EN
The Pleszew district (51°55’–52°05’ N, 17°30’–18°02’ E) lies in western Poland, in the faunistic land of the Wielkopolska-Kujawska Lowland, which is generally well researched in terms of the occurrence of true water beetles. However, there is almost no data from this district: only three species have been published. The aim of the paper is to present a preliminary analysis of the district’s fauna and to indicate the most urgent research needs. In the years 1984-1986, 1988, 1990, 1992, 1997, 2003, 2010, 2011 and 2014-2021, several projects not dedicated to water beetles were carried out in the Pleszew district, which resulted in the creation of a small collection of these insects, consisting of 263 individuals belonging to 71 species. Only three species of these materials have been published, including one erroneously – Hydrophilus aterrimus as H. piceus. An unpublished list of beetles from the arboretum in Gołuchów (21 species) was also used. In total, 78 species were recorded, which constitutes 23% of the Polish fauna. Nine species are considered rare in Poland and/or are included in the national Red List: Agabus striolatus, Ilybius montanus, Graphoderus austriacus, G. zonatus, Dytiscus semisulcatus, Nebrioporus canaliculatus, Hydroporus incognitus, H. nigrita, Hydrophilus aterrimus. Five species were recorded for the first time from the Wielkopolsko-Kujawska Lowland: Ilybius montanus, Hydroporus figuratus, H. nigrita, Hydrobius rottenbergii and H. subrotundus. The preliminary data suggests a large species and ecological diversity of the fauna of the Pleszew district. The recorded rare and redlisted species indicate that this is probably an important area for the protection of water beetles. Valuable are peat bogs, dystrophic waters in forest complexes and various types of small water bodies. Systematic surveys that representatively cover all aquatic and wetland habitats, including running water that have not been studied at all, are now desirable. The authors also discuss materials collected using nonhydrobiological methods. Wintering beetles were caught, in dispersion before or after wintering, and looking for stable habitats in summer after probably their reproductive waters had dried up. This is valuable data on their biology.