Challenging the popular belief, mosquito larvae breath underwater (but pupae do not)

ALVAREZ-COSTA, A.; LEONARDI, M.S.; GIRAUD, S.; SCHILMAN, P.E.; LAZZARI, C.R.

Congreso; XII European Congress of Entomology (ECE 2023); 2023

It is often taken for granted that mosquito larvae only breathe through their siphons when they rest attached to the water surface. In order to establish whether or not immature mosquitoes are able to survive without contact with the surface and to obtain physiologically relevant amounts of oxygen from water, we analyzed the survival of the last instar-larvae of Aedes aegypti fully submerged at different temperatures. We also measured the consumption of oxygen from the air and dissolved in the water, of larvae and pupae of this species under different conditions. When kept submerged in water and no food was provided, larvae survived much longer than expected, some individuals, more than 2 moths at 15°C. Individuals kept submerged rarely molted. When remained at the water surface, larvae obtained 12.72% of the from the water, while pupae obtained only 5.32% form the water. When they are completely immersed, larvae were able to gather 100% of the needed oxygen for surviving from the water while pupae did not. Temperature affected larvae respiration rate both from air and from water, with relatively close Q10 values. So, while oxygen consumption was not a limiting factor for surviving, molting seems to constitute the critical factor responsible for the death of the A. aegypti larvae. Our findings force us to reconsider the classical idea that mosquito larvae only breathe air, as well as the potential effectiveness of control methods based on asphyxiating larvae.