Determining the Insemination Status of Aedes Mosquitoes

Abstract

Within the genus Aedes, the reproductive biology of two species has been most thoroughly studied: Aedes aegypti and Aedes albopictus In these species, females tend to copulate with one or more males once sexually mature. Within a few hours after an initial insemination, most females become refractory to insemination for the rest of their lives. Aedes females store sperm in three sclerotized spherical structures called spermathecae, where they can remain viable for >3 mo after copulation. This protocol outlines a quick (∼3-5 min per female once you are practiced in dissection) and effective method for dissecting the female spermathecae from Ae. aegypti and Ae. albopictus mosquitoes and scoring them for the presence or absence of sperm in cases in which the researcher does not need the female for further studies.

FIGURE 1.

Steps of spermathecae dissection for determining insemination status of Aedes mosquitoes. (A) Anesthetized female placed laterally in a drop of saline buffer on glass slide. (B) Female’s cerci and terminal abdominal segments pulled apart with forceps, containing spermathecae that are visible but not yet exposed. (C) Female’s cerci and terminal abdominal segment covered by exoskeleton, with spermathecae exposed. (D) Opened spermathecae without sperm. (E) Opened spermathecae with sperm.