Revealing the effect of brain size on the cognitive abilities of animals is a major challenge in the study of brain evolution. Analysis of the effects of miniaturization on brain function in the smallest insects is especially important, as they are comparable in body size to some unicellular organisms and next to nothing is known about their cognitive abilities. We analyse for the first time the structure of the brain of the adult featherwing beetle Nephanes titan, one of the smallest insects, and results of the first ethological experiments on the capacity of learning in this species. N. titan is capable of associative learning, in spite of the structural modification in its nervous system and the greatly reduced number of neurons compared to the nervous systems of larger insects. Microinsects can become useful model organisms for neurobiology. On the one hand, the structural simplicity and extremely small size of their central nervous system make it possible to study it very efficiently. On the other hand, their learning capacity and retained principal cognitive abilities make them suitable objects for behavioural experiments.

中文翻译：

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微小大脑的认知能力：Nephanes titan（鞘翅目：Ptiliidae）中的神经元结构和联想学习。

揭示大脑大小对动物认知能力的影响是大脑进化研究的主要挑战。在最小的昆虫中分析微型化对脑功能的影响尤为重要，因为它们的体形可与某些单细胞生物媲美，并且对其认知能力几乎一无所知。我们首次分析了成年的羽翼甲虫Nephanes titan（最小的昆虫之一）的大脑结构，以及有关该物种的学习能力的首次人类学实验的结果。尽管泰坦猪笼草的神经系统结构发生了变化，并且与大型昆虫的神经系统相比，神经元的数量大大减少，但它仍能够进行联想学习。微型昆虫可以成为神经生物学的有用模型生物。一方面，它们的中枢神经系统结构简单且尺寸极小，因此可以非常有效地对其进行研究。另一方面，他们的学习能力和保留的主要认知能力使他们成为行为实验的合适对象。