The evolution of mechanosensory perception in the context of oviposition site choice in Drosophila

动物的多样性是显而易见的，不仅表现在它们形态上看似无限的变化，而且表现在它们天生行为的多样性上。虽然我们今天对形态变异的理解采取了遗传原则的形式，但我们对行为进化的理解却远远落后。出于这个原因，我的团队最近建立了一个简单的范式来检查行为简单变化背后的遗传和神经元变化。我们正在研究雌蝇如何选择合适的地点产卵。我们发现，这一关键的生殖决策是由不同生态环境的果蝇密切相关的物种不同。我们研究过的所有物种都与模式物种D相似。黑腹果蝇，并利用它们的触觉来探测基板是否适合它们的卵。然而，他们对基板刚度的偏好已经改变。特别是入侵害虫D. Suzukii几乎不会在不同硬度的基质之间进行选择，除非这种差异相当于绿色草莓与成熟草莓的差异。与此相反，D.黑腹果蝇非常挑剔，喜欢腐烂水果的硬度，而不是非常成熟的水果。在第一个项目中，我们想解剖一只雌性苍蝇（D。黑腹动物）在遗传和神经元水平上感知和选择底物硬度。我们将详细阐述最近的发现，这些发现已经确定了这个过程中的关键基因，以破译如何以及在哪些神经元中使用这个基因，以及这些初级神经元在哪里发送感觉信息。我们将充分利用丰富的果蝇神经遗传学资源。在第二个项目中，我们想了解产卵基质的偏好是如何演变的。我们将首先关注具有不同偏好的不同物种的单个苍蝇，并定量描述它们的行为，以了解它们如何操作它们的选择。然后，我们会问，上面提到的决定选择行为的关键基因本身是否在其编码序列或其调节机制中积累了变化，从而解释了行为的变化。最后，我们将通过比较它们的解剖结构和操纵物种之间的关键基因（交换等位基因）来寻找介导选择的初级感觉神经元的可能变化。总之，这两个项目将提供一个概述的神经遗传学基础的机械感觉偏好，这种偏好的演变。

Animal diversity is manifest, not only in the seemingly infinite variations of their morphology, but also in the variety of their innate behaviors. While our understanding of morphological variation takes the form of genetic principles today, our understanding of behavior evolution is lagging far behind. For this reason, my group as recently set up a simple paradigm to examine the genetic and neuronal changes underlying a simple change in behavior. We are studying how a female fly choses a suitable site to lay her eggs. We found that this key reproductive decision is made differently by closely related species of Drosophila with different ecologies. All species we have examined are akin to the model species D. melanogaster and use their sense of touch to probe substrate suitability for their eggs. Yet, their preferences for substrate stiffness have changed. In particular, the invasive pest species D. suzukii hardly choses between substrates of different stiffness, unless the difference is equivalent to that of a green strawberry vs. a ripe strawberry. By contrast, D. melanogaster proves extremely choosy, and prefers the stiffness equivalent to that of a rotten fruit over that of a very ripe fruit. In a first project, we want to dissect how a female fly (D. melanogaster) senses and selects substrate stiffness at the genetic and neuronal levels. We will elaborate on recent finding that have identified a key gene in this process, to decipher how and in which neurons this gene is used, and where these primary neurons dispatch the sensory information. We will take advantage of the abundant ressources available for Drosophila melanogaster neurogenetics. In a second project, we want to understand how the egg-laying substrate preferences have evolved. We will first focus on single flies of different species with different preferences, and describe their behavior quantitatively to understand how they operate their choice. We will then ask if the key gene for the choice behavior mentioned above, has itself accumulated changes in its coding sequence or in its regulation explaining the change of behavior. Finally, we will search for possible changes in the primary sensory neurons mediating the choice, by comparing their anatomy and by manipulating the key gene between species (exchanging alleles). Together, these 2 projects will provide an overview of the neurogenetics underlying a mechanosensory preference, and the evolution of this preference.