SHARP-EATMAN
NATURE
PHOTOGRAPHY
ID GUIDE TO WILD BEES - NEW YORK
DIGGER BEES
These are entertaining bees – Anthophora terminalis digger bees are unusually noisy, and they have a distinctive way of flying. They zip speedily around flowers and then stop abruptly, hovering in front of a blossom, sometimes angling their long tongues down the flower’s throat without letting their feet touch the petals. Or they buzz loudly, while clinging to the flowers, and thrust their faces down so deeply into the blossoms that when the bees emerge, their heads and thoraxes are coated in pollen.
Female Anthophora terminalis bees carry pollen on the bottom sections of their hind legs and practice buzz pollination -- that is, they vibrate their wing muscles, shaking pollen from the anthers of flowers. These honey-bee sized insects are exceptionally effective pollinators.
The Greek word Anthophora means “flower-bearer," or "flower-producer," but these bees are commonly referred to in English by the more pedestrian name “digger bees”. Most digger bees construct nests in the ground by digging with their front legs and using their mandibles to loosen dirt. The Anthophora terminalis is unusual among digger bees, however, because this species constructs its nests in pithy stems and rotted wood. The bees line their nests with oils collected from plants.
Anthophora terminalis digger bees appear in the park during late spring and throughout the summer, but are a fairly uncommon sight. The male bees shown here were spied feeding on wild penstemon on sunny park trails during late June of 2016 and 2017. This wildflower emerges in the park during the last weeks of spring and attracts many Anthophora terminalis bees during its bloom cycle, in three separate park locations. Anthophora terminalis bees also can be found occasionally in the park near Swan Lake in July and August, feeding on dead nettle and the variety of ,wild impatiens known as jewel weed. The bees also have been sighed in the Rockwood Hall section of the park in mid-July, feeding on the deep-throated legume known as toadflax.
In gardens and fields, these digger bees tend to gravitate toward blue lobelias and the lavender-hued native bee balm known as Monarda fistulosa. The female bees shown here were discovered foraging on the native blue lobelia called lobelia siphilitica.
Anthophora terminalis bees play an important role in maintaining wildflower diversity, because of their ability to pollinate deep-throated and tubular blossoms, among them endangered wild orchids.
Identification information: Most digger bees in the United States and Canada live in western states and provinces. Only five species inhabit New York state. Because of their generally robust and furry appearance, digger bees are sometimes mistaken for a kind of bumble bee – some species of digger bees are even called “bumble bee mimics” because they are nearly indistinguishable from bumble bees. Digger bees belong to the same bee family (Apinae) as bumble bees, honey bees and long-horned bees. Digger bees, however, form their own separate tribe, known as Anthophorini.
Anthophora terminalis bees are striking -- robust and furry-looking, with heads and thoraxes covered with fluffs of pale hair. Their abdomens are pitch black and traversed by precise white bands. Their legs are dark and their feet a striking reddish color. The tips of the female bees’ abdomens are fringed with golden-red hairs, as shown in the photos here, and the pollen-carrying scopal hairs on their back legs are luxuriant and pale yellow.
Both male and female Anthophora terminalis bees have dark-veined wings, black heads, dark antennae, green eyes and unusual three-toothed mandibles. Both also possess exceptionally long tongues, which allow them to gather nectar or pollen from tubular flowers.
The male Anthophora terminalis bee, as shown above right, has a yellow clypeus (the part of the face under the antennae and above the jaws.), with two black dots on it that look like false nostrils. Males of other New York digger bee species share this trait; an example is the Anthophora abrupta digger bee shown below.
TAXONOMY - Anthophora terminalis Digger Bees
Order: Hymenoptera
Family: Apidae
Subfamily: Anthophorinae
Tribe: Anthophorini (Digger Bees)
Genus: Anthophora
Subgenus: Clisodon
Species: Anthophora terminalis
Anthophora terminalis Digger Bee
Anthophora terminalis
1/2" (medium-sized)
A Female Anthophora terminalis Digger Bee
Anthophora terminalis bees have exceptionally long tongues. Females, like the bee shown here, carry pollen on the lower sections of their hind legs, which are covered with yellow hairs.
A female Anthophora terminalis digger bee using its long tongue to reach into a lobelia flower, while remaining hovering in mid-air in front of the blossom.
Anthophora terminalis digger bees' long tongues allow them to gather nectar and pollen from deep-throated flowers like the lobelia shown here.
The female bee here is poking its tongue into the lobelia flower's corolla to drink nectar -- while using its head to prop open the blossom's column, which holds the lobelia's pollen-covered style and filaments.
While the female bee collects pollen and nectar, its head and thorax rub against the flower's anthers -- thus, pollen collects on other parts of the bee and is transported to other blossoms, increasing pollination rates.
