SHARP-EATMAN
NATURE
PHOTOGRAPHY
ID GUIDE TO WILD BEES
OF THE NATIONAL BUTTERFLY CENTER
Mission, Texas
ASHMEADIELLA
Ashmeadiella
ASHMEADIELLA
Tribe Osmiini - Genus Ashmeadiella
Ashmeadiella belong to the tribe Osmiini of the family Megachilidae -- like the Heriades resin bees and Osmia mason bees of this guide's previous sections.
Bees of the genus Ashmeadiella are found only in North America and Central America. Within the United States, Ashmeadiella occur principally in western desert and semi-arid areas. Two species are native to the Valley: both are found in dry habitats where cactus and other xeric plants abound.
Distinguishing traits of Ashmeadiella
Ashmeadiella are small to medium-small bees with robust builds; nonmetallic, usually black heads and bodies; and abdomens banded with pale hairs. Some species have red or partly-red abdomens. As with other members of the family Megachilidae, the forewings of Ashmeadiella have two submarginal cells, and females transport pollen on scopal hairs located under the sternum (the underside of hte abdomen). The tarsal claws of Ashmeadiella possess arolia. The front surface of the first segment of an Ashmeadiella abdomen is widely concave and bounded with a ridge.
Ashmeadiella can be separated from similar bee genera by the following two traits. (1) The tip of the male Ashmeadiella’s abdomen (T6) usually has four prongs. (2) On both males and females, the mesepisternum (the middle segment of the side of the thorax) is divided by a weak ridge: the area in front of the ridge is smooth and shiny, and the area behind it is pitted. The second of these traits requires strong magnification to isolate, and it may be obscured under hairs. The distinctive four-pronged abdomen of the male bee, however, is readily recognizable, even to the naked eye, and is the best means of diagnosing the genus in the field.
Ashmeadiella are sometimes confused in the field with Heriades, but within Texas, Ashmeadiella females are generally larger and stouter; Heriades males lack the abdominal prongs; and the eyes of Ashmeadiella are a more brilliantly-colored blue or green.
Behavior
All Ashmeadiella are solitary cavity nesters. They nest in a variety of places, among them, pre-existing holes in wood, dead or decaying cactus, beetle burrows, shells or (less often) the ground. Ashmeadiella nests usually take the form of a tunnel divided at the end into egg cells. The cells contain one or several eggs and are separated by partitions made of chewed-up plant materials and saps.
A female Ashmeadiella cactorum. Ashmeadiella are robustly built black bees with abdomens striped by pale hair bands. Females carry pollen on scopal hairs located on the sternum (under the bee's abdomen)
Ashmeadiella of the Valley have green or blue eyes, a trait that helps distinguish them from Heriades, which have black (or occasionally violet) eyes.
The elongate prongs on the rear of the abdomen (T6) of a male Ashmeadiella. This distinctive trait distinguishes all male Ashmeadiella from similar bees such as Heriades resin bees.
A female Ashmeadiella cactorum
TRAITS OF ASHMEADIELLA
A female Ashmeadiella cactorum: Ashmeadiella are robustly-built, and usually black, bees with abdomens striped by pale hair bands.
Female Ashmeadiella carry pollen on scopal hairs located on the sternum (under the bee's abdomen).
The elongate prongs on the rear of the abdomen (T6) of a male Ashmeadiella: this distinctive trait distinguishes most male Ashmeadiella from similar bees such as Heriades resin bees.
TAXONOMY OF ASHMEADIELLA
Order: Hymenoptera
Family: Megachilidae
Subfamily: Megachilinae
Tribe: Osmiini
Genus: Ashmeadiella
Species shown on this page:
Ashmeadiella (Ashmeadiella) cactorum cactorum
Ashmeadiella (Ashmeadiella) maxima
Ashmeadiella Species of the Lower Rio Grande Valley
Greater Ashmeadiella
Ashmeadiella (Ashmeadiella) maxima
Family: Megachilidae
Size: 7-9 mm (females)
8 mm (male)
Associated plants:
Lotebush
(Ziziphus obtusifolia )
Plant family: Rhamnaceae
Arkansas dozedaisy
Aphanostephus skirrhobasis
Plant family: Asteraceae
When and where seen:
May 11, 2021
Pixie Preserve (Hidalgo Co.)
