31 March 1999
Don't Bug The Babies
Good insect moms ferociously protect their young by fanning their wings and charging predators--but only when they must pin all their hopes on a single batch of eggs, a University of Delaware scientist reports in the new issue of the journal, Animal Behaviour.
Bug moms who lay multiple batches are far more likely to hide their young, thereby avoiding guard duty, and often "turn tail and run" from egg-munching predators, says Douglas W. Tallamy, whose latest study is expected to reach journal subscribers this week.
His theory, in print for the first time, may better explain why the vast majority of insects shun parental responsibilities, while a few fight to the death to safeguard their young. Because "semelparous" insects lay a single clutch, they staunchly defend their only shot at a genetic legacy, he says.
"Today's human moms are carrying on a long and noble tradition!" says Tallamy, a professor of entomology and applied ecology. "We tend to mistakenly think we're the pinnacle of evolution, and lowly insects couldn't possibly be capable of parenting.
In fact, mothering is an ancient trait, which originated in early invertebrates, then persisted in insects when they evolved."
Tallamy cautions against explaining different human mothering styles by pointing to insect behaviors. Unlike insects, he says, people are influenced by cultural and societal factors, and their behaviors are far more complex. "It would be silly to say, `Oh, this explains why So-and-So is so protective of her only daughter.' Insects and people are completely different in that regard."
But, learning why some insects show strong maternal instincts, while most immediately abandon their eggs, "should help us appreciate this amazing process of biological evolution, and the importance of parental care," says Tallamy, whose co-author was UD graduate student William P. Brown.