Dietary niche overlap in sympatric asexual and sexual livebearing fishes Poecilia spp.

The present study investigated the spatiotemporal patterns in trophic resource use in a system of a gynogenetic poeciliid fish, the Amazon molly Poecilia formosa, and its sexual congeners the sailfin molly Poecilia latipinna and the Atlantic molly Poecilia mexicana using gut contents analysis. No statistically significant differences in trophic resource use were found between sexual and gynogenetic species, but gut contents varied significantly across sites and over time. In addition, variation in trophic morphology (i.e. gut length) was significant across sites but not species, and laboratory experiments indicated that gut length is phenotypically plastic. Overall, trophic differentiation between coexisting asexual and sexual Poecilia appears to be minimal, and it is unlikely that niche differentiation contributes to a stable coexistence of the two reproductive forms.