Combining two Genetic Sexing Strains allows sorting of non-transgenic males forAedesgenetic control

Abstract

Chemical control of the mosquito vectors Aedes albopictus and Aedes aegypti is costly, unsustainable, and increasingly ineffective due to the spread of insecticide resistance. The Sterile Insect Technique is an autocidal control tactic that represents a valuable alternative but is limited by the slow, error-prone, and wasteful sex-separation stage. Here, we present four genetic sexing strains (two for each Aedes species) based on fluorescence markers linked to the m and M sex loci, allowing the isolation of transgenic males. Furthermore, we show how combining these sexing strains allows the production of non-transgenic males. Scaling-up would allow the sorting of 100,000 neonate male larvae in under 1.5 hour with 0.01-0.1% female contamination. The resulting males present similar survival and flight ability to laboratory-reared wild-type males. By facilitating the sorting of transgenic or non-transgenic males, these Genetic Sexing Strains should enable a major upscaling in control programmes against these major vectors.

Nutritional sex-specificity on bacterial metabolites during mosquito development leads to adult sex-ratio distortion

“…We took advantage of a recently established Ae. aegypti genetic sexing strain (Aaeg-M) characterized by the insertion of the eGFP transgene in the male-specific M locus (Lutrat et al 2023). This allowed us to sort first instar larvae by sex right after egg sterilization and perform the full experiment on male and female larvae in parallel.…”

“…Surprisingly, this addition in the absence of biotin did not significantly affect the proportion of fully developed adults in germ-free conditions, in contrast to what we typically observe ((Romoli et al 2021), Figure 3A). This discrepancy could potentially be explained by differences in the mosquito strains used in the two sets of experiments (New Orleans and Aaeg-M GSS, which was created from mosquitoes sourced in Thailand (Lutrat et al 2023)). However, we think that the variations in the timing between the two types of experiments were responsible for the different outcomes of folate supplementation.…”

“…Aedes aegypti mosquitoes belonged either to the New Orleans strain or to the Aaeg-M genetic sexing strain (GSS, (Lutrat et al 2023)). Both colonies were maintained under standard insectary conditions at 28-30 °C on a 12:12 h light/dark cycle.…”

Combining two genetic sexing strains allows sorting of non-transgenic males for Aedes genetic control

“…All data handling and statistical calculations were performed using the R statistical software version 4.1.0 48 . All R scripts used for this project can be found on Zenodo 49 . Briefly, COPAS raw data were filtered by the user via the visual examination of the individuals' size measurements (i.e., "log(EXT)" and "log(-TOF)") to remove outliers (e.g., egg debris and dust).…”

“…This function uses common R-base 48 functions as well as functions from the 'purrr' and 'tidyverse' packages 57 . It was permanently deposited on Zenodo 49 . The output costs were converted in US dollars ($).…”