Changes in ecological preference, often driven by spatial and temporal variation in resource distribution, can expose populations to environments with divergent information content. This can lead to adaptive changes in the degree to which individuals invest in sensory systems and downstream processes, to optimize behavioural performance in different contexts. At the same time, environmental conditions can produce plastic responses in nervous system development and maturation, providing an alternative route to integrating neural and ecological variation. Here, we explore how these two processes play out across a community of Heliconius butterflies. Heliconius communities exhibit multiple Mullerian mimicry rings, associated with habitat partitioning across environmental gradients. These environmental differences have previously been linked to heritable divergence in brain morphology in parapatric species pairs. They also exhibit a unique dietary adaptation, known as pollen feeding, that relies heavily on learning foraging routes, or trap-lines, between resources, which implies an important environmental influence on behavioural development. By comparing brain morphology across 133 wild-caught and insectary-reared individuals from seven Heliconius species, we find strong evidence for interspecific variation in patterns of neural investment. These largely fall into two distinct patterns of variation; first, we find consistent patterns of divergence in the size of visual brain components across both wild and insectary-reared individuals, suggesting genetically encoded divergence in the visual pathway. Second, we find interspecific differences in mushroom body size, a central component of learning and memory systems, but only among wild caught individuals. The lack of this effect in common-garden individuals suggests an extensive role for developmental plasticity in interspecific variation in the wild. Finally, we illustrate the impact of relatively small-scale spatial effects on mushroom body plasticity by performing experiments altering the cage size and structure experienced by individual H. hecale. Our data provide a comprehensive survey of community level variation in brain structure, and demonstrate that genetic effects and developmental plasticity contribute to different axes of interspecific neural variation.

中文翻译：

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可塑性和遗传效应导致模仿 Heliconius 蝴蝶群落中不同轴的神经分歧。

生态偏好的变化通常是由资源分布的时空变化驱动的，可以使人口暴露在具有不同信息内容的环境中。这可能会导致个人对感觉系统和下游过程的投资程度发生适应性变化，以优化不同环境下的行为表现。同时，环境条件可以在神经系统发育和成熟过程中产生可塑性反应，为整合神经和生态变异提供了另一种途径。在这里，我们探讨了这两个过程如何在 Heliconius 蝴蝶群落中发挥作用。赫利科尼乌斯群落表现出多个缪勒拟态环，与跨环境梯度的栖息地划分有关。这些环境差异此前已被认为与近亲物种对大脑形态的遗传差异有关。它们还表现出独特的饮食适应，称为花粉喂养，很大程度上依赖于学习资源之间的觅食路线或陷阱线，这意味着环境对行为发展有重要影响。通过比较来自 7 个 Heliconius 物种的 133 个野生捕获和昆虫饲养个体的大脑形态，我们发现了神经投入模式种间差异的有力证据。这些很大程度上分为两种不同的变异模式；首先，我们发现野生个体和昆虫饲养个体的视觉大脑成分大小存在一致的差异模式，这表明视觉通路中存在基因编码的差异。其次，我们发现蘑菇体大小存在种间差异，蘑菇体大小是学习和记忆系统的核心组成部分，但仅限于野生捕获的个体。在普通花园个体中缺乏这种效应表明发育可塑性在野生种间变异中发挥着广泛的作用。最后，我们通过改变 H. hecale 个体所经历的笼子大小和结构的实验来说明相对小尺度的空间效应对蘑菇体可塑性的影响。我们的数据提供了对大脑结构群落水平变异的全面调查，并证明遗传效应和发育可塑性有助于种间神经变异的不同轴。