Dr. Sarah Farris, assistant professor in the Department of Biology in the Eberly College of Arts and Sciences at West Virginia University, had her paper,Coevolution of generalist feeding ecologies and gyrencephalic mushroom bodies in insects,published in the Nov. 29 edition of the Proceedings of the National Academy of Sciences (PNAS), the scientific journal of the NAS .

The paper studied the”mushroom bodies”of the insect brain, which are named for their shape, and which have the function of sensory integration, learning and memory. The study focused primarily on species of scarab beetles, which may have either large or small mushroom bodies. Measurements of the two types of mushroom bodies showed that, similar to the mammalian cerebral cortex, larger mushroom bodies are folded, or”gyrencephalic,”resulting in a greater surface area and volume for the structure.

Large mushroom bodies were found only in beetles that feed on a wide variety of foods (generalists), while those which feed on a few specific foods (specialists) have much smaller and smoother mushroom bodies.

Farris hypothesized from these data that the behavioral requirements for a more generalized diet drove the evolution of large mushroom bodies in these species. The generalists needed to be able to detect more types of food by identifying and integrating many sensory signals, to learn whether the foods would be edible, and to remember this information for future encounters.

The specialists, however, need only a few signals to identify their appropriate food, as they do not need to differentiate between many different possible foods. This lifestyle would not be expected to require the evolution of large mushroom bodies.

Dr. Farris co-authored the paper with Nathan Roberts, formerly an undergraduate student from Washington and Jefferson College, who was working on a summer research fellowship.

Established in 1914, PNAS is one of the world’s most-cited multidisciplinary scientific serials. Coverage in PNAS includes research reports, commentaries, reviews, perspectives, and colloquium papers that span the biological, physical, and social sciences, as well as the actions of the academy. PNAS is published weekly in print, and daily online in PNAS Early Edition at http://www.pnas.org .

For more information please contact Dr. Farris at Sarah.Farris@mail.wvu.edu .