much as possible. It seems to me that there is an abundance of butterflies this year, particularly the large yellow and black Swallowtail butterflies. And earlier this spring, I noticed many Mourning Cloak butterflies around as well. It could be that I am simply paying more attention, so in the absence of hard data don’t consider this a trend. My life has led me to butterflies, which means I am seeing and appreciating more of them during the fleeing time they are here, that is all.

Butterflies under go what is called complete metamorphism, in that they have four fully differentiated stages of their development: egg, larva, though in the case of butterflies and moths the larva is by definition called a caterpillar, pupa and adult. Each of these forms is markedly different from the others, and this difference is one of the reasons we find insects so remarkable. The adult female lays the egg, typically one of hundreds of eggs, on or near an appropriate host plant for the soon to hatch caterpillar. The host plant is important, because as soon as the egg hatches, the caterpillar begins to eat, and it is usually pretty picky about what it likes (like so many kids). The caterpillar’s job is to eat and grow, which they do quite well, though most of them get eaten themselves, either directly by birds and other small hungry animals, or worse, by internal parasites. Many many other insects including certain flies and wasps use caterpillars as mobile feeding stations for their young. Eggs are either deposited directly into the caterpillar, or laid on host plant material, where the very hungry caterpillar unsuspectingly ingests the parasite egg. Once inside the caterpillar, the parasite egg hatches and the larva develops inside the caterpillar. Recall that the job of an insect larva is to eat. One source I read remarked casually that the parasitizing larva carefully eats the caterpillar alive from the inside, saving the vital organs for last, to keep the host caterpillar alive longer.  If the caterpillar doesn’t get eaten or parasitized, it will grow. We think of caterpillars as soft and squishy, but really they must follow the same rules as all other arthropods. Arthropods have exoskeletons, and must molt, or shed their old exoskelton for a new larger one when they grow. Caterpillars do the same, shedding their tough outer skin. Each time they do this, they get bigger, and may even change color or shape, each version of the caterpillar is called an instar, for example you might identify a caterpillar as “the third instar of the eastern Tiger Swallowtail”. During the last molt or shedding of caterpillar skin, what emerges is not another caterpillar, but the pupa. This stage of the life cycle is often referred to as a resting stage, but really it is anything but. It is true that the pupa (contained in a chrystalis in butterflies and which occurs in the cocoon in moths) is usually immobile, but inside the protective exterior, the entire body of the caterpillar breaks down and is rearranged into an adult. The adult body structures form from just a few cells, sort of like stem cells, called imaginal discs,  that originate in the insect egg, and are carried dormant inside the caterpillar all along. Just like us. A part of who you are comes from your maternal grandmother’s health and well being, as one of the eggs that became you developed in the embryo that became your mother inside your grandmother’s womb. Other bits of you come from your father, who continuously generates new genetic material throughout his life. As humans we take those bits of DNA and we develop, we grow, we age, we come into our fully articulated being, and we wonder where this person we’ve become came from. Just like the butterfly, emerging after so much work and shape shifting, we have to remember, we were there all along.

References:

Many online references exist for butterflies, none better than Bug Guide http://bugguide.net/node/view/81

A link from the Bug Guide site, to a California lepidopterist: http://mamba.bio.uci.edu/~pjbryant/biodiv/lepidopt/GettingIntoButterflies.htm

Bug Guide Mourning Cloak page: http://bugguide.net/node/view/3188

Good stuff on insect metamorphism from Scientific American: http://www.scientificamerican.com/article/insect-metamorphosis-evolution/

And specifically butterflies and moths: http://www.scientificamerican.com/article/caterpillar-butterfly-metamorphosis-explainer/

Frass Happens

Note: This program first aired on September 14, 2013.

