Differential partitioning of maternal fatty acid and phospholipid in neonate mosquito larvae

In animals, lipids are a source of energy, cell membrane components, signaling pathway modulators and emulsifying agents. In egg-laying animals, maternal yolk lipids, imported into the egg before laying, are metabolized or distributed in the developing embryo to serve these functions. Studies with birds, reptiles and insects have described lipid metabolism in adults and in eggs, but no studies have addressed how lipids are distributed in developing organs in the embryo. Here we show that maternal fatty acid and phospholipids segregate differently in tissues of newly hatched mosquito larvae. In the mother, both lipids are colocalized in yolk granules of developing oocytes and distributed evenly. In neonate larvae, however, the maternal fatty acid is stored along the side of the body, especially at the base of the body hair, and in the thorax, where the muscles are located, probably to provide energy for the rapid movements needed to find food immediately after birth. Most maternal phospholipids, however, are concentrated in the motile intestinal gastric caeca, from which they are released into the gut lumen where they may act as emulsifiers, probably to facilitate assimilation of the food the neonate ingests. Similar phenomena were observed in both Anopheles gambiae and Aedes aegypti mosquitoes, suggesting that such differential segregation of lipids is common to both insects. This study may lead to improved delivery of larvicidal agents and to efficient killing of newly hatched mosquito larvae as a control strategy for mosquito-borne diseases.