Nesting in the Gladiator Frog, Hypsiboas boans (Anura: Hylidae), in Trinidad and Tobago

Abstract

Nests of the gladiator frog, Hypsiboas boans (Anura: Hylidae), were monitored in a tributary of the Caura River, north Trinidad, during the wet season (July 2013) and during the following dry season (March 2014). Most nests were found at the stream edge, in easy communication with flowing water. Nests were either small basins excavated in gravel/sand with a mat of eggs floating on the surface of the contained shallow pool of water or were in vegetation-bound inlets out of the current, with eggs present but with no evidence of an excavation. Excavated and non-excavated “nests” occurred in similar frequencies. Mean clutch sizes of wet season nests were 1078 + 170 SD (n = 6), whereas those of dry season nests were 1070 + 271 (n = 6). Even when hatchlings could reach the stream easily, they remained in the nest until seven days after oviposition. One excavated nest was more than 2 m from the stream. During the three-week monitoring period, there were no heavy rains, and the larvae remained in the nest with little sign of growth or progressive development. Hypsiboas boans is widely distributed in South America, but these nesting details from Trinidad are different enough from those of South American populations to suggest some local adaptation.