Influence Of Abiotic And Biotic Factors On The Population Dynamics Of Diplonychus Indicus Venk.&Rao (Hemiptera: Belostomatidae) A Potent Biocontrol Agent For Mosquito Larva

Study of aquatic insect population has assumed importance in the context of pollution to water bodies and the potentialities of many aquatic bugs in controlling vector population especially Culex mosquitoes. The population dynamics of Diplonychus indicus was studied in a perennial pond in Kanyakumari district, Tamil Nadu, Southern India for a period of eleven months from February 2018 to December 2018. The study yielded eleven aquatic species, viz ., Agriocnemis species, Anisops bouvieri , Culex species, Diplonychus indicus , Dytiscus marginalis , Gerris spinolae , Laccotrephes griseus , Lethocerus indicus , Limnogonus nitidus , Mesogomphus lineatus and Ranatra filiformis . Abiotic factors like dissolved oxygen, pH, air and water temperature, relative humidity and rainfall were recorded. Cor- relation between the abiotic factors and Diplonychus indicus nymphs and adults showed positive correlation except for temperature. Cor- relation between the nymphal population and adults of Diplonychus indicus and all the coexisting insects exhibited a perfect positive cor- relation and between Culex larvae and Diplonychus indicus it was +0.6797. Further, field value ratios of Diplonychus indicus and biotic factors especially with Culex during the south west monsoon indicated the fact that Culex larval population was under control.