As children my brother and I used to see butterflies, moths, and caterpillars at our little organic farm. We didn't just think that the wings are pretty and the crawling bodies are ugly; we thought, "Is it a friend or an enemy? What does or did it eat?"
Information was hard to find back then. The old books, which were fairly authoritative, had mostly worn out. The new writers couldn't copy the old books and had nothing to add to them, so new books on butterflies tended to be dumbed down.
Often authors would spend pages theorizing about how lifeforms (not limited to butterflies) would theoretically have evolved, instead of telling us anything we couldn't see for ourselves about how lifeforms fit into the environment now. That really is why I associate blather about macroevolution with feeling bored, impatient, and as if somebody was waffling on and on to cover up a lack of knowledge. If you can't tell me what a butterfly's food plants are, I want you to admit that rather than babbling about when it might have evolved. I'm not attached to creationism either, although a literal interpretation of the first chapter of Genesis is easier to believe than a serious consideration of macroevolution. I want to stick to the science of how living things exist now.
Anyway you might think that Wikipedia, which has room for everything, would have room for complete comprehensive articles on all of the butterfly species. Well, no such. Actually many butterfly species remain unstudied, but Wikipedia doesn't even bother telling us what's known about the ones that have been. And much has been learned about how at least the North American butterflies behave in this world.
So after doing some paid writing about Monarch butterflies, Painted Ladies, and Mourning Cloaks, I had the idea of writing the book we children didn't have. But publishing it as a traditional book soon presented problems. Color pictures are expensive. So is the heavy, glossy paper that takes true colors and lasts for years. As a printed book this book would be too big and too expensive for most people.
Solution: Publish it on my blog. People may print out and bind as many pages as are useful to them. They should credit me for the text. I'll credit the photographers whose work I gank. This will be a nonprofit venture for as long as sponsors fund it. You can be a sponsor.
This series of blog posts, which is actually a book manuscript, is intended for the use of middle school children and their older friends. When possible it uses ordinary words rather than technical terms, and presupposes that a microscope is not handy. It presupposes that readers know where babies come from and aren't going to giggle about it in the middle of a funeral. It also presupposes that readers are not obsessive enough to study the reproductive parts, or other microscopic details, of butterflies under a microscope, although in fact each species' reproductive parts are slightly different and in some cases that's how experts identify confusable species.
Books about different species of living things usually begin with a general consideration of the features all of them have in common...
Butterflies have short lives, typically one to two months after emerging from the chrysalis. A few butterflies are able to hibernate through the winter and/or estivate through the summer, and can potentially live up to a whole year, spending much of the year resting.
Butterflies are so small and light that it's hard to imagine how they can have any sense of direction or intention, but they do. Though tossed about by every breath of wind, they move toward sources of food and prospective mates, sometimes following their senses of scent and temperature for hundreds of miles. In fact many butterflies can be described as forming parts of a seasonal migration nothrward in spring and southward in fall, though only Monarchs seem to flap from Canada to Mexico every year,
Butterflies are called insects because their bodies are divided (Latin secta) into (in) parts. Each butterfly has a head (with antennae and a proboscis), thorax (to which the legs and wings join on), and abdomen (tail end) consisting of distinct segments.
Butterflies have no bones. They are described as having exoskeletons because a skin or shell of chitin, enclosing their softer parts, defines their bodies instead of a skeleton.
Each butterfly has two pairs of wings, described as fore and hind wings. The upper and lower sides of the wings often show completely different color patterns. Wing shapes vary among species and are used to classify butterflies into genera of species that generally have similar wing shape and venation. Venation means equipping with veins, which circulate haemolymph (insect blood) through the wings, legs, and body.
Monarch butterflies' color pattern follows their wing venation.
Tiger Swallowtail butterflies' color pattern crosses over their wing venation:
Butterflies can usually continue to fly on slightly damaged wings. The Swallowtail family, especially, seem to have "tails" that flutter behind the ends of their hind wings just to give predators something to grab without harming the butterfly. More extensive damage to the wings can, however, kill the insects.
Butterflies are either male or female--except for a few who seem to be both. In some butterfly species the male and female look and behave alike, the only obvious difference being that only the females lay eggs. In others the male and female are different in size, shape, and color--and a few individuals have male-type wings on one side and female-type wings on the other. Most butterflies are fertile. Female butterflies make some effort to lay their eggs in a good environment for their caterpillars, but very rarely have any chance to see the caterpillars hatch, and do nothing else to "mother" their young.
Butterflies go through complete metamorphosis, with each butterfly going through eight to ten different skins that may have eight or ten completely different looks. Their looks can change somewhat even within one skin, but for identification purposes they are described in terms of the life stage spent in each skin:
1. Egg: One egg is sometimes called an ovum; several eggs are called ova. Butterfly eggs are often barrel-shaped rather than egg-shaped. They are very small, sometimes microscopic, and are usually hidden on the undersides of leaves, or among dead leaves on the ground.
