Southeastern blueberry bees are easily mistaken for bumblebees – they are furry with black and tan bands and they make a loud buzzing sound when they zoom by.  These bees specialize in foraging on blueberry plants.  Also known as blueberry digger bees, Habropoda laboriosa belong to the same bee tribe as Anthophora digger bees -- Anthophorini.  

 

Habropoda gloriosa bees nest in the ground. Like blueberries, southeastern blueberry bees have a predilection for sandy soil.  In north Florida, they often nest along sandy trails of coastal pine woods. They hatch and emerge as early as mid-February  in north Florida, often many days before the first blueberries in the area begin to bloom.   According to the Xerces Society’s Attracting Native Pollinators, the factors that trigger the bees’ awareness of early spring remain unknown. 

 

Habropoda laboriosa bees are a principal pollinator of commercial blueberry crops in the Northeast, particularly rabbit-eye and highbush blueberry.  In the coastal pine woods of northern Florida, these bees are frequent visitors of wild shiny blueberry (Vaccinium myrsinites).

 

Blueberries are fairly tricky to pollinate.  The pollen generated by their flowers is too heavy and sticky to be carried efficiently by wind.  Although blueberries are considered “self-compatible” – that is, a plant can fertilize itself - the hurricane-lamp shape of blueberry flowers prevents their pollen from falling easily from their anthers onto their stigmas and thus makes self-fertilization difficult.  To produce fruit well, blueberries require insects that practice “buzz pollination”.  Insects  that practice buzz pollination include honey bees, bumblebees, carpenter bees and southeastern blueberry bees. Southeastern blueberry bees are the only known bees of the genus Habropoda to practice buzz pollination. 

 

When practicing buzz pollination, southeastern blueberry bees grab a flower anther and shake it by vibrating their flight muscles, thus dislodging the pollen along the same principles of physics that make salt shakers emit salt.  The pollen in the anthers is electrostatically charged, and is attracted to oppositely charged hairs on the bees’ bodies.

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Southern blueberry bees produce a startlingly loud buzz when pollinating blueberry bushes in this manner.  (The Science page of The New York Times has described this noise as being like the sound of someone “giving you a raspberry”. (Blueberry pollinators have been known to use a mechanical invention called an Electric Bee, which imitates buzz pollination, but this invention is not as efficient or reliable as the southeastern blueberry bee.) 

 

Southeastern blueberry bees are especially good at buzz pollination -- they are three times faster than bumblebees in pollinating blueberries and far more efficient than honey bees. Female southeastern blueberry bees are said to be capable of visiting 50,000 blueberry flowers and of producing 6,000 blueberries in a single lifetime.

 

Southestern blueberry bees are deemed oligoletic on plants belonging to the Vaccinum family (which includes blueberries, cranberries and huckleberries).  Oligoletic is the term used to describe bees that prefer foraging on plants of a specific group to the general exclusion of other flora.  Despite this classification, Southeastern blueberry bees do visit other spring-flowering plants that bloom in blueberry season in Florida.  These include oaks, redbuds and azaleas,   Habropoda laboriosa also have been documented nectaring on a variety of other early-spring flora, including snow drops, daffodils, crabapples and dead nettle; in the south they may beed on Chickasaw plum, honeysuckle and yellow jessamine as well.

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Nesting behavior

 

Southeastern Blueberry bees are solitary ground nesters that burrow deep underground – as far as eighteen inches – to lay eggs.  They prefer loose or sandy soil, but also frequent woodlands, where they dig nests under leaf litter, or in holes under uprooted trees.  Biologists Wilson & Carril write in The Bees in Your Backyard that Southeastern blueberry bees can form nest aggregations numbering in the hundreds of individuals.  Each bee, however, forms its own separate nest, depositing just one egg in one cell at the end of each nest.  Male bees hatch first, and then await the emergence of females –impatiently listening for the vibrations of females digging their way to the surface, and sometimes even digging back down to meet them partway or fighting with other males to dig a female out.

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Although the bees are solitary, they tend to build their nests close to one another.  They are non-aggressive and do not swarm.  Male bees sometimes can be observed basking on leaves in order to warm themselves on cold spring days. 

 

Southeastern blueberry bees live only a few weeks each year, and produce only one generation annually.  They disappear at the end of blueberry season.

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Identification information: 

 

Southeastern Blueberry bees are the sole representatives of their genus Habropoda east of the Mississippi.

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Southeastern blueberry bees look on first glance like small bumble bees.  (They are somewhat larger than a typical honey bee).  Southeastern blueberry bees have broad, hefty bodies with widely-spaced wings. The bees’ thoraxes (mid-sections) are covered with tan fur, and their heads, antennae, legs and abdomens are black.  Males are slightly longer than ½ inch; females are larger, in the 4/5” range.

Both male and female southeastern blueberry bees have protuberant faces. Male southeastern blueberry bees have yellow masks on the bottom half of their faces; the masks have two small black dots near the top that look like false nostrils.  The females’ faces are entirely black. The females bees’ legs are covered with thick black hair. Males’ legs are not as bushy, but they are hairier than is typical of many male bees. 

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According to entomologist Charles D. Michener, Habropoda bees can be distinguished from all other members of the tribe Anthophorini  (such as Anthophora digger bees) in one aspect -- they lack a fan-shaped organ on their tongue-tips, called a flabellum.  In addition, the distinct wing venation of Habrapoda bees helps distinguish them from Anthophora digger bees.  As shown in the photo strip at right, the third marginal cell of the southeastern blueberry bee’s wing is squarish, and the first recurrent vein of the wing meets the second submarginal cell near the middle.  The marginal cell of the bee's wing is also notably long, extending far behind the marginal cells.

 

Southern blueberry bees are also sometimes mistaken for eastern carpenter bees (particularly the males, which have yellow face markings). Male eastern carpenter bees, however, tend to be much larger and to have bulbous green eyes.

 

 

TAXONOMY  -  Southeastern Blueberry  Bees

Order:  Hymenoptera 

Family:   Apidae

Subfamily:  Apinae

Tribe:  Anthophorini (Digger Bees)

Genus:  Habropoda

Species:  Habropoda laboriosa