Wednesday, 20 November 2002

This presentation is part of : Display Presentations, Section B. Physiology, Biochemistry, Toxicology, and Molecular Biology

Lipid biosynthesis and oxidation in a polymorphic cricket: The biochemical basis of morph specializations for reproduction vs flight-capability

Zhangwu Zhao and Anthony J. Zera. University of Nebraska, School of Biological Sciences, 348 Manter Hall, P.O.Box 68588-0118, Lincoln, NE

Wing polymorphism has been studied extensively from evolutionary, ecological and physiological perspectives to understand the mechanisms underlying trade-offs between dispersal and reproduction. However,little is known about the biochemical basis of morph specializations for these conflicting fuctions. Using either 14C-acetate or 14C palmitate we have documented that the flight-capable morph(LW,long-winged) biosynthesizes a greater amount of total lipid and triglyceride than the flightless(SW,short-winged)morph during the first week of adulthood. Flight experiments have documented that triglyceride is the main flight fuel of Gryllus. On the other hand the SW morph biosynthesizes a greater quanitity of phospholipid(important in egg production) and oxidizes a greater amount of fatty acid than the LW morph. The greater production of triglyceride in the LW morph occurs during the first week of adulthood when ovarian growth is reduced in this morph. All of these biochemical and reproductive differences between morphs are genetically based. Topical application of the Juvenile hormone agonist, methoprene, to the LW morph changed all aspects of lipid metabolism to resemble those of the SW morph. These results document that the LW morph is genetically programmed to accumulate more lipid than the SW morph by increased biosynthesis and decreased lipid oxidation. These adaptations also likely divert nutrients away from egg production and account for the reduced egg production of the LW morph. Genetically-based differences in lipid metabolism between morphs appear to be caused, at lease in part, by modifications of the endocrine control of lipid metabolism.

Species 1: Orthoptera Gryllidae Gryllus (cricket)
Keywords: lipid metabolism, wing polymorphism

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