EFFECTS OF TWIG MORPHOLOGY ON OVIPOSITION BEHAVIOR AND HATCHING SUCCESS OF THE TWIG-GIRDLING BEETLE ONCIDERES CINGULATA (SAY) (COLEOPTERA, CERAMBYCIDAE)

I measured characteristics of shagbark hickory, Carya ol nta (Mill.) t wigs selected as oviposition sites by twig girdlers, Oncideres cingula ta (Say), to determine any patterns that may affect reproductive succe ss. Best subsets multiple regression analysis of seven twig characteri stics revealed that measurements of twig size and number of lateral br anches were significant (P < 0.001) determinants of both numbers of eg gs laid (r(2)=0.33) and eggs hatched (r(2)=0.18). though much variabil ity was unaccounted for by the models. The pattern of eggs laid approx imated a normal distribution along the length of a branch, with fewer eggs near the girdle and the terminus of the branch. The large amount of variability left unexplained by the regression models may be explai ned by generational survivorship which varies greatly, from less than one to 60 percent or more.