Dynamic shifts in social network structure and composition within a breeding hybrid population

1. Mating behavior and the timing of reproduction can inhibit genetic
exchange between closely related species; however, these reproductive
barriers are challenging to measure within natural populations. Social
network analysis provides promising tools for studying the social context
of hybridization, and the exchange of genetic variation, more generally.
2. We test how social networks within a hybrid population of California
(Callipepla californica) and Gambel’s quail (Callipepla gambelii) change
over discrete periods of a breeding season. We assess patterns of
phenotypic and genotypic assortment, and ask whether altered associations
between individuals (association rewiring), or changes to the composition
of the population (individual turnover) drive network dynamics. We use
genetic data to test whether social associations and relatedness between
individuals correlate with patterns of parentage within the hybrid
population. 3. To achieve these aims, we combine RFID association data,
phenotypic data, and genomic measures with social network analyses. We
adopt methods from the ecological network literature to quantify shifts in
network structure and to partition changes into those due to individual
turnover and association rewiring. We integrate genomic data into networks
as node-level attributes (ancestry) and edges (relatedness, parentage) to
test links between social and parentage networks. 4. We show that rewiring
of associations between individuals that persist across network periods,
rather than individual turnover, drives the majority of the changes in
network structure throughout the breeding season, and that the traits
involved in phenotypic/genotypic assortment were highly dynamic over time.
Social networks were randomly assorted based upon genetic ancestry,
suggesting weak behavioral reproductive isolation within this hybrid
population. Finally, we show that the strength of associations within the
social network, but not levels of genetic relatedness, predict patterns of
parentage. 5. Social networks play an important role in population
processes such as the transmission of disease and information, yet there
has been less focus on how networks influence the exchange of genetic
variation. By integrating analyses of social structure, phenotypic
assortment, and reproductive outcomes within a hybrid zone, we demonstrate
the utility of social networks for analyzing links between social context
and gene flow within wild populations. 08-Jul-2020