Diversity and community structure of aquatic insects in a pond in Midnapore town, West Bengal, India.

In total 20 species of aquatic insects have been recorded from a weed infested pond. Odonata was numerically the most abundant group constituting of 54% of the total aquatic insects even though these belonged to three species. Coleoptera though constituted only 22% of aquatic insects had 10 species. Urothemis signata and Ranatra filliformes were eudominant and dominant species respectively. Hydrometra butlen is recorded from West Bengal for the first time. Five species of Hemiptera, Ranatra filiformes, Ranatra elongata, Diplonychus rusticus, Micronecta merope, Genis nitida and Hydrometra butlen; three species of Odonata, Urothemis signata, Agriocnemis pygmoea and Enllagma parvum and one species of Coleoptera viz., Coplatus indicus have been recorded from Paschim Medinipore district for the first time. Species diversity and evenness indices fluctuated from month to month and from one sampling site to other being <1 suggest a stressed and disturbed environment.