Optimizing and synchronizing Aedes aegypti colony for Sterile Insect Technique application: egg hatching, larval development, and adult emergence rate.

ABSTRACT

Mosquito Sterile Insect Technique (SIT) programs can be developed in smaller agencies through synchronization of the colony development to take advantage of the natural male early emergence. This paper examined key aspects of Ae. aegypti colony synchronization work, including egg hatching, larval development, and adult emergence to produce sufficient numbers of adult male mosquitoes within a specific timeframe for irradiation and release. Our data indicated that a relatively low percentage of males are required for colony propagation. Additional results highlighted that fresher Ae. aegypti eggs could yield as high as a 93% hatching success than older eggs when placed under vacuum pressure in yeast infused water for 1.5 hours. Eggs that were one-month old hatched (93%) better than older eggs (0-32%). A higher egg density in the hatching flask was correlated to a lower hatch rate, and higher larval density was related to unsynchronized pupae and delayed adult emergence. By keeping Ae. aegypti larvae at reasonable density, over 95% of adults emerged on the first two days of emergence - indicating a high synchronicity. A standardized colony maintenance protocol therefore renders a synchronized larval development and adult male emergence which are critical in SIT programs.