EFFECT OF PREY SEX, DENSITY, AND AGE ON OVIPOSITION OF CYBOCEPHALUS SP. NR. NIPPONICUS (COLEOPTERA, CYBOCEPHALIDAE), A NATURAL ENEMY OF EUONYMUS SCALE (HOMOPTERA, DIASPIDIDAE)

Cybocephalus sp. nr. nipponicus Endrody-Younga (Coleoptera: Cybocephal idae) females males lay their eggs individually under the cover of sca le insects, similar to some hymenopteran parasitoids. Because this bee tle's oviposition occurs in close association with individual scale in sects, qualities of individual scale insects or patches of scale insec ts are factors that can potentially be used by beetles to select ovipo sition sites. The effect of two such factors (scale sex and density) o n the oviposition of C. sp. nr. nipponicus were evaluated in the labor atory using the euonymus scale Unaspis euonymi (Comstock) as the ovipo sitional prey. For comparison, the effect of scale sex, density, and a ge on beetle oviposition also was investigated for a second ovipositio n prey, San Jose scale (Quadraspidiotus perniciosus (Comstock)). Ovipo sition rates for C. sp. nr. nipponicus were strongly affected by prey sex when ovipositing on euonymus scale, with 97% of all eggs being pla ced under covers of male scales. In contrast, beetles placed eggs in e qual proportions under covers of mature (> 29 days) female and the emp ty scales of emerged male San Jose scales. Oviposition rates were affe cted by San Jose scale density. There were significantly more beetle e ggs laid in patches with more than 70 scales than in those with fewer scales. Increasing scale age positively affected beetle oviposition on San Jose scale. Fifty-five percent of all eggs were laid in the oldes t group of scales (age 53-58 days), whereas no eggs were laid in the y oungest group of scales (age 9-14 days).