Aleksei was born in a Russian noble family in Ekaterinburg and grew up in Montreux, Switzerland, educated by private tutors.
He took an interest in the cicadas but the October revolution of 1917 and his wealthy background meant that he could not join university.
His work on mites led him to propose in 1952, based on the development of the fourth pair of legs, the classification of the Acarina into Acariformes, Parasitiformes, and Opiliocarina.
[2][3] His major books were Tyroglyphoid mites (Tyroglyphoidea) (1941) and Comparative embryology of lower invertebrates (1949).
[3] A number of mite genera are named in his honour including Zachvatkinia Dubinin, 1949 and Zachvatkinella Lange, 1954.