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Observational evidence that maladaptive gene flow reduces patch occupancy in a wild insect metapopulation
Author(s) -
Farkas Timothy E.,
Mon Tommi,
Comeault Aaron A.,
Nosil Patrik
Publication year - 2016
Publication title -
evolution
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.84
H-Index - 199
eISSN - 1558-5646
pISSN - 0014-3820
DOI - 10.1111/evo.13076
Subject(s) - metapopulation , biological dispersal , biology , occupancy , ecology , abundance (ecology) , gene flow , habitat , host (biology) , local adaptation , evolutionary biology , population , genetic variation , gene , genetics , demography , sociology
Theory predicts that dispersal throughout metapopulations has a variety of consequences for the abundance and distribution of species. Immigration is predicted to increase abundance and habitat patch occupancy, but gene flow can have both positive and negative demographic consequences. Here, we address the eco‐evolutionary effects of dispersal in a wild metapopulation of the stick insect Timema cristinae , which exhibits variable degrees of local adaptation throughout a heterogeneous habitat patch network of two host‐plant species. To disentangle the ecological and evolutionary contributions of dispersal to habitat patch occupancy and abundance, we contrasted the effects of connectivity to populations inhabiting conspecific host plants and those inhabiting the alternate host plant. Both types of connectivity should increase patch occupancy and abundance through increased immigration and sharing of beneficial alleles through gene flow. However, connectivity to populations inhabiting the alternate host‐plant species may uniquely cause maladaptive gene flow that counters the positive demographic effects of immigration. Supporting these predictions, we find the relationship between patch occupancy and alternate‐host connectivity to be significantly smaller in slope than the relationship between patch occupancy and conspecific‐host connectivity. Our findings illustrate the ecological and evolutionary roles of dispersal in driving the distribution and abundance of species.