Response of Catolaccus grandis (Hymenoptera : Pteromalidae) to its naturalhost after ten generations of rearing on a factitious host, Callosobrucus maculatus (Coleoptera : Bruchidae)

Catolaccus grandis (Burks), an ectoparasitoid of the boil weevil, Anthonomu s grandis, grandis (Boheman) (Coleoptera: Curculionidae),was reared in labo ratory conditions on the cowpea weevil, Callosobruchus maculatus (F.), as a factitious host to reduce costs on a mass propagation system. Total fecund ity, daily oviposition, net reproductive rate, and sex ratio were evaluated and compared among females reared on A. grandis and C. maculatus. The larv al data showed that C, maculatus is a viable alternative host for the reari ng of C. grandis. After 10 generations of continuous rearing on C, maculatu s, C, grandis females showed a significant switch in host acceptance as an oviposition site and remained even after rearing on A. grandis for 1 genera tion. For this reason, we do not recommend rearing C. grandis on C. maculat us for >1 generation. However, the use of A. grandis and C. maculatus as ho sts may be an acceptable practice, given that host preference was not signi ficantly affected on 1st-generation C. grandis females reared on C. maculat us.