Effects of mortality risk and growth on a model of reproductive effort: Why the shine and Schwarzkopf model is not general

摘要

Using data and reanalysis of a model published by Shine and Schwarzkopf (1992) we reject the two unsubstantiated assertions made by Shine et al. (1996) about modeling the evolution of reproductive effort in squamate reptiles: (1) mortality schedules do not affect predictions of the Shine and Schwarzkopf (1992) model; and (2) growth rates that would affect the predictions of the original model are biologically unreasonable. On the basis of these two points alone, we strongly reject Shine et al.'s (1996) claim that a critique by Niewiarowski and Dunham (1994) actually reinforces the original conclusions of Shine and Schwarzkopf (1992). Furthermore, results and data presented here are strong enough to severely circumscribe the generality of the Shine and Schwarzkopf (1992) model. Though we do not provide data or new analyses of the potential effects of offspring size variation, we reaffirm the position of Niewiarowski and Dunham (1994) that the sensitivity of the Shine and Schwarzkopf (1992) model to such effects should be explored before using it as a basis for structuring future research on the evolution of reproductive effort in squamate reptiles. [References: 12]