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The Effects of Xenoestrogens on Optimal Mate Choice and Offspring Fitness in the Gulf Pipefish, Syngnathus scovelliEPA Grant Number: FP916441
Title: The Effects of Xenoestrogens on Optimal Mate Choice and Offspring Fitness in the Gulf Pipefish, Syngnathus scovelli
Investigators: Partridge, Charlyn
Institution: Georgia Institute of Technology - Main Campus
EPA Project Officer: Manty, Dale
Project Period: January 1, 2004 through December 31, 2006
Project Amount: $98,211
RFA: STAR Graduate Fellowships (2004) RFA Text | Recipients Lists
Research Category: Fellowship - Toxicology , Academic Fellowships , Health Effects
Over the past 20 years, a number of synthetic compounds have been shown to exhibit estrogen-like activity. These xenoestrogens cause a disruption to specific endocrine pathways and possess the potential to have a major impact on the reproductive viability of a number of different systems. The long-term objective of this research is to determine if endocrine disruptors can disrupt sexual selection mechanisms and optimal mate choice behaviors in natural populations. The model system used in this study is the Gulf pipefish because of its reversal of sex roles concerning mating behavior. Female competition has led to secondary sexual traits that are used as visual signals by males to determine female quality. Because these sexual character traits are estrogen regulated, the manipulation of perceived female quality through exposure to a synthetic estrogen (17α-ethinylestradiol, EE2) can be achieved. This study will allow us to determine the effect of xenoestrogen exposure on female dominance recognition by males and how male mate choice affects offspring fitness.
Female pipefish will be exposed to either a control, 0.5 ng/L EE2, or 1 ng/L EE2 for 10 days, and the intensity of female secondary sexual traits will be scored. The effect of each treatment on male mate choice will be determined by standard mate choice experiments, which evaluate the amount of time the male spends courting each female and the female chosen by the male for mating. The effects of exposure on reproductive success and offspring fitness will be assessed by observing embryonic development time after impregnation, offspring growth rates, and offspring survival. Both a subtraction library and candidate gene approach will be used to determine how genetic regulation of these secondary sexual traits is affected by EE2 exposure.