Functional response of Pardosa altitudis Tikader and Malhotra, Teragnatha maxillosa Thorell, Neoscona mukherjei Tikader and Theridion sp. to rice green leafhopper
Laboratory experiments were performed to determine the functional response of visual hunting spider, Pardosa altitudis Tikader and Malhotra and web-building spiders, Teragnatha maxillosa Thorell, Neoscona mukherjei Tikader and Theridion sp. to 2nd and 3rd instar nymph of rice grasshopper. The functional response of P. altitudis, T. maxillosa, N. mukherjei and Theridion sp. to the different density of 2 nd and 3rd instar nymph of rice grasshopper was typically of Holling Type II with a steep initial rise in prey capture rates as the density increased. P. altitudis consumption increased to 26.7 per day 2 nd instar nymphs of rice grasshopper which was higher than that of N. mukherjei (23.1), T. maxillosa (22.4) and Theridion sp. (18.8). However, in case of 3 rd instar nymph of rice grasshopper, the consumption of N. mukherjei was increased to 21.2 per day which was higher than that of L. altitudus (20.4), T. maxillosa (19.2) and Theridion sp. (16.2). The search rate of N. mukherjei was not significantly higher than L. altitudes against 2nd instar nymph of rice green hopper and handing time of L. altitudes was significantly lowest as compared to N. mukherjei. In case of 3 rd instar nymph of rice green hopper, the search rate of N. mukherjei was significantly higher followed P. altitudus, T. maxillosa and Theridion sp. while the handing times of N. mukherjei was not significantly higher than L. altitudes. The lowest search rate and highest handling time taken by Theridion sp. for both 2nd and 3rd instar nymph of rice grass hopper. The result suggested that P. altitudis have potential for being effective biocontrol agents.
Author : Akhtar Ali Khan
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