In evolutionary terms, sex ratio evolution is a classic example of negative frequency-dependent selection
by wild birds promotes polymorphism in model salamanders.
Keywords: Alces alces, antlers, frequency-dependent selection
, moose, phenotypic change, selection plateau, social stress
Clarke (1969) and others (reviewed in Allen 1988) have argued that frequency-dependent selection
on color morphs as a result of differential predation (apostatic selection) is responsible for the maintenance of many visible polymorphisms.
Chemical agents, which are behaviorally and evolutionarily static, may be less likely to induce frequency-dependent selection
on target pests than arise from biocontrol agents, which may be behaviorally plastic and also have their own evolutionary dynamics.
However, this is not necessarily the case: frequency-dependent selection
involving the ADH (alcohol dehydrogenase) locus in laboratory populations of D.
has received wide attention from evolutionary biologists.
The chapters include life-history evolution, foraging theory, frequency-dependent selection
, evolutionary game theory, kin selection, sex ratio theory, sexual selection (in 14 pages!), and the evolution of sex.
, disruptive selection, and the evolution of reproductive isolation.
In addition, Jaenike (1996) proposes that polymorphism may be maintained by frequency-dependent selection
, if distorting males are more rapidly sperm depleted than standard males in multiple matings.
At least one polymorphism was stably maintained by frequency-dependent selection
via a cross-feeding interaction (Turner et al.
434-580), and deals with density-dependent and frequency-dependent selection
and selection on host-pathogen relations.