Use of immunomarking to determine foraging patterns of Osmia cornifrons (Radoszkowski) in a cherry orchard

Background/Question/Methods: Foraging patterns of bee species should be understood for proper placement of nest sites and to ensure adequate pollination. Field and laboratory studies were conducted to quantify the foraging patterns of Osmia cornifrons (Radoszkowski) (Megachilidae, Hymenoptera) with an immunomarking method in a commercial cherry orchard in Pennsylvania. Individuals of O. cornifrons were marked with egg-white protein powder and released from a dispenser nest placed at the center of the study orchard at early stage of bloom. After 30 h of foraging, samples were collected from randomly selected sampling cherry trees located at different distances (up to 55 m) in all directions from the O. cornifrons dispenser nest. Samples were analyzed for the presence of immunomarker protein with enzyme-linked immunosorbent assay. Foraging patterns were determined by calculating the distance and direction of marked flowers from the nest. The proportion of protein marked samples for each tree was compared with the tree’s distance and direction from the nest and fruit density per limb cross-sectional area (cm²). At harvest, fruit density in the test orchard was compared with fruit density in a control orchard that did not have O. cornifrons. Results/Conclusions : A high percentage of sampled flowers were protein-marked up to 40 m radius. Percentage of marked flowers dropped markedly between 41 and 55 m from the nest. Fruit density per limb cross-sectional area was significantly higher in the orchard with O. cornifrons compared with the control (P = 0.000), indicating valuable pollination services of O. cornifrons in cherry orchards. O. cornifrons adults are efficient cherry pollinators, but their foraging range is limited requiring strategic next placement to ensure proper orchard pollination.