Egg hatching and survival of immature stages of Aedes aegypti (Diptera: Culicidae) under natural temperature conditions during the cold season in Buenos Aires, Argentina

MARÍA SOL DE MAJO; PEDRO MONTINI; SYLVIA FISCHER

JOURNAL OF MEDICAL ENTOMOLOGY

ENTOMOLOGICAL SOC AMER

Lugar: Lanham; Año: 2017 vol. 51 p. 106 - 113

0022-2585

In temperate regions, theseasonal dynamics of Aedes aegypti (L.) (Diptera: Culicidae) is mainlyinfluenced by temperature. It is assumed that, during the winter season, thepopulation remains as eggs and that the development and population growth ofsurviving eggs begin during the following spring. The aim of the current studywas to assess egg hatching of Ae. aegypti during the winter in Buenos Aires city(Argentina), and analyze the survival of immature stages. The experimentsconsisted of immersing eggs and studying the development of immature stages ofcohorts from June and September under natural temperature conditions. Theproportion of hatched eggs was compared between weeks of immersion and relatedto environmental variables. Survival was compared among cohorts and thedevelopment rate was related to the mean temperature during development. Theresults showed that, with few exceptions, egg hatching was over 45% during thewinter period. The proportion of hatched eggs was positively associated withimmersion temperature, pre-immersion temperature and photoperiod. The immaturestages completed the development during the cold season, with a trend towardsincreased survival of late-hatching cohorts. Survival was 30% at 13.2°C andabove 90% at 20°C, whereas the development time at low temperatures was 49.4days at 13.2°C, and 17.7 days at 20°C. The high hatching and survival comparedto other studies suggest that the local population might be adapting to winterconditions. The anticipated emergence of adults would be adaptive if they areable to reproduce successfully in the early spring.