Population-level variation in thermal and photoperiodic responses of Pryeria sinica (Lepidoptera: Zygaenidae): a comparative study of Korean and Japanese populations.

Abstract

Pryeria sinica Moore is a leaf-feeding pest of ornamental Euonymus species, with a broad distribution across East Asia, as well as parts of Europe and North America. Despite its ecological and economic impact, little is known about its biological characteristics in Korea. This study investigated the developmental biology of the Korean population of P. sinica and compared it with the Japanese population to evaluate adaptive traits related to temperature and photoperiod. Larval development, pupal period, emergence rate, and adult longevity were examined under various controlled thermal and photoperiodic conditions. The Korean population showed optimal larval development at 15 °C, whereas the Japanese population exhibited higher mortality at 15 °C during early instars but better adaptation at 15 and 20 °C in later stages. While both populations showed photoperiod-dependent changes in pupal duration, the Japanese population exhibited more pronounced reductions under short-day conditions, suggesting relatively stronger photoperiod sensitivity than the Korean population. Adult longevity declined significantly with increasing temperature in both populations, with females consistently outliving males. These findings highlight population-level variation in thermal tolerance and photoperiodic response, reflecting ecological adaptations to local environments. The biological characteristics observed in the Korean population offer essential baseline data for improving pest prediction and developing region-specific management strategies. Additionally, the results provide valuable insights into the species' potential for range expansion under future climate change scenarios.