The many roles of fat for overwintering insects
Department of Biology, Western University, London, ON, Canada
Temperate, polar, and alpine insects generally do not feed during overwintering, and as a result they must manage stored energy reserves to fuel overwintering metabolism, as well as the energetic demands of development and (in many cases) reproduction in the spring. I will first examine the accumulation, use, and conservation of fat reserves in overwintering insects. Next I will delve into these fat reserves as a dynamic pool of their constituents, and explore the ways insects modify fats to facilitate their selective consumption or conservation. Finally, I will explore other potential roles for fats in overwintering insects. Acetylated triacylglycerols remain liquid at low temperatures and interact with water molecules, providing intriguing possibilities for a role in cryoprotection. Similarly, antifreeze glycolipids may play an important role in structuring water and ice during overwintering. There are several currently unexplained fat-related phenomena in overwintering insects; I will discuss one of these – the accumulation of large quantities of free fatty acids – and speculate on potential new directions for exploring the importance of fat during the winter.