Reproductive performance of alatae and apterae of cowpea aphid, Aphis craccivora Koch on cowpea,Vigna unguiculata (L.) Walp

An experiment was conducted to study the ratio of alatae and apterae nymphs produced by alatae and apterae parents of Aphis craccivora Koch and their reproductive performance in IITA(International Institute of Tropical Agriculture) Ibadan, Nigeria. The aphids used in the experiment were viviparous females taken from the culture maintained in a growth chamber. The cowpea seedlings used were ten days old Prima plants.The experiment was initiated by releasing twenty apterous aphids into a leaf cage on Prima seedling. The newly born aphids were left to develop while the adults were removed. At the fourth instar stage twenty four apterous and twenty four alate aphids were caged singly in different cages. Observations were made daily on individual aphids between 0800-1700 hours on the pre-reproductive period, post reproductive period, fecundity and number of alates and apterae produced by apterous and alate parents. The results showed that regardless of parent’s morphs the number of alates produced is always lower than the number of apterae and also the average number of progeny produced by alate forms was less than the progeny produced by apterous forms.