ID GUIDE TO WILD BEES
OF THE NATIONAL BUTTERFLY CENTER
& THE TEXAS LOWER RIO GRANDE VALLEY
This guide began as part of a native bee survey project for the National Butterfly Center of Mission, Texas. The guide now showcases notable native bee species found in the Texas Lower Rio Grande Valley, in which the NBC is situated.
The Texas Lower Rio Grande Valley is located in the floodplain of the Rio Grande River, along the border of south Texas and the Mexican state of Tamaulipas. The Texas Lower Rio Grande Valley reaches nearly as far south as the Florida Keys. Its climate is subtropical, and the Valley is thus home to many warm-climate bee species unknown in most of the United States.
The Texas Lower Rio Grande Valley occupies a unique ecological niche: it contains eleven distinct habitats acclaimed for their biodiversity. The Valley is home to more than 1,200 documented plant species; hundreds of bird species; and distinctive mammals, among them the endangered ocelot. This environment also fosters extraordinary pollinator diversity: nearly 250 butterfly species have been documented at the National Butterfly Center alone, more than 150 of which are found only in the Valley.
Bee populations of the region are remarkably varied as well. The Lower Rio Grande Valley harbors a multitude of native bee species that are specialist pollinators of blossoming plants peculiar to the area. The Valley's varied flora and long growing season also enable a broad spectrum of generalist bee species to thrive.
in September 2018, while conducting a survey at the National Butterfly Center, this website's authors encountered and photographed a red-legged leafcutter bee unlike anything they had seen before.
World bee authority, John S. Ascher, Hadel Go of the American Museum of Natural History, and John L. Neff, Director of the Central Texas Melittological Institute, conferred over the leafcutter and agreed that it belonged to a subgenus that had never been encountered previously in the United States. This bee has been identified as Megachile (Tylomegachile) cf. toluca.
Many other bee species of the NBC are rarely seen north of the Mexican border, or they are found exclusively or nearly exclusively in Texas. A sampling of these is shown in the accompanying photo strip: most visitors to the Valley have never encountered an Aztec cuckoo leafcutter, the apiform crooked-legged bee, the honey-footed Exomalopsis or Florilegus and Melissoptila long-horned bees.
The National Butterfly Center additionally harbors several imperiled bee species. Among these is the American bumble bee (Bombus pensylvanicus). This pollinator has been categorized as a species of "greatest conservation need" under the Texas Conservation Action Plan. The International Union for Conservation of Nature has placed the American bumble bee on its red list of vulnerable species.
NOTABLE BEES OF THE LOWER RIO GRANDE VALLEY
The Texas Lower Rio Grande Valley is divided into Cameron, Hidalgo, Starr and Willacy Counties. These counties contain an abundance of state, federal and private nature preserves that harbor diverse and unique bee populations.
Starr County's Falcon State Park, for example, is home to the Zapotec cuckoo leafcutter (Coelioxys zapoteca), and the sole location where this bee has been sighted within the United States. La Puerta Land Tract, part of the Lower Rio Grande Valley U.S. Fish & Wildlife Refuge system, harbors the unusually large Zacatec triepeolus and beautiful glorious protaxea shown here.
Some of the other many notable species of the Valley include the Mexican feather-tongued bee (Ptiloglossa mexicana), which emerges in early morning and late evening; the Totonac cuckoo leafcutter (Coelioxys totonaca), whose thorax is armed with three long spines; the rare Texas mesoxaea (Mesoxaea texana); the emerald-green Aztec sweat bee and the beautifully-patterned discordant pebble bee.
INFORMATION ON AUTHORS, RESEARCH & IDENTIFICATION
Paula Sharp and Ross Eatman are the creators of this website and its bee guide. They are co-founders of Sharp-Eatman Nature Photography, a society dedicated to documenting conservation issues. An exhibit of Sharp and Eatman's' macro photography, titled Wild Bees, is currently on a national tour. Paula Sharp is also the author of the forthcoming book Native Bees of the Texas Lower Rio Grande Valley, to be published by Texas A & M University Press in 2023.
John L. Neff, Director of the Central Texas Melittological Institute, generously extended his aid and expertise in identifying rare and unsual bees appearing on this website. Dr. Karen Wright of Texas A & M University identified Svastra sabinensis.
NBC bee surveys have been made possible by Jeffrey Glassberg, President of the North American Butterfly Association; by Marianna Trevino Wright, Executive Director of the National Butterfly Center; by Stephanie Lopez, NBC Native Plant Nursery Manager; and through the kind assistance of the NBC's impressive staff.
From 2020 to the present, the authors have conducted year-round bee surveys, pursuant to research permits, in regional Texas state parks, and in federal land tracts and wildlife refuges. The authors also have conducted surveys in local preserves and parks; in private ranches; and in hardscrabble areas such as vacant lots, road shoulders and railroad right-of-ways.
For more information on photographers Paula Sharp and Ross Eatman, visit this website's About page.
A Gulf fritillary butterfly at the National Butterfly Center
The Aztec cuckoo leafcutter bee: this chiefly Mexican species is rare in the United States.
A female crooked- legged bee entering an alamo vine blossom: this unusual species is seldom seen north of southernmost Texas.
A Melitoma marginella chimney bee: this longtime inhabitant of the National Butterfly Center is ordinarily found only in subtropical areas.
Thriving and recurrent colonies of threatened American bumblebees (Bombus pensylvanicus) inhabit the National Butterfly Center.
A portly long-horned bee (Melissoptila pinguis): this scantily documented bee is the only member of its genus in the United States.
The worthy long-horned bee (Florilegus condignus) is seen in few areas of the United States: a large and entrenched population of this species occupies the NBC.
UNUSUAL BEES OF THE NATIONAL BUTTERFLY CENTER
The Texas mesoxaea (Mesoxaea texana) is among the rarest bee species in the United States. It inhabits the Tamulipan thornscrub of Hidalgo and Starr Counties.
The Texas mesoxaea (Mesoxaea texana) is also nearly an inch long, among the largest bees in the United States.
The related glorious protoxaea (Protoxaea gloriosa) is an uncommon, burly, red-legged bee with golden hair and green eyes. This species often appears together with the Texas Mesoxaea.
The Mexican feather-tongued bee (Ptiloglossa mexicana) is most likely to be seen at dawn and sunset. Its luminous small eyes (called ocelli) allow it to navigated low-light conditions.
This female Totonac cuckoo leafcutter (Coelioxys totonacus) is the first of its species recorded in the United States. It appeared in 2021 at Quinta Mazatlan nature center, located in McAllen, Texas.
A zapotec cuckoo leafcutter (Coelioxys zapoteca): this bee is the first of its species and its subgenus recorded in the United States. It appeared at Falcon State Park (Starr. Co.) in 2023.
The red-legged leafcutter, Megachile cf. toluca
An Aztec cuckoo leafcutter bee (Coelioxys azteca)
UNUSUAL BEES OF THE LOWER RIO GRANDE VALLEY