tailieunhanh - Biological control of vector mosquitoes by some common exotic fish predators

Predation experiments using Cyprinus carpio Linnaeus (1758), Ctenopharyngodon idella (Valenciennes 1844), Oreochromis niloticus niloticus (Linnaeus 1758) and Clarias gariepinus (Burchell 1822) were conducted against fourth instar Anopheles stephensi Liston (1901) larvae and pupae at varying prey and predator densities. | Turk J Biol 29 (2005) 167-171 © TÜB‹TAK Biological Control of Vector Mosquitoes by Some Common Exotic Fish Predators Anupam GHOSH, Samir MANDAL, Indranil BHATTACHARJEE, Goutam CHANDRA Mosquito Research Unit, Department of Zoology, Burdwan University, West Bengal - INDIA Received: Abstract: Predation experiments using Cyprinus carpio Linnaeus (1758), Ctenopharyngodon idella (Valenciennes 1844), Oreochromis niloticus niloticus (Linnaeus 1758) and Clarias gariepinus (Burchell 1822) were conducted against fourth instar Anopheles stephensi Liston (1901) larvae and pupae at varying prey and predator densities. The relative prey consumption rates of the four fish species for An. stephensi larvae and pupae during 24-hour experiments under laboratory conditions were C. gariepinus > C. idella > C. carpio > O. n. niloticus. Predatory efficacy was positively related with prey density and inversely related with water volume (search area). A significant decrease in larval abundance in dipper samples was observed at 30 and 45 days after introduction of fishes (30 individuals each) in field conditions. The efficacy of the fish under field conditions was also indicated by significant increases of larval mosquito abundance at 30 and 45 days after removal of fishes. Key Words: Biological control, larvivorous fish, Anopheles stephensi, immature mosquitoes Introduction Biological control is defined as the action of predators, parasites (parasitoids) or pathogens in maintaining the density of another organism at a lower average than would occur in their absence. Biological control of vectors is an essential and effective means for controlling transmission of several mosquito-borne diseases such as malaria, filariasis, JE, dengue fever, etc. Modern researchers are inclined to use biocontrol agents rather than chemical insecticides due to the residual effects of chemical insecticides, widespread resistance in target insects, high refusal rate for indoor spray, soaring .