Reproductive Performance of cowpea aphid, Aphis craccivora Koch at different points in the birth sequence on cowpea, Vigna unguiculata (L.) Walp

During the Biological study of cowpea aphid, Aphis craccivora koch, the observation showed that some adults from a batch molted together but started reproducing earlier than others and were named as fast developers and slow developers respectively. A study was conducted to see the reproductive performance of cowpea aphid at different points in their birth sequence in International Institute of Tropical Agriculture, IITA. For this study two weeks old cowpea seedlings were used. The experiment was initiated by releasing five apterous fourth instar nymphs into a cage containing two weeks old cowpea seedlings. The nymphs produced within the first six hours, (fast developers) and the once produced 42-48 hours later (slow developers) were removed to separate cages individually on new seedlings. Developmental studies were conducted on individual aphids. There were twelve replications and the experiment was repeated twice. The study showed that the fast developers produced more off springs than slow developers but the longevity of slow developers was significantly longer than that of fast developers.