Magnesium Regulation in Mosquito Larvae (Aedes Campestris) Living in Waters of High MgSO4 Content

Abstract

1. Although larvae of A. campestris can live in natural waters in which the magnesium content may vary seasonally from extremes of 1 to more than 100 mM, the haemolymph levels of magnesium vary only from 1·5 to 4 mM. 2. Larvae survive in water containing 90 mM-Mg and drink their own body weight every few hours, the ingested fluid and the magnesium ions being largely absorbed into the haemolymph via the midgut. 3. The urinary concentration of Mg²⁺ ions was always substantially higher than that of the external media and up to 23 times that of the haemolymph. 4. It is suggested that magnesium is not excreted across the general body surface, the Malpighian tubules and hindgut being largely responsible for removing magnesium from the haemolymph. 5. These physiological observations are discussed in relation to the environmental conditions under which larvae are naturally found.