Oviposition behavior of oligota kashmirica benefica naomi (coleoptera: Staphylinidae). I. Adaptive significance of egg-covering behavior by adult females

Abstract

The materials used for the egg-covering behavior of adult females of Oligota kashmirica benefica NAOMI, a natural enemy of spider mites, were investigated on leguminous arrowroots, Pueraria lobata (WILD.) OHWI, in 1989-1991. Most eggs (93.3%) on leaves collected in the field were covered, partially or completely, with a pile of debris (feces, skins, egg shells and dead bodies of Tetranychus spider mites), but prey eggs were rarely used as egg-covering materials. Females of a closely-related species, O. yasumatsui KISTNER, also showed similar behavior with the same materials. A series of experiments was conducted under laboratory conditions at 25±1°C to evaluate the adaptive value of this egg-covering behavior. Covered eggs were preyed upon less frequently by their predators (Stethorus japonicus KAMIYA, Scolothrips takahashii PRIESNER, and Amblyseius longispinosus (EVANS) etc.), compared to uncovered eggs as well as eggs covered articially with prey eggs. On the other hand, egg-covering hardly influenced hatchability at various humidities. These results suggest that egg-covering plays a significant role in protecting eggs from attack by predators rather than in protecting them from harsh physical conditions (e.g. desiccation). © 1994, JAPANESE SOCIETY OF APPLIED ENTOMOLOGY AND ZOOLOGY. All rights reserved.