Abstract:

A study conducted in Uganda on Callosobruchus chinensis showed that adults emerging from dry seed-infested and immature pod-infested pigeon pea differed in a number of morphological and biological characteristics in one or both sexes. Adults emerging from dry seed-infested pigeon pea were more or less uniform in a number of these characteristics; in contrast, adults emerging from green pod infested pigeon pea differed depending upon when they emerged: the differences were greatest between those emerging during the 2nd to the 6th days from ®rst emergence, and those emerging from the 8th to the last days of emergence. In one or both sexes, these differences were expressed in terms of elytral hue and size, body length, distance between the compound eyes, length of pygidium, body water content, pre-maturation periods, fecundity and adult longevity. We suggest that these differences are due to polymorphism, and specifically the predominance of light forms among late emerges from pod-infested pigeon pea. The differences observed in the two morphs of C. chinensis and ascribed to the light and lightless forms, are thought to be adaptations for survival and propagation under ®eld and storage conditions, respectively. The predominance of emerged adults of the lightless forms from dry seed and the light forms from green pods were associated with low moisture content in dry seed and high moisture content in green pods, respectively. These observations show that bruchid control measures are needed in the ®eld as well as in storage. # 1999 Published by Elsevier Science Ltd. All rights reserved.