Thursday, December 15, 2011

New Natural History: Sex on Six Legs

Sorry. It’s not a book about threesomes. But it’s arguably a lot more interesting than that. Sex on Six Legs: Lessons on Life, Love, and Language from the Insect World by Marlene Zuk is an engaging work of natural history about the sexual and social life of insects. Zuk’s concern is with what we might learn from observations of insect life, both about insects and about ourselves. In the process, she must debunk the common misconceptions about insects that exist in popular culture. She does this ground-clearing with wit, and has produced an entertaining narrative. The insect world tempts us to make popular analogy to the social world of humans, because so much of their behavior seems to mirror our own. At the same time, we are fascinated by insects because some of that behavior is so macabre and alien to our own nature.

It is the apparent sophistication of insect behavior that gives us big-brained animals pause, causing us to wonder about the association between large brains and animal intelligence. Zuk writes, “Insects make us question virtually every assumption we have about what makes us human.” The reason insect behavior tends to look like it is the result of “intelligent” thought is because we give more credence to the visible morphological changes that can be wrought by evolution than behavioral changes that are encoded in genetic modifications. “Natural selection can produce what looks uncannily like intelligent thought or emotion but is no more than the relentless culling of minute variations in genetic makeup, generation after generation.” We have learned through experiment that genetic variations work together to alter behavior in astonishingly complex ways in even the simplest and quickest breeding organisms.

Zuk gives us, as an illustration of her theme, the erroneous popular conclusions that have been drawn from studies that have explored the orchestration of steps in the sexual behavior of the fly Drosophila. When a particular gene is modified in male flies, they tend to exhibit “gay” behavior. News stories have heralded the discovery of a “gay” gene in flies. But it turns out the story is much more complex than that, and that to produce certain kinds of behavior the environment in which modified genes express themselves, an organism’s neurochemical environment (itself a product of other genes and their interactions) must be altered as well. There are no simple conclusions or analogies that can be drawn to human behavior, and yet how the mechanism of sexual attraction, courting behavior and mating works in insects suggests to us that explanations of behavior in humans are going to involve ultimately an understanding of very complex biological phenomena and how they interact with sensory processing to produce behavior. This is but one of the topics Zuk explores concerning the behavior of insects, showing us that our understanding of the insect world can suggest patterns and insight about the way biological processes may work in other animals, but that we need to be cautious about looking for single and simple answers and presenting analogies as either complete or conclusive explanations. This is a book about humans and insects that opens our eyes to the subtle difference between affinity and sameness, and makes insects a subject of interest in their own right.

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