At present, two research endeavors are being pursued -- cooperation and communication in bats and the evolution of genetic covariation and sexual dimorphism in flies. Current bat studies include field work in Trinidad and captive work at the National Zoo on vocal advertisement in the greater spear-nosed bat, Phyllostomus hastatus. The field work involves playbacks of audible and ultrasonic vocalizations, video recording using infra-red sensitive cameras, radio-telemetry and light-tagging of free-ranging individuals. Information content of vocalizations and social learning are being investigated with playbacks to captive bats in flight rooms. These studies represent an extension of Dr. Wilkinson's previous work on food-sharing in vampire bats, Desmodus rotundus, and communal nursing and information transfer in evening bats, Nycticeius humeralis. Field and laboratory studies on stalk-eyed flies, family Diopsidae, are also being conducted to test predictions of recent models of sexual selection and to investigate the evolution of genetic correlations between morphological and behavioral traits. This work involves field studies in Africa and Malaysia, quantitative genetic experiments, and DNA sequencing of motochondrial genes for reconstructing the phylogenetic relationships among species and genera of diopsids.