NOMAD CUCKOO BEES
Like the Epeolus and Triepeolus cuckoo bees shown on the previous page of this guide, Nomad bees are cleptoparasites of the bee tribe Nomadini.
Nomad bees lay eggs in the nests of ground-nesting bees -- most commonly, Andrena mining bees. When the nomad eggs hatch in Andrena nests, the nomad larvae – which have large, sickle-like mouth parts -- kill off the Andrena larvae and eat the provisions stored in the nest by the Andrena mother. According to The Xerces Society Guide to Attracting Native Pollinators, male nomad bees can imitate the scent of Andrenas and have the capacity to transfer this scent to female nomads during mating. This allows the female bees to sneak more easily into Andrena nests to hijack their food supplies.
Some nomad bees are generalists that parasitize the nests of multiple Andrena species. Other nomads target specific host species. For example, the neighborly nomad bee (Nomada vicina) targets the nests of hairy-banded mining bees (Andrena hirticincta). The spotted nomad bee (Nomada maculata), preys on the neighborly mining bee (Andrena vicina). The beautiful nomad bee (Nomada bella) is a cleptoparasite of Andrena imitatrix.
Nomad bees also exist that prey on Agapostemon, Halictus, and Lasioglossum sweat bees. Some nomad species target Colletes bees, long-horned bees in the genus Eucera or bees in the genus Melitta. The most common nomad species found at the National Butterfly Center, Nomada texana, is thought to parasitize the nests of Agapostemon sweat bees.
Species Identification Information:
Nomad bees are found throughout the world. There are nearly 300 nomad species in North America alone. Texas has a large array of Nomada. These include the Texas nomad bee like that shown below, as well as the Nomada vegana shown at top right.
Nomad bees look wasp-like and tend to have the flashy appearance of custom-detailed race cars. They have sleek bodies, often adorned with well-defined stripes and crisp markings. They are usually red, black, yellow or a combination of these colors. Most nomad bees found in Texas have black or red bodies adorned with yellow markings; red or yellow legs; striking, red, reddish-brown or partly yellow antennae; and red, green or brownish eyes.
General coloration varies from one type of nomad bee to another and can be used to help identify species.
The Texas nomad bee, Nomada texana, for example, can be identified in part by its black body, red legs, the yellow stripes on its abdomen, the yellow spots on its thorax (middle section), and its yellow facial mask. More detailed information on this species is given in the guide entry below.
Nomad bees have several distinctive minute traits that aid in identifying their genus: (1) the thoraxes of nomad bees are heavily pitted; (2) female nomad bees have specialized hair patches on the tips of their abdomens; (3) the pygidial plate (abdomen tip) of male nomad bees is pronounced and often notched; (4) The jugal lobe of the nomad bee's wing is small. These traits are illustrated in the photo strip at right.
Nomad cuckoo bees do not gather pollen from flowers, because they obtain it instead by plundering other bees' nests. As a result, female nomad bees do not have scopae (pollen-collecting hairs) on their legs or abdomens.
Nomad bees do, however, drink nectar from flowers. They tend to gather on the flowers visited by their hosts or to patrol the ground looking for host bee nests. The Texas nomad bees featured below were found feeding on seaside goldenrod and Bidens alba, aster-family flowers. This nomad bee species has been documented, however, on a vast array of plants from several different families.
Nomad Bees at the National Butterfly Center
At the National Butterfly Center, Texas nomad bees (Nomada texana) is by far the most common nomad species. Texas nomad bees are most visible in late fall, when they emerge to nectar on goldenrod. During this same period, the honey-tailed Agapostemon sweat bee (Agapostemon melliventris) -- this nomad's possible host -- appears in large numbers at the NBC.
A male Nomada vegana nomad bee
Characteristics of nomad bees
The honey-tailed Agapostemon, a possible host species for the Texan nomad bee
TAXONOMY OF NOMAD BEES
Species found at the National Butterfly Center
Nomad Bee Species of the National Butterfly Center
Nomada texana (female)
Size: 11 mm (female)
9 mm (male)
Associated plants at NBC:
A female Texas nomad bee
The Texas nomad bee, Nomada texana, can be identified in part by its black body, red legs, reddish antennae and the yellow stripes on its abdomen and thorax. Among the most distinctive features of the bee are the two prominent yellow spots on the propodeum (the rear face of the thorax). The specific traits of this bee are noted in more detail in the photo strip at left.
The female bee shown here has two yellow marks on its face; the male Texas Nomad bee has a more extensive yellow mask covering most of its face. Such sexual dimorphism is common in nomad species.
According to Texas bee expert Jack Neff, Nomada texana is a very common and widespread Texas species but little is known about its habits. It is thought to parasitize the nests of Agapostemon sweat bees.