Skip to main page content
Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2010 Dec 7;277(1700):3659-67.
doi: 10.1098/rspb.2010.1095. Epub 2010 Jun 30.

Kin Competition, Natal Dispersal and the Moulding of Senescence by Natural Selection

Affiliations
Free PMC article

Kin Competition, Natal Dispersal and the Moulding of Senescence by Natural Selection

Ophélie Ronce et al. Proc Biol Sci. .
Free PMC article

Abstract

Most theoretical models for the evolution of senescence have assumed a very large, well mixed population. Here, we investigate how limited dispersal and kin competition might influence the evolution of ageing by deriving indicators of the force of selection, similar to Hamilton (Hamilton 1966 J. Theor. Biol. 12, 12-45). Our analytical model describes how the strength of selection on survival and fecundity changes with age in a patchy population, where adults are territorial and a fraction of juveniles disperse between territories. Both parent-offspring competition and sib competition then affect selection on age-specific life-history traits. Kin competition reduces the strength of selection on survival. Mutations increasing mortality in some age classes can even be favoured by selection, but only when fecundity deteriorates rapidly with age. Population structure arising from limited dispersal however selects for a broader distribution of reproduction over the lifetime, potentially slowing down reproductive senescence. The antagonistic effects of limited dispersal on age schedules of fecundity and mortality cast doubts on the generality of conditions allowing the evolution of 'suicide genes' that increase mortality rates without other direct pleiotropic effects. More generally, our model illustrates how limited dispersal and social interactions can indirectly produce patterns of antagonistic pleiotropy affecting vital rates at different ages.

Figures

Figure 1.
Figure 1.
Age-specific vital rates and the strength of selection acting on them for two different juvenile dispersal rates and a life cycle with an extended period of fecundity. Continuous line: partial dispersal (d = 0.5). Dashed line: complete dispersal (d = 1). (a) Age-specific survival probability p(x) as given by the Siler equation (equation (3.11)) with parameters α1 = 0.1, α2 = 0.01, β1 = 0.8 and β2 = 0.05. Note that this is unaffected by the dispersal rate of juveniles. (b) Effective fecundity formula image as defined by equation (2.2) with intrinsic fecundity b(x) given by equation (3.12) with parameters ɛ = 10 and φ = 0.05. (c) Strength of selection on age-specific log-survival measured by formula image (see equation (3.5)). (d) Strength of selection on age-specific fecundity measured by formula image (see equation (3.10)). With limited dispersal (d = 0.5), the strength of selection on the fecundity of the first age class (not shown) is here about twice as large as the same measure in the case of complete dispersal (d = 1). For clarity of presentation, the indicators of the force of selection have all been standardized by the mean generation time in the case of complete dispersal (T) as given by equation (3.3). The cost of dispersal is null (c = 0).
Figure 2.
Figure 2.
Age-specific vital rates and the strength of selection acting on them for two different juvenile dispersal rates and a life cycle with a narrow period of fecundity. Continuous line: partial dispersal (d = 0.5). Dashed line: complete dispersal (d = 1). (a) Age-specific survival probability p(x) as given by the Siler equation (equation (3.11)) with parameters α1 = 0.1, α2 = 0.01, β1 = 0.8 and β2 = 0.05 (same as in figure 1). Note that this is unaffected by the dispersal rate of juveniles. (b) Effective fecundity formula image as defined by equation (2.2) with intrinsic fecundity b(x) given by equation (3.12) with parameters ɛ = 10 and φ = 0.2. (c) Strength of selection on age-specific log-survival measured by formula image (see equation (3.5)). (d) Strength of selection on age-specific fecundity measured by formula image (see equation (3.10)). With limited dispersal (d = 0.5), the strength of selection on the fecundity of the first age class (not shown) is here about twice as large as the same measure in the case of complete dispersal (d = 1). For clarity of presentation, the indicators of the force of selection have all been standardized by the mean generation time in the case of complete dispersal (T) as given by equation (3.3). The cost of dispersal is null (c = 0).
Figure 3.
Figure 3.
Effective generation time (as given in equation (3.5)) as a function of juvenile dispersal rate. Age-specific survival rates p(x) and fecundities b(x) are as in figure 1 (wide fecundity period, continuous line) and in figure 2 (narrow fecundity period, dashed line), respectively.

Similar articles

See all similar articles

Cited by 7 articles

See all "Cited by" articles
Feedback