Mosquito Prey Vulnerability in Intraguild Predation Between Ranatra filiformis and Anisops bouvieri: Implications in Biological Control

Abstract

Wetlands are common habitats of a range of predatory water bugs (Heteroptera) constituting a guild that exhibit similar dietary choice including mosquito. Differences in body size and micro habitat preference among the heteropteran guild members provide a fair possibility of intraguild predation that can influence the regulatory effect on the prey species. This proposition was tested under laboratory conditions, using varying density of Ranatra filiformis (IG predator) and Anisops bouvieri (IG prey) as predators against mosquito larvae as shared prey. Compared to single predator system, mosquito larvae were proportionately less vulnerable to predation in intraguild predation (IGP), at low density of shared prey. In IGP system, vulnerability of shared prey increased with increase in density accompanied by a decline in mortality of IG prey. The mean mortality of shared prey and IG prey increased with the density of IG predator. It was apparent that the mosquito prey vulnerability was enhanced with increase in density of mosquito and R. filiformis while reducing the mortality of A. bouvieri partly. The interaction between R. filiformis and A. bouvieri as a part of IGP system indicate about the possible mechanism of coexistence of predators and prey in the wetlands. The density dependent effects on reduction and enhancement of shared prey (mosquito) mortality indicate that appropriate ratio of R. filiformis, A. bouvieri and mosquito larvae will be required to make biological regulation of wetland mosquitoes feasible.