Drosophila pupae resist drying with 29–37-carbon hydrocarbons made by elongase EloHL
Researchers identified the lipid barrier that protects Drosophila melanogaster pupae and young adults from water loss, and the enzyme needed to make it.
In a study published in Science Advances, researchers identified the chemical composition and biosynthetic origin of a lipid barrier that protects Drosophila melanogaster from desiccation at the pupal and sexually immature adult stages science.org
Science Advancesscience.orgOpen source ↗. In many terrestrial insects, the onset of metamorphosis marks a transition from humid to dry environments, but how pupae protect themselves from dehydration had remained unclear.
The barrier consists of unisex hyper-long hydrocarbons, 29 to 37 carbons in length. They are synthesized by larval oenocytes and stored in the larval fat body, then deployed on the pupal and young adult cuticles. The authors show that the fatty acid elongase EloHL is required for the synthesis of these hydrocarbons, which are essential for the barrier to water loss during metamorphosis.
Across the Drosophila genus, many species express unisex profiles of hyper-long hydrocarbons and, as young adults, switch to shorter sex-specific hydrocarbons with known pheromonal functions. The desert species D. mojavensis, however, retains hyper-long hydrocarbons in adulthood, which the authors consider likely an adaptation to an arid environment. According to the authors, the cuticular lipid barrier is tuned to changing environmental pressures during insect development and evolution.
