Picking Up on the Smell of Evolution

Tue, 19 May 2015 15:44:50 -0400

_UA researchers have discovered some of the changes in genes, physiology and behavior that enable a species to drastically change its lifestyle in the course of evolution._ For most of us, switching to a vegetarian diet might be a matter of a New Year's resolution and a fair amount of willpower, but for an entire species, it's a much more involved process — one that evolutionary biologists have struggled to understand for a long time. Researchers at the University of Arizona have taken a peek behind the curtain of evolution to find out what happens when an insect species dramatically changes its way of life. The processes they discovered involve never-seen-before remodeling of genes, behaviors and diet. The results, published in the Proceedings of the National Academy of Science, or PNAS, are likely to make you ponder evolutionary questions next time you find a fruit fly floating in your glass of wine. Herbivorous insect species make up half of all known insect species, but the switch from a non-plant diet to herbivory evolved in only one-third of living insect orders. That discrepancy has puzzled biologists for a long time. "It implies that the transition to herbivory happened rarely, but when it happened, it turned out to be a major push for speciation spawning the evolution of a disproportionate number of species in that group," said Benjamin Goldman-Huertas, a fifth-year doctoral candidate and National Science Foundation graduate research fellow in the UA's Department of Ecology and Evolutionary Biology, and the lead author of the paper. One of the possible answers is that plants are very difficult to colonize, said Noah Whiteman, an assistant professor of ecology and evolutionary biology and senior author of the study. To ward off their predators, plants have evolved an arsenal of defenses, such as spines, tough outer "skin" or compounds that render their tissues indigestible, unpalatable or even fatally toxic to insects attempting to feed on them... _Read full article >>._