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 acclimation regimes in the laboratory, after which they were subjected to diverse chilling treatments. Larvae that survived chilling as eggs survived to the pupal stage. Eggs of Aedes aegypti (L.) and Aedes triseriatus (Say) were included as control species. Eggs of temperate Ae. albopictus were more cold-hardy than eggs of Ae. aegypti but less cold-hardy than the eggs of Ae. triseriatus. Cold acclimation and diapause enhanced cold hardiness of only temperate Ae. albopictus. Cold acclimation had a greater influence on cold hardiness than did diapause. Both the temperature and the duration of cold acclimation modulated cold hardiness. Cold hardiness induced in the laboratory was similar to cold hardiness induced in the field in northern Indiana. The cold hardiness of Ae. albopictus from central Florida was intermediate in comparison with temperate and tropical strains. Tropical Brazilian Ae. albopictus and tropical Asian Ae. albopictus were similar in cold hardiness.