Age-Specific Reproductive Tactics

A simple graphical model for maximization of total lifetime reproductive success is developed using the demographic parameters of current fecundity and residual reproductive value. Trade-offs between present progeny and expectation of future offspring are treated in terms of costs and profits to lifetime reproductive success. Various limitations of the model and some relevant data are presented and discussed. Single-clutched species are distinguished from those that lay multiple clutches each reproductive season, because residual reproductive value in the latter group varies proportionally much more during ontogeny than in the former group. Some difficulties in measuring reproductive effort in a changing environment are pointed out.