ID GUIDE TO WILD BEES - NEW YORK

PANURGINAE MINING BEES:   CALLIOPSIS & PERDITA

PANURGINAE  MINING BEES:   Bees of the genus Calliopsis and the genus Perdita nest in the ground, a practice that has earned them the name "mining bees".   Bees of both genera belong to the family Andrenidae  -- like the Andrena mining bees shown on the next page of this guide. Calliopsis and Perdita mining bees, however, belong to a different subamily than Andrenas -- the subfamily Panurginae.  Bees in this subfamily are usually pollinator specialists that target a particular kind of plant or plant group. 

Panurginae, such as the Calliposis and Perdita mining bees shown here, often have yellow or pale markings on their faces, thoraxes, abdomens and legs.  The examples of Calliopsis  and Perdita shown below share another common trait:  both are very small and easy to miss.

Both Calliopsis and Perdita mining bees are special to the Western Hemisphere.  Within the United States, they are most common and most diverse in the southwest and west.  Although there are more than 650 species of Perdita and at least 90 of Calliopsis, both genera are underrepresented on the east coast.  Only a handful of species of each genera are found in New York.

Campus Bee

aka Calliopsis Andreniformis Mining Bee

Calliopsis andreniformis

(Family Andrenidae / Subfamily Panurginae)
1/5" (small)

 

Various authors have noted that Calliopsis derives from the Greek word for "beautiful" (kalli) -- and that Calliopsis mining bees are, in their own special way, beautiful.  Many Calliopsis bees have decorative yellow or cream-colored markings and brightly-colored eyes.  

Mining bees of the species Calliopsis adreniformis have striking faces:  both males and females have green eyes, and males have bright yellow faces and legs as well.  These singular bees are nonetheless easy to overlook, because they are so small:  an adult Calliopsis  andreniformis, as shown in the photo strip at right, can fit easily on a dime, with room to spare.  The bees photographed here were found inadvertently, when they stumbled into the range of a macro lens while the photographer was focusing on larger pollinators.

 

Called a “campus bee” in 1940’s articles on this species, Calliopsis andreniformis is a solitary pollinator that nests in the ground.  Campus bees prefer inhabiting sandy areas and the hard-packed soil of trails and well-traveled parcels of land (hence the name "campus bee").  The bees produce one generation per year.

Female campus bees dig individual underground nests, usually in compacted soil and close to flowering plants that serve as food sources. The nests are built in the form of long horizontal tunnels, lined with egg chambers, in which the mother bee stores eggs and provisions. When the campus bee eggs hatch, the young feed on the provisions and overwinter as larvae.  They wait until spring to pupate into the next generation of adult bees.  

Female campus bees excrete an oily waterproof substance containing the chemical citral (the same chemical found in lemongrass, lemon verbena and lemons), from a special organ called the Dufour’s gland. The bees paint this substance on the walls of their egg chambers and on their nectar and pollen stores, in order to waterproof them and protect them from flooding.

According to Wilson & Carril’s The Bees in Your Backyard, Calliopsis bees have an odd mating ritual – once males couple with females, the bees remain attached as the female flies from flower to flower, until she enters her nest.  This singular behavior aids in identifying the species.

Campus bees have a preference for plants in the pea family (Leguminosae), particularly clover and melilot -- both the male and female bees shown here were found feeding on white clover (Trifolium repens).  Nevertheless, Calliopsis andreniformis is a generalist pollinator that forages on an array of plants, among them milkweed, coreopsis, catmint, cinquefoil, indigo, black-eyed Susans, fleabane, wild carrot, salvia, peonies, arrowwood, verbena, geraniums, mallow and buckwheat.  Campus bees are documented pollinators of a variety of crops as well, including alfalfa, apples, blueberries, strawberries, blackberries, raspberries and melons.

Campus bees are widespread in the eastern and midwestern United States – Calliopsis andreniformis is found as far north as Maine, as far south as Florida, and as far west as Utah.  The bees tend to appear in late spring and to linger through the summer.  They can be found in early June in the Rockwood Hall section of Rockefeller State Park Preserve.

The nests of campus bees are preyed on by the small red-and-black cleptoparasitic cuckoo bee, Holcopasites calliopsidis.
 

Identification Information:

Calliopsis bees belong to the tribe Calliopsini; in our area, they are the sole representatives of this tribe. Entomologist Charles D. Michener noted that distinctive traits of the bee tribe Calliopsini include the following:   they have robustly-shaped bodies, whatever their size; they rarely show metallic coloration; both males and females have pale markings on their faces; and the bees' forewings (as shown in the photo strip at right) have two submarginal cells (instead of three, like Andrenas and many other varieties of bees).

