Details on the natural history and behavior of Nordus fungicola (Sharp) in Barro Colorado Island, Panama are presented. These beetles have bright coloration and wave their abdomen conspicuously. They feed on small drosophilid flies or fly larvae, and the typical grooming behavior after feeding is described. Beetles interacted aggressively with ants of the genus Ectatomma, and a preliminary experiment shows that beetles may use chemical secretions for defense. Male–male and male–female interactions, and copulatory courtship are described. Males were not observed guarding females after mating. Females are not receptive after copulation.