On a long-term scale, this storage effect can have significant impacts on selection, especially if selection is fluctuating over a long period of time. It is inarguable that selection will fluctuate over time with varying levels of environmental stability. For example, fluctuations in population density can drive selection on sex-limited traits. In less dense populations, females will have less opportunity to choose between males for reproduction. In this case, attractive males may experience both reduced reproductive success and increased predation pressure.
Thus, selection on males for sex-limited traits such as increased size (elephant seals) and weaponry (claws on fiddler crabs, horns on rhinoceros beetles) will change direction with fluctuation in population density.
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