Predation Potential of Some Aquatic Insects (Pantala, Coenagrion, Tropisternus, Notonecta and Sigara) on Common Carp Fry

Abstract

This study deals with the predation potential of aquatic insects from five genera, upon the fry of common carp, Cyprinus carpio. The fry ranged in size from 7-19 mm. Aquatic insects from five genera were divided by size into three classes. Pantala (Libellulidae). Coenaarion (Coenagrionidae) and Notonecta (Notonectidae) increased their predation potential as they increased their length. as opposed to Tropisternus (Hidrophilidae), which ate more fry when smaller. The largest insects ate very few small fry but ate larger fry that were longer than their own body length. Pantala was the most effective fry predator, eating an average of 1.64 fry per day, followed by Notonecta (1.5), Coenagrion (0.43), and Tropisternus larvae (0.35 fry/day). Sigara were not predators and did not eat any fry; The insect size/fry size interaction proved to be directly proportional for all insects; that is, the larger the insect, the larger the fry it could capture.