A central question in life history theory is, what combination of traits and behaviors will lead to the highest reproductive success throughout a lifetime. The trade-off between current and future reproduction is central to the lifetime reproductive success of an organism. If there is a cost to reproduction, then allocation of energy to current reproduction will come at a cost to future reproduction. We expect young individuals to favor future reproduction over current reproduction and that balance shifts to current reproduction as they age (i.e. terminal investment hypothesis). However, how this transition from an emphasis on future reproduction to emphasis on current reproduction changes throughout a lifetime should depend on environmental factors like mortality and resource availability. We test for the generality of terminal investment across three species of poecilliid fishes in a range of environments. We found evidence of terminal investment in all three species in both high and low mortality environments and high and low resource availability environments. In general, high mortality or high resource availability tended to result in a decreased slope of the relationship between reproductive allocation and body size. Terminal investment appears to be general, even though there was an effect of high mortality and resource availability, it was not sufficient to completely preclude terminal investment.



College and Department

Life Sciences; Biology



Date Submitted


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life history, terminal investment, cost of reproduction, Poeciliidae, reproductive investment

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Biology Commons