Early last month, as many local plants began blooming a couple of weeks earlier than usual, the native Vaccinium spp. we’d planted as part of an edible perimeter started to attract a buzzing crowd. Blueberries and their close relatives produce dangling bell-shaped flowers that are pollinated by a variety of native bees in addition to honeybees. In SE NC, cultivars of Vaccinium virgatum (syn. V. ashei, known as rabbiteye blueberries (evidently named for the pinkish eyeball appearance of the fruit) are very popular. This southeastern coastal plain species, sometimes also called ‘swamp blueberry,’ naturally occurs in swamps and pocosins, as well as drier upland areas. (Weakley, 2015)
The March visitor to the flowering blueberry buffer was Hapropoda laboriosa, the Southeastern Blueberry Bee. This species is a member of Apidae, a large family which also includes honey bees, bumble bees, and carpenter bees, among many others. These are the longer-tongued bees that are more adapted for gathering nectar from deeper flowers. Southeastern Blueberry Bees, as their name suggests, are oligolectic – they collect pollen primarily from a single genus, although this species is also occasionally seen on other early spring-flowering species such as Gelsemium sempervirens, Cercis canadensis, and Linaria canadensis. (1) Southeastern Blueberry Bees collect pollen via sonication, or more descriptively, buzz-pollination’ – they vibrate their flight muscles while gathering nectar, shaking pollen from the anthers of the flowers.
The genus Hapropoda, aka Digger Bees, like most of the native bee species in the US, are solitary ground nesters. (2,3) Although a number of other species also pollinate blueberries, it has been estimated that a single female Southeastern Blueberry Bee can visit 50,000 blueberry flowers, producing 6000 blueberries that have a market value of about $20. (4)
Now that it is well into April, the blueberry crop is ripening, confirmation of successful pollination. Although the Habropoda are no longer in sight, other insects are taking notice of the blueberry plants.
Larvae of the Triton Dagger Moth, Acronicta tritona, and Azalea Caterpillar Moth, Datana major, also favor Vaccinium species, along with other members of Ericaceae. For the feathered members of this food web, these juicy-looking caterpillars may be more enticing this time of year than the burgeoning fruit…
*For more about native bees of the southeast, here’s a link to a nice publication produced by USDA Forest Service with the Pollinator Partnership.
- Cane, J., Payne, J. A. 1988. Foraging ecology of the bee Habropoda laboriosa (Hymenoptera: Anthophoridae), an oligolege of blueberries (Ericaceae: Vaccinium) in the southeastern United States. Annals of the Entomological Society of America, 81:419-427.
- Cane, J. 1994. Nesting biology and mating behavior of the southeastern blueberry bee, Habropoda laboriosa (Hymenoptera: Apoidea). Journal of the Kansas Entomological Society, 67:236-241.
- Xerces, Society The. Attracting Native Pollinators: Protecting North America’s Bees and Butterflies. North Adams, MA: Storey Pub., 2011. Print
- Cane, J.H. 1997. Lifetime monetary value of individual pollinators: the bee Habropoda laboriosa at rabbiteye blueberry (Vaccinium ashei reade). Acta Hortic, 446:67-70.