ABSTRACT
An initial period of carbohydrate-fueled flight undoubtedly allows time for the hormonally induced mobilization of lipids to gather pace and allows “activation” of flight muscle enzymes to facilitate their utilization. In most lipid-utilizing insects, adequate supplies of lipids to the flight muscles during flight are provided by the mobilization of triacylglycerol stores in the fat body. The chapter is concerned specifically with the mobilization of fuels and their transport. Insects transport their major fuels predominantly in forms that are nonreducing, neutral, and contribute less to osmotic pressure. The major form in which lipids are transported through the hemolymph is as diacylgly-cerols, 13-15 although many lipid-utilizing insects may also use carbohydrates to some extent during flight. The water-insoluble nature of neutral lipids dictates that they are transported through the hemolymph as part of soluble complexes, lipoproteins, to enable high concentrations to be attained.
