In the animal kingdom, behavioral traits encompass a broad spectrum of biological phenotypes that have critical roles in adaptive evolution, but an EvoDevo approach has not been broadly used to study behavior evolution. Here, we propose that, by integrating two leech model systems, each of which has already attained some success in its respective field, it is possible to take on behavioral traits with an EvoDevo approach. We first identify the developmental changes that may theoretically lead to behavioral evolution and explain why an EvoDevo study of behavior is challenging. Next, we discuss the pros and cons of the two leech model species, Hirudo, a classic model for invertebrate neurobiology, and Helobdella, an emerging model for clitellate developmental biology, as models for behavioral EvoDevo research. Given the limitations of each leech system, neither is particularly strong for behavioral EvoDevo. However, the two leech systems are complementary in their technical accessibilities, and they do exhibit some behavioral similarities and differences. By studying them in parallel and together with additional leech species such as Haementeria, it is possible to explore the different levels of behavioral development and evolution.

中文翻译：

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两个水ches的故事：理解行为神经回路的演化和发展

在动物界，行为特征包括广泛的生物表型，它们在适应性进化中起关键作用，但是EvoDevo方法尚未广泛用于研究行为进化。在这里，我们建议，通过集成两个水ech模型系统，每个系统都已经在各自的领域中取得了一些成功，可以通过EvoDevo方法来表现行为特征。我们首先确定理论上可能导致行为进化的发展变化，并解释为什么EvoDevo对行为的研究具有挑战性。接下来，我们讨论两种水ech模型物种（无脊椎动物神经生物学的经典模型Hirudo和Helobdella）的利弊，这是一种新兴的气候发育生物学模型，是EvoDevo行为研究模型。考虑到每个水ech系统的局限性，这两种行为对于EvoDevo行为都没有特别强的作用。但是，这两个水ech系统在技术可及性上是互补的，并且确实表现出一些行为上的异同。通过并行研究它们，并与其他水ech物种（例如Hamenteria）一起研究，有可能探索行为发展和进化的不同水平。