Observation of granulations in the basal body of ovarioles and follicular dilatations for the determination of physiological age of Anopheles gambiae s.s

Objective: To explore ovariole basal body granulations and follicular dilatations for determining physiological age in Anopheles gambiae s.s. (An. gambiae s.s.). Methods: Mosquitoes were collected by using window trap catch and identified morphologically. For the first lot of mosquitoes, they were dissected, and ovary was left in distilled water for reading ovarian tracheoles and the second was cut and transferred to another blade in a physiological liquid for verification of ovariole basal body granulations. The same approach was followed with the second lot of mosquitoes where follicular dilatations were found after classic dilaceration of ovaries were transferred into physiological liquid. The other body parts of mosquitoes were used to identify the species of the An. gambiae s.s. complex by PCR. Results: Among the 123 An. gambiae s.s. of the first lot, the method of Detinova determined the age of 89 mosquitoes versus 114 for the observation of granulations (P > 0.05). Among the 112 An. gambiae s.s. of the second lot, the method of Detinova determined the age of 84 mosquitoes versus 93 for the observation of follicular dilatations (P > 0.05). Unlike the method of Detinova, observation of follicular dilatations and basal body granulations of ovarioles were possible beyond the stage II Christophers. Conclusions: Overall, the observation of follicular dilatations and ovariole basal body granulations are reliable for the determination of the physiological age in An. gambiae s.s. Furthermore, these two methods can be used beyond the stage II.