Frogs as potential biological control agents in the rice fields of Chitwan, Nepal

Anuran frogs are often considered generalist predators in rice fields and feed upon a variety of invertebrates. They may thus provide an invaluable ecosystem service, as many species belonging to the orders coleoptera, lepidoptera, orthoptera, homoptera and hemiptera are regarded as notorious rice pests, inflicting significant losses on rice production. In this study, we surveyed frogs in rice paddies of lowland Nepal during the dry and rainy seasons, approximately 3-4 weeks after rice had been planted. We used stomach flushing to study the dietary habits of anuran species encountered, and provide empirical evidence of the ecological service provided by frogs in this agricultural landscape. We found that frogs included a high proportion of crop pests in their diet, but consumption of pests varied between the rainy and dry seasons, frog species and even individual frogs. The ecosystem services provided by frogs are not limited to crop pest control, but, as our observations revealed, include consumption of a large number insects known to be important vectors of zoonotic diseases. We encourage both farmers and conservation planners to consider frogs as important biological pest controllers during the development of pest management and strategies in agricultural landscapes.