Body size is an important determinant of resource use, fecundity and mortality risk. Evolution of maturation size in response to size-dependent selection is thus a fundamental part of life-history theory. Increased mortality among small individuals has previously been predicted to cause larger maturation size, whereas increased mortality among large individuals is expected to have the opposite effect. Here we use a continuously size-structured model to demonstrate that, contrary to these widespread expectations, increased mortality among small individuals can have three alternative effects: maturation size may increase, decrease or become evolutionarily bistable. We show that such complex responses must be reckoned with whenever mortality is size-dependent, growth is indeterminate, reproduction impairs growth and fecundity increases with size. Predicting adaptive responses to altered size-dependent mortality is thus inherently difficult, since, as demonstrated here, such mortality cannot only reverse the direction of but also cause abrupt shifts in evolutionarily stable maturation sizes.
|Journal||Royal Society of London. Proceedings B. Biological Sciences|
|Publication status||Published - 2006|
Bibliographical noteThe information about affiliations in this record was updated in December 2015.
The record was previously connected to the following departments: Theoretical ecology (Closed 2011) (011006011)
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