Ants Rise With Temperature

Mar. 21, 2013 — Warm nights might be more important than hot days in determining how species respond to climate change. "Rising minimum temperatures may be the best way to predict how climate change will affect an ecosystem," said Robert Warren, assistant professor of biology at SUNY Buffalo State. "Cold extremes that once limited warm-adapted species will disappear in a warming global climate."

Global Change Biology published a study conducted by Warren with Ph.D. candidate Lacy Chick of the University of Tennessee-Knoxville. The study shows that the lowest- -- not the highest--temperatures are critical in determining the migration of warmth-loving ants, Aphaenogaster rudis, to higher elevations.

As they migrate, A. rudis--a reddish ant with light-colored legs -- displace Aphaenogaster picea, a dark ant with dark legs. A. picea thrive at temperatures about 2ºC colder than A. rudis can tolerate. Aphaenogaster ants are the dominant woodland seed dispersers in eastern forests. "So it's possible that the displacement of A. picea may affect the spread of seeds produced by early spring ephemerals," said Warren.

By comparing data collected in 1974 to current data, Warren and his team were able to compare the percentage of A. rudis and A. picea at different elevations in the Southern Appalachian Mountains in Georgia. In 1974, A. rudis accounted for less than 60 percent of the two species at 500 meters and less than 20 percent at 700 meters. At 900 meters (nearly 3,000 feet), A. rudis were almost nonexistent.

Continued:  http://www.sciencedaily.com/releases/2013/03/130321081505.htm