Effect of Osmia bicornis supplemental pollination on seed yield of forest seed orchards

Our study investigated the possibility of using the red mason bee Osmia bicornis as a pollinator of forest seed orchards of frequently grown European trees: insect - pollinated Tilia cordata and Prunus avium. Moreover, we checked whether the presence of O. bicornis has an impact on the pollination results of Quercus petraea, which is wind - pollinated. Data were collected from 8 forest seed orchards in western Poland between 2018 and 2020. We assessed whether the presence of O. bicornis populations affects the number and mass of seeds and seed quality. Supplementing forest orchards with O. bicornis affected seed yield. The generalized linear mixed models indicated that the number of seeds and the proportion of viable seeds, but not seed mass, were higher in the Tilia cordata trees, when additionally pollinated with O. bicornis added as a pollinator.