Insects Are Forever; November 1993; Scientific American Magazine; by John Rennie; 2 Page(s)
Anyone who has ever shared an apartment with cockroaches has suspected as much, but now it¿s official: insects almost never go away. After surveying the fossil literature, two researchers have concluded that at the family level, insects have shrugged off catastrophes that exterminated fragile, dainty creatures--such as the dinosaurs. "Because of the low rate of extinction, you have insect lineages that are very long lived, approaching 100 million years in some cases," notes Conrad C. Labandeira, one of the new study¿s authors and a paleoentomologist at the National Museum of Natural History of the Smithsonian Institution. That family durability seems to explain why bugs are so numerous and varied today.
By almost any standard, insects are phenomenally successful. They were the first animals to invade the land and, later, the air. They are the most diverse group, too: by some estimates, about 876,000 insect species have been identified, and entomologists believe a full tally would be in the millions. (By comparison, taxonomists know of only about 4,000 mammal species.) According to Douglas Futuyma, an expert on insect evolution at the State University of New York at Stony Brook, insects¿ success has often been attributed to a presumably exceptional talent for becoming new species. Agricultural scientists know, for example, that insects can readily evolve new traits, such as resistance to pesticides. Some experiments also suggested that specific groups of insects, such as the fruit flies in the Hawaiian Islands, also diverged into separate species very quickly.