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Elaborate mating displays and the physiological costs they incur.
Delph, Lynda*,1, 1 Indiana University, Bloomington, IN
ABSTRACT- Genetically based variation exists in the number and size of flowers produced among populations of the dioecious plant Silene latifolia , which also exhibits strong sexual dimorphism in floral traits (males make many, small flowers compared to females). Artificial selection experiments have revealed that flower size/number is strongly genetically correlated with vegetative and physiological traits. Direct selection on floral display comes with correlated responses for a host of other traits, including leaf traits, overall plant size, and metabolism. For example, plants that make many, small flowers are smaller and produce smaller, thinner leaves with higher rates of photosynthesis and respiration than do lines selected for making few, large flowers. These results suggest that selection on floral traits cannot be independently selected without also indirectly selecting for physiological traits, and vice versa. Hence, the potential exists for the abiotic environment to constrain selection on floral traits via mating success or pollinator-mediated selection. Clearly, an understanding of why populations of this species vary in their floral traits requires knowledge of the genetic correlations among traits.
Key words: artificial selection, sexual dimorphism, correlated responses