| Resumo: |
Caswell and Hastings (1980) introduced an explicit model for the relative merits, in terms of growth rate <i>lambda</i>, of developmental shifts vs. fecundity increases. Some aspects of their model are clarified by concentrating on the (fitness >1) half-plane rather than on the (accelerated reproduction) half-plane. There is no strict equivalence between Caswell and Hastings' key parameter <i>lambda/P</i> and the dynamic behaviour of the population which is governed by <i>lambda</i>. Thus in some stationary/declining populations time shifts of reproduction (forward or backward, according to the value of <i>lambda/P</i>) are just as effective in promoting a high <i>lambda</i> as they are in growing populations; therefore selection for higher <i>m</i>, may, but need not, prevail in stationary/declining populations.
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