The Metabolic/Biochemical Basis of Life History Variation and Trade-Offs

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Zera 9808249 One of the most important differences among species is variation in life history traits, such as longevity, the age at which reproduction begins and dispersal capability. Almost nothing is known about the biochemical-genetic basis of life history variation within species, which provides the raw material for the evolution of these traits. This study constitutes the first detailed investigation of this issue and will use wing polymorphism as a model. The polymorphism is common in insects and consists of a long-winged (LW) form which is capable of flight but which delays reproduction, and a short-winged (SW), flightless form which reproduces early in adulthood. The LW form produces large quantities of lipid flight fuel which reduces egg production relative to levels found in SW females. This study will identify the features of lipid metabolism which differ between the wing morphs and which account for both the greater amounts of lipid and the reduced egg production in LW females. Rates of lipid biosynthesis and catabolism and the enzymes involved in these processes will be compared between genetically determined LW vs. SW individuals. In addition, the biochemical and hormonal mechanisms by which increased lipid accumulation causes decreased egg production in the LW form will also be investigated. This study will contribute importantly to our understanding of the biochemical genetic mechanisms responsible for the evolution of life history traits.