Despite the prevalence and research interest of animal personality, its underlying mechanisms are not yet fully understood. Due to the essential role of monoamines in modulating behaviour, we manipulated the monoaminergic systems of Mediterranean field crickets (Gryllus bimaculatus) to explore whether this altered behavioural responses commonly used to describe also animal personality. Previous work has shown that both serotonin and dopamine manipulations can alter cricket behaviour, although results differ depending on the drug in focus. Here, we investigate the effect of Fluphenazine, a dopamine antagonist which also interacts with serotonin receptors, on activity, exploration, boldness, and aggression. These results are compared with those of our early work that investigated the effect of drugs that more specifically target serotonin and dopamine systems (Fluoxetine and Ropinirole, respectively). Due to limited research on dose-effects of Fluphenazine, we created dose-response curves with concentrations ranging from those measured in surface waters up to human therapeutic doses. We show that compared to control animals, Fluphenazine manipulation resulted in lower levels of both exploration and boldness, but did not affect activity nor aggression. The effect on explorative behaviour contradicts our previous results of serotonin and dopamine manipulations. These results together confirm the causal role of monoamines in explaining variation in behaviour often used to describe animal personality, effects that can be both dose- and behaviour-dependent. Further, our results suggest that previous results assigned specifically to the dopaminergic system, may at least partly be explained by effects of the serotonergic system. Thus, future studies should continue to investigate the explicit underlying roles of specific monoamines in explaining behavioural variation.

中文翻译：

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操纵单胺减少了地中海蟋蟀的探索和大胆

尽管动物个性的普遍性和研究兴趣，但其潜在机制尚未完全了解。由于单胺在调节行为中的重要作用，我们操纵了地中海蟋蟀（Gryllus bimaculatus）的单胺能系统来探索这是否改变了通常用于描述动物个性的行为反应。以前的工作表明，血清素和多巴胺的操作都可以改变蟋蟀的行为，尽管结果因焦点药物而异。在这里，我们研究了氟奋乃静（一种也与血清素受体相互作用的多巴胺拮抗剂）对活动、探索、大胆和攻击性的影响。这些结果与我们早期工作的结果进行了比较，这些工作研究了更具体地针对血清素和多巴胺系统（分别为氟西汀和罗匹尼罗）的药物的作用。由于对氟奋乃静的剂量效应研究有限，我们创建了剂量反应曲线，其浓度范围从地表水中测量的浓度到人类治疗剂量。我们表明，与对照动物相比，氟奋乃静的操作导致探索和大胆的水平较低，但不影响活动或攻击性。对探索行为的影响与我们之前的血清素和多巴胺操作结果相矛盾。这些结果共同证实了单胺在解释通常用于描述动物个性的行为变化方面的因果作用，可以是剂量和行为依赖性的影响。此外，我们的结果表明，先前专门分配给多巴胺能系统的结果，至少可以部分地由血清素能系统的影响来解释。因此，未来的研究应继续调查特定单胺在解释行为变异方面的明确潜在作用。