Effects of Corridors on Genetics of a Butterfly 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 butterfly
species, Junonia coenia, within a largescale, experimental system.
Using allozyme electrophoresis, a total of nine loci were identified
and scored, six of which exhibited polymorphism. Our data demonstrated
consistently higher levels of expected (He) and observed (Ho)
heterozygosity in butterflies 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
significant 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 flow 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 fitness in butterflies.