Abstract
The study was conducted on 16 water bodies located in Olsztyn, most of them natural and dominated by astatic ones (dystrophic, eutrophic, and artificial with elevated mineralization levels). Heteroptera was identified to 32 species represented by five synecological groups, i.e., species typical of dystrophic water bodies (Cymatia bonsdorffi, Hesperocorixa linnaei, H. moesta, H. sahlbergi, Gerris lateralis, G. sphagnetorum, Hebrus ruficeps), lacustrine species (Gerris argentatus, Aquarius paludum), halophilous species (Cymatia rogenhoferi, Paracorixa concinna, Gerris thoracicus), psammophilous and argilophilous species (Sigara lateralis) and eurytopic species typical of small water bodies (18). It was found that the degree of permanency of astatic water bodies affects both the species diversity and abundance of the Heteroptera fauna. Migrations play a crucial role with respect to the colonization of newly-formed bodies of water and to the abandonment of those that are drying up.