COLD-ACCLIMATION, DIAPAUSE, AND GEOGRAPHIC ORIGIN AFFECT COLD-HARDINESS IN EGGS OF AEDES-ALBOPICTUS (DIPTERA, CULICIDAE)

Eggs of five strains of Aedes albopictus (Skuse) were obtained in both diapause and nondiapause conditions and exposed to various cold accli mation regimes in the laboratory, after which they were subjected to d iverse chilling treatments. Larvae that survived chilling as eggs surv ived to the pupal stage. Eggs of Aedes aegypti (L.) and Aedes triseria tus (Say) were included as control species. Eggs of temperate Ae. albo pictus were more cold-hardy than eggs of Ae. aegypti but less cold-har dy than the eggs of Ae. triseriatus. Cold acclimation and diapause enh anced cold hardiness of only temperate Ae. albopictus. Cold acclimatio n had a greater influence on cold hardiness than did diapause. Both th e temperature and the duration of cold acclimation modulated cold hard iness. Cold hardiness induced in the laboratory was similar to cold ha rdiness induced in the field in northern Indiana. The cold hardiness o f Ae. albopictus from central Florida was intermediate in comparison w ith temperate and tropical strains. Tropical Brazilian Ae. albopictus and tropical Asian Ae. albopictus were similar in cold hardiness.