TY  - JOUR
A1  - Gros, Andreas
A1  - Poethke, Hans Joachim
A1  - Hovestadt, Thomas
T1  - Sex-specific spatio-temporal variability in reproductive success promotes the evolution of sex-biased dispersal
N2  - Abstract: Inbreeding depression, asymmetries in costs or benefits of dispersal, and the mating system have been identified as potential factors underlying the evolution of sex-biased dispersal. We use individual-based simulations to explore how the mating system and demographic stochasticity influence the evolution of sex-specific dispersal in a metapopulation with females competing over breeding sites, and males over mating opportunities. Comparison of simulation results for random mating with those for a harem system (locally, a single male sires all offspring) reveal that even extreme variance in local male reproductive success (extreme male competition) does not induce male-biased dispersal. The latter evolves if the between-parch variance in reproductive success is larger for males than females. This can emerge due to demographic stochasticity if the habitat patches are small. More generally, members of a group of individuals experiencing higher spatio-temporal variance in fitness expectations may evolve to disperse with greater probability than others.
KW  - sex-biased dispersal
KW  - demographic stochasticity
KW  - metapopulation
KW  - individual-based simulation
KW  - sex-specific competition
Y1  - 2009
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-48711
ER  - 
TY  - JOUR
A1  - Gros, Andreas
A1  - Hovestadt, Thomas
A1  - Poethke, Hans Joachim
T1  - Evolution of sex-biased dispersal : the role of sex-specific dispersal costs, demographic stochasticity, and inbreeding
N2  - Abstract: Inbreeding avoidance and asymmetric competition over resources have both been identified as factors favoring the evolution of sex-biased dispersal. It has also been recognized that sex-specific costs of dispersal would select for sex-biased dispersal, but there is little quantitative information on this aspect. In this paper we explore (i) the quantitative relationship between cost-asymmetry and a bias in dispersal, (ii) the influence of demographic stochasticity on this effect, and (iii) how inbreeding and cost-asymmetry interact in their effect on sex-specific dispersal. We adjust an existing analytical model to account for sex-specific costs of dispersal. Based on numerical calculations we predict a severe bias in dispersal already for small differences in dispersal costs. We corroborate these predictions in individual-based simulations, but show that demographic stochasticity generally leads to more balanced dispersal. In combination with inbreeding, cost asymmetries will usually determine which of the two sexes becomes the more dispersive.
KW  - asymmetric dispersal costs
KW  - kin-selection
KW  - numerical model
KW  - individual-based simulations
Y1  - 2008
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-48705
ER  - 
TY  - JOUR
A1  - Gros, Andreas
A1  - Hovestadt, Thomas
A1  - Poethke, Hans Joachim
T1  - Evolution of local adaptions in dispersal strategies
N2  - The optimal probability and distance of dispersal largely depend on the risk to end up in unsuitable habitat. This risk is highest close to the habitat’s edge and consequently, optimal dispersal probability and distance should decline towards the habitat’s border. This selection should lead to the emergence of spatial gradients in dispersal strategies. However, gene flow caused by dispersal itself is counteracting local adaptation. Using an individual based model we investigate the evolution of local adaptations of dispersal probability and distance within a single, circular, habitat patch. We compare evolved dispersal probabilities and distances for six different dispersal kernels (two negative exponential kernels, two skewed kernels, nearest neighbour dispersal and global dispersal) in patches of different size. For all kernels a positive correlation between patch size and dispersal probability emerges. However, a minimum patch size is necessary to allow for local adaptation of dispersal strategies within patches. Beyond this minimum patch area the difference in mean dispersal distance between center and edge increases linearly with patch radius, but the intensity of local adaptation depends on the dispersal kernel. Except for global and nearest neighbour dispersal, the evolved spatial pattern are qualitatively similar for both, mean dispersal probability and distance. We conclude, that inspite of the gene-flow originating from dispersal local adaptation of dispersal strategies is possible if a habitat is of sufficient size. This presumably holds for any realistic type of dispersal kernel.
KW  - Ausbreitung
KW  - Evolution
KW  - Computersimulation
KW  - Ökologie
KW  - nearest-neighbour dispersal
KW  - global dispersal
KW  - evolution
KW  - individual based simulation
Y1  - 2006
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-45406
ER  -