We don't generally like insects much, remembering how they sting, sicken, or impoverish us, and forgetting that they do us invaluable service in the reproduction of new generations of countless plant species. We do like butterflies because they are so beautiful and harmless, but we do not like caterpillars because they are squirmy and eat our plants. There are countless books featuring pictures of beautiful butterflies and moths, but few featuring the larval forms of the insect. A look at _100 Caterpillars: Portraits from the Tropical Forests of Costa Rica_ (The Belknap Press of Harvard University Press) by Jeffrey C. Miller, Daniel H. Janzen, and Winifred Hallwachs shows that the emphasis on the flying forms may be misplaced. The gorgeous, large-format pictures here show all the colors of which adult butterflies can boast, plus an enormous variation in patterns, spikes, hairs, body plans, and more. Indeed, after the hundred photographs, there is a section of the book devoted to detailed descriptions of the behavior and ecology of each caterpillar, and for each there is a small picture of the adult into which it will grow. Almost all the adults are more drab and less interesting than their larvae.
Caterpillars exist to perform two duties, eating and avoiding being eaten. The pictures seldom show the caterpillars feeding, but frequently show the defensive structures that keep others from feeding upon them. There are many caterpillars here with hairs or "urticating spines", filled with an irritant that can cause sharp pain. So watch out for the spines, although you never have to worry about a bite; caterpillars never evolved a venomous bite, so you can let even the spined ones walk over you. The wonderful _Acraga hamata_ looks as if it is covered in a mosaic of transparent glass beads; this is gelatinous material that breaks away if the caterpillar is grabbed. Several of the specimens here are hard to see because they look just like a torn leaf or a branch or a mat of fungus. For mimicry, there is nothing to beat _Hemeroplanes triptolemus_, an undistinguished drab green caterpillar when at rest. When disturbed, however, it raises and inflates its hind end, which takes on the appearance of a viper's head, complete with eyes, mouth, and nose spots. It holds still in this position, but if further provoked, can even make the viper's head strike at the offending predator, although there is no threat of a bite. The authors say that even if you know that, it is hard to keep from withdrawing your hand in shock if you are performing the experiment yourself.
This beautiful book includes pictures of the "Area de Conservación Guanacaste", the World Heritage Site that contains the forest from which these specimens come, and also pictures of the locals who work as collectors, and the barn where bags of specimen caterpillars feed and develop. There are also descriptions of the equipment used to make these spectacular photos, and recommendations for how others can do the same. The authors include a commendable section about ethics concerning the handling of the little creatures that they obviously admire and love: you must not anesthetize or chill the caterpillar as a means to force quiescence, and you must not tease the caterpillar excessively: "it will respond negatively, either by curling up for hours on end, fainting and falling off the prop, breaking into a running bout, or worse, spitting up gut contents." Words to live by.
