Host-Finding, Host-Recognition, and Host-Acceptance Behavior of Cephalonomia tarsalis (Hymenoptera: Bethylidae)

Several bethylids, including various Cephalonomia spp., are commonly associated with the stored-commodity environment. These parasitoids are often host-specific and can be important biocontrol agents. Although C. tarsalis (Ashmead) reportedly uses several different stored-product beetle hosts, it appeal's to be primarily associated with the saw-toothed grain beetle, Oryzaephilns surinamensis (L.). This article reports on some of the sensory modalities 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 searching until she releases the host in preparation for oviposition. Comparative ethograms for putative alternative hosts of C. tarsalis are also given. Vision plays only a limited role in host-finding and -recognition. Chemical cues, primarily borne on the cuticle of the host and perceived through the wasp's antennae, as well as movement by the host once contacted, are major host-recognition cues used by the parasitoid. Analysis of the ethograms indicates that a complex behavioral repertoire is used by C. tarsalis in the sequence of searching for the host, host-location, -recognition, -stinging, and host-feeding before oviposition occurs. The putative alternative hosts studied showed markedly truncated ethograms (which never include stinging) compared with the ethogram with the sawtoothed grain beetle, indicating that the parasitoid would not be likely to use these alternative hosts under normal situations.