The ecology and population genetics of an alpine checkerspot butterfly, Euphydryas anicia.

The population structure, ecology and genetics of alpine and subalpine populations of Euphydryas anicia were investigated in Gunnison County, Colorado. Distances moved by individuals between recapture events at Cumberland Pass, elevation 3700 m, averaged less than 100 meters, but were greater than for most Euphydryas populations and other alpine Euphydryas populations in particular. Individuals often moved long distances, in patterns reminiscent of Euphydryas chalcedona populations and the more vagile populations of E. editha. The population size of 50,000 to 100,000 individuals was the largest encountered in nineteen years of studying dozens of Euphydryas populations. Gene frequencies at nine allozyme loci were determined for the population in 1974 through 1977, and in other Colorado E. anicia populations in several of those years. Although large population sizes make drift unlikely, genetic differences were detected between samples taken in different years. Genetic differences were also detected between this and other alpine E. anicia populations, although there is some indication that E. anicia shows less genetic differentiation than E. editha or E. chalcedona.