Foraging patterns of the southeastern blueberry bee Habropoda laboriosa (Apidae, Hymenoptera): Implications for understanding oligolecty
John B Pascarella
Previous observations have suggested that the blueberry bee (Habropoda laboriosa, Apidae) is oligolectic on blueberries (Vaccinium sp.) but visits a number of secondary plant species for nectar. To examine how oligolecty persists in human modified habitats: (1) observations were made of plants it visited in both urban and rural habitats, (2) the type of pollen on its body was measured when foraging on either Vaccinium or Gelsemium, and (3) foraging behavior on Vaccinium, Gelsemium, and Azalea was studied across an rural/suburban/urban land use gradient in a foraging preference experiment. Male and female blueberry bees were recorded foraging on a wide range of plants in urban, suburban, and rural areas for both pollen and nectar. Female bees collected pollen from five genera in four families. Pollen on male and female bees collected on either Vaccinium or Gelsemium was predominantly from the species from which it was collected, but many specimens had both pollen types present. There were significant differences in foraging preferences among the three plant species and between gender. Overall, females preferred Gelsemium to Vaccinium, but males showed the opposite pattern. For both females and males, Azalea was the least preferred. Variation in the local abundance of flowers among the sites was not related to foraging preference. The foraging patterns of H. laboriosa in the landscape of human modified ecosystems suggests that H.laboriosa may be a mesolectic bee, using pollen from a few unrelated species, as opposed to a narrow oligolege (using pollen from only a few related species of Vaccinium). The preference for Gelsemium among female bees suggests that plantings of Gelsemium might be useful in enhancing populations of H. laboriosa in blueberry cultivation.