I’ve been noticing lately, and maybe you have been too, what seems like an awful lot of insect frass around. Frass on my porch, my roof, my adirondack chairs. Put up a tent or a tarp, and as long as it is underneath some trees, it will be covered with the stuff. What this tells me is that there are a lot of insects in the trees, specifically, larval insects, and they are apparently doing a lot of eating. Frass is indeed linked to food, because frass, my friends, is insect poo. Just like you and me, the more they eat, the more they excrete.

Summer is the time of the insect, the warm temperatures bring plentiful food sources, and insects have evolved to take full advantage of this brief window. The insect life cycle is a fascinating one; I, for one, can’t stop thinking about how cool it is. There are three main paths to becoming an adult insect. The first is simple metamorphism, and it has a couple of sub categories. Of those, the first is gradual metamorphism (also called paurometabolous (small or slight change) metamorphism). The egg is laid by an adult, and what hatches out of the egg is essentially a tiny little adult, that eats and grows and molts its exoskeleton and grows some more, molting and growing until it gets big enough to be sexually reproductive and is considered and adult. This is the M.O. of grass hoppers, for example. The other form of simple metamorphosis is incomplete or hemimetabolous (half change) metamorphism. An egg is laid by an adult insect, and out of the egg hatches a juvenile stage that looks different than the adult. In this immature stage they are called nymphs or naiads and are aquatic. This nymph eats and grows, molting its exoskeleton, until its last molt, when what comes out is not another nymph but an adult insect. Dragon flies grow this way.

The second category is complete metamorphism also called homometabolous (whole change) metamorphisman. An adult lays an egg, from which hatches a larvae, (caterpillar, grub etc) which grows through several different stages, called instars, molting an exoskeleton or outer skin as it passes from one instar to the next. Then the larvae turns into a pupa, the stage of true metamorphosis, during which the cells of the insects body completely rearrange themselves. It is often referred to as a resting stage in the literature, but the insect is only appearing to rest. Inside there is a major transformation going on. This is the cocoon stage of the butterfly, as an example. From the pupa emerges the adult, totally and utterly reconfigured from the larvae.

Complete metamorphism is by far the most popular means of insect growth, found in approximately 10 times as many species as incomplete metamorphism. There are some distinct advantages to having such wide variation in the different stages of growth, and the first is division of labor. Ken Kaufman in his guide to insects refers to each stage of the insect as having a different job, and the analogy is a good one. The egg has it the easiest, it simply has to incubate. The larvae are “eating machines”, their job is to get as much nutrition as they can because the metamorphosis that occurs in the pupa stage is so incredibly hard and energy consuming. The adults may or may not eat, but their main job is to reproduce. Typically the larvae also live in different habitats than the adults (sometimes really different habitats, for example the larvae of black flies and mosquitos are totally aquatic, they live under water). This can reduce intergenerational competition for resources, always a good thing.

So it is larvae in the trees that is making all that frass, larvae doing all the work of eating, for many of these caterpillars turn into moths and butterflies that don’t eat at all. It’s a division of labor so stark it is hard to imagine. Its also perfectly synched to the rhythm of nature, those caterpillars, grown fat on summer’s greenery, will pupate and spend the long winter slowly rearranging their cells, preparing to emerge in the spring as new beings. It makes me feel crass and ill fitted in comparison. As the days grow shorter, we would do well follow their example, respecting the season and using what it offers, a break from the frenetic frass making of summer, to renew and reorganize ourselves as well.

References:

www.bugguide.net The definitive internet insect resource, email in your photos to get identifications from an online community of bug nerds.

Ken Kaufman’s Field Guide to Insects of North America 2007 Houghton Mifflin, I love this book, it (like all Kaufman guides) uses actual photographs, but at the same time manages not to be too creepy.

Freeman, Quillin, Allison Biological Science 5th ed. 2014, Pearson
Most any modern biology textbook will give you some good basic information about Arthropods

Nice site from the West Virginia University Extention service, clarifying  different types of metamorphosis,
http://www.caf.wvu.edu/~forage/insect_m_morph.htm