If you pick up a copy of Marlene Zuk's brilliant, brilliantly titled SEX ON SIX LEGS expecting to find a Nature Channel-friendly book about the wonders or dreadfulness of the insect world, you might be a little bit disappointed.
Sure, the book is filled with stories that seem alternately torn from a Disney script and a horror movie. Zuk writes of parasitic wasps who lay their eggs on caterpillars, producing larva that consume their hosts. She discusses ant species that "enslave" the ants from other colonies, kidnapping them and making them feed their workers and care for their queen. More towards the Disney range of the spectrum, Zuk tells the wholesome tale of parent cockroaches, who sometimes remain together as a kind of family after mating, with both the mother and father cooperating to raise their young and the mothers feeding their offspring with milk-like secretions.
But Zuk's real topic seems to be what the sex behavior of insects can teach humans about themselves. Those same parasitic wasps can shed fascinating light on why an equal number of human girls and boys are produced year to year, for example. If a wasp has more food (caterpillars and maggots) to herself, she'll produce more female eggs, since her female offspring will have plenty to eat and will only need a few of their own brothers to fertilize their own eggs. (Incest is not a grave concern to wasps). But when there is more competition for food, the mother wasp will produce more males, so they can have a chance at fertilizing competing mothers' offspring. That simple discovery led to similar studies on humans; and in 2008, a British study showed that women who were under-nourished produced more baby girls. This might seem counter-intuitive to the lesson of the wasps, but not when you consider that the ultimate goal of reproduction for both people and insects is to ensure the perpetuation of their genes. Hence, even smaller, less healthy females were preferable to less healthy males because females are more likely to find a mate and reproduce. For mothers who had nutritious diets, however, males were preferable since there was a greater chance of them fertilizing many females over the course of their lives.
Zuk goes further than this, and shows how, in the future, insects could potentially be used to enhance the lives of humans. If bees can be taught to count, as they can be, it's possible that they can help us understand and help humans with learning disabilities. If a neurochemical abnormality in "amnesiac" fruit flies affects their memories, then there's hope that the same neurochemical in humans could be targeted to affectively treat our own memory disorders. Zuk calmly presents the potential benefits of research with insects, and just as calmly reveals how surprising she finds it that this research is so under-funded.
As fascinating as insects are, it's hard to get over the ick factor, of course. While reading the book, you may find yourself wondering, as I did, why a scientist who seeks to show what living creatures can teach us (and not teach us) about ourselves, would choose insects as a calling instead of cuddlier monkeys and guinea pigs? Zuk provides many answers to that one. Insects aren't cuddly, for one thing. Insects don't have facial expressions we can identify with, and there's little chance we can anthropomorphize them and risk polluting the lessons they hold for us with human-specific concepts like emotion, or love, or sexual attraction. Insects are ubiquitous, for another. There are insects in slums and in high-rise apartments. There are millions of species of them, all evolving relatively rapidly because of their short lives. Their sheer numbers provide almost unlimited data to study. They can behave in surprisingly complex ways, from nurturing their offspring to showing other insects where the food is, from goofing off to turning their food sources into zombies with a sting to the brain. But they don't need our big human brains to do all of this. Insects force us to question our own feelings of superiority and uniqueness as a species. If a humble bee, with a nervous system the size of a speck, can speak, learn and teach, it forces us to ask ourselves: what makes us so special?
As Zuk herself writes: insects "make us see that our way of life is not the only one -- and I don't mean that we could be eating dung instead of cheeseburgers. I mean that it is possible to be unselfish without a moral code, sophisticated with an education, and beautiful wearing a skeleton on the outside."
Zuk's tone itself is fascinating. Sometimes she reads like a goofy, insect-loving version of famed bird-watching cheerleader Scott Weidensaul. Sometimes, her writing can be as snarky, pointed, and fun as the environmental essays of writer Joy Williams. She really loves crickets -- no, I mean, really loves them. Earwigs too. She charmingly recalls going to a conference in Hawaii with her husband, but arriving a week early to look for crickets and dissect them to examine them for parasites. As entertainment. "I now wonder," she writes, "just why this seemed to be the inevitable, or at least the best, option as a recreational activity, but regardless..."
I found her enthusiasm incredibly contagious. As icky as I personally find insects, I can now look at them and think that at least someone gets them. And, from a distance, I root Zuk on.