Data from: The making of winners (and losers): how early dominance interactions determine adult social structure in a clonal fish

Across a wide range of animal taxa, winners of previous fights are more likely to keep winning future contests, just as losers are more likely to keep losing. At present, such winner and loser effects are considered to be fairly transient. However, repeated experiences with winning and/or losing might increase the persistence of these effects generating long-lasting consequences for social structure. To test this, we exposed genetically identical individuals of a clonal fish, the Amazon molly (Poecilia formosa), to repeated winning and/or losing dominance interactions during the first two months of their life. We subsequently investigated whether these experiences affected the fish’s ability to achieve dominance in a hierarchy five months later during adulthood. Individuals that had only winning interactions early in life consistently ranked at the top of the hierarchy. Interestingly, individuals with only losing experience tended to achieve the middle dominance rank, whereas individuals with both winning and losing experiences generally ended up at the bottom of the hierarchy. In addition to demonstrating that early social interactions can have dramatic and long-lasting consequences for adult social behaviour and social structure, our work also shows that higher cumulative winning experience early in life can counter-intuitively give rise to lower social rank later in life.在广泛的动物分类群中，先前在争斗中获胜的个体后续更易持续赢得竞争，而先前落败的个体也更可能继续遭遇失败。目前学界普遍认为，这类胜负效应的持续时间相对短暂。然而，反复经历获胜或/和失败，或许会增强这些效应的持久性，进而对种群社会结构产生长期影响。为验证这一假说，我们将基因完全一致的克隆鱼——亚马逊花鳉（Amazon molly, *Poecilia formosa*）——在其生命的前两个月，置于反复的获胜或/和失败的支配性互动情境中。随后，我们在五个月后，即这些幼鱼发育至成年阶段时，探究了早期的这些经历是否会影响它们在群体优势等级中获得支配地位的能力。仅在早期经历获胜互动的个体，始终在优势等级中处于顶端位置。值得注意的是，仅经历过失败的个体往往会处于优势等级的中间位次；而同时经历过获胜与失败的个体，最终大多处于等级的底层。本研究不仅证实了早期社会互动会对成年个体的社会行为与社会结构产生显著且持久的影响，同时还揭示了一个反直觉的现象：生命早期积累的获胜经验越多，个体在成年后的社会地位反而越低。