Low temperature hatching response of Aedes aegypti eggs: effects of hatching media and storage conditions

BARBARA BYTTEBIER; MARÍA SOL DE MAJO; SYLVIA FISCHER

JOURNAL OF MEDICAL ENTOMOLOGY

ENTOMOLOGICAL SOC AMER

Lugar: Lanham; Año: 2014 vol. 51 p. 97 - 103

0022-2585

In temperate regions, Aedes aegypti (L.) populations remain in the egg stage during the cold season. Therefore, egg hatch at the beginning of the favorable period is a critical event to ensure the start of a new breeding season. The aim of the present study was to investigate the hatching response of two Ae. aegypti egg batches, collected and stored for three months under different conditions, to different low immersion temperatures. Two different hatching media (water and yeast solution) were used for the first batch, whereas only one hatching medium (water) was used for the second egg batch. Eggs were immersed for 8 days, during which the number of hatched eggs was recorded daily. The proportion of hatched eggs, the delay of the hatching response, the proportion of dead larvae, and the proportion of remaining eggs within the first egg batch were compared between the two hatching media at each temperature. These parameters were also compared between the two batches immersed in water. Hatching rates were higher and faster in the yeast solution. The hatching response was lower as the immersion temperatures decreased and among eggs stored under field conditions at colder temperatures (second batch). Among the eggs stored in the laboratory (first batch), older eggs exhibited a lower hatching percentage. The proportion of dead larvae was higher in the yeast solution and in the eggs stored in the laboratory. The conditions that triggered a lower hatching response led to higher proportions of remaining eggs, allowing the population to maintain an egg bank for future favorable opportunities.