Cold Acclimation, Diapause, and Geographic Origin Affect Cold Hardiness in Eggs of Aedes albopictus (Diptera: Culicidae)

Abstract

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.

Photoperiodic Diapause and the Establishment ofAedes albopictus(Diptera: Culicidae) in North America

“…In another study of diapause under field conditions, Hanson and Craig (1994) found that diapause eggs of a temperate strain of Ae. albopictus exhibited relatively high overwinter survivorship of 78% at a South Bend Indiana field site in 1990-1991, but no eggs survived the winter of [1989][1990].…”

“…albopictus in the mid-western United States, Hawley et al (1989) demonstrated that diapause eggs exhibited increased overwinter survivorship relative to nondiapause eggs at three field sites-South Bend, IN; Indianapolis, IN; and Evansville, IL. This increased overwinter survivorship of diapause eggs during the midwestern winter is presumably due to the increased cold tolerance of diapause eggs (Hanson and Craig 1994), as well as enhanced desiccation resistance (Sota andMogi 1992, Urbanski et al 2010) and increased lipid content (Reynolds et al 2012). Interestingly, Hanson and Craig (1995b) showed that although cold acclimation and diapause independently decreased the lower lethal temperature of eggs from À8 C to À12 C, these temperatures are still substantially above the supercooling point of $À27 C, which was not affected by either diapause or cold acclimation (Hanson and Craig 1995b).…”

“…albopictus exhibited relatively high overwinter survivorship of 78% at a South Bend Indiana field site in 1990-1991, but no eggs survived the winter of [1989][1990]. Interestingly, these dramatic differences in overwinter survivorship cannot be explained by differences in the average or minimum winter temperature, since 1990-1991 was actually colder than 1989-1990(Hanson and Craig 1994. One possible factor contributing to these results is that conditions during the late-summer and early-fall stages of hibernal diapause, when the eggs are in diapause but temperatures are still relatively warm, can affect overwintering success.…”

“…albopictus has emerged as a particularly useful model system for studying photoperiodic diapause. Numerous studies have investigated the field ecology of photoperiodic diapause in North America (Hawley et al 1989, Hanson and Craig 1994, Hanson and Craig 1995a and in Japan (Mori et al 1981). These studies have provided important insights into the overwintering capability of Ae.…”

Climate Change, Biological Invasion and Emerging Diseases: a Longitudinal Sociological Study Monitoring the Spread of Asian Tiger Mosquitoes in a European Region

“…Firstly, the natural distribution area of A. albopictus includes both tropical and quite temperate areas (Hawley, 1988). Second, laboratory research, modelling and fi eld observations have further confi rmed the great ability of A. albopictus to also adapt to colder temperate climates (Hanson and Craig, 1994;Kobayaski et al, 2002;Delatte et al, 2009;Lacour et al, 2014). Th ird, modelling based on data collected in the south of France shows that, at the regional scale, human transportation is the most important factor in the dispersion of A. albopictus and that land use is a major factor in its establishment (Roche et al, 2015).…”