Effect of host availability on reproductive performance in Callosobruchus maculatus (F.) (Coleoptera: Bruchidae)

Abstract

The number of eggs laid by individual females of C. maculatus (F.) usually depended upon the number of cowpeas to which they had sole access. Strains from Brazil and the Yemen laid more eggs on 40 than on either 5 or 10 cowpeas, but showed no further increase when offered 100 or 140. Females of a Nigerian strain laid insignificantly different numbers of eggs when offered 5 or more cowpeas. The number of adults produced from the eggs laid by individual females on different numbers of cowpeas varied with the number of cowpeas and the strain which the females represented. The Yemen strain was restricted to producing a mean of around one adult from each cowpea bearing at least one egg, and therefore the number of adult progeny of each female increased steadily with the number of cowpeas on which her eggs were laid. The Nigerian strain produced more adults when eggs were laid by individual females with access to 40 cowpeas rather than 5 or 10, but no further increase occurred if females had more cowpeas available to them. The Brazilian strain required 100 cowpeas for each female to produce a maximum number of adult progeny. It is concluded that conditions for the determination of maximum fecundity and adult progeny production are different within and between strains. This is of particular importance when data are to be used in population modelling and because it indicates the inherent variability in bionomic factors within this pest species.