DIADASIA CHIMNEY BEES
Diadasia

ID GUIDE TO WILD BEES
OF THE NATIONAL BUTTERFLY CENTER

Mission, Texas

Diadasia bee, Diadasia ochracea, Diadasia enavata

DIADASIA CHIMNEY BEES
Genus Diadasia

 

Diadasia are small-to-moderate-sized, often beautiful bees. Most are a tawny color, with abdomens that are either striped with pale bands or covered with pale-gold hairs.  Female Diadasia have bushy pollen-collecting hairs on their hind legs and  distinctive brushes of long hairs on their forelegs.

Diadasia often appear in popular literature under the name “Chimney Bees,” because they build small chimney-shaped turrets outside of their tunnel entrances.  The function of these chimneys is debatable.  Diadasia have been observed disassembling the chimneys, after egg-laying, and using them to plug nest entrances. Other sources hold that the chimneys prevent flooding; keep debris out of the bees' tunnels; and even serve to discourage invaders such as velvet ants. 

Like most of the wild bees in this guide, Diadasia are solitary -- that is, each bee builds and provisions its own nest.  Diadasia nests tend to take the form of shallow vertical burrows in the ground.  Some Diadasia soften the earth with nectar to make nest-digging easier. 

In Texas, Diadasia overwinter in the ground and then emerge during spring blooming periods to begin building nests.  Despite their solitary status, many Diadasia species are gregarious and form aggregations (or groups) when nesting. Depending on the species and environmental conditions, Diadasia may nest more than once in a given year.  

According to Jack Neff of the Central Texas Melittological Institute, some Diadasia males gather outside of nests, guarding their entrances in order to waylay the female occupants.  In the species Diadasia rinconis, males sometimes pile on one another, forming tangles of grappling bees vying for supremacy over a single briefly-interested female.

At the National Butterfly Center, male Diadasia rinconis (shown below) appear before female bees emerge.  Multiple male bees often gather together inside golden prickly poppies in late March, short before before Texas prickly pear begins to bloom. According to Jack Neff, prickly poppy is a good pollen source but produces little nectar.  Thus, given that male bees (unlike females) do not gather pollen, male Diadasia probably hang out in the poppies because the large blossoms furnish comfortable resting places.  Even after prickly pears are in full bloom in the area, male Diadasia rinconis can be found sleeping in the mornings in yellow prickly poppies at the NBC.

Diadasia and Specialist Plants

Diadasia often appear under such common names as “Sunflower Bee” or “Cactus Bee.”  These names reflect the fact that most Diadasia are "oligolectic," or pollen specialists that feed on a narrow range of flora.  Thus, particular species of Diadasia become inextricably linked with particular plants.  Accordingly, Diadasia enavata, shown below, is sometimes called “a sunflower chimney bee,” because it pollinates plants of the sunflower family nearly exclusively. 

 

A number of Diadasia species belonging to the subgenus Coquillettapis visit cactus flowers.  In Texas, such species include  Diadasia rinconis; the very similar Diadasia australis; Diadasia opuntiae; and Diadasia piercei.  Some of these are cactus specialists and others, despite their common name "cactus bee," visit other varieties of flowers.  Diadasia pierci, for example, collects pollen predominantly from prickly pear cactus.  Diadasia opuntiae, whose Latin name might be translated to “prickly pear chimney bee,” visits sunflowers as well as cactus. Diadasia rinconi and Diadasia australis, perhaps the most common visitors to prickly pear cactus in the immediate vicinity of the Butterfly Center, visit a vast array of flowers from several plant families, among them members of the poppy, mallow, aster, pea and verbena families.

Some Texas Diadasia are closely associated with plants of the mallow family.  Diadasia tropicalis, for example, shown below, is a mallow specialist.  Diadasia diminuta (also known as the globe mallow bee), and Diadasia ochracea both visit mallows in a number of genera, and are most frequently found at the NBC on mallows.  (Neither of these two species is a strict mallow specialist, however; both frequent flowers of other plant families as well.)

In other states, Diadasia are found that specialize in varieties of morning glory; aster-family flowers; evening primrose; and clarkia. According to entomologist Charles D. Michener's The Bees of the World, Diadasia that specialize on mallow and evening primrose tend to be small, with a covering of "uniform, pale hairs" on their abdomens.  By contrast, Diadasia that specialize on cactus or sunflowers tend to be robust and to have "distinctively banded" abdomens. 

Where to find Diadasia

Diadasia tend to prefer hard-packed and sandy soils and are most likely to appear in arid grasslands and desert habitats. They are found only in the Americas.  There are roughly 45-50 Diadasia species, 25 of which appear north of Mexico.  All but one occur west of the Mississippi, and most inhabit the southwestern United States.  Within Texas, at least thirteen Diadasia species have been documented.

As a general rule, Diadasia ochracea and the sunflower chimney bee Diadasia enavata are the Diadasia species most likely to be seen at locations distant from the Mexican border.  D. ochracea is found in California, Mexico and throughout the southwestern United States.  According to the Discover Life Database, the sunflower chimney bee has the largest distribution of any Diadasia.  It ranges from as far north as western Canada, as far west as Washington state and California and as far east as Mississippi.  Diadasia  tropicalis, by contrast, is found within the United States only near the Mexican border.