May 1, 2023
Dos Venadas Ranch
Rio Grande City TX (Starr Co.)
A male Ashmeadiella maxima: note the bee's black tarsi (feet).
A male Ashmeadiella maxima: on both male and female bees, the abdominal hair bands appear on the first five segments (T1 - T5). Both males and females have hairy thoraxes and heads.
The male Ashmeadiella maxima has a broad face with green eyes. Dense white hairs cover its face.
Profile of male bee's head
A female Ashmeadiella maxima
Dorsal view of a female Ashmeadiella maxima
Close-up of vertex and thorax of female bee: note the female's broad head.
The wide face of a female Ashmeadiella maxima
A male Ashmeadiella maxima
The tip of the abdomen of a male Ashmeadiella maxima
A female Ashmeadiella maxima
Ashmeadiella maxima is a black bee with a robust build and an abdomen banded by pale hairs. As its name implies, Ashmeadiella maxima is large for its genus -- its size helps to identify it in the field.
Male Ashmeadiella species are separated in part by the characteristics of the prongs on the bees’ abdomens, and by the positioning of the ocelli on the vertex. The male Ashmeadiella maxima also can be recognized by its black tarsi, and the dense white hairs on its face. The female Ashmeadiella maxima can be recognized by its size and its braod head.
Within the United States, Ashmeadiella maxima is found principally along southern border areas of Arizona, New Mexico and Texas. This species appears in mid- through late spring in the Valley.
Cactus Ashmeadiella
Ashmeadiella (Ashmeadiella) cactorum)
Family: Megachilidae
Size: 6-8 mm (female)
6 mm (male)
Associated plants:
Arkansas dozedaisy
(Aphanostephus skirrhobasis)
Plant family: Asteraceae
Bladdermallow
Herissantia crispa)
Plant family: Malvaceae
Texas palo verde
(Parkinsonia texana)
Plant family: Fabaceae
When and where seen:
May 9, 2021, June 20, 2021
El Mesteno Ranch
Puerto Rico (Hidalgo Co.)
Rio Grande City (Starr Co.)
A female Ashmeadiella cactorum: this is a moderately small, black bee with a coarsely-punctured body; an abdomen striped by pale hair bands on T1-T5; a thorax and face sparsely covered with white hairs; black legs; and blue eyes.
A female Ashmeadiella cactorum
The face of the female Ashmeadiella cactorum is distinctive: the top of the cylpeus is pitted and its bottom edge slightly concave. The female Ashmeadiella cactorum also has sparse orange hairs on the outer mandibles. All females of the subgenus Ashmeadiella (Ashmeadiella) have 3-toothed mandibles.
Profile of female bee's head
A female Ashmeadiella cactorum
Ashmeadiella cactorum is a moderately small, black bee with a coarsely-punctured body; an abdomen striped by pale hair bands on T1-T5; a thorax and face sparsely covered with white hairs; and (on females) pale-blue eyes. The bee’s tegulae are black and its wings are glassy brown with dark brown veins. Females have yellowish-white scopal hairs under their abdomens. Ashmeadiella cactorum is smaller than the Ashmeadiella maxima shown above, and less densely haired, and lacks its broad face.
Ashmeadiella cactorum is found in the southwestern and western United States, and throughout Mexico. It occurs in both Starr and Hidalgo Counties. Despite its name, Ashmeadiella cactorum is not a cactus specialist. It is a generalist pollinator that visits plants from a broad range of families.
CITE THIS PAGE: Sharp, Paula and Ross Eatman. "Ashmeadiella." Wild Bees of the National Butterfly Center of Mission, Texas. 15 Jan. 2019, http://www.wildbeestexas.com. Accessed [day/month/year guide accessed].