MELISSODES LONG-HORNED BEES
Long-horned bees belong to the bee tribe Eucerini and have unusually long antennae – hence the name "long-horned". Eucerini serve as essential pollinators for multi-million-dollar crop industries and include, among others, Svastra bees, instrumental in sunflower production; and Eucera bees that serve as key pollinators of melons and squash. The tribe Eucerini also includes Melissodes long-horned bees, a genus of irreplaceable pollinators of garden flowers, native wildflowers and sunflower crops.
All Melissodes bees are ground-nesters. The bees carve holes in the earth, where they construct individual nests containing brood cells lined with a waxlike material, each holding one egg and a single pollen ball. The nests, which may be isolated or built in groups, are frequently hidden under brush.
Female long-horned bees tend to be easiest to find when they are out pollinating flowers. Males often rest hanging by their jaws from the stems of plants. In early morning, it is sometimes possible to surprise whole groups of male long-horned bees sleeping together in this manner.
Texas Melissodes long-horned bees tend to be most abundant in summer and fall. Many are generalist pollinators. Some, as noted below, specialize in aster-family flowers that bloom in late summer and autumn. Others specialize on such flowers as thistles, mallow and evening primrose.
Identification Information & Melissodes Subgenera
Melissodes long-horned bees are robust, medium-sized bees with hairy heads and bodies. Females have prominent , bushy pollen-collecting scopal hairs on their back legs. Males have narrower builds than females; lack scopal hairs on their hind legs; and usually sport much longer antennae. Both female and male Melissodes bees may have striking green or blue-gray eyes; eye color within a given species may vary according to gender.
Texas has an exceptionally rich diversity of Melissodes long-horned bees. Long-horned bees of three distinct subgenera, each with its own special characteristics, are found within the National Butterfly Center. These subgenera include Eumelissodes, Melissodes and Tachymelissodes.
Subgenus Eumelissodes. Many Texas Melissodes long-horned bee species belong to the subgenus Eumelissodes, known by the common name “true long-horned bees”. True long-horned bees are usually about the size of a honey bee, or slightly smaller or slightly larger. They have hairy faces and thoraxes, and their abdomens are typically dark and striped with bands of pale hairs. An example is the Melissodes tristis shown below.
According to entomologist Charles D. Michener, all females of the subgenus Melissodes (Eumelissodes) have feathery scopal hairs, and males usually have pale clypeuses and antennae on which the first segments are less than half as long as the second segments. True-longed horned bee species often specialize in pollinating plants of the family Asteraceae, which includes flowers such as goldenrod, sunflowers, asters, black-eyed Susans and ironweed.
Subgenus Melissodes. Other Texas Melissodes long-horned bees belong to the redundantly-named subgenus Melissodes.
Bees of the subgenus Melissodes (Melissodes) often resemble true-long-horned bees – that is, they are hefty, with hairy faces and thoraxes, and banded abdomens. Females have bushy legs, and males typically have pale clypeuses and very long antennae (that reach at least to the front of their abdomens).
The Tepanec long-horned bee, Melissodes tepaneca is the most common example of the subgenus Melissodes found at the National Butterfly Center. This bee has rust-colored thorax hairs, and an abdomen banded by stripes of pale hair. Blond bushy hairs cover the legs of female Tepanec long-horned bees. Male Tepanec long-horned bees have pale-yellow clypeuses and striking green eyes. Females have bluish eyes and dark clypeuses covered with pale hairs.
Tepanec long-horned bees are generalists, visiting an array of flowers as diverse as milkweeds, legumes and cactus. At the National Butterfly Center, these bees tend to collect during early fall around the verbena-family plant known as pigeonberry. Females emerge after males and are seen most frequently on wild sunflowers.
