SHARP-EATMAN
NATURE
PHOTOGRAPHY
ID GUIDE TO WILD BEES
OF THE NATIONAL BUTTERFLY CENTER
Mission, Texas
NORTHERN CACTUS WOOD-BORER BEES
Lithurgopsis
Lithurgopsis Species of the National Butterfly Center
Littoral Cactus Wood-borer Bee
Lithurgopsis littoralis
Family: Megachilidae
Size: 9-14 mm (male);
14-15 mm (female)
Associated plants at NBC:
Golden prickly poppy
(Argemone aenea)
Plant Family: Papaveraceae
Red prickly poppy
(Argemone sanguinea)
Plant Family: Papaveraceae
Texas Prickly Pear
(Opuntia engelmannii var. lindheimeri)
Plant Family: Cactaceae
March - April 2019-2023
A female Lithurgopsis littoralis inside a prickly pear blossom
A female Lithurgopsis littoralis from above: note the bee's robust build.
The front of the bee's face has a broad, thick ridge that terminates on each side in curved projections that look, from the side, like short bulbous horns. These traits are diagnostic of females of this species.
A male Lithurgopsis littoralis
This is a large bee, with a very long body and long hind legs.
The powerful hind legs of the male bee: this male bee is digging headfirst into a prickly pear blossom.
A Lithurgopsis littoralis female on a prickly pear blossom
A male Lithurgopsis littoralis cactus wood-borer bee
Within the United States, the genus Lithurgopsis is represented by a mere 6 species (Lithurgopsis apicalis, L. echinocacti, L. gibbosa, L. listrota, L. littoralis and L. planifrons). Cactus wood-borer bees are found mainly in arid habitats of western states and along the U.S. - Mexican border.
The species Lithurgopsis littoralis occurs principally in south Texas and in Mexico, although this bee has been documented as far north as Oklahoma, Kansas and even Illinois. It is the dominant Lithurgopsis species of the Valley. Its name (littoralis means "coastal") reflects the fact that Wilmatte Cockerell found her specimen in Port Isabel, located by the Gulf of Mexico.
In the field, Lithurgopsis littoralis can be distinguished fairly easily from black leafcutters with banded abdomens. The wood-borer bees can be recognized by their association with cactus, their large size and long legs, and their armored appearance (resulting from the hornlike protuberances on the bees' faces and the bumps and spikes on their legs). A trait useful for separating live Lithurgopsis from leafcutters in field is eye color: live Lithurgopsis littoralis have jet-black eyes, while leafcutters of the Valley have blue or green eyes.
Lithurgopsis found in the Valley are typically Lithurgopsis littoralis. (Lithurgopsis apicalis and L. gibbosa have been recorded elsewhere in Texas, but are unlikely to appear in the Valley.) Lithurgopsis species are separated in part by their geographical location and by minute differences in their facial characteristics.
CITE THIS PAGE: Sharp, Paula and Ross Eatman. "Lithurgopsis." Wild Bees of the National Butterfly Center of Mission, Texas. 15 Jan. 2019, http://www.wildbeestexas.com. Accessed [day/month/year guide accessed].
NORTHERN CACTUS WOOD-BORER BEES
Genus Lithurgopsis
Cactus wood-borer bees -- like the leafcutter and resin bees featured in this guide's ensuing section -- belong to the family Megachilidae. Bees of this family carry pollen on scopal hairs located under their abdomens, rather than on their legs like most bees.
Lithurgopsis look a little like hefty leafcutter bees. Both male and female cactus wood-borer bees have black bodies, sculpted dark heads, and banded abdomens that taper abruptly at the end -- all traits of many leafcutters.
Cactus wood-borer bees, however, belong to a different subfamily (Lithurginae) than leafcutters and their close kin. Lithurgopsis do not trim leaves or gather resins from plants to build their nests as leafcutters do. Instead, cactus wood-borer bees nest in pre-existing holes found in dead and decaying plant stalks and other plant matter. In the Lower Rio Grande Valley, Lithurgopsis are invariably associated with cacti.
Lithurgopsis, cactus and prickly poppy
In March 1917, Wilmatte Porter Cockerell, a biology teacher and the author of Collecting Bees in Southern Texas, took a road trip along the Texas border. She described the journey as an excursion through the Texas bush, in which she was grateful to rely on the skillful driving of her companion Miss Mary Cowgill. Along the way, Cockerell stopped to document bees and other insects.
Cockerell discovered several new species, among them the singular Wilmatte's long-horned bee and the constricted metallic bee. One of her discoveries was the cactus wood-borer Lithurgopsis littoralis shown here: she stumbled on a male bee feeding on a yellow composite flower in Port Isabel, located in the Lower Rio Grande Valley about 80 miles from where the National Butterfly Center now lies.
Cockerell’s journal documenting her excursion begins with a rapt description of prickly pear cactus and the many-colored prickly poppies that filled the landscape along the Lower Rio Grande Valley in the spring of 1917. More than 100 years later, these plants still adorn spring landscapes in southmost Texas, and they still attract Lithurgopsis littoralis.
Nowadays, during mid-March in the Valley, shortly before the prickly pear cactus bloom, male littoral cactus wood-borer bees emerge and begin appearing in conspicuous numbers on red prickly poppies (Argemone sanguinea) and golden prickly poppies (Argemone aenea).
Prickly poppies are armored with barbed leaves and bear large, chalice-shaped flowers that can accommodate several male Lithurgopsis at a time. Prickly poppies furnish abundant pollen, but very little nectar. Because male bees drink nectar but do not gather pollen, cactus wood borer males in all likelihood gather in these flowers not to feed on them, but instead because they are comfortable shelters from wind and rain. Prickly poppies close during the night, providing extra protection from the elements. Ensconced in the poppies, the males await the bloom period of Texas prickly pear cactus and the emergence of female bees from their winter nests.
In late March and early April, Texas prickly pear cactus (Opuntia engelmannii) begins to bloom in abundance in the Valley. When this occurs, female Lithurgopsis emerge to gather pollen from prickly pear flowers. The female bees dig deeply into the anthers of the cactus flowers, often disappearing in their depths. The blossoms of Texas prickly pear produce exuberant amounts of pollen.
During the same period, male Lithurgopsis populations forsake the prickly poppies and linger in and around the flowering cactus. Female bees, however, occasionally pause in collecting cactus pollen to gather pollen from prickly poppies.
Physical traits of Lithurgopsis
Lithurgopsis look a little like hefty, armored leafcutter bees. Both male and female cactus wood-borer bees are robustly-built, with large heads, black abdomens girded with pale hair bands, and long hind legs. The scopal hairs on Lithurgopsis females' abdomens are predominantly pale.
Viewed under a macro lens, other notable traits emerge: the hind-leg tibiae of a Lithorgopsis are covered with small bumps and spikes; and female Lithurgopsis have ridges and hornlike protrusions on their faces. These traits are shown in the photo strips below.
According to Texas bee expert John L. Neff, individual Lithurgopsis within a species can be quite variable in size. This results at least in part from the fact that Lithurgopsis have odd nests without well- defined cells; egg chamber size varies, and thus so does the size of hatchlings.
A Lithurgopsis littoralis female on a prickly pear blossom
A golden prickly poppy (Argemone aenea)
A male Lithurgopsis littoralis: note the tank-like build. Cactus wood-borer bees look a little like hefty, armored leafcutters.
TAXONOMY OF LITHURGOPSIS
Order: Hymenoptera
Family: Megachilidae
Subfamily: Lithurginae
Genus: Lithurgopsis
Species found at National Butterfly Center:
Lithurgopsis littoralis
(Littoral cactus wood-borer bee)