Overwintering survival of adults of Aedes albopictus and Aedes cretinus (Diptera: Culicidae) in a sheltered microclimate in northern Attica, Greece

The mosquito species Aedes cretinus, which is native to Greece, has become increasingly scarce following the invasion of the highly competitive and widespread Aedes albopictus. The ability of mosquitoes to survive low winter temperatures plays a pivotal role in their population dynamics of the next season. In this study, we investigated the overwintering capacity of Ae. albopictus and Ae. cretinus adults under semi-field, sheltered microclimatic conditions in the northern area of Attica, Greece, during the winter of 2023-2024. Our findings revealed that 11% of Ae. albopictus females and 21.1% of Ae. cretinus females were capable of overwintering, highlighting the importance of sheltered microclimates in enabling overwintering survival under low outdoor temperatures. In contrast, males of both species failed to overwinter. The winter survival ability of adults was significantly greater in Ae. cretinus than in Ae. albopictus, and this may account for the occurrence of Ae. cretinus in the cooler environments of vegetated and wooded locations in northern areas of the Attica region. Nevertheless, the ability of Ae. albopictus females to also overwinter under the same sheltered microclimatic environment may affect the potential of interspecific competition in these areas.