The U-shape variation pattern of glycerol-trioleate hydrolase activity during embryonic development ofPhilosamia ricini suggests its maximum activity during initial and final stages of embryogenesis and evinces the marked utilization of lipoidal energy both for development and tissue formation. High lipase activity during the enormous feeding larval period depicts its role in lipid transport to the site of utilization. During prepupal stage the enzymic activity declines and practically becomes nil during larval-pupal transformation. This is subsequently followed by a rise till day 9. After registering the minimum activity on day 13, the enzyme becomes very active after emergence of the adult suggesting the role of triglycerides as fuel for movement.
Fat body lipolytic activity pattern concurs with that for the entire tissue depicting an overall utilization of lipids during rest as well as movement. Thus triglycerides inPhilosamia ricini appear to play the role of an energy regulator during periods of high metabolic demands like oogenesis, development and flight and are transported to the active site under the influence of triglyceride hydrolases to provide the necessary supply of long chain fatty acids. The increase in triglyceride hydrolase activity during development could be correlated with the increase in general metabolic rate.