2. Caterpillar: One caterpillar may also be called a larva; more than one would be larvae. Caterpillars have six true legs that will remain legs as they mature, eight "prolegs" that will disappear, and a pair of "claspers" on the hindmost segment that develop into whatever structure the adult butterfly has at its tail end. They can use their jaws to clasp surfaces on which they are crawling, too. This gives a caterpillar nine pairs of bristly little appendages, contact with which activates most humans' primal reaction to avoid "formication" (the sensation of being crawled on by insects).
Caterpillars' heads face down toward the plants they crawl on and eat. Some species have markings on the top and back of the head that may resemble eyes. Some species' heads are hidden by a conspicuous hump on the caterpillar's back that may look like a face, usually the face of a little snake. There are usually more than two working eyes, or ocelli, in a cluster near the mouth.
Caterpillars hatch out of their tiny eggs looking like thick bits of thread. They are always "very hungry." They spend most of their lives chewing up plant material and growing. Unlike other animals, they are designed to burst out of their skins and grow into new ones every few days. Each change of skin is called an instar. There are usually five instars, in each of which the caterpillar grows bigger. North American butterflies and caterpillars are smaller than tropical butterflies and caterpillars. The length of a caterpillar before it pupates is usually, though not always, close to the wingspan of the butterfly it becomes, and in North America anything over two inches is classified as large.
After hatching some caterpillars' first instinct tells them to eat the shells or shed skins from which they hatched. This is a tidy habit that helps to discourage predators. Mother butterflies of these species will normally try to place each egg on a separate food plant so that caterpillars never meet their siblings. If they do meet siblings, as may happen when they are reared in captivity, each caterpillar will instinctively want to eat the other skin. They seem to have no counterbalancing instinct warning them that a sibling is living inside that other skin. Usually one caterpillar succeeds in eating the other skin and most of the rest of the sibling with it. Other caterpillars, however, leave their shells behind them and may grow up in little family groups, eating and resting side by side and thus making themselves less attractive to predators. No butterfly caterpillars seem to have an instinct, as a few moth caterpillars seem to have, positively to help or protect younger siblings.
3. Chrysalis: Some butterflies spin cocoons; others molt into a thick skin called the chrysalis while they pupate. This stage of life is also called the pupa (plural, pupae).
4. Adult butterfly: The adult form of a butterfly is sometimes called the imago. It takes some time and effort to emerge from its pupal skin, then stretch and firm its wings, before it can fly. If you are watching a butterfly emerge you must resist any temptation to try to help it along, which would harm the butterfly. Some butterflies start travelling as soon as they can fly; some stay in the same neighborhood for a few days.
Butterflies don't seem to form attachments to places or people. Couples usually don't stay together for more than a few hours, and no butterfly behaves like a human parent. When the caterpillars hatch they are on their own, with only their instincts to guide them. Most caterpillars do not live long enough to become butterflies.
All caterpillars have jaws (like beetles) and may use their jaws to grip when they are trying to escape, as it might be when humans pick them up. Most caterpillars' jaws are not strong enough to cause much pain to humans. Butterfly caterpillars, though often bristly enough to be hard to swallow, don't have venomous spines to "sting" humans, either. They are harmful only when eaten. You may occasionally find a butterfly caterpillar eating a garden plant, but no butterfly species is considered a serious pest by farmers.
All adult butterflies have long tube-shaped "tongues" (like bugs). The butterfly's proboscis is usually rolled up in a coil at the front of the head. Butterflies seem to have some sense of taste in their feet. When their feet tell them that a liquid tastes good (to them), they unroll the proboscis and slurp up a little liquid. They can eat only liquids.
Some butterflies are classified as pollinators who drink flower nectar and transfer pollen among flowers as they go along. Others are composters who drink mineral-rich polluted water and decomposing animal matter such as dung and carrion. In several species, females are primarily pollinators and males are primarily composters. Females of these species get their minerals from males in the mating process; if unable to find males they may become desperate enough to do some composting on their own.
Butterflies have very little social instinct, but some individuals claim territories and chase intruders away, and some participate in social behavior known as lekking. When animals lek, several males gather in one place. (In the case of butterflies this is often an oil-filmed puddle/) Females may then gather around the edge of the group of males.
All butterflies have six legs (unless a predator has grabbed one). However, several large butterflies use only four legs to walk. The foremost pair of legs are shorter, and seem to be used more like arms rather than legs.
Butterflies "fight" by flying at each other, trying to knock each other off course. Occasionally a few species, like the Monarchs, actually bump into each other. They are not heavy enough to hurt each other and seem to do this as a friendly game. Monarchs who knock each other to the ground are usually couples in which the bigger male knocks down the smaller female, after which they may fly away separately or together. One observer reported that, after these deliberate collisions, about a third of the butterfly couples mated. Butterflies are nonviolent but they can be stupid. In some species young males are often killed by trying to chase cars off their territory.
At all stages of life butterflies get bright colors from chemicals in their food plants. Most, not all, of these chemicals are toxic to the butterflies' predators. Some butterflies get some survival benefit from resembling other butterflies that are more toxic than they are.
In following posts we'll look at specific butterfly species. When I was growing up the truth was that nobody knew just how many butterflies, even in North America, had matured from eggs to butterflies. We now have much more information about what the caterpillars eat and look like, but for some species information remains unavailable or unreliable.
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