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Optimizing pear orchard productivity through managed Osmia bicornis L.: A study on pollination efficiency and its role in geitonogamy
AbstractMost pear cultivars require cross‐pollination to enhance yields in both self‐fertile and partially self‐fertile cultivars. Due to the deficit of wild bees and the limited pollination efficiency of honey bees, alternative commercial pollinators should be considered. This study examined the pollination efficiency of the managed bee Osmia bicornis in a pear orchard containing three cultivars: ‘Conference’, ‘Deyonne du Comice’, and ‘Alexander Lucas’. The introduction of O. bicornis into the pear orchard proved effective, with this species comprising up to one‐fifth of the total pollinator population when nesting sites were located within 60 m of the trees. The management of O. bicornis improved fruit set in self‐sterile cultivars but did not affect parthenocarpic cultivars. The higher number of fruits per inflorescence, as well as greater fruit weight and diameter, when flowers were pollinated by red mason bees rather than self‐pollination, predict an improvement in the total yield. compared to self‐pollination. The pollen bag method employed in the study highlighted the vital role of O. bicornis in geitonogamy in pears. The findings demonstrate that the use of these managed bees can enhance yields in single‐cultivar orchards, including self‐pollinating and parthenocarpic cultivars.
Methoprene, a Juvenile Hormone Analog, Causes Winter Diapause Elimination in Univoltine Bee Species Osmia bicornis L.
Osmia bicornis syn. O. rufa is a univoltine bee species in which adults fly in spring and the offspring overwinter as cocooned imagoes. The flight period of solitary bees is short, so methods of control for development and emergence time are needed to synchronize the activity of managed pollinators with blooming. In our study, we tested the effectiveness of a juvenile hormone analog for the prevention of winter diapause. Bees developed in settled nests outdoors or in the laboratory (22 °C) until the end of the pre-pupa stage, then cocoons were removed from the nest cells and treated with a JH analog—methoprene—during the pupa and young imago stages. Then, bees were activated at 25 °C until the adults left the cocoons. Topical application of methoprene to the cocoon at the pupa or imago stage induced the emergence of some adult bees in the pre-diapause period, while no adults emerged when the bees were not treated with methoprene. Most adults emerged (about 50%) when treated with methoprene on 3-week-old cocooned imagoes. Bees treated in the pupal stage had a lower emergence rate (20–30%), but adult bees emerged earlier. The emergence time of adults for the laboratory group was, on average, from 70 to 91 days, and that for outdoor groups was from 57 to 72 days.
Effect of Osmia bicornis supplemental pollination on seed yield of forest seed orchards
AbstractOur 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.