Different species of long-horned bees within the subgenus Melissodes (Melissodes) vary greatly in appearance. For example, in sharp contrast to the Tepanec long-horned bee, the two-spotted long-horned bee, Melissodes (Melissodes) bimaculatus, has a coal-black body, and lacks bands on its abdomen. The eyes of both males and females are a distinctive gray-blue. The hind legs of both sexes are clothed in thick white hair. This species has not been documented at the National Butterfly Center, but is a common sight in Central Texas during the summer.
Subgenus Tachymelissodes. This subgenus has relatively few members, which are found only in Western North America, principally in desert regions. Melissodes (Tachymelissodes) bees have distinctively bold white banding on their abdomens and relatively short antennae for Melissodes long-horns. The little prickly pear long-horned bee, Melissodes opuntiellus, shown at right, belongs to the subgenus Tachymelissodes. This bee is unusually small for a Texas long-horned bee -- under 1/3 inch long. More information on this interesting pollinator of cactus, prickly poppies and other native Texas plants, is provided in the section below.
TAXONOMY OF MELISSODES BEES
Species shown below:
Melissodes (Euelissodes) tristis (Mournful long-horned bee)
Melissodes (Melissodes) tepaneca (Tepanec long-horned bee)
Melissodes (Tachymelissodes) opuntiellus (prickly pear
A female Melissodes true long-horned bee of the subgenus Eumelissodes: Note the bushy scopal hairs on the bee's back legs.
A female Tepanec long-horned bee of the subgenus Melissodes
A male Tepanec long-horned bee of the subgenus Melissodes: note the very long "horns" (antennae) and the yellow clypeus.
The predominantly black two-spotted long-horned bee (Melissodes bimaculatus) is an example of the subgenus Melissodes.
A male Melissodes opuntiellus of the subgenus Tachymelissodes
Long-horned Bee Species of the National Butterfly Center
Tepanec Long-horned Bee
Melissodes (Melissodes) tepaneca
Size: 11 mm (male); 12 mm (female)
Food plants at NBC:
Retama (a kind of Palo Verde)
Plant family: Fabaceae
Plant family: Verbenaceae
Plant Family: Asteraceae
April & July 2019
A female Melissodes tepaneca. This bee was feeding on retama, a kind of palo verde, with dozens of other female bees of the same species, during mid-April of 2019.
As shown here, the thorax of the female Melissodes tepaneca can be a rich reddish brown.
A male Tepanec long-horned bee. Males have green eyes and longer antennae than females.
A male Tepanec long-horned bee, gripping a stem with its jaws. Males often sleep suspended from their clamped jaws. Male long-horned bees lack the bushy scopal (pollen-collecting) hairs of females.
A female Tepanec long-horned bee
A male Tepanec long-horned bee
Melissodes opuntiellus Long-horned Bee
Melissodes (Tachymelissodes) opuntiellus
Size: 8 mm (female and male)
Associated plants at NBC:
Red prickly poppy
Plant family: Papaveraceae
Texas prickly pear
Plant family: Cactaceae
Plant family: Malvaceae (formerly Sterculiaceae)
When seen: March-April 2019
A male Melissodes opuntiellus long-horned bee of the long-horned bee subgenus Tachymelissodes. Male bees of this species have bright blue eyes and boldly-defined pale bands on their abdomens.
The bee inside a red prickly poppy: in early spring in the Lower Rio Grande Valley, male Melissodes opuntiellus frequently can be found resting in prickly poppies.
A female Melissodes opuntiellus on a cactus blossom
Female Melissodes opuntiellus long-horned bees have bright blue eyes and hind legs covered with bushy hairs. White hairs cover the bees' faces and thoraxes and band their abdomens.
A male Melissodes opuntiellus long-horned bee
A female Melissodes opuntiellus long-horned bee
A note on the Melissodes opuntiellus long-horned bee: The species name "opuntiellus" is a reference to Opuntia, the scientific name for prickly pear cactus. The Latin suffix "ellus" is a diminutive ending. Thus this bee's name might translate as "the little prickly pear bee". In April, male Melissodes opuntiella long-horned bees appear in large numbers on the flowers of Texas prickly pear cactus (Opuntia englemannii), at the NBC and in surrounding areas.
