Does a Frog Change its Diet along a Successional Forest Gradient? The Case of the Shovel-Nosed Treefrog (Diaglena spatulata) in a Tropical Dry Forest in Western Mexico

Biologists have increasingly recognized the importance of secondary forests as facilitators of passive landscape restoration and recovery of faunal communities in landscapes fragmented by farming. To evaluate the role of secondary forests as providers of food resources for anurans, we studied the diet of the Shovel-Nosed Treefrog (Diaglena spatulata) from five vegetation stages of tropical dry forest (pasture, early forest, young forest, intermediate forest, and old-growth forest) on the coast of Jalisco, Mexico. We examined the stomach content of 97 individuals using a stomach-flushing method. We found 14 different types of prey (Class or Order) in the frog's diet. Araneae, Lepidoptera, and Orthoptera occurred in frogs from all five vegetation stages. We recorded the highest number of prey types (11) in the young and intermediate forest stages, and the highest prey volume and prey frequency in stomachs from frogs inhabiting the old-growth forest. We found no difference in size or body condition of frogs among vegetation stages, but there was a positive relation between size and body condition with the volume of stomach content. Our results suggest that D. spatulata presents high dietary plasticity and that secondary stages of dry tropical forest contribute to the persistence of this species in human-modified landscapes.