Mate Choice And Reproductive Biology Of Hypsiboas Albomarginatus (Anura: Hylidae) In The Atlantic Forest, Southeastern Brazil

We studied the reproduction of Hypsiboas albomarginatus in the Atlantic forest on the north coast of São Paulo State, southeast Brazil. Males called from May to February and egg bearing females were registered from August to February. Males began calling after sunset and remained active for up to 8 hours. Hypsiboas albomarginatus exhibits sexual dimorphism in body size, with females being larger and heavier than males. We found a positive correlation between mass of males and females found in amplexus, but not for snoutvent length. This indicates that heavier females choose heavier males than do lighter females. However, the mass ratio of amplectant pairs was not constant; rather, it was inversely correlated with female body mass. This may reflect differences in the choice context between heavier females, which may have difficulty in finding heavier males, and lighter females, which should avoid excessively heavy males. Egg-laying occurred only after calling activity ceased, about 5 to 6 hours after amplexus began. This may prevent clutches from being disturbed by passing frogs, including those of different species. Females swam in circles before egg laying and immediately deposited a long mass of ova that floated on the water surface.