The pteromalid parasitoid Pteromalus cerealellae (Ashmead) is nominally a host-speciÞc ectoparasitoid of the stored-product pest the Angoumois grain moth. It is readily cultured, however, on a number of other stored-product pests, including the cowpea weevil. The parasitoids resulting from these different hosts are disparate in size, leading me to ask if the cuticular hydrocarbons of P. cerealellae reared on different hosts would be different. This question is of importance because many

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... ids of stored-product pests use cuticular hydrocarbons as major species-and gender-recognition cues, and moth and beetle hosts differ greatly in their hydrocarbon proÞles. The parasitoid hydrocarbon proÞle reported here was much more complex than the proÞles of either host and showed both gender and host effects. Parasitoids reared on the larger cowpea weevils were larger than those reared on moths and contained substantially more hydrocarbon on their cuticle. Regardless of host, female wasps were always larger than males and contained more hydrocarbon than males. The hydrocarbon chemistry of wasps reared on different hosts were qualitatively the same, but quantitatively different. Both gender and host are important in the relative abundance of individual hydrocarbons. There are four major hydrocarbons of females constituting 49% of the total female proÞle: 3-MeC 29 , 11-MeC 31 , 3, 7-DiMeC 31 and 11, 17-, 11, 19-and 11, 21ÐDiMeC 33 . There is one major male-speciÞc hydrocarbon comprising 18% of the total hydrocarbons, 3, 7-and 3, 9 ÐDiMeC 33 . Although major gender differences occur between hydrocarbon classes, these differences are not host-related.