Intermixed Cellophane Bee
Size: 10 - 12 mm (female)
9 - 10 mm (male)
Plant family: Solanaceae
When and where seen:
May 4, 2021
McAllen Nature Center
McAllen (Hidalgo Co.)
A female intermixed cellophane bee (Colletes intermixtus)
Colletes intermixtus is a black bee with narrow white bands on its abdomen. The bee’s thorax and abdomen have a faint dark-blue luster. This is a female bee.
The tegulae of Colletes intermixtus are dark brown, and its wings transparent brown with dark brown veins. The scopal hairs on the female bee’s hind legs are white.
The face of the female Colletes intermixtus is densely pitted, long and black. The bee’s clypeus has a longitudinal groove that runs from its base to its tip, a trait often hidden under facial hairs.
Profile of face, showing protuberant clypeus and a short malar space (the gap between the mandible's base and the bottom of the compound eye.)
This species ranges from the west coast to east Texas. Within Texas, it appears as far north as Dallas County. The female bee shown here appeared at Quinta Mazatlán (Hidalgo Co.) in early May, 2021. Colletes intermixtus has been reported in Cameron County.
As noted, within the Lower RIo Grande Valley, Colletes intermixtus is a buzz pollinator of nightshade. This species has been documented visiting a variety of other plants, however, among them large-flowered Asteraceae, huisache (Vachellia farnesiana), whitebrush (Aloysia gratissima) and lemon beebalm (Monarda citriodora).
A male Texas Cellophane bee
Colletes texanus was named in 1872 by entomologist Edward Townsend, whose description of the species was based on a female bee found in Comal County. Within the United States, the Texas Cellophane bee is found nearly exclusively in Texas. It has been documented in recent years in Cameron, Dallas, Hidalgo and Travis Counties.
Pale-gold Cellophane Bee
Size: 9 mm (female)
7-8 mm (male)
Plant family: Asteraceae
When and where seen:
El Mesteno Ranch
Puerto Rico (Hidalgo Co.)
Bahia Grande NWR
Brownsville (Cameron Co.)
Campos Viejos Ranch
Rio Grande City (Starr Co.)
Colletes mandibularis is a small, broadly-built bee.
Here, a Colletes mandibularis female is shown on a quarter, for scale. This species is small for a cellophane bee.
The female Colletes mandibularis has a head and thorax covered in ivory and pale-gold hairs. Its abdomen is striped with beige or ivory hairs.
Face of a female Colletes mandibularis
A female Colletes mandibularis
A female Colletes mandibularis
Colletes mandibularis is a petite cellophane bee with a head and thorax covered with blond and ivory hairs, and an abdomen banded by beige or ivory hairs. Females’ hind-leg scopal hairs are long and pale. The relatively small size of this cellophane bee and its general pale-gold coloring make it distinctive. Colletes mandibularis is an aster-family specialist. In the Valley, this bee is usually found on small-flowered Asteraceae.
Bees of the genus Colletes line the cells of their nests with a waterproof material which, when dry, resembles clear plastic. Accordingly, they are sometimes called “cellophane bees” or, alternately, “polyester bees”. Cellophane bees are equipped with unusual forked tongues, which they use to paint the plastic-like material onto their nest walls in order to keep their nests dry. The bees produce the material from a special abdominal organ called the Dufour’s gland, named after French naturalist Léon Jean Marie Dufour, who first recorded his fascination with the bees’ fabrication of plastique in 1835.
Cellophane bees also spray their egg-cell walls with a natural fungicide and bacteriacide, linalool, secreted from a gland in the bees' mandibles. After coating their cells, the bees fasten their eggs onto the cell walls rather than leaving them on nest floors where moisture might collect. The bees provision their cells by mixing pollen and nectar together to make a liquid “bee bread” for their offspring; these provisions are stored in cellophane sacs that look a little like elongated plastic sandwich bags. The special measures taken by the bees to protect their eggs against water and fungus allow them to build nests near stream banks and other areas with wet soils.
Cellophane bees are solitary. They construct individual nests in the ground, excavating tunnels that exit through small round holes. Despite their solitary status, the bees tend to build their nests near one another. Groups of nesting cellophane bees sometimes number into the tens of thousands. These bees, however, are non-aggressive and do not form swarms. They are important pollinators of spring trees, crops and wildflowers.
The nests of cellophane bees are parasitized by cuckoo bees in the genus Epeolus, which are sometimes called "cellophane cuckoo bees". Epeolus sneak into the egg chambers of cellophane bees and deposit their own eggs there. When the cuckoo larvae hatch, they kill off the cellophane bee young and eat the food stores left by the mother cellophane bee for her own offspring.
Cellophane bees are about the size of honey bees (or slightly smaller or slightly larger). They are hairy bees: their thoraxes are usually covered with pale, brown or rust-colored hairs; and their abdomens are often dark and banded with pale hairs.
