ID GUIDE TO WILD BEES
OF THE NATIONAL BUTTERFLY CENTER
LEIOPODUS CUCKOO BEES
Genus Leiopodus - Tribe Protepeolini
The bee tribe Protepeolini occurs only in the Western Hemisphere, from the southern United States through South America. The small genus Leiopodus is the sole member of this tribe. Like the Nomada, Epeolus and Triepeolus cuckoo bees shown in the preceding sections of this guide, Leiopodus are cuckoo bees of the family Apidae that parasitize the nests of of other bees.
The species Leiopodus singularis
Leiopodus singularis is the only member of its genus (and of the tribe Protepeolini) occurring north of Mexico. Within the United States, this species is found primarily in south Texas, New Mexico, Arizona and southern California. Its population extends through Mexico and at least as far south as Guatemala. Leiopodus singularis is considered generally uncommon, and it has been documented rarely in the Valley -- perhaps because its small size and muted coloring make it inconspicuous in most settings.
Entomologists J.R. Rozen, Jr., K.R. Eickwort and G.R. Eickwort first described the nesting habits of Leiopodus singularis in 1978.
Leiopodus cuckoos are brood parasites that invade the nests of chimney bees (Diadasia, Melitoma and Ptilothrix). Leiopodus singularis is a known cleptoparasite of the chimney bees Diadasia angusticeps and D. olivacea. The female Leiopodus shown here, discovered at the National Butterfly Center in November 2022, was feeding in the vicinity of the chimney bees Diadasia ochracea and Diadasia tropicalis. (A third chimney bee species, Diadasia diminuta, was also present -- however, Rozen et al. reported in 1978 that this species is not subject to attack by parasitic bees.)
Female Leiopodus singularis are most likely to be found lurking near the nests of their Diadasia hosts. Female Leiopodus singularis may compete with one another at nest sites, facing off in aerial combat. Diadasia -- which are considerably heftier -- also attack and chase away female Leiopodus singularis from nesting areas.
Leiopodus singularis tend to linger outside of nests, watching and waiting for the host to leave. Thereafter, the cuckoos enter the Diadasia nests and deposit eggs, one by one, in the nests' cell chamber walls. The cuckoo bees cover the eggs with soil after laying them. They depart the nests afterward.
Leiopodus singularis eggs have an unusually long incubation period. By the time first-instar (first-stage) Leiopodus larva emerge, their hosts' larvae are already preparing to enter the final instar -- and thus are far larger. The newly-emerged Leiopodus larvae are barely one mm in length and legless. Nonetheless, equipped with long, sharp mandibles, they handily kill off the Diadasia larvae.
The first-instar Leiopodus larva do not eat; instead, they molt and enter the second instar. They then consume food provisions stored in the nest by the adult Diadasia host for her own offspring.
A female Leiopodus singularis cuckoo bee
TAXONOMY OF THE BEE TRIBE PROTEPEOLINI
Leiopodus -- like Nomada, Epeolus and Triepeolus cuckoo bees -- belongs to the subfamily Nomadinae. Nonetheless, Leiopodus is difficult to categorize, and at times in its taxonomical history, Leiopodus has been classified as member of the subfamily Apinae.
Leiopodus and its tribe Protepeolini are unusual in many respects. Among other singularities, the first instar (stage) of Leiopodus larva is unlike that of any other Nomadinae larvae.
In Bees of the World, Charles D. Michener wrote that Protepeolini share the following distintive traits: (1) The tip of the female bee's abdomen (S6) tapers to a point, and its lateral edges curve upward, forming guides for the stinger. (2) The last segment of the female bee's abdomen (T6) lacks a pygidial plate -- although it has a slender, parallel-sided, flat projection flanked by spines. (The male also lacks a pygidial plate.)
TAXONOMY OF LEIOPODUS
Species shown below on this page:
Leiopodus Species of the National Butterfly Center
Singular Cuckoo Bee
Size: 7-9.8 mm (female)
7.5-10 mm (male)
Plant Family: Asteraceaea
Plant Family: Boraginaceae
November 2022 & 2023
National Butterfly Center
A female Leiopodus singularis cuckoo bee
A female Leiopodus singularis: this small bee has a dark head partly covered with pale hairs; a black and red thorax covered with a pattern of pale and dark longish hairs; and a black abdomen striped with bands of short pale-yellow hairs.
Note the female's long, thick hind legs, covered with short pale hairs, and the conspicuous spines on all six of the bee's legs. Note also the red tegulae and the red knob on the side of the thorax.
This female bee's upper legs are dark and its lower legs are reddish.
Dorsal view: the bee's scutum (the front of the thorax) is dark, and its scutellum (behind the scutum) is reddish.
Alternate view of reddish knob on the lateral edge of the scutum.
Leiopodus singularis is a small, multi-colored bee with long, robust legs armed with long spurs. It has a dark head and thorax covered with a mixture of long and short, white and brown hairs; and a black abdomen striped with bands of appressed pale-yellow hairs. The hairs on the bee's thorax and abdomen form distinctive patterns. Such patterns vary remarkably between one individual of the species and another.
Individual Leiopodus singularis also may vary in color -- some have predominantly dark heads, bodies and legs, while others may have extensive red coloration. The tegulae of the female Leiopodus singularis shown here, and parts of its thorax, are red or reddish. Its legs are dark on the upper segments and otherwise reddish. The bee's eyes are liver-colored, and its antennae and jaws mostly reddish.
Viewed with the naked eye, this bee has a mottled brownish appearance that makes it blend easily into its surroundings. The longish hairs on the bee's thorax and head give it a mussy and messy look -- on first glance, an observer might not think it is even a bee.
CITE THIS PAGE: Sharp, Paula and Ross Eatman. "Leiopodus." Wild Bees of the National Butterfly Center of Mission, Texas. 15 Jan. 2019, http://www.wildbeestexas.com. Accessed [day/month/year guide accessed].