The stretchin-null flight inability is a promising trait for controlling the population of the vector mosquito, Aedes aegypti

Aedes aegypti is a critical vector for transmitting Zika, dengue, chikungunya, and yellow fever viruses to humans. The efficiency of genetics-based population control strategies, which limit mosquito survival based upon disruption of development, can vary depending on what life stage it is designed to target. In the mosquito life cycle, female adults target host animals for blood to complete egg development. After oviposition on moist substrates occurs in stagnant water, larvae must compete for limited food sources. Early acting lethality may reduce this competition and allow more survivors, while lethality specifically delivered to the pupal phase may preserve this larval competition and therefore may yield more promising population reduction effects in natural habitats. Here, we show that Ae. aegypti stretchin plays significant roles in adult flight behaviors, establishing this gene as a valuable target for late-acting lethality. Through CRISPR/Cas9-mediated genome editing, we revealed that stretchin-null mutations resulted in flightless mosquitoes with an abnormal open wing posture. The inability of stretchin-null mosquitoes to fly restricted their escape from aquatic rearing media following eclosion, and substantially reduced adult survival rates. We also showed that stretchin exhibits an expression pattern in the indirect flight muscles in the pupal thorax, suggesting that Stretchin functions in both the structural assembly of flight muscles during pupal morphogenesis and the dynamics of adult flight. In conclusion, Ae. aegypti pupae-specific stretchin is a key late-acting lethal target for mosquito-borne disease control.