DISSERTATION RESEARCH: Costs of Parental Behavior, and Patterns of Paternal Effort and Paternity in the Pumpkinseed Sunfish (Lepomis gibbosus)

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Like other sunfish, male pumpkinseeds invest substantially in parental care. However, because eggs are fertilized externally, a window of opportunity is open for males adopting an alternative reproductive tactic. These "sneaker" males do not provide parental care; instead they sneak fertilizations in the nest of parental males. Because parental males are cuckolded and their parental behavior is parasitized, the question of how paternity affects parental care is of substantial interest. Using behavioral observations, experimental manipulations, and molecular analyses of paternity in a wild population of pumpkinseed sunfish, this study investigates the success of sneaker males and explores how paternal care is affected by paternity in this species.Intuitively, paternity should be related to parental care, since reproduction is costly and investment in unrelated offspring may be wasted. However, theoretical models suggest that males may adjust their parental care in response to low levels of paternity within their brood under certain conditions but not others. Most of the empirical work testing this theory has been conducted with birds and has produced mixed results. Data and experiments using fish may prove more manageable to studies involving experimental manipulation. This study will be among the first to use molecular techniques to investigate the relationship between paternity and paternal care in a fish, and will also examine the four factors thought to be critical to such a relationship. This study is expected to provide not only valuable information regarding paternal care and alternative reproductive strategies in fishes, but also a different system that may clarify our understanding of paternal effort and paternity.