Data from: Evolution of non-kin cooperation: social assortment by cooperative phenotype in guppies

Cooperation among non-kin constitutes a conundrum for evolutionary
biology. Theory suggests that non-kin cooperation can evolve if
individuals differ consistently in their cooperative phenotypes and assort
socially by these, such that cooperative individuals interact
predominantly with one another. However, our knowledge of the role of
cooperative phenotypes in the social structuring of real-world animal
populations is minimal. In this study, we investigated cooperative
phenotypes and their link to social structure in wild Trinidadian guppies
(Poecilia reticulata). We first investigated whether wild guppies are
repeatable in their individual levels of cooperativeness (i.e. have
cooperative phenotypes) and found evidence for this in seven out of eight
populations, a result which was mostly driven by females. We then examined
the social network structure of one of these populations where the
expected fitness impact of cooperative contexts is relatively high, and
found assortment by cooperativeness, but not genetic relatedness. In
contrast, in accordance with our expectations we did not find assortment
by cooperativeness in a population where the expected fitness impact of
cooperative contexts is lower. Our results provide empirical support for
current theory and suggest that assortment by cooperativeness is important
for the evolution and persistence of non-kin cooperation in real-world
populations.