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Experimental competition induces immediate and lasting effects on the neurogenome in free-living female birds

ABSTRACT: Periods of social instability can elicit adaptive phenotypic plasticity to promote success in future competition. However, the underlying molecular mechanisms have primarily been studied in captive and lab-reared animals, leaving uncertainty as to how natural competition among free-living animals affects gene activity. Here, we experimentally generated social competition among wild, cavity-nesting female birds (tree swallows, Tachycineta bicolor). After territorial settlement, we reduced the availability of key breeding resources (i.e., nest boxes), generating heightened competition; within 24 hr we reversed the manipulation, causing aggressive interactions to subside. We sampled females during the peak of competition and 48hr after it ended, along with date-matched controls. We measured transcriptomic and epigenomic responses to competition in two socially relevant brain regions (hypothalamus and ventromedial telencephalon). Gene network analyses suggest that processes related to energy mobilization and social aggression (e.g., dopamine synthesis) were upregulated during competition, the latter of which persisted 2 days after competition had ended. Cellular maintenance processes were also downregulated after competition. Competition additionally altered methylation patterns, particularly in pathways related to hormonal signaling, which appeared transcriptionally poised to respond to future competition . Thus, experimental competition among free-living animals shifts gene expression in ways that may facilitate the demands of competition at the expense of self-maintenance. Further, some of these effects persisted after competition ended, demonstrating the potential for epigenetic biological embedding of the social environment in ways that could “prime” individuals for success in future social instability.

ORGANISM(S): Tachycineta bicolor

PROVIDER: GSE155864 | GEO | 2021/03/10

REPOSITORIES: GEO

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Experimental competition induces immediate and lasting effects on the neurogenome in free-living female birds

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