We studied the distributional patterns of phoretic deutonymphs of the genera Oodinychus and Trichouropoda (Uropodina) on the longhorn beetles Monochamus sartor urussovii, Plagionotus detritus, Tetropium castaneum, and Te. fuscum, based on large samples of specimens (992 beetles and 25,587 mites) collected in the Białowieża Primeval Forest in Central Europe in the years 2008 and 2012–2016. All the studied phoretic phoront-host associations are characterized by different patterns of the attachment sites of mites on beetle’s body. In the case of O. ovalis and M. sartor urussovii association, the deutonymphs were found mostly on the pronotum and dorsal surface of the elytra. This is the only instance in which phoronts were absent on the legs. Deutonymphs of T. sociata on P. detritus preferred the abdomnen (both tergites and ventrites) and the hindlegs. Only in this case the phoronts were attached inside the subelytral space. The highest number of deutonymphs of T. shcherbakae on both Tetropium species occured on the legs. In the case of Te. castaneum, similar proportions of mites were recorded on all pairs of legs, while the preferred location of mites phoretic on Te. fuscum were the forelegs. Both the preferences of phoretic deutonymphs for specific parts of the host’s body and the participation of carriers transporting deutonymphs on particular parts of their bodies were very consistent.

The importance of dead wood in forest ecosystems for the existence of invertebrates has been widely discussed in the literature. The major aim of this study is to test the hypothesis that the presence of dead wood in forests considerably increases the species diversity of Uropodina (Acari: Parasitiformes) communities in a given area. The areas selected for the study are unique from a natural point of view. They are the Białowieża Primeval Forest, Cisy Staropolskie im. Leona Wyczółkowskiego Nature Reserve, and five oak-hornbeam nature reserves in western Poland. The study is based on materials collected since the 1960s of the last century. The highest number of species (37) both in soil and dead wood microhabitats was recorded in the Białowieża Primeval Forest and Cisy Staropolskie Nature Reserve, though the dead wood material from the second area contained the highest number of species (33). The results of the analysis show that the presence of dead wood increases species diversity of Uropodina communities in all locations under scrutiny. Moreover, dead wood increases the species diversity of Uropodina communities by attracting rare and stenotopic species, and therefore leaving dead trees in forests is extremely important for the habitat protection of these species.

We studied the phoretic relationships between the mites of the genus Trichouropoda Berlese, 1916 (Uropodina) and the longhorn beetle Plagionotus detritus (Linnaeus, 1758) based on large samples of specimens (2050 beetles and 19,216 mites) collected in the Białowieża Primeval Forest in Central Europe. Phoresy was studied over the years 2014, 2015, and 2016, with the emphasis on multi-annual trends in host–phoront associations, seasonal changes in intensity of phoresy, proportion of carriers of mites in the beetle population, and preferences of phoretic deutonymphs for specific parts of the host’s body. The high repeatability in all the variables we studied indicates high stability of the phoretic relationships, probably resulting from the synchronization of life cycles of beetle dispersants and phoretic mites. The long-term coevolution of phoronts and carriers in a natural forest ecosystem, as well as the expected close association of mites with specific beetle-generated microhabitats in larval galleries, may be important factors affecting the strength of the phoretic relationship.