Bugs eat like humans, UA entomologists say

Arizona Daily Wildcat Photo courtesy of UA Regents professor Elizabeth Bernays Winged, wing-less and baby aphids, shown here, are clinging to a ragweed plant. Aphids are insects that lower their beaks to receive nourishment from plants and flowers.

Elizabeth Bernays, a University of Arizona Regents professor emeritus in entomology, and Daniel Funk, post-doctoral associate for Arizona's Center of Insect Science, discovered why insects specialize - eating one kind of plant so they don't have to make several different choices.

Bernays compares "specialists" to humans who would rather eat one type of food than become distracted by too many options. The two scientists believe the brain has a harder time making decisions when there are several choices.

"We think it is easier to pay attention to one thing than to make many choices," Bernays said.

Generalists, however, munch on a variety of plants and are not picky eaters.

"Specialists should be more efficient at finding its food then generalists," Bernays said.

The scientists took aphids - "sap-sucking bugs" that have small, beak-like mouths to pierce plants - and "wired them up and noticed what they did inside the plant electronically," Bernays said.

The research examined how quickly the insects find plants and lower their beaks to suck them dry.

Funk and Bernays tested aphids that feed on ragweed plants from the east and southwest United States, she said.

Afterwards, they evaluated how efficiently the eastern aphids use the ragweed compared to the western plants, Bernays said.

"Lots of insects feed on plants...almost all insects eat a small amount of plants," Funk said.

The aphid study results were printed in the Proceedings of the Royal Society of London.

"The most exciting was how consistent (the results) were," Funk said. "We got the same the same results - that was significant."

Bernays is also a professor in ecology and evolutionary biology. She plans to do similar experiments on moths.