National Geographic : 2010 Sep
ride on the backs of ies. ey are as colorful as stones, shaded in turquoises, slates, and ambers. Spines are common, as are spots, helices, and stripes. More than biology, their designs sug- gest the work of an artist le to obsess among tiny forms. ey are natural selection's trillion masterpieces; inside each is an animal waiting for some cue to break free. e basic workings of insect eggs, however, like the basics of any egg, are recognizable. e egg develops its shell while still inside the moth- er. ere the sperm must nd and swim through an opening at one end of the egg, the micropyle. Sperm wait inside the mother for this chance, sometimes for years. One successful sperm, wea- ried but victorious, fertilizes each egg, and this union produces the undi erentiated beginnings of an animal nestled inside a womblike mem- brane. Here eyes, antennae, mouth parts, and all the rest form. As they do, the creature respires using the egg's aeropyles, through which oxygen di uses in and carbon dioxide out. at all of this occurs in a structure typically no larger than a grain of raw sugar is simultaneously beyond belief and ordinary. is is, a er all, the way in which most animals ever to have lived on Earth had their start. What you see on these pages are the eggs of a few small branches of the insect tree of life. Among them are those of some butter- ies that face extraordinary travails to defend themselves against predators and, sometimes, against plants on which they are laid. Some passion owers transform parts of their leaves into shapes that resemble butter y eggs; mother butter ies, seeing the "eggs," move on to other plants to deposit their babies. Such mimics are imperfect, but fortunately so is butter y vision. Eggs must also somehow escape having the eggs of another type of insect, parasitoids, laid inside of them. Parasitoid wasps and ies use their long ovipositors to thrust their eggs into the eggs and bodies of other insects. Roughly 10 percent of all insect species are parasitoids. It is a well-rewarded lifestyle, punished only by the existence of hyperparasitoids, which lay their eggs inside the bodies of parasitoids while they are inside the bodies or eggs of their own hosts. Many butter y eggs and caterpillars eventually turn into wasps as a consequence of this theater of life. Even the dead and preserved eggs shown here are likely to hold mysteries. Inside some are young butter ies, but inside others may be wasps or ies that have already eaten their rst supper and, of course, their last. Every so o en, and against all odds, a group of insects has regressed a little and decided to care more actively for its young. Here and there we see the evidence. Dung beetles roll dung balls for their babies. Carrion beetles roll bodies. And then there are the roaches, some of which carry their newborn nymphs on their backs. e eggs of these insects have become featureless and round again, like lizard eggs, and in so doing also become more vulnerable and in need of care, like our own young. Yet they sur- vive. Perhaps they are the vanguard of what will come next, the next kingdom beginning to rise. ough perhaps not. Recently I watched a dung beetle rolling a ball, and the ball looked like a rising sun. Above that beetle was a y trying to lay an egg inside the beetle's head. Insects have been cracking out of eggs for hundreds of millions of years. It is happening now, all around you. If you listen, you can almost hear the crumbling of the shells as tiny feet, six at a time, push into the world. j Rob Dunn and Martin Oeggerli worked together on the story about pollen in the December 2009 issue.