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Abstract

Callosbruchus maculatus (Fab.) is a cosmopolitan species of bruchids and is popularly called as cowpea weevil as it is a major pest of Vigna ungiculata (L.). However it attacks a number of edible legumes in addition to V. ungiculata in different regions. Moreover it also shows variable behavior during its life cycle, being a field type in some parts and storage type species in others. It also acts as an intermediate species spending some part of its life in the field and some part in the store. C. maculatus has been reported to appear in two forms during the course of the year, a normal form and an active form or flight form which is more active and much less fecund than the normal form. The active form shows facultative reproductive diapause. The behavior of this form is quite different in different parts of the globe, with its Indian strain showing complete sterility. We have carried out detailed investigations on the Indian strain of C. maculatus during last many years. The present report includes a review of our own work as well as other relevant studies on this subject in order to project its phenotypic plasticity in the Indian strain as of exceptional type. Suggestions for its true status have also been recorded.