INDUCTION OF PROLONGED DIAPAUSE IN BARBARA COLFAXIANA (LEPIDOPTERA: OLETHREUTIDAE): CORRELATIONS WITH CONE CROPS AND WEATHER

Abstract

AbstractStudies were carried out in the field and in the laboratory to determine if prolonged diapause of the Douglas-fir cone moth, Barbara coifaxiana (Kearfott), was correlated with the sizes of the cone crops maturing in the year of larval feeding (N) and in the year following larval feeding (N + 1), and to determine if weather during the period of larval feeding (year N) influenced the size of the maturing cone crop or the incidence of prolonged diapause the following year (N + 1). Field studies showed that prolonged diapause induction in B. coifaxiana was not rank correlated (but approached significance) with the size of the cone crop maturing in year N, but was negatively rank correlated with that in year N + 1. Two of seven weather parameters, mean maximum temperature and mean daily temperature, measured during the larval feeding period were positively rank correlated with cone crop size. No parameter was correlated with the incidence of prolonged diapause. In the laboratory, the incidence of prolonged diapause was negatively correlated with temperature. Photoperiod and parental diapause habit had no direct effect.