Partial trophic segregation in co-occurring Gambusia species (Cyprinodontiformes: Poeciliidae) in a natural wetland of Cuba/ Segregación trófica parcial entre especies de Gambusia (Cyprinodontiformes: Poeciliidae) en un humedal natural de Cuba

Gambusia punctata and Gambusia puncticulata show a distinctive distribution pattern in Cuba: G. punctata dominates mountain streams, whereas G. puncticulata is more abundant in lowland wetlands. Nevertheless, there are some transition zones along few freshwater basins in which these species co-exist in similar abundance. Recent studies in wild populations revealed similar use of food resources for both G. punctata and G. puncticulata. However, little is known about possible evolutionary mechanisms in the feeding strategies of these species allowing them to co-exist. We assessed the diet composition, feeding strategy, niche width, and dietary overlap between species and between sexes of these two Gambusia species in a natural wetland of Cuba. Our results showed partial segregation in the consumption of available resources between G. punctata and G. puncticulata. Such incomplete trophic niche segregation may be facilitated by their generalist trophic niche and their specific feeding strategies. G. punctata showed a generalist strategy, given that several individuals shared a high number of food items. Whereas, G. puncticulata showed a specialist strategy explained by the variation amongst individual feeding on different food items. The wide spectra of consumed food items could explain the low trophic segregation found between sexes of both species. Sex-specific reproductive roles known for this fish family, seem not to induce differences in the diet between male and female individuals of G. punctata and G. puncticulata.