The behavioral origins of novelty: did increased aggression lead to scale-eating in pupfishes?

Behavioral changes in a new environment are often assumed to precede the origins of evolutionary novelties. Here, we examined whether an increase in aggression is associated with a novel scale-eating trophic niche within a recent radiation of Cyprinodon pupfishes endemic to San Salvador Island, Bahamas. We measured aggression using multiple behavioral assays and used transcriptomic analyses to identify differentially expressed genes in aggression and other behavioral pathways across three sympatric species in the San Salvador radiation (generalist, snail-eating specialist, and scale-eating specialist) and two generalist outgroups. Surprisingly, we found increased behavioral aggression and differential expression of aggression-related pathways in both the scale-eating and snail-eating specialists, despite their independent evolutionary origins. Increased behavioral aggression varied across both sex and stimulus context in both species. Our results indicate that aggression is not unique t...

新环境中的行为变化通常被认为先于进化新奇性的起源。在此，我们研究了在巴哈马圣萨尔瓦多岛特有的Cyprinodon pupfish近期辐射演化中，攻击性增强是否与一种新的食鳞营养生态位相关。我们通过多种行为测定法测量攻击性，并利用转录组分析，在圣萨尔瓦多辐射演化的三种同域物种（广食性、食螺特化种和食鳞特化种）及两种广食性外类群中，鉴定了攻击性及其他行为通路中的差异表达基因。令人惊讶的是，尽管食鳞特化种和食螺特化种具有独立的进化起源，我们仍在这两种物种中发现了行为攻击性增强及攻击性相关通路的差异表达。在这两种物种中，行为攻击性的增强在性别和刺激情境间均存在差异。我们的结果表明，攻击性并非独属于……