From the research of the faunal diversity of stafilinids from the Republic of Moldova, there were selected species for which sequences from the ecological field were exposed, specifying some classification based on certain criteria. In this context, the aspects of trophic categories (based on the type of nutrition), ecological preferences (type and variety of the populated biotope) and the influence of abiotic factors during the development processes were considered. Classification of stafilinid communities into bioecological groups by vital form and habitat preferences is interdependent by adaptation and popularization of various substrates and microhabitats. Stafilinid species adapted to an open way of life with free location: on the soil, on substrates, on plants, in the grassy floor, are treated as representatives of the group of epibiont species. As a specific general characteristic of this group there are pedobionts,the individuals with slim, elongated, slender body, proportionally developed and adapted for running legs. The groups which species have a semi-hidden way of life: underground, on the surface and in the substrate, are referred to cavernous species, as an example the saprobiont, coprobiont and mycetobiont stafilinids could be given. By the cryptobiont classification, the species adapted to a hidden way of life (underground and in the bark of trees, caves, etc.) are nidicols and xylobionts,. Stafilinids with a symbiotic way of life are the symphyl species. They interact with social insects (ants), populate anthills, are a part of the group of myrmecobionts. Ocypus fulvipennis Erichson, 1840, Figure 1, is a predatory/necrophagous stapylinid from the subfamily Staphylococcininae Latreille, 1802, registered for the fauna of our country, treated as a species with polybiont ecological status and with important place for the environment. It participates in the natural ecosystem as a regulating species in the biological control of some harmful insects in cultivated crops. By the size of the adult that is accentuated, of 12 mm, it ranks in the group of large stafilinids. It can be observed both in the natural ecosystem and in agrobiocenoses. Figure 1. Ocypus fulvipennis Erichson, 1840, staphylinid from subfam.Staphylininae Latreille, 1802 (database: Mihailov Irina)Observed for several years in the field, analyzed according to the specialized literature and in laboratory conditions, this species was included in the fundamental and applied research in the period 2021-2022. The material extracted from samples collected from various biotopes showed a wide trajectory of expansion of this species on the territory of our country. According to the recorded points, it appeared in different types of forests in the central regions (Horăști, Cocieri, Strășeni) and North (Brînzeni, Zăbriceni), under litter, in soil traps, under trees knocked down by the wind, on decaying stumps, in layers gathered by grass, on decomposed animal matter.