Implication of predation incidences by ant species on green turtle nests in Chagar Hutang, Readang Island

Abstract

In Chagar Hutang, Redang Island, Dorylus laevigatus and Pheidologeton affinis were the dominant predatory ant species of the green turtle nests, and it was hypothesized that they were competitors to each other. Both species consisted of polymorphic workers, and conducted mass raiding upon turtle nests. As a result of the observation of foraging behavior of ant species in 2004 by using food traps, D. laevigatus (a subterranean species) shared the bait with some terrestrial ant species in the early stage of the experiment except P. affinis. However, P. affinis was a terrestrial species and established satellite nests in the traps to occupy the bait. Traps placed in the habitat of Anoplolepis gracilipes were immediately occupied by them during whole experimental period and other terrestrial ant species were not found in the traps. Anoplolepis gracilipes seemed to be the strongest competitor among the terrestrial ant species in Chagar Hutang, which might result in reduction of the population number of P. affinis with the existence of A. gracilipes. As a result, D. laevigatus became a major predator upon turtle nests, which might have caused the high rate of predation incidences in this area in 2004. The elimination of A. gracilipes may reduce predation incidences upon turtle nests by D. laevigatus.