The Adaptation of Mosquito Larvae to Salt Water

It is well known that the larvae of certain mosquitoes can thrive both in fresh water and in water of a high degree of salinity, while the larvae of other mosquitoes are quickly killed by salt water ; and that such differences may exist even between local races of the same species (Evans, 1931). It is evident that we have here to deal with a physiological adaptation, and it was the object of the present work to discover what the nature of this adaptation might be. The physiological properties of larvae of the yellow-fever mosquito (Aedes (Stegomyia) argenteus Poir), which were accustomed to salt water, have been compared with those same properties in normal larvae. It so happens that this particular larva is unable to tolerate very salt water ; but it is probable that the relatively small degree of resistance which it can acquire is of the same kind as that occurring in more tolerant species, and therefore the mechanism of this resistance may throw light upon the general problem.