He continued his studies at Kyiv University, where he worked in the laboratory of Ivan Schmalhausen and simultaneously at the biological station of the Academy of Sciences of the Ukrainian SSR, situated on the Dnieper River.

He studied the fauna of this group living in lakes Ladoga and Onega, in the Caspian and Azov seas and in a number of smaller water bodies.

Attracted by Pavlovsky's concept of parasitocenosis, Markevych analyzed new facts obtained by parasitologists and microbiologists since Pavlovsky's publications, wrote several papers on this issue, and defined the task of parasitocenology as the "elucidation of objective patterns of life of parasitosymbiocenoses as well as biocenotic groupings of free-living parasite stages, in order to elaborate methods for directing the formation processes of parasitic communities".

[1] Markevych created a school of parasitologists in Ukraine and sparked the interest of a number of zoologists and botanists in the research of Carpathian fauna and flora.

Markevych's authority among colleagues, students and followers, is evident from the many organisms named in his honour: For helminths, he is honored by: And for myxozoans: Media related to Aleksandr Prokofyevich Markevich at Wikimedia Commons