Identifying the genetic architecture underlying phenotypic variation in natural populations and assessing the consequences of polymorphisms for individual fitness are fundamental goals in evolutionary and molecular ecology. Consistent between‐individual differences in behaviour have been documented for a variety of taxa. Dissecting the genetic basis of such behavioural differences is however a challenging endeavour. The molecular underpinnings of natural variation in aggression remain elusive. Here, we used comparative gene expression (transcriptome analysis and RT–PCR), genetic association analysis and pharmacological experiments to gain insight into the genetic basis of aggression in wild‐caught jumping spiders (Portia labiata ). We show that spider aggression is associated with a putative viral infection response gene, BTB/POZ domain‐containing protein 17 (BTBDH), in addition to a putative serotonin receptor 1A (5‐HT1A) gene. Spider aggression varies with virus loads, and BTBDH is upregulated in docile spiders and exhibits a genetic variant associated with aggression. We also identify a putative serotonin receptor 5‐HT1A gene upregulated in docile P. labiata . Individuals that have been treated with serotonin become less aggressive, but individuals treated with a nonselective serotonin receptor antagonist (methiothepin) also reduce aggression. Further, we identify the genetic variants in the 5‐HT1A gene that are associated with individual variation in aggression. We therefore conclude that co‐evolution of the immune and nervous systems may have shaped the between‐individual variation in aggression in natural populations of jumping spiders.

中文翻译：

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雌性蜘蛛的攻击行为与神经系统的遗传基础和对病原体的免疫反应有关。

识别自然种群表型变异背后的遗传结构并评估多态性对个体适应性的影响是进化和分子生态学的基本目标。各种分类单元的行为之间始终存在一致差异。剖析这种行为差异的遗传基础是一项具有挑战性的工作。侵略性自然变化的分子基础仍然难以捉摸。在这里，我们使用了比较基因表达（转录组分析和RT-PCR），遗传关联分析和药理实验，以了解野外跳跃蜘蛛（Portia labiata）侵略的遗传基础。）。我们显示蜘蛛的攻击行为除了可能的血清素受体1A（5-HT1A）基因外，还与假定的病毒感染应答基因，包含BTB / POZ域的蛋白17（BTBDH）相关。蜘蛛的侵略性随病毒载量而变化，并且顺服性蜘蛛中的BTBDH上调，并表现出与侵略性相关的遗传变异。我们还发现了温顺的体育唇形虫中5-羟色胺受体5-HT1A基因上调。。用5-羟色胺治疗的个体的攻击力减弱，但是用非选择性5-羟色胺受体拮抗剂（甲氧西平）治疗的个体也减少了攻击性。此外，我们确定了5‐HT1A基因中与攻击性个体变异相关的遗传变异。因此，我们得出结论，免疫系统和神经系统的共同进化可能已经塑造了跳跃蜘蛛自然种群中个体之间攻击性的差异。