This species was first described by the entomologist T. D. A. Cockerell in 1911, in a one page article titled "Some New Bees from Flowers of Cactaceae," shown below left, which appeared in Volume 35 of The Canadian Entomologist.
Prickly poppies in the Lower Rio Grand Valley begin flowering just before the bloom period of Texas prickly pear cactus. Male Melissodes opuntiellus long-horned bee appear on prickly poppy (Argemone sanguinea) in mid-March at the NBC.
We have noted that various genera of male bees that feed on prickly pear flowers (including Lithugopsis and Diadasia) appear to use prickly poppies in the spring for shelter, without feeding on them. (Male bees drink nectar but do not gather pollen; prickly poppies produce pollen but very little nectar.) Possibly, the bees choose the poppies to rest in because they are comfortable and roomy and provide protection from wind and rain.
Females of this species have been documented on an array of plants including mallows and palo verde. In 1980, during a survey of sunflower pollinators, entomologists Hurd and LaBerge observed this species foraging on sunflowers. At NBC, female bees have appeared on prickly poppies, prickly pear cactus and teabush.
Mournful Long-horned Bee
or Dark-faced Long-horned Bee
Melissodes (Eumelissodes) tristis
Size: 9-12 mm (male)
10-14 mm (female)
Associated plants at NBC:
Shrubby blue sage
Plant family: Lamiaceae
Plant family: Fabaceae
April 2019, March 2020
A female mournful long-horned bee (Melissodes tristis) foraging on shrubby blue sage in Hidalgo County in April 2019.
A male Melissodes tristis on milkweed. The male Melissodes tristis has a black clypeus (the face-part above the jaws), an unusual trait for a male long-horned bee. The clypeus is hidden here behind a thatch of white facial hair. (Photograph copyright 2017 J. A. Winget).
A female Melissodes tristis long-horned bee from Hidalgo County. All of the hairs on the female and male bee's thorax and vertex (the part of the head behind the eyes) are white.
Female mournful long-horned bees have feathery, predominantly white hind-leg scopal hairs.
Close-up of the scopal hairs of the female bee. Note that the hair on the inner basitarsis (lower leg) is dark. This is a trait common to true long-horned bees of the subgenus Eumelissodes.
A female Melissodes tristis long-horned bee on shrubby blue sage
A male Melissodes tristis long-horned bee (Photograph copyright 2017 J. A. Winget)
A female Melissodes tristis long-horned bee
A note on the mournful long-horned bee: The name tristis means "sad" or "mournful," but Melissodes tristis is sometimes referred to as "the dark-faced long-horned bee," because the male of this species has a dark clyepus (the face-part above the jaws). This trait is unusual in male Melissodes (Eumelissodes) long-horns, which usually have partly-yellow faces.
As noted above, longed-horned bees of the subgenus Eumelissodes often specialize in pollinating composite flowers of the family Asteraceae such as sunflowers and daisies. The mournful long-horned bee, however, is a prodigious generalist that has been documented visiting the flowers of more than twenty plant families.
According to entomologist Wallace E. LaBerge, author of a comprehensive study of the genus Melissodes published in 1961, the mournful long-horned bee is the most polyetic species of the subgenus Eumelissodes. Melissodes tristis has a remarkably long flight season, from March through November, and is able to adapt to an array of habitats with very different flora. LaBerge believed that this species produces as many as three generations per year in Texas.
Female Melissodes tristis appear in late March and early April at the National Butterfly Center as honey mesquite begins to bloom. Male bees have not been observed to date at the NBC. (The example shown here of a male bee was contributed to this website by nature photographer J. A. Winget, who found it in Grand Canyon Village, Arizona). Melissodes tristis is endemic to much of Texas, and to south central Mexico as far south as the state of Oaxaca. This species ranges through the southwestern United States and extends from western Oklahoma, Kansas and Nebraska through Colorado, Nevada, Utah, and southern Wyoming, into California and Oregon.