Effectiveness of a New Self-Marking Technique in Aedes aegypti under Laboratory Conditions

SIMPLE SUMMARY: Marking techniques are generally used to differentiate colony mosquitoes from wild ones in the implementation of vector control programs using the Sterile Insect Technique. Different mosquito marking techniques have been developed in the past years but need improvement due to the extensive handling that can affect the quality of mosquitoes. We present here a self-marking technique that can reduce the damage associated with mosquito handling in mass rearing. The marking technique consists of adding fluorescent powder (DayGlo: A-17-N Saturn yellow) directly to the surface water of the receptacle containing Aedes aegypti male pupae. The marking efficacy, powder persistence and mosquito survival were assessed for male mosquito. We observed a high marking rate that increased with increasing amounts of fluorescent powder. Fluorescent powder lasted long on the mosquito body and did not induce a negative effect on their survival. This self-marking method reduces human intervention and mosquito handling, improving the quality of marked mosquitoes. ABSTRACT: In the implementation of mosquito control strategy programs using Sterile Insect Technique and other rear and release strategies, knowledge on the dispersion, competitiveness and survival of mosquitos is considered essential. To assess these parameters, marking techniques are generally used to differentiate colony mosquitoes from wild ones. Most of the existing mosquito marking methods require numerous manipulations that can impact their quality. In this study, we have developed a self-marking technique that can reduce the damage associated with mosquito handling. The marking technique consisted of adding fluorescent powder (DayGlo: A-17-N Saturn yellow) directly to the surface water of the receptacle containing Aedes aegypti male pupae. Different quantities of powder were used, and marking efficacy, powder persistence and mosquito survival were assessed. The results show a mean marking rate of 98 ± 1.61%, and the probability of marking increased significantly (p < 0.001) with increasing concentrations of fluorescent powder. Fluorescent powder persisted up to 20 days and did not induce a negative effect on mosquito survival (χ(2) = 5.3, df = 7, p = 0.63). In addition, powder transfer did not occur between marked and unmarked populations. This marking method significantly reduces human intervention and mosquito handling during the marking process, improving the quality of marked mosquitoes used to assess SIT programs.