Coevolution of generalist feeding ecologies and gyrencephalic mushroom bodies in insects
Coevolution of generalist feeding ecologies and gyrencephalic mushroom bodies in insects
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DOI：
10.1073/pnas.0508430102
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发表时间：
2005-11-29
影响因子：
11.1
通讯作者：
Roberts, NS
中科院分区：
文献类型：
--
作者：
Farris, SM;Roberts, NS
在这里，我们证明了在相似的适应压力下，不同昆虫分类群甚至跨门的独立获得惊人相似的脑结构。在某些种类的昆虫的大脑中，蘑菇体花萼具有卷曲的皮质回状结构；我们详细研究了圣甲虫科（圣甲虫科）中这种形态的细胞和生态相关性。“无脑型”蘑菇体的表面积和体积增加，以及内在神经元数量增加，这些特征只存在于那些属于一般植物食性亚科的物种中，而“无脑型”蘑菇体则存在于更专业的粪食性圣甲虫中。这种变化并不是圣甲虫或食草动物所特有的，因为掠食性甲虫的蘑菇体在通才和专才中表现出类似的形态差异。我们还表明，在多面手圣甲虫中，gyrencephalic mushroom bodies与它们的主要输入神经节、触角叶或触角叶肾小球的数量的增加无关，而是与肾小球的密度明显增加和肾小球的获得有关。这些差异表明花萼电路的变化促进了多面手摄食生态进化对处理能力和灵活性的要求增加。
Here we demonstrate the independent acquisition of strikingly similar brain architectures across divergent insect taxa and even across phyla under similar adaptive pressures. Convoluted cortical gyri-like structures characterize the mushroom body calyces in the brains of certain species of insects; we have investigated in detail the cellular and ecological correlates of this morphology in the Scarabaeidae (scarab beetles). "Gyrencephalic" mushroom bodies with increased surface area and volume of calycal synaptic neuropils and increased intrinsic neuron number characterize only those species belonging to generalist plant-feeding subfamilies, whereas significantly smaller "lissencephalic" mushroom bodies are found in more specialist dung-feeding scarab beetles. Such changes are not unique to scarabs or herbivores, because the mushroom bodies of predatory beetles display similar morphological disparities in generalists vs. specialists. We also show that gyrencephalic mushroom bodies in generalist scarabs are not associated with an increase in the size of their primary input neuropil, the antennal lobe, or in the number of antennal lobe glomeruli but rather with an apparent increase in the density of calycal microglomeruli and the acquisition of calycal subpartitions. These differences suggest changes in calyx circuitry facilitating the increased demands on processing capability and flexibility imposed by the evolution of a generalist feeding ecology.