Habitat connectivity alone can determine who disperses
Dispersal is usually studied as a function of whether, when and how far individuals should move. When dispersal is obligatory, a more fundamental question arises: who should disperse? Here we show that habitat connectivity can shape the answer. Using evolutionary graph theory, we model situations in which either the parent or offspring controls the probability of remaining at the breeding site versus dispersing. Although one individual must disperse after every reproductive event, connectivity heterogeneity consistently selects for philopatry by the controlling individual. Consequently, parental control produces natal dispersal, whereas offspring control produces breeding dispersal. This effect arises solely from network structure and persists across demographic update rules and competition regimes. The resulting stationary distribution of the evolving philopatry trait is uniformly distributed on regular networks but increasingly biased toward philopatry on heterogeneous networks. The strength of this bias depends on how connectivity heterogeneity scales with habitat size. In star habitats, the bias becomes analytically tractable. Our results reveal habitat connectivity as a source of selection on who disperses. These results have ramifications for evolutionary graph theory, showing that dispersal strategies can endogenize population-structure effects that are typically imposed as fixed model features.
This is work with Nikhil Sharma, Mark Broom and Arne Traulsen.
This IFISC Seminar will be broadcasted in the following zoom link: https://us06web.zoom.us/j/89466064429?pwd=po9p99eAEYVPaNI8xIIGoOIz0hOqaF.1
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