A bee assassin bug, Apiomerus flaviventris Herrich-Schäffer (Hemiptera: Reduviidae), of the arid or semiarid southwestern North America is known to exploit resins from plants and apply them to the eggs for protection. To elucidate the source and possible functions of the resin, A. flaviventris were collected in the Anza Borrego Desert State Park, California, and observed in the laboratory. Female A. flaviventris collected the resin from a desert perennial shrub, brittlebush, Encelia farinosa Gray ex Torr. (Asteraceae). Bioassays with the predatory ant species Forelius pruinosus (Roger) and Linepithema humile (Mayr) (Hymenoptera: Formicidae) indicated that the brittlebush resin coating is important in preventing A. flaviventris eggs from being picked up by omnivorous predators.