The faces of cellophane bees are heart-shaped -- that is, a cellophane bee's eyes slant toward one another, and its head tapers downward toward its mandibles. Cellophane bees' faces are usually covered with pale or light-brown hairs, and their antennae are medium-length. Female cellophane bees carry pollen on the upper parts of their hind legs.
Species identification of cellophane bees often hinges on such traits as size; geographic location; the time of year they emerge; the color of hairs on the thorax and head; the width of the hind-leg basitarsi; and the appearance of the bands of pale hair on the bee's abdomen.
A cellophane bee peering from its nest hole
An aggregation of cellophane bee nests
The heart-shaped face of a cellophane bee
TAXONOMY OF CELLOPHANE BEES
Species shown here:
Cellophane Bee Species of the National Butterfly Center
Birkmann's Cellophane Bee
Size: 12 mm (female)
9-10 mm (male)
Associated plants at NBC:
Plant Family: Euphorbiaceae
Plant Family: Asteraceae
October & November 2019
This is a female Birkmann's cellophane bee.
Note that the hind-leg basitarsus of this female Birkmann's cellophane bee is long and narrow (3 3/4 as long as it is broad). The yellow material on the bee's feet is pollinia (pollen clusters) from flowers.
The female Birkmann's cellophane bee has white hairs on its face. The hairs are denser near the antennae. The flagellar segments of the antennae (the 3rd through uppermost segments) are broader than they are long.
A male Birkmann's cellophane bee
All of the hairs on this male bee are white or very pale orange.
Alternate view of male bee
A female Birkmann's cellophane bee (Colletes birkmanni)
A male Birkmann's cellophane bee (Colletes birkmanni)
Colletes birkmanni is a medium-sized bee with a dark abdomen boldly striped with white hairs. The female bee shown here has thorax hairs that are a light rust color; a face covered with white hairs; and a dark abdomen with bold white bands. The male bee is much paler: it has exuberant white hairs on its face and thorax and white bands on its abdomen.
According to John L. Neff, Director of the Texas Melittological Institute, Birkmann's cellophane bee is common in south Texas. Nonetheless, there has been little written about its nesting behavior or biology. Neff reports that the species is bivoltine -- that is, there are two crops of of the bee each year, with fall and spring generations. Birkmann's cellophane bee is a generalist pollinator commonly found feeding on plants in the family Asteraceae.
The female bee shown here appeared at the National Butterfly Center in November 2018, feeding on woolly croton near an irrigation canal. In November 2019, both male and female bees were found foraging on seaside goldenrod in the front garden of the National Butterfly Center.
Food plants at NBC:
Plant Family: Solanaceae
When seen: April 2019
Swenk's Cellophane Bee
Size: 11 mm (female)
A female Swenk's cellophane bee (Colletes swenki)
A female Swenk's cellophane bee gathering pollen from purple ground cherry
Dorsal view of female bee
Alternate view of female bee
The pitted face of the female Swenks's cellophane bee
Purple groundcherry (Quincula lobata)
Plants of the nightshade family Solanaceae require "buzz pollination," because their pollen is trapped tightly within the anthers of their flowers. Bees known as buzz pollinators (or vibratile pollinators) have the ability to vibrate their flight muscles while grasping a flower: this shakes pollen loose from the anthers in a manner commonly compared to jiggling a salt shaker to dislodge salt. Vibratile pollinators exist in several bee families.
Three of the cellophane bees featured here are noisy buzz pollinators that visit Solanaceae native to the Valley: Swenk's cellophane bee pollinates purple groundcherry (Quincula lobata) and prostrate ground cherry (Chamaesaracha coniodes). The Texas cellophane bee featured below visits downy ground cherry (Physalis pubescens). The intermixed cellophane bee visits silverleaf nightshade (Solanum elaeagnifolium).
The female Swenk's cellophane bee shown here appeared at the National Butterfly Center in April 2019.foraging on purple groundcherry. Entomologist Myron H. Swenk first described Colletes swenki after examining specimens found in Texas in the fifties. Colletes swenki is chiefly a Texas bee. It has been recorded in the counties of Bexar, Cameron, Hidalgo, Jim Wells, Kerr, Maverick, Shackelford, Travis and Val Verde.
Downy ground cherry
Texas Cellophane Bee
Size: 7-8 mm (male)
9 mm female
A male Texas cellophane bee (Colletes texanus) on physalis
A male Texas cellophane bee.
This is a small Colletes -- it measures approximately 7 mm.
Pale and gray hairs cover the bee's thorax and vertex (the top of the head). The bee's hind basitarsus is narrow. Its tegulae (wing nodes) are black, and the white bands on its abdomen are narrow and well-defined.
The male bee's antennae, eyes and mandibles are black. Thick pale hair covers the bee's face and is especially dense around the bee's antennae and along the inner edges of it compound eyes. Females of this species share these attributes.
CITE THIS PAGE: Sharp, Paula and Ross Eatman. "Colletes." Wild Bees of the National Butterfly Center of Mission, Texas. 15 Jan. 2019, http://www.wildbeestexas.com. Accessed [day/month/year guide accessed].