Calliopsis andreniformis (literally, "beautiful, Andrena-shaped bees") are notably small:  males are barely 1/5 inch long (5-6 mm.)  Females are slightly larger than males (up to 7 mm). Both males and females have predominantly dark thoraxes, adorned with two oblong stripes on the pronotal ridge (the front rim); heads that are dark or mostly dark; and dark abdomens striped with bands of pale hairs.  

Male bees, like that shown at right, have striking green eyes and predominantly yellow legs.  The bottom half of the male bee’s face is bright yellow; a handful of sparse pale hairs sprout from the yellow mask. The male bee’s clypeus (the face section above the jaws) juts forward, and its jaws are yellow, red and black.  The male bee’s antennae are yellow below and reddish above.  The scapes of the antennae (the bottommost segments) are yellow. 

Female bees differ substantially in appearance from males.  Like the males, females have jutting clypeuses and light green eyes.  Females, however, lack the yellow legs and faces of the male bees.  Instead, females have dark legs covered with short, fairly sparse, pale hairs. Females'  faces are either entirely dark, or dark with distinctive off-white markings:  two pale blotches line the inside edges of the bottom portions of bee’s compound eyes; between them, a narrow stripe, topped by a pale trapezoid, bisects the bee's clypeus;  and two small pale spots flank the trapezoid.  Female bees have black jaws with reddish areas near the middle and tips of the mandibles.

Similar species:  Only one other bee of the genus Calliopsis is found in New York -- the Nebraska Calliopsis (Calliopsis nebraskensis).  This bee, however, is an unusual find in New York and more common in the mid-western and prairie states.  The male Calliopsis nebraskensis has black as well as yellow markings below the level of the antennae, unlike the male campus bee, whose lower face is entirely yellow. The female Nebraska Calliopsis bee's face lacks the central stripe characteristic of  the face of the female campus bee.  The campus bee also can be distinguished from the Nebrasksa Calliopsis by its dietary habits -- as noted, the campus bee is a generalist pollinator that prefers legumes such as clover, while the Nebraska Calliopsis forages only on a narrow group of plants within the verbena genus, such as vervain.

TAXONOMY: 

Calliopsis andreniformis is a species of mining bee belonging to the family Andrenidae.  The family Andrenidae is divided into three subfamilies – Andreninae – which includes  Andrena mining bees; Oxaeinae, a group principally inhabiting the western and southwestern united States; and Panurginae, which includes, among others,  the genus Calliopsis and its bee tribe Calliopsini.

FAMILY: Andrenidae (Mining Bees)
SUBFAMILY:  Panurginae
TRIBE:  Calliopsini
GENUS:  Calliopsis
SPECIES:  Calliopsis andreniformis

Eight-spotted Perdita Mining Bee

Perdita octomaculata

(Family Andrenidae / Subfamily Panurginae)
1/4" (small)

As noted in the introduction to this guide page, hundreds of species of Perdita have been identified in the New World. In the United States, however, most Perdita are found in desert areas west of the Rockies.  A mere 30 species exist east of the Mississippi, and only 11 species have been documented in New York. 

 

​True to their subfamily Panurginae, bees of the genus Perdita tend to build solitary nests in bare ground. Some Perdita, however, nest communally, with several females sharing common tunnels and a common nest entrance, each laying its eggs in its own individual cell.  Perdita are somewhat unusual, because instead of lining their cells or nests with waterproofing material, as many mining bees do, Perdita cover their pollen stores with a water-resistant coating.  When Perdita young hatch, they eat through the protective coating. in order to devour the pollen underneath.

Because Perdita are so small, discovering their nests can be difficult. The species shown here, the Eight-spotted Perdita, tends to nest in sandy or gravelly soils. According to entomologist George C. Eickwort, eight-spotted Perditas  females dig as many as five nests apiece  and inhabit each nest for up to nine days. 
 

Some Perditas are generalists, but most are specialist pollinators.  The eight-spotted Perdita mining bee is a goldenrod specialist.  Nonetheless, it tends to feed on other pollen sources as well, particularly members of the aster family – including late-blooming purple asters; chicory; groundsel; knapweed; blue cornflowers; gumweed; marsh fleabane; the small white aster known as boltonia; coreopsis; and boneset.  Eight-spotted Perditas also have been documented foraging on bee balm, heather and peppermint.  The female bee shown here was found feeding on goldenrod in mid-September, 2017.

Eight-spotted Perdita females often can be spied lugging bright-orange balls of moistened pollen on their hind tibias, gathered from goldenrod.  The pollen balls are striking because they are pellet-shaped and proportionately large burdens for such small bees. According to Eickwort, the substance the female eight-spotted Perdita bee uses to stick the pollen balls to her scopal hairs is so strong that the pollen balls stay on the bees’ legs and maintain their round shape even while the bee is digging through sand to its nests.

