Data from: Familiarity affects network structure and information flow in guppy (Poecilia reticulata) shoals

How individuals respond toward one another can depend on the level of
familiarity between them. Variation in the proportion of familiar
individuals comprising a group can shape group-level outcomes and group
members’ fitness, but less is known about how this variation shapes the
emergence and structure of social networks or the resulting consequences
for social processes. We formed guppy (Poecilia reticulata) groups in
which individuals were: 1) all familiar with one another, 2) all
unfamiliar, or 3) part of a mixed group of familiar and unfamiliar
individuals. We then examined the fission–fusion dynamics of these shoals,
their social network structure, and the speed and pattern by which
foraging information diffused through them. Although fission–fusion
dynamics were not driven by group composition, differences in social
network structure were observed. Both familiar and unfamiliar groups
exhibited nonrandom network structure, whereas mixed groups expressed more
homogeneous social organization. How quickly—and in what order—individuals
discovered foraging sites was socially influenced, but there was little
evidence for social transmission. More likely, closely associated
individuals discovered foraging sites at similar times to one another as a
result of traveling together. Group composition affected the speed of
information diffusion, with knowledge of the foraging site spreading most
rapidly through mixed groups, potentially due to either their less
structured networks or the dense clustering of highly social individuals
observed in those groups. Our study joins a growing body of literature
pointing to the importance of group composition in driving group-level
patterns and outcomes.