Effects of Corridors on Genetics of a Butterfl y in a Landscape Experiment

To investigate the possible role of landscape connectivity on the genetic structure of isolated populations, we examined the effects of habitat corridors on the population genetics of a vagile butterfl y species, Junonia coenia, within a largescale, experimental system. Using allozyme electrophoresis, a total of nine loci were identifi ed and scored, six of which exhibited polymorphism. Our data demonstrated consistently higher levels of expected (He) and observed (Ho) heterozygosity in butterfl ies sampled from patches connected by corridors compared to unconnected patches. A t-test comparing He and Ho in connected versus unconnected patches found a marginally signifi cant difference in one locus, the glycolytic enzyme phosphoglucose isomerase (PGI). Connected patches exhibited overall lower FST values compared to unconnected patches, indicating potentially increased levels of gene fl ow due to corridors. Our results support previous investigations on dispersal and population size for J. coenia, and show that higher dispersal through corridors promotes genetic variability at a locus (PGI) implicated in dispersal and fi tness in butterfl ies.