Serajuddin et al /Research Journal of Life Sciences (May- 2013), Vol.01, Issue 02, pp.21-24 ISSN 2052-5176 Available online at www.worldscience.co.uk 21 Predatory Insects of various Fish ponds Detrimental to Polyculture: A Survey Ankur Kashyap 1 , Manjula Gupta 2 and M. Serajuddin 1* 1 Department of Zoology, University of Lucknow, Lucknow-226007 2 Dr. K. C. Baghel Govt. P. G. College, Bhilai-3, Durg, Chattisgarh *Email: lu.fisheries@gmail.com Abstract Several inland water bodies particularly fish farms in the northern and central states of India were surveyed for studying the species compositions and distribution of predatory aquatic insect fauna detrimental to polyculture. It was observed that the depth of the water affects the aquatic insects directly or indirectly. The insects were seldom found in greater depth. Mostly insects were collected from the surface and upper part of the water bodies. The insects were found to be more abundant in comparatively shallow water bodies. Aquatic insects recorded in various types of fish ponds such as nursery, rearing and stocking were considered to be harmful for planktivorous fish used in polyculture in general and particularly their larval stages such as spawn, fry and fingerlings. Nursery ponds designed to rear spawn of major carps were found to be invariably populated with large number of aquatic insects over greater part of year and especially during and after rains. They do not comprise a systematic group but are scattered through a large number of insect orders. Out of total insects only 5% are reported to be aquatic belonging to 11 orders of class Insecta, and out of which the aquatic insects belonging to orders Coleoptera, Hemiptera and Odonata are considered to be detrimental to polyculture. The freshwater bodies such as lakes, stream and ponds sustain the greatest population of aquatic insects. Keywords: Detrimental, Polyculture, Planktivorous, Insecta 1. Introduction Aquatic insects which occur in various types of fish ponds such as nursery, rearing and stocking are considered to be harmful for planktivorous fish which are used for polyculture in general and particularly their larval stages such as spawn, fry and fingerlings. These fish ponds are invariably heavily infested with aquatic insects after manuring particularly during monsoon period. The destructive role of predatory aquatic insects in different types of fish ponds are well documented (Distant, 1960; Gorai and Ray Chaudhry, 1962; Tripathi and Sharaf, 1974). Many predatory aquatic insects not only directly prey upon spawn, fry and fingerlings of carps but also compete with them for their food organisms (Julka, 1965; Ganguly and Mitra, 1961).The damage by predatory insects has often been mentioned as one of the major constraints to the aquaculture production (Penak, 1953 and Alikunhi, 1956a). The freshwater bodies such as lakes, stream and ponds sustain the greatest population of aquatic insects. Aquatic insects are occasionally found living under extreme conditions. They may exist in very small bodies of water. Insects rarely live in extensive bodies of water such as the oceans. Some live on or near the surface water while other penetrates into deep water. Many obtain oxygen from the air above the surface (the semi-aquatic species) while some truly aquatic insects obtain their oxygen from water. There are various degrees of adaptation to the aquatic habitat. They modify themselves in various ways to obtain food. As a rule, aquatic situations offer an abundance of food, chiefly in the form of plants. Many of the Chrysomelidae and Lepidoptera feed upon the portions of the plants that protrude above water. Hydrophilid beetles and many other species devour the submerged portions of plants. Bellura bores into stem of lilies. Donaica larvae feed upon roots of aquatic plants. However, predacious Heteroptera-Notonecta, Nepa and Ranatra attack living insects and even turn upon fish and other small animals. 2. Materials and Methods Several inland water bodies particularly fish farms in the northern and central states of India were surveyed for studying the species compositions and distribution of aquatic insect fauna. Insects were collected using scoop nets, soon after their capture the insects were preserved in 5% formalin in the field. The collected insects were brought to the laboratory for their identification using manuals and further investigations.