Selection of tadpole deposition sites by male Trinidadian stream frogs, Mannophryne trinitatis (Dendrobatidae): An example of anti-predator behaviour

Trinidad's only dendrobatid frog, Mannophryne (=Colostethus) trinitatis, li ves by the small streams draining the slopes of the Northern Range mountain s and at Tamana Hill in the Central Range. Adults are often very abundant, but tadpoles are found patchily in the streams. In the absence of two poten tial predators - the fish Rivulus hartii and shrimps of the genus Macrobrac hium - tadpoles are abundant in pools. Where the predators are present, tad poles are uncommon or absent. Tadpoles may also be found in small, isolated bodies of water at some distance from streams. Males carrying tadpoles ret ained them for 3-4 days, in the absence of suitable pools. When presented w ith a choice of pools, males preferred to deposit their tadpoles in pools l acking predators. There were differences in behaviour between males from th e northern and southern slopes of the Northern Range. For example, north co ast males deposited tadpoles in pools containing other conspecific tadpoles in preference to empty pools, whereas males from southern slopes made the opposite choice. When presented only with pools containing predators (i.e. shrimps or fish), north coast males shed their tadpoles in damp leaf litter rather than in the pools, while males from the southern slopes deposited t adpoles in pools with shrimps predators uncommon in the southern slopes str eams. The results indicate that male frogs spend some time searching for pr edator-free pools in which to deposit their tadpoles. These results are dis cussed in the context of other examples of anti-predator reproductive behav iour in frogs, and of life history evolution under the influence of differe nt selective pressures.