Host-finding, host-recognition, and host-acceptance behavior of Cephalonomia tarsalis (Hymenoptera : Bethylidae)

Several bethylids, including various Cephalonomia spp., are commonly associ ated with the stored-commodity environment. These parasitoids are often hos t-specific and can be important biocontrol agents. Although C. tarsalis (As hmead) reportedly uses several different stored-product beetle hosts, it ap pears to be primarily associated with the saw-toothed grain beetle, Oryzaep hilus surinamensis (L.). This article reports on some of the sensory modali ties that female C. tarsalis use to find, recognize, and accept a host, and it provides an ethogram for the behavior of the parasitoid from initial se arching until she releases the host in preparation for oviposition. Compara tive ethograms for putative alternative hosts of C. tarsalis are also given . Vision plays only a limited role in host-finding and -recognition. Chemic al cues, primarily borne on the cuticle of the host and perceived through t he wasp's antennae, as well as movement by the host once contacted, are maj or host-recognition cues used by the parasitoid. Analysis of the ethograms indicates that a complex behavioral repertoire is used by C, tarsalis in th e sequence of searching for the host, host-location, -recognition, -stingin g, and host-feeding before oviposition occurs. The putative alternative hos ts studied showed markedly truncated ethograms (which never include stingin g) compared with the ethogram with the sawtoothed grain beetle, indicating that the parasitoid would not be likely to use these alternative hosts unde r normal situations.