Biodiversity of entomofauna in part in cotton field in and around nanguneri taluk tirunelveli district tamil nadu south india

Abstract

Cotton is a major fibre crop of global importance and India has emerged as the second newlinelargest producer of cotton. Tamil Nadu is one among the major states that grows cotton in newlineIndia. Being commercially important, cultivation of cotton is taken up by even small farmers newlineand further natural growth of cotton can be taken up during hot or dry weather. In the present newlinestudy, entomofaunistic survey of the cotton agroecosystems of Nanguneri taluk of newlineTirunelveli district was undertaken with a view to identify the insect diversity during the newlinegrowth stages of cotton plant. newlineField survey conducted in Kunthankulam, Moolaikaraipatti and Chinthamani of newlineNanguneri taluk from February 2015 to September 2015 and February 2016 to September newline2016 revealed a total insect population of 28439 and 17368 respectively representing 10 newlineinsect orders, 68 families, 123 genera, 148 species of insects. Order Hemiptera recorded newlinehighest percentage (71%), followed by order Hymenoptera (17%) and order Coleoptera (5%). newlineSpecies Richness is high in the months of July and August due to flowering and fruiting newlineseasons of the cotton plants. Abundance of insects in these months are mainly due to insects newlinebelonging to order Hemiptera. However the alpha diversity do not change much. newlineSince weather parameters such as temperature rainfall and humidity play a role in the newlinedistribution of insects they were considered for the present survey. Eventhough not much newlinevariation was recorded with regard to temperature, rainfall was high during 2015 (52.1mm) newlinethan 2016 (2.3mm). This drastic difference had influenced the insect population and newlinediversity. newlineFrom the cluster analysis the population structure could be considered homogeneous newlinebelow a Bray-Curtis similarity of 50%. Cluster analysis revealed three distinct clusters above newline50% indicating homogeneity. newline