A female Diadasia chimney bee:  note the brush of long hairs on the underside of  the bee's front femur, a defining characteristic of female Diadasia.

Diadasia rinconis bees sleeping in prickly poppy - (c) Copyright 2019 Paula Sharp

Male Diadasia rinconis "cactus bees" resting inside a golden prickly poppy 

A male "cactus bee"  (Diadasia rinconis) inside a prickly pear blossom

Diadasia enavata - (c) Copyright 2019 Paula Sharp

A male "sunflower bee"  (Diadasia enavata)

TAXONOMY OF DIADASIA CHIMNEY BEES

Order:   Hymenoptera

Family:   Apidae

Subfamily:  Apinae

Tribe:  Emphorini

Genus:   Diadasia

Species shown below:  
   Diadasia diminuta (Subgenus Coquillettapis)   

   Diadasia enavata (Subgenus Diadasia)
   Diadasia ochracea (Subgenus Dasiapis)
 

   Diadasia rinconis (Subgenus Coquillettapis)
   Diadasia tropicalis (Subgenus Dasiapis)
 

Diadasia Chimney Bee Species of the National Butterfly Center

Diadasia rinconis Chimney Bee
Diadasia (Coquillettapis) rinconis

Size:  11-12  mm (male); 12 mm (female)

Associated plants at NBC:  
Texas Prickly Pear

(Opuntia engelmannii)
Plant Family:  Cactaceae

Golden Prickly Poppy
(Argemone aenea)

Plant Family:  Papaveraceae

When seen:

March  - April  2019  

Detailed Photographs: 

male bee

A male Diadasia rinconis chimney bee - (c) Copyright 2019 Paula Sharp

A male Diadasia rinconis chimney bee

Diadasia rinconis chimney bee - (c) 2019 Paula Sharp

A male Diadasia rinconis chimney bee stretching its long legs to grip a span prickly pear flower petal

female bee

Diadasia rinconis chimney bee - (c) 2019 Paula Sharp

A female Diadasia rinconis / Diadasia australis chimney bee

Globe Mallow Bee

Diadasia (Coquillettapis) diminuta

Family:  Apidae

Size:  6 - 8 mm  

Associated plants at NBC:  
False spiked mallow
(Malvastrum americanum)

Teabush

(Melochia tomentosa)
Plant Family:  Malvaceae

When seen:

September & November 2018

May 2019

Female bee

Male bee

Diadasia diminuta chimney bee - (c) Copyright 2019 Paula Sharp

A female globe mallow bee (Diadasia diminuta)

Male globe mallow bee (Diadasia diminuta) - (c) Copyright 2019 Paula Sharp

A male globe mallow bee (Diadasia diminuta) on a dime

Ochraceous Chimney Bee

Diadasia (Dasiapis) ochracea

Family:  Apidae

Size:  8 mm  (female)

Associated plants at NBC:  
False spiked mallow
(Malvastrum americanum)
Plant Family:  Malvaceae

When seen:

September & November 2018

Detailed Photographs:

Diadasia ochracea chimney bee - (c)  Copyright 2018 Paula Sharp

A female ochraceous chimney bee

Detailed Photographs: 

Tropical Diadasia Chimney Bee

Diadasia (Dasiapis) tropicalis

Family:  Apidae


Size:  7-8 mm (male)

Associated plants at NBC: 
Rio Grande Abutilon

(Abutilon hypoleucum)

Spiked Malvastrum

Malvastrum americanum
   
var. Americanum *

Plant family:  Malvaceae

When seen:  April & July 2019  

Diadasia tropicalis bee - (c) Copyright 2019 Paula Sharp

A male Diadasia tropicalis chimney bee

Diadasia tropicalis bee - (c) Copyright 2019 Paula Sharp

A male Diadasia tropicalis chimney bee

Sunflower Bee

Diadasia (Diadasia) enavata

Family:  Apidae

Size:  12-15 mm  (male & female)

Associated plants at NBC:  
Common sunflower

(Helianthus annuus)

Cowpen Daisy
( Verbesina encelioides)

Plant family:   Asteraceae

When seen: 
November 2018,  April 2019 

June 2019 

A male Diadasia enavata chimney bee - (c) Copyright 2019 Paula Sharp

A male sunflower  bee (Diadasia enavata)

Diadasia enavata chimney bee - (c) Copyright 2019 Paula Sharp

A female sunflower chimney bee (Diadasia enavata)

Diadasia enavata sunflower bee - (c) Copyright 2019 Paula Sharp

A female sunflower bee (Diadasia enavata)

Permissions and Copyright Information:   All images on this site are (c) Copyright 2018-2019 Paula Sharp and Ross Eatman.  All rights reserved. All photographs are protected by registered copyright.  Please contact Sharp-Eatman Nature Photography for written permission before using any of these images for any purpose. 

Last updated November 2019

 1-15-19