The behavioral origins of novelty: did increased aggression lead to scale-eating in pupfishes?
The behavioral origins of novelty: did increased aggression lead to scale-eating in pupfishes?
复制标题
新奇的行为起源：攻击性的增加是否会导致鳉鱼吃鳞？
DOI：
10.1093/beheco/ary196
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发表时间：
2019
影响因子：
2.4
通讯作者：
Martin, Christopher H
中科院分区：
文献类型：
--
作者：
St. John, Michelle E;McGirr, Joseph A;Martin, Christopher H
新环境中的行为变化通常被认为先于进化新奇事物的起源。在这里，我们研究了攻击性的增加是否与最近巴哈马圣萨尔瓦多岛特有的鲤鱼蛹鱼辐射中一种新的食鳞性营养生态位有关。我们使用多个行为分析来测量攻击性，并使用转录分析来确定在圣萨尔瓦多辐射中的3个共域物种(多面手、吃蜗牛专家和吃鳞专家)和2个多面手外群中攻击性和其他行为途径的差异表达基因。令人惊讶的是，我们发现，尽管鳞片食蜗牛专家和吃蜗牛专家的进化起源是独立的，但他们的行为攻击性和攻击相关途径的差异表达都有所增加。在两个物种中，行为攻击性的增加在性别和刺激环境中都有所不同。我们的结果表明，攻击性并不是食鳞专家所特有的。相反，选择可能会在其他情况下增加攻击性，例如一般的小生境专门化或配偶竞争。或者，攻击性的增加可能是由于对头面部特征、色素沉着或新陈代谢的间接选择--所有这些特征都是高度分化的，表现出选择性扫描的迹象，并受到与攻击相关的遗传途径的影响，这些遗传途径在这个系统中有差异地表达。总之，在最近的适应性辐射中，一种新的捕食性营养生态位的进化并不像先前假设的那样具有明确的行为起源，突出了适应的多变量性质以及行为与其他表型特征的复杂整合。
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 ofCyprinodonpupfishes 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 3 sympatric species in the San Salvador radiation (generalist, snail-eating specialist, and scale-eating specialist) and 2 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 to scale-eating specialists. Instead, selection may increase aggression in other contexts such as niche specialization in general or mate competition. Alternatively, increased aggression may result from indirect selection on craniofacial traits, pigmentation, or metabolism—all traits which are highly divergent, exhibit signs of selective sweeps, and are affected by aggression-related genetic pathways which are differentially expressed in this system. In conclusion, the evolution of a novel predatory trophic niche within a recent adaptive radiation does not have clear-cut behavioral origins as previously assumed, highlighting the multivariate nature of adaptation and the complex integration of behavior with other phenotypic traits.