Predator morphology affects prey consumption: evidence from an anuran population in subtropical wetlands

Morphology and diet are key factors in the ecology of organisms, determining aspects of natural history and evolution of the species. In this work, we evaluated the diet-morphology relationship in an anuran population, measuring the influence of morphological traits on the variation in the diet of individuals of Leptodactylus latrans. For this purpose, we collected individuals from a natural grassland habitat in southern Brazil. We analyzed the stomach content of individuals and consumed food items were classified up to the level of order. We also measured four morphological traits per individual of L. latrans: snout-vent length, relative limb length, distance between eyes and relative mouth width. We applied Linear Mixed Effect Models to evaluate the relationship of anuran morphological traits, number of prey taxa and volume of consumed prey. We tested the hypothesis that the configuration of predator morphological traits determines both the number of taxa and the volume of consumed prey. Our results indicate that individuals of L. latrans with larger body size consume a larger volume of prey and mouth width is directly and positively associated with the number of consumed taxa. In the same way that body size seems to define the capacity to ingest a large number of prey items, mouth width could be a limiting factor in prey selection. The capacity to consume a large prey volume could be an advantage in unpredictable environments, especially those with great daily thermal amplitudes such as the subtropical Brazilian grasslands.