Temporal dynamics of the egg bank of Aedes aegypti (Diptera: Culicidae) in the winter-spring transition in a temperate region

Barbara Byttebier ¹, Verónica Loetti ¹, María Sol De Majo ¹

⁰Departamento de Ecología, Genética y Evolución, and Instituto IEGEBA (UBA-CONICET), Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina.

Acta Tropica +

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April 30, 2024

View abstract on PubMed

Summary

Aedes aegypti mosquito eggs survive winter in Buenos Aires, with 51% remaining viable after 12 weeks. This egg survival is crucial for population persistence in the next reproductive season.

Area Of Science

Medical Entomology
Ecology
Insect Physiology

Background

Temperate regions host Aedes aegypti populations overwintering in the egg stage.
Egg bank survival is critical for initiating the next reproductive season in Aedes aegypti populations at the edge of their distribution.

Purpose Of The Study

To analyze Aedes aegypti egg mortality, field-hatching, and survival under natural winter and spring conditions.
To assess the post-exposure hatching response of Aedes aegypti eggs after simulated overwintering.

Main Methods

Four batches of Aedes aegypti eggs were exposed to field conditions for 3, 6, 9, and 12 weeks.
Recovered eggs were counted (intact, collapsed, hatched), and intact eggs were tested for hatching response in the lab.
A control batch remained under laboratory conditions.

Main Results

Progressive increases in egg loss (predation), mortality, and hatching were observed with longer field exposure.
Field-hatching commenced in late winter, with initial hatchlings facing unfavorable development conditions.
51% of recovered eggs remained viable after 12 weeks of field exposure.
Laboratory hatching response increased with longer field exposure duration, suggesting a potential photoperiod-induced diapause.

Conclusions

Aedes aegypti egg survival through the winter-spring transition in Buenos Aires ensures population persistence.
The study highlights the importance of overwintering egg banks for mosquito population dynamics in temperate climates.
Photoperiod may play a role in regulating egg hatching during the transition from winter to spring.

Keywords:

Field-hatching Hatching response Mortality Mosquito eggs Unfavorable period