Coniferous plants as potential reservoirs of phytoseiid mites (Parasitiformes: Phytoseiidae) in Poland

Coniferous trees and shrubs growing in natural stands are important reservoirs of naturally-occurring predators belonging to the family Phytoseiidae (Mesostigmata: Phytoseioidea). The fauna of these mites on eight native coniferous species in Poland was surveyed and an exploratory statistical investigation was carried out into mite-conifer associations. The conifers were growing in forests, national parks and nature reserves throughout Poland. A total of 2,540 specimens of phytoseiids belonging to nine species was identified. Four species were new for the Polish fauna, i.e., Typhlodromus (Anthoseius) inopinatus (Wainstein), T. (A.) caucasicus (Abbasova), T. (A.) singularis Chant and Neoseiulus gracilentus (Hirschmann). Among the studied coniferous taxa, Picea abies (L.) H. Karst supported the greatest numbers of both species and individual mites. The highest biodiversity indexes for the phytoseiids were obtained for Taxus baccata L. and Juniperus communis L. Among the phytoseiid species found, T. (T.) tiliae Oudemans occurred on all eight host species surveyed. Typhlodromus (A.) bakeri (Garman) and T. (T.) tiliae were the most dominant species and occurred on conifers with high constancy. Amblyseius andersoni (Chant) co-dominated with them on J. communis and P. abies. New to the knowledge of Phytoseiidae-host plant records were T. (A.) singularis on P. abies, T. (T.) tiliae on Pinus mugo Turra, Pi. cembra L., J. communis and T. baccata, N. gracilentus on J. communis and Pi. mugo, and T. (A.) inopinatus on Abies alba Mill., Larix decidua Mill. and P. abies. Additionally, for Poland, new Phytoseiidae-host plant associations were T. (A.) inopinatus on Pinus sylvestris L., T. (A.) bakeri on J. communis and T. baccata, T. (A.) caucasicus on A. alba, T. baccata and P. abies, and T. (A.) singularis on L. decidua.