Behavior of individual insects and interactions with conspecifics are often overlooked aspects of insect biology. Beetles in the genus Chauliognathus (Coleoptera: Cantharidae) have been observed guarding nectar-producing inflorescences and fighting with conspecifics over these resources in Central and South America. To determine if North American Chauliognathus marginatus (margined leatherwing beetles) exhibit these or similar behaviors, adult beetles were observed on mixed wildflowers over 8- to 10-hour periods throughout the summers of 2018 and 2019. Beetle behavior and interactions were recorded hourly. The most common interaction between beetles was mating, with almost no instances of aggression or resource guarding. Individuals also engaged in traveling, preening, and resting behaviors. Behaviors differed significantly throughout the day. Though resource guarding was not observed in C. marginatus beetles, other interesting patterns of diurnal behavior were present and constitute an important contribution to the biology of this species.
