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ID GUIDE TO WILD BEES
OF THE NATIONAL BUTTERFLY CENTER
& THE TEXAS LOWER RIO GRANDE VALLEY

American bumble bee - Copyright 2018 Paula Sharp

GUIDE  INTRODUCTION 

LOWER RIO GRANDE VALLEY NOTABLE BEES

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 and beautiful insect known as the  glorious protaxea (Protoxaea gloriosa).  South Padre Island Birding and Nature Center, located in Cameron County, sustains a substantial population of the threatened American bumble bee (Bombus pensylvanicus), and a multitude of rare and uncommon bee species.  

 

Among many other notable species of the Valley are 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 hefty Texas mesoxaea (Mesoxaea texana); the emerald-green Aztec sweat bee (Augochlora azteca); and the beautifully-patterned discordant pebble bee (Dianthidium discors).

INFORMATION ON THE PHOTOGRAPHERS,

RESEARCH, AND BEE IDENTIFICATIONS

Paula Sharp and Ross Eatman are co-founders of Sharp-Eatman Nature Photography, a society dedicated to documenting conservation issues.  This website features their photographs.  An exhibit of Sharp and Eatman's macro photography, titled Wild Bees, is currently on a national tour. Paula Sharp is the creator of this website, and the author of the book Native Bees of the Lower Rio Grande Valley, published by Texas A & M University Press in 2025.  

John L. Neff,  Director of the Central Texas Melittological Institute, generously extended his aid and expertise in identifying rare and unusual bees appearing on this website.  Dr. Karen Wright of Texas A & M University identified Svastra sabinensis.  World bee authority. Dr. John S. Ascher, and Hadel Go of the American Museum of Natural History aided in identifying the red-legged leafcutter bee, Megachile cf. toluca.

 

NBC bee surveys have been made possible by Jeffrey Glassberg, President of the North American Butterfly Association; and by the current and former Executive Directors of the National Butterfly Center, Stephanie Lopez  and Marianna Trevino Wright.

From 2020 to the present, Sharp has conducted year-round bee surveys, pursuant to research permits, in regional Texas state parks, and in federal land tracts and wildlife refuges.  Sharp and Eatman also have recorded and photographed bee species of the Valley in private ranches, and in hardscrabble areas such as vacant lots, road shoulders and railroad right-of-ways.

PROCEED TO GUIDE

Gulf fritillary - (c) Copyright 2018 Ross Eatman
Toluca Leafcutter; Megachile cf. toluca; (c) Copyright 2018 Paua Sharp. Registered copyright.

The red-legged leafcutter, Megachile cf. toluca

Aztec cuckoo leafcutter bee; Coelioxys azteca; (c) Copyright 2018 Paula Sharp

An Aztec cuckoo leafcutter bee (Coelioxys azteca)

Our bee guide began as part of a native bee survey project for the National Butterfly Center of Mission, Texas.  With time, the  guide expanded to cover 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 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 Lower Rio Grande Valley occupies a unique ecological niche:  it contains eleven distinct habitats acclaimed for their biodiversity.  It 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 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. 

NATIONAL BUTTERFLY CENTER NOTABLE BEES

 

Many 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 on this page:  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.

Each year, visitors to the National Butterfly Center add to its list of unusual bee species. This guide was inspired in part by the 2018 discovery at the NBC of the red-legged Toluca leafcutter (Meagchile cf. toluca), the first example of its subgenus found in the United States.    

 

SInce then, NBC visitors have continued to discover and document native bees rarely seen in the United States.  These include such species as the singular cuckoo bee (Leiopodus singularis), the marginal chimney bee (Melitoma marginella), Griswold's carpenter bee (Xylocpa griswoldi), the zaptlana leafcutter (Megachile zaptlana) and the Mexican longhorn-cuckoo bee (Triepeolus mexicanus).

A Gulf fritillary butterfly at the National Butterfly Center

UNUSUAL BEES OF THE NATIONAL BUTTERFLY CENTER

UNUSUAL BEES OF THE LOWER RIO GRANDE VALLEY

Last updated May 30, 2026

All images and text protected by registered copyright.
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 1-15-19

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