Immature survival and female longevity of Aedes aegypti under natural winter conditions in the temperate region of Argentina

Abstract

The performance of Aedes aegypti was evaluated under natural winter nutritional and thermal conditions in the temperate region of Argentina. Immature stages were reared using leaf litter as a food source. The rearing was structured in three cohorts, the first started in late-fall, the second in early-winter and the last in mid-winter, and in each cohort two treatments were arranged according to solar exposure (sun and shade). The mean monthly temperature during the experiment ranged from 10.1 °C in July to 14.3 °C in the early days of October. Survival in the experiment was low (average 16.2 %), with a maximum (33 %) in mid-winter cohort. Development time from first instar larva to adult emergence varied between 24 and 103 days, was affected by cohort, treatment and their interaction, and showed an inverse relationship with temperature, particularly in the sun treatment. Individuals from the sun treatments of mid-winter and late-fall cohorts had shorter development times. Adult longevity was very low and was only affected by sex, being higher in females (4.5 days) than in males (3.1 days). The results of this work suggest that although immature stages may complete their development and reach the adult stage during the winter in temperate Argentina, females may not survive long enough to reproduce successfully.