Perdita mining bees tend to be most active during the hot months of summer.  In our area, they are most visible in late August and early September, a period that coincides with the bloom of goldenrod, boneset and various species of white aster.  The male bee shown in the photo strip at right, however, appeared in the park in late June.

 

Perdita have been observed only rarely in the woodland / wetland habitat of Rockefeller State Park Preserve,.  This habitat's soil tends to be rich and full of organic materials, rather than sandy.  (Perdita bees have proven to be more common nine miles to the north of the preserve, in a scruffy and sandy railroad access road, nestled between a swamp and a town dump.)


Identification Information:
 

Both male and female eight-toothed Perditas are

very small – females run slightly longer than 1/4” (7 mm), and males slightly smaller than 1/4” (6 mm).  To the naked eye, eight-spotted Perditas appear to be tiny black wasps with pale stripes. 

Observed more minutely, eight-spotted Perditas have dark heads with green eyes; dark faces and thoraxes with pale-yellow markings; and abdomens decorated with pale or bright yellow “spots”.  Both males and females have wings that are a transparent light brown  with darker brown veins.  The bodies of both males and females are relatively hairless, a fact that makes these bees appear all-the-more wasplike.

Female eight-spotted Perditas are best identified by the pale marks on their abdomens.  Females have eight well-defined yellow “spots” situated in pairs on either side of the first through fourth segments of their abdomens (T-1 to T-4) .  This trait distinguishes female bees from similar New York species of Perditas. According to entomologist Theodore B. Mitchell’s  Bees of the Eastern United States, the fifth segment of the female eight-spotted  Perdita's abdomen is entirely black.

Male eight-spotted Perditas have spots or broken bands on two or more segments of their abdomens.  The spots and bands on males are often a brighter yellow than is typical of the females’ (which tend to be pale yellow). Males have ten yellow spots – one on each side of the first through fifth segments of their abdomens (T-1 to T-5),

The thoraxes of female bees have pale-yellow markings on the pronotum (the front end of the thorax) and on each pronotal lobe (the roughly-circular nodes just under the tegulae, where the wings attach). The pronotum of the male bee can be entirely dark or dark with pale-yellow markings (but not all-yellow). Male eight-spotted Perditas also have yellow markings on their predominantly black legs.

As noted, these bees also have green eyes and faces decorated with yellow markings. As shown at right, the facial markings of female bees are distinctive: the female bee’s clypeus (the part above the jaws) is described by the Discover Life Databse as usually yellow “with two thin dark stripes invading the yellow on either side of center,” which do not quite extend to the edge of the clypeus.  The scapes (or first segments) of the female eight-soitted Perdita's antennae are entirely dark.   These markings help help distinguish them from females of very similar New York Perdita species . The jaws of female eight-spotted Perdita are yellow with rust-colored tips.

Male eight-spotted Perditas have varied facial markings that differ from those of typical females.  The male eight-spotted Permita has a yellow clypeus (the face part above the jaws), but the male’s clypeus lacks the two dark stripes found on females. Male bees’ antennal scapes and the area above the male bee’s clypeus can be dark, pale or bright yellow. The hind tibias of male bees are partly yellow.

Female eight-spotted Perditas have short scopal hairs because they use moisture to stick pollen loads to their hind tibias (according to John S. Ascher).  Under magnification, as shown in the photos at right, the scopal hairs on the female bees’ legs are singular looking – they stick out a little like cactus prickers, nearly perpendicular to the leg.  Under more intense magnification, the individual hairs appear  “unbranched” – that is, with a simple structure, without smaller hairs branching from the sides of each hair.   (Branched hairs are a trait common in most other bees, because this allows for efficient pollen-collection.)

TAXONOMY: 

Perdita octomaculata is a species of mining bee belonging to the family Andrenidae.  The family Andrenidae is divided into three subfamilies – Andreninae – which includes  Andrena mining bees; Oxaeinae, a group principally inhabiting the western and southwestern united States; and Panurginae, which includes, among others, the tribes Callopsini and Perditina.  The genus Perdita belongs to the later tribe.

FAMILY: Andrenidae (Mining Bees)
SUBFAMILY:  Panurginae
TRIBE:  Panurgini

SUBTRIBE:  Perditina
GENUS:  Perdita
SUBGENUS:  Perdita
SPECIES:  Perdita octomaculata

A male Calliopsis andreniformis.  This bee is 1/5 inches long.

Face of a male Calliopsis andreniformis

A female Calliopsis andreniformis.  This bee is barely more than 1/5 inches long.

Face of a female Calliopsis andreniformis

All photos (c) 2014 - 2017 Sharp-Eatman Nature Photography

A female Perdita octomaculata. 

A female Perdita octomaculata. 

Face of a female Perdita octomaculata

All photos (c) 2014 - 2017 Sharp-Eatman Nature Photography

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:

 8-23-15
 

A male campus bee resting on a dime -- this image highlights the minute size of this species.