Biotic potential of three coccinellid predators on six different aphid hosts

Biotie potential of three coccinellid predators, viz., Coccinella septempunctata Linnaeus, C. transversalis Fabricius and Cheilomenes sexmaculata (Fabricius) was studied on six species of aphids, viz., Aphis craccivora Koch, A. gossypii Glover, A. nerii Boyer de Fonscolombe, Lipaphis erysimi (Kaltenbach), Rhopalosiphum maidis (Fitch) and Uroleucon compositae (Theobald). These three coccinellid predators accepted all the hosts, but U. compositae was the least preferred resulting in no egg production in C. septempunctata and C. transversalis. Developmental period on different aphid hosts, viz., C. septempuncata and C. transversalis varied from 16.5 to 21.4 and 15.2 to 18.0 days, respectively. C sexmaculata voraciously predated and bred well on all these hosts including U. compositae, indicating its wide host range. But, it developed faster on A. nerii (12.2 days) than other hosts and was more fecund on A. craccivora and A. nerii. A. craccivora was the most preferred host for all the coccinellids with higher rate of consumption and higher fccundity.