ИСТИНА

Целью проекта является комплексное изучение строения, ультраструктурной организации и пластичности мозга мельчайших насекомых и его ключевых ассоциативных центров.

Miniaturization is not only a common trend in the evolution of animals, but also one of the main trends in the development of biomimetics. The shift from the study of individual neurons to the reconstruction and analysis of large neural networks at the cellular level is one of the most important areas of modern neuroscience. The large size of the brain and the high number of neurons in most model species make this work extremely difficult. Microinsects, by contrast, share a combination of minute size, a small number of neurons, and preserved brain functionality, which makes them convenient models for connectomics and other advanced areas of neuroscience (Makarova et al., 2021). Despite their tiny size and the number of neurons by orders of magnitude smaller than in other animals, microinsects have been shown to be capable of associative learning and long-term memory (Hoedjes et al., 2012; Hoedjes and Smid, 2014; Woude et al., 2018; Polilov et al. ., 2019). A key place among microinsects is occupied by Megaphragma (Hymenoptera: Trichogrammatidae), one of the smallest egg parasitoid wasps, for three species of which anucleate neurons and the unique phenomenon of lysis of the bodies and nuclei of up to 95% of all brain cells at the late stages of pupal development were described (Polilov, 2017). As part of the implementation of our previous project, we also discovered the presence of an almost anucleate nervous system in representatives of another family, Mymaridae. Thus, the phenomenon of lysis of the bodies and nuclei of brain cells turned out to be widespread among the smallest insects. A detailed study of the structure and ultrastructural organization of the brain of these insects is of fundamental importance for understanding the organization, functioning, and evolution of the brain of microinsects. In the course of this project, we plan to perform a comprehensive study of the structure of the brain of the smallest insects, paying special attention to the structure of the associative centers of the Megaphragma brain, as centers for integrating information incoming from the sense organs. With unique three-dimensional electron microscopy data on the entire head of Megaphragma, we will proceed to reconstruct the connectome of the mushroom bodies and the central complex, which will make it possible to model the cellular composition and projections of the sense organs to the key centers of the brain. A separate objective of the project will be a comprehensive study of the plasticity of the brain of microinsects using the example of Trichogramma telengai (Trcihogrammatidae), a miniature egg parasitoid wasp. Experiments will be carried out to study the efficiency of learning and different forms of memory in artificially bred and natural lines of Trichogramma with different body sizes, using a setup developed by us for ethological experiments on microinsects. A large-scale analysis of the effects of body size on the structure of the brain of parasitoid wasps will be carried out and an assessment will be made of changes associated with the effects of brain size on learning efficiency. The results of studying the brain of miniature insects will be of fundamental importance in understanding the structure of an animal brain and optimization of its neural pathways during miniaturization; it may also be useful for applied neurobiological problems in the development of biomorphic neural networks and processors.