Aphytis melinus is an internal parasite of the California Red Scale, Aonidiella aurantii, which is a pest of citrus in California and elsewhere. This chalcid wasp drums its antennae against the scale insect to find out if it is healthy, if it is already parasitized, how large it is, etc., to decide how to use this prey. It has four choices (from worst to best): leave the scale to keep searching, feed directly on the scale, use the scale as a host for a male A. melinus, or use the scale for a female A. melinus.