As temperatures rise across the globe, scientists have identified a specialized lipid barrier that protects developing fruit flies from dehydration. This finding may help explain insects\u2019 ability to adapt to changing temperatures.<\/p>\n
Fruit flies, or Drosophila, begin life as larvae that feed and burrow in decomposing fruit. Before becoming adults, they move to drier environments and enter the pupal stage, during which they undergo metamorphosis. <\/p>\n
According to the team at the Francis Crick Institute, adult fruit flies have a hydrophobic lipid coating made of long hydrocarbon molecules that blocks water loss. Before this, researchers did not know how pupae protected themselves against dehydration.<\/p>\n
To investigate this protective mechanism, the team adapted analytical methods used in the petroleum industry and combined them with molecular imaging techniques.<\/p>\n
Secret to hydration<\/p>\n
The researchers found no detectable hydrocarbons on the outer body of the pupae, called the cuticle. Instead, the protective barrier was lined on the inner side of the cuticle and contained hyper-long hydrocarbons, much longer than those typically found on mature adult flies<\/a>.<\/p>\n The study also found that specialized cells in the larva, called oenocytes, produce these hydrocarbons before metamorphosis. The molecules are stored in the larval fat body until they are needed during the transition to the pupal stage.<\/p>\n Co-first author and principal laboratory research scientist at the institute, Clare Newell said that the immobile pupal stage is especially vulnerable because it cannot move to a cooler or less dry environment.<\/p>\n \u201cIt\u2019s fascinating that the larva prepares for this challenge before metamorphosis, building a resource of hyper-long hydrocarbons. Embracing techniques normally used outside biology helped us to reveal one of the many hidden secrets of metamorphosis,\u201d she added.<\/p>\n In the study, they discovered \u201ca key enzyme that ensures the development of a specific lipid barrier in the pupa that protects it from water loss in hot and arid conditions.\u201d<\/p>\n The researchers noted that Drosophila can survive only within certain environmental limits, and their research on this enzyme has helped define those boundaries.<\/p>\n According to the study, longer hydrocarbons were associated with greater dehydration resistance. Shorter hydrocarbons were more volatile and functioned as airborne chemical signals.<\/p>\n The researchers examined six fruit fly species and found that five generally transitioned toward shorter hydrocarbons during adult maturation.<\/p>\n However, the desert species Drosophila mojavensis retained hyper-long hydrocarbons even as an adult.<\/p>\n The study\u2019s authors suggested that maintaining these longer molecules may reflect the importance of dehydration resistance in arid environments, possibly helping their survival<\/a> in extreme conditions.<\/p>\n Climate change impacts insects<\/p>\n The researchers concluded that the lipid barrier protecting Drosophila melanogaster during metamorphosis cannot prevent lethal dehydration when high temperatures and low humidity occur together.<\/p>\n