Effects of a blood-free mosquito diet (BLOODless) on fitness and gonotrophic cycle parameters of laboratory reared Anopheles gambiae sensu stricto (IFAKARA)

Abstract

Abstract Background The current rise of new innovative tools for mosquito control such as the release of transgenic mosquitoes carrying a dominant lethal gene and Wolbachia-based strategies necessitates a massive production of mosquitoes in the insectary. However, currently laboratory rearing depends on vertebrate blood for egg production and maintenance. This practice raises, ethical concerns, incurs logistical and cost limitations, and entails potential risk associated with pathogens transmission and blood storage. Consequently, an artificial blood-free diet emerges as an essential alternative to address these challenges. This study aims to evaluate the effects of a previously formulated artificial blood-free diet (herein referred to as BLOODless) on Anopheles gambiae sensu stricto (An. gambiae s.s; IFAKARA) gonotrophic parameters and fitness compared to bovine blood. Methods The study was a laboratory-based comparative evaluation of the fitness, fecundity and fertility of An. gambiae s.s (IFAKARA) reared on BLOODless versus vertebrate blood from founder generation (F0) to eighth generation (F8). A total of 1000 female mosquitoes were randomly selected from F0, of which 500 mosquitoes were fed with bovine blood (control group) and the other 500 mosquitoes were fed with BLOODless diet (experimental group). The feeding success, number of eggs per female, hatching rate and pupation rate were examined post-feeding. Longevity and wing length were determined as fitness parameters for adult male and female mosquitoes for both blood-fed and BLOODless -fed populations. Results While blood-fed and BLOODless-fed mosquitoes showed similar feeding success OR 1.12 (95% CI, 0.82–1.53; P = 0.488), significant difference emerged in their reproductive parameters. The mean number of eggs laid per female was significantly higher for blood-fed mosquitoes P < 0.001 whereas BLOODless-fed mosquitoes had significantly lower hatching rates OR 0.17 (95% CI, 0.14–0.22; P < 0.001). Wing length and longevity parameters were similar between both groups. Conclusion This study demonstrates the potential of the BLOODless diet as a viable and ethical alternative to vertebrate blood feeding for rearing An. gambiae s.s facilitating large-scale mosquito mass production in captivity. This breakthrough paves the way for more efficient and ethical studies aimed at combating malaria and other mosquito-borne diseases.