Insects depend on their olfactory sense as a vital system. Olfactory cues are processed by a rather complex system and translated into various types of behavior. In holometabolous insects like the red flour beetle Tribolium castaneum, the nervous system typically undergoes considerable remodeling during metamorphosis. This process includes the integration of new neurons, as well as remodeling and elimination of larval neurons. We find that the sensory neurons of the larval antennae are reused in the adult antennae. Further, the larval antennal lobe gets transformed into its adult version. The beetle’s larval antennal lobe is already glomerularly structured, but its glomeruli dissolve in the last larval stage. However, the axons of the olfactory sensory neurons remain within the antennal lobe volume. The glomeruli of the adult antennal lobe then form from mid-metamorphosis independently of the presence of a functional OR/Orco complex but mature dependent on the latter during a postmetamorphic phase. We provide insights into the metamorphic development of the red flour beetle’s olfactory system and compared it to data on Drosophila melanogaster, Manduca sexta, and Apis mellifera. The comparison revealed that some aspects, such as the formation of the antennal lobe’s adult glomeruli at mid-metamorphosis, are common, while others like the development of sensory appendages or the role of Orco seemingly differ.

中文翻译：

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红谷甲（赤拟谷盗，Herbst）嗅觉系统的变态发育


昆虫的重要系统依赖于嗅觉。嗅觉线索由一个相当复杂的系统处理并转化为各种类型的行为。在像赤拟谷盗这样的全变态昆虫中，神经系统通常在变态过程中经历相当大的重塑。这个过程包括新神经元的整合，以及幼虫神经元的重塑和消除。我们发现幼虫触角的感觉神经元在成虫触角中被重复使用。此外，幼虫触角叶转变为成虫版本。甲虫的幼虫触角叶已经具有肾小球结构，但其肾小球在最后的幼虫阶段溶解。然而，嗅觉感觉神经元的轴突仍保留在触角叶体积内。然后，成体触角叶的肾小球从变态中期形成，独立于功能性 OR/Orco 复合体的存在，但在变态后阶段依赖于后者的成熟。我们深入了解红粉甲虫嗅觉系统的变态发育，并将其与果蝇、烟草天蛾和意大利蜜蜂的数据进行比较。比较显示，某些方面是常见的，例如触角叶成年肾小球在变态中期的形成，而其他方面，例如感觉附属物的发育或Orco的作用似乎有所不同。