Are survival, mating and oviposition of grape berry moth Paralobesia viteana (Clemens) affected by temperature?

Grape berry moth, Paralobesia viteana (Clemens), is a major vineyard pest in eastern North America, where multiple generations occur during the growing season, and damage from this moth increases through each subsequent generation. The difference in temperature conditions experienced by these succeeding generations is likely to influence this pest’s reproductive biology and the resulting temporal pattern of cluster infestation by larvae. To explore this idea, we investigated the effects of temperature on adult longevity and on behaviors associated with mating and reproduction.  In laboratory experiments, we measured adult survival at different temperatures, and found a strong inverse relationship between temperature and survival. Moths held at 10°C survived almost six and a half times longer than moths held at 28°C. Observations of mating through the diurnal cycle revealed that the number of mating pairs in lab colonies held at different temperatures was considerably higher at warmer temperatures, and mating events occurred over a longer period of time. The influence of temperature on oviposition on grapes was also investigated, and egg laying at 28°C was significantly higher than at 10°C. The patterns observed in adult longevity, mating and egg laying suggest that temperature is an important contributing factor to the seasonal pattern of vineyard infestation by this pest, and help to explain why high levels of moth capture in spring do not translate into high larval abundance.