Geographic variation in life-history traits of the ant lion, Myrmeleon immaculatus : Evolutionary implications of Bergmann's rule

摘要: In eastern North America, body size of the larval ant lion Myrmeleon immaculatus increases from south to north, following Bergmann's rule. We used a common-garden experiment and reciprocal-transplant evaluate effects food temperature on growth, size, survivorship. laboratory experiment, first-instar larvae two southern (Georgia, South Carolina) northern (Connecticut, Rhode Island) populations were reared in incubators under high- low-food low-temperature regimes. For all populations, high increased final mass growth rate decreased development time. Growth rates higher at low temperatures, but did not affect or adult mass. Survivorship was highest high-food treatments. Across treatments, exhibited larger mass, shorter time, faster rate, greater survivorship than populations. Results similar for field third-instar between Connecticut Oklahoma: grew Oklahoma larvae, regardless transplant site. Conversely, transplanted Connecticut, population source. These results suggest that variation availability, temperature, may account differences lions. Although reached both experiments, environments should suppress because reduced availability limited growing season. This study provides first example countergradient selection causing rule an ectotherm.