Apiform Crooked-Legged Bee
Size: 7-8 mm (female); 6 mm (male)
Associated Plants at NBC:
Plant Family: Convolvulaceae
Plant Family: Bignoniaceae
November 2018, April 2019
A female crooked-legged bee (Ancyloscelis apiformis) entering an alamo vine blossom.
This is a common view of a female Ancyloscelis apiformis -- with her abdomen pointed skyward and her face buried in the deep throat of an alamo vine flower.
The female Ancyloscelis apiformis has a dark head and thorax, a dark abdomen banded by pale stripes, and bushy hind legs.
The hind leg scopal hairs of the female are feathery and predominantly black, with some white hairs. The female's protuberant clypeus makes it look "roman-nosed". This trait is shared by males of the species.
This is a male Ancyloscelis apiformis gripping an esperanza flower with his jaws. Note the enlarged femur and hook-shape of the bee's hind leg.
A male Ancyloscelis apiformis from behind
A male Ancyloscelis apiformis spreading its long hind legs to maintain balance
Male (left) and female (right) Ancyloscelis apiformis bees preparing to mate
A female Ancyloscelis apiformis on alamo vine
A male Ancyloscelis apiformis using its long legs for leverage while mating
Female and male Ancyloscelis apiformis differ somewhat in appearance: males are slighter smaller, and they are more readily identifiable because they possess long, hooked hind legs. The hind legs of female Ancyloscelis are conventionally-shaped and not elongated. Females' hind-leg scopal (pollen-collecting) hairs are stiff, widely-spaced and feathery-looking, a characteristic common to members of the chimney bee tribe (Emporini).
In other ways, male and female Ancyloscelis apiformis bees are generally alike: they are small, fairly hairy bees with black abdomens striped with crisp white bands. Their faces are oval, and their heads somewhat small (narrower than their thoraxes.)
Female and male Ancyloscelis apiformis have relatively short antennae, and both tend to have pale markings on their mandibles. Males additionally may show extensive pale patterns on their clypei and labrums (the face parts above and between the mandibles). Both male and female bees’ clypei are sometimes protuberant, giving them a roman-nosed look in profile.
The term "apiform," the literal translation of the species name apiformis, means "shaped like a honey bee" (or, more specifically, a female worker honey bee). The term is applied to bees that are neither slender nor particularly husky but somewhere in the middle. Nonetheless, the female of this species has a fairly robust appearance.
Male Ancyloscelis are easily recognized by their elongated and ornately curved hind legs. The genus name “Ancyloscelis,” which means “crooked-leg,” derives from this singular feature.
Ancyloscelis males use their long, hooked legs for leverage when mating or feeding. They spread their back legs to keep from falling into wide-mouthed flowers as they sip nectar, or as they peer down into blossoms in search of mates.
At the National Butterfly Center, female crooked-legged bees are usually found gathering pollen from the pink-and-white flowers of alamo vine, their heads plunged into the deep-throated blossoms, with only their striped abdomens visible from above. Males fly in quick figure-eight patterns as they patrol vegetation frequented by females. At night, Ancyloscelis males sleep hanging by their jaws from plants visited by females during the day.
Male and female Ancyloscelis apiformis
According to Michener, McGinley & Danforth’s The Bee Genera of North and South America, crooked-legged bees are rare within the United States. Ancyloscelis is a neotropical genus, occurring principally in Mexico and Central and South America. Although approximately 20 Ancyloscelis species live south of the Texas border, only three inhabit the United States: Ancyloscelis apiformis, A. melanostoma and A. sejunctus. All appear nearly exclusively in Texas and a handful of southwestern states. Ancyloscelis apiformis is the dominant crooked-legged species of the Valley; the other two species are generally found considerably north of the Valley.
Ancyloscelis apiformis abound at the National Butterfly Center in areas abutting canals running from the Rio Grande River. Crooked-legged bees tend to nest in shaded, vertical banks like those along the canal's edge. They are solitary ground nesters, with each female bee provisioning its own nest. Nonetheless, Ancyloscelis apiformis often build nests in close proximity to one another and sometimes form large aggregations.
The hind legs of a male crooked-legged bee (Ancyloscelis apiformis)
All three Ancyloscelis species found in the United States are specialist pollinators of morning glory family flowers (Convolvulaceae), particularly those of the genus Ipomoea. Thus, one productive method for finding these bees is to seek out morning-glory-like flowers and to observe what insects visit them.
As noted, Ancyloscelis apiformis is closely associated at NBC with alamo vine (Merremia dissecta), a kind of Convolvulaceae. Alamo vine flowers are large and trumpet shaped; they look like white morning glories with magenta centers (as shown in the photo strip here).
Despite Ancyloscelis species’ strong preference for Convolvulaceae, at the National Butterfly Center, both male and female crooked-legged bees are frequently seen on esperanza (Tecoma stans), an ornamental shrub in the plant family Bignoniaceae, native to the neighboring Mexican state of Tamulipas. The proclivity of Ancyloscelis for visiting esperanza has been well-documented among Ancyloscelis populations in Central America.
TAXONOMY OF ANCYLOSCELIS
Species shown on this page:
An alamo vine blossom (Merremia dissecta): Alamo vine flowers resemble morning glories and belong to the same plant family, Convolvulaceae.
These are esperanza blossoms (Tecoma stans). Like flowers of the morning glory genus, esperanza blossoms have wide mouths that serve as excellent platforms for bees reaching into the flowers' tubular throats.
A female Ancyloscelis entering an esperanza blossom
Flowers frequented by crooked-legged bees at the NBC: alamo vine and esperanza
A female crooked-legged bee polliinating alamo vine
Ancyloscelis Species of the National Butterfly Center
CITE THIS PAGE: Sharp, Paula and Ross Eatman. "Ancyloscelis" Wild Bees of the National Butterfly Center of Mission, Texas. 15 Jan. 2019, http://www.wildbeestexas.com. Accessed [day/month/year guide accessed].