The female Anthophora terminalis digger bee's abdomen is black with thin white stripes.
A Male Anthophora terminalis Digger Bee
Anthophora abrupta digger bees are a rare sight in the park. So far, they have been observed only in mid-June, when they emerge to feed on wild penstamon that grows along the edges of Pocantico River Trail, close to a stream. The picture of a male Anthophora abrupta at right is, so far, the only photograph in this guide that captures a moment in the life of this species of digger bee in the park. Appropriately, the picture was taken as the Anthophora abrupta bee zipped by. These are boisterous, active and fast bees.
In 1929, the entomologist Phil Rau wrote of Anthophora abrupta bees: “They are neither timid nor aggressive, but they certainly are self-reliant…how conspicuous they are as they noisily swing their ponderous bodies to and fro on the wing, arrive home and scramble into their burrows or come tumbling out headlong and dash off into the sunny fields, with all the exuberance of boys just out of school. They have none of the shy, stealthy ways of maneuvering, whereby some of the smaller and daintier varieties of bees and wasps hold their own in a competitive world.”
Male Anthophora abrupta bees have additional endearing traits. In the evening, they like to climb to tops of stems and grass blades, grip them with their jaws, and fall asleep dangling from their jaws.
Like most other digger bees, Anthophora abrupta bees nest in the earth; they prefer vertical banks rather than level ground. Female Anthophora abrupta bees haul mud through the air with their front legs in order to moisten dirt and clay to better dig nests tunnels in the ground. When Anthophora abrupta bees are expanding their underground lairs, they pile excavated dirt outside their holes in tall thin stacks called tumuli that look like makeshift chimneys.
Anthophora abrupta bees are solitary – that is, each bee builds and provisions its own nest --- but these bees are also gregarious. They prefer building their nests close by one another. “The result,” Rau wrote, is a very conspicuous village, sometimes a very crowded and busy town of these masonry turrets … At a busy season when many of these huge bees are bustling about with very audible hum and zip, the entire village with its many wonderful towers and industrious citizens form a spectacle which is in itself quite capable of overawing any but the most unemotional individual.”
Anthophora abrupta have been documented pollinating a fairly wide range of plants. They are partial to roses, inkberry, azaleas, staghorn sumac, purple milkweed, delphinium and jewelweed. In agricultural areas, these bees pollinate asparagus, tomatoes, caneberries and cranberries.
Identification information: Anthophora abrupta digger bees are round-bodied, robust and yellow-and-black; because of these traits, they are they are sometimes mistaken for bumble bees. Bumble bees, however, never appear with the combination black head / pale thorax / black abdomen. This is the pattern characterizing these digger bees: the heads and abdomens of Anthophora abrupta bees are dark brown or black, and their thoraxes are covered with pale-gold hairs. Their legs sport shaggy black hair.
Anthophora abrupta digger bees lack narrow white bands on their abdomens – a trait that helps distinguish them fairly easily from the Abrupta terminalis digger bees shown above in this guide. Anthophora abrupta bees are also quite hefty for New York digger bees – both males females run as large as 3/5” in length. Males can be slightly smaller than females.
As noted above in the entry on Anthophora terminalis bees, male digger bees found in New York tend to have yellow masks – that is, the clypeuses and labrums (face parts above the bees’ jaws) are predominantly yellow. Masks vary from species to species. Anthophora abrupta bees additionally have yellow markings on their jaws and scapes (lowest antennae segments), a trait that distinguishes them from Anthophora terminalis bees. Although not apparent in the photograph here, Anthophora abrupta males also have a distinctive mustache of hair just above their jaws. Female bees have black faces; they also have “roman noses” or concave profiles.
TAXONOMY - Anthophora abrupta Digger Bees
Order: Hymenoptera
Family: Apidae
Subfamily: Apinae
Tribe: Anthophorini (Digger Bees)
Genus: Anthophora
Subgenus: Melea
Anthophora abrupta Digger Bee
Anthophora abrupta
1/2" - 3/5" (medium-sized to medium-large)
A male Anthophora abrupta bee, in flight, with a furry gold thorax and yellow mask.
A close-up of the bee's face, showing the yellow bottom segments (scapes) of the bee's antennae, and the yellow markings on its mandibles.
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A Male Anthophora terminalis Digger Bee
A Male Anthophora abrupta Digger Bee
PHOTO CREDITS: All photos and text © Copyright 2014-2017 Paula Sharp and Ross Eatman, unless otherwise noted. All rights reserved. If you wish to use any of the photographs here for educational or other purposes, please read permissions page.
REFERENCES: For a comprehensive list of references used in compiling this guide, click here:
