Winter survival of Aedes aegypti (Diptera: Culicidae) eggs at its southern limit distribution

OBHOLZ, GISELLA; SAN BLAS, GERMÁN; FISCHER, SYLVIA; DIAZ, ADRIAN

ACTA TROPICA

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2022 vol. 231 p. 1 - 7

0001-706X

Aedes aegypti (L.) (Diptera: Culicidae) survives in the egg stage under unfavorable environmental conditions. Inthis study, we assessed the survival of Ae. aegypti eggs under natural winter conditions as an overwinteringmechanism. To address this, field collected eggs (from Buenos Aires city) were exposed for three months duringthe winter season in three sites of Santa Rosa and General Acha (La Pampa province, Argentina). Eggs survivaland hatching response were analyzed considering two factors (site of exposure and time of oviposition). Of the1397 analyzed eggs, 936 (67%) were viable at the end of the study. Egg survival showed to be high in all sites(between 53% and 84%), except in one site of Santa Rosa. Also, eggs survival was higher in eggs laid in May(94%) (late-fall) as compared to those laid in March (61%) and April (56%) (early- and mid-fall respectively).Eggs hatching response was only affected by the time of oviposition, being lower for eggs laid in May (33%) ascompared to March (38%) and April (50%). These results provide information regarding the winter resistance ofAe. aegypti at the limit of its distribution in temperate regions. Given the high percentages of survival found inthis study, we consider that the low winter temperatures would not be a limitation for its establishment insouthern areas.