Differences in Endohelmith Parasite Infection Between Male Morphotypes of Bluegill Sunfish ( Lepomis macrochirus)

Bluegill sunfish ( Lepomis macrochirus) are an important North American sport fish distributed across the United States and Canada. These fish are sexually dimorphic, with males being larger and more brightly colored than females. Additionally, there are 2 male morphotypes, dominant, brightly colored α-males, and β-males, which resemble females in both appearance and behavior. The 2 male morphotypes differ significantly in terms of mating behavior, territoriality, and diet. These behavioral and feeding differences may result in α-males harboring greater parasite diversity and parasite loads compared to β-males. This was tested by collecting, necropsying, and identifying parasites from 636 L. macrochirus sampled from 9 ponds in northwest Virginia and comparing parasite species richness and parasite load in the male morphotypes. The parasite infracommunities infecting the male morphotypes differed significantly between them at 7 of the 9 sample sites. When compared to β-males, α-males consistently had greater parasite species richness as well as greater abundance for a majority of both trophically and non-trophically transmitted parasite species sampled in this study. The separation of male morphotypes must be accounted for in studies of L. macrochirus parasites due to sex bias differences between males and females being masked when male morphotypes are combined.