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Tribe Caenohalictini - Genus Agapostemon      

Agapostemon are brilliantly-colored green bees that look like flying emeralds.  To the naked eye, bees of the genus Agapostemon may resemble the iridescent green bees of the Augochlorini tribe discussed in this guide's nextsection.  Nonethelss, differences in wing and leg structure, facial characteristics and evolutionary history have led to the genus Agapostemon's placement in a different tribe known as the Caenohalictini. 


Traits of the Genus Agapostemon

Most Agapostemon are generalist pollinators that build nests in the ground.  Their nests consist of vertical tunnels, and are usually kept well-hidden under leaves or other plant matter.  Agapostemon are solitary, with each female provisioning her own nest, but the bees may act gregariously, building in close proximity with one another. Agapostemon sometimes share burrows whose entrances are watched by guard bees.

Agapostemon tend to be larger than most green Augochlorini-tribe sweat bees. Agapostemon species also often show pronounced sexual dimorphism:  females may be an intense iridescent green all over, while males are only partly green, with striped yellow-and-dark abdomens -- as exemplified by the Texas agapostemon (Agapostemon texanus).  In other species, such as Tyler's agapostemon (Agapostemon tyleri) and the honey -tailed agapostemon (Agapostemon melliventris), males and females both have striped abdomens. 


Male and female Agapostemon differ in other ways as well.  Females usually have dark legs covered with short pale hairs, while males have predominantly yellow legs.  Females' faces are frequently mostly  green, while males have extensive yellow markings on their faces. 

Differentating among Agapostemon species

Male Agapostemon species are differentiated by such traits as the colors of their abdominal bands; their facial characteristics; markings on their hind legs; and markings on the sternum (the underside of the abdomen).


Female Agapostemon species are usually told apart by such traits as the colors of their abdomens (whether they are entirely green vs. striped, and if striped, by the colors of the stripes); their facial characteristics; and wing color.  In more challenging cases, females are distinguished by minute traits invisible to the naked eye, such as the colors of hairs on their legs; and the patterns formed by pits and indentations on the bees' thoraxes.   


Females of some Agapostemon species can be difficult to identfy.  In Texas, for example, females of the two species  Agapostemon angelicus and Agapostemon texanus are morphologically identical.  They can be told apart  only through microscopic analysis or DNA testing -- or if they are caught mating with more easily identified males of their respective species.  

Augochlora mellifera - (c) Copyright 2018 Paula Sharp

A female honey-tailed Agapostemon (Agapostemon melliventris)



Order:   Hymenoptera

Family:   Halictidae  (Sweat Bees)

Subfamily:   Halictinae

Tribe:  Caenohalictini

Genus:   Agapostemon

NBC Species: 

    Agapostemon melliventris (Honey-tailed Agapostemon) 
    Agapostemon texanus (Texas Agapostemon)

    Agapostmeon typeri (Tyler's Agapostemon) 


Mission, Texas

Agapostemon tyleri; Copyright 2023 Sharp-Eaatman Nature Photography


Agapostemon Species of the National Butterfly Center & Lower Rio Grande Valley

Honey-tailed Agapostemon
Agapostemon melliventris

Family:  Halictidae

Size:  6 - 7 mm (male); 8-9 mm (female)

Associated plants at NBC:  

Berlandier’s fiddlewood 

(Citharexylum berlandieri)

Golden dewdrops
(Duranta erecta)

Plant Family:  Verbenaceae

Hierba del marrano

(Symphyotrichum sp.)
(Chromolaena odorata)

Seaside goldenrod

(Solidago sempervirens)
Plant Family:  Asteraceae


When seen at NBC:

Sept. - Nov. 2018 - 2019

Agapostemon melliventris; (C) Copyright 2018 Paula Sharp

A female honey-tailed Agapostemon  (Agapostemon melliventris)

Agapostemon melliventris; (C) Copyright 2018 Paula Sharp

A male honey-tailed Agapostemon (Agapostemon melliventris)

An Agapostemon melliventris sweat bee in the grips of an orb weaver spider - (c) Copyright 2018 Ross Eatman

A male honey-tailed Agapostemon in the grips of a spinybacked orb weaver spider

Agapostemon melliventris is the predominant Agapostemon species of the Valley.  It is common in Cameron, Hidalgo and Starr Counties.  The distribution of Agapostemon melliventris is centered in the southwestern United States, Texas and northern Mexico.  It ranges west to California and is found as far north as Montana and as far south as the Mexican state of Chiapas. 


The male and female Agapostemon melliventris both have brilliant iridescent green heads and thoraxes, and striped abdomens.  In the Valley, the female bee’s abdomen is usually honey-colored and striped with bands of short white hairs.  (In other regions of the United States,  the typical female's abdomen may be black.)  The male’s abdomen is striped with narrow black and honey-colored bands; these bands are part of the integument (exoskeleton) and not formed by hairs.

The striped honey-brown abdomen and partly-yellow face of the female Agapostemon melliventris easily identify it in the Valley.  Males usually can be recognized by their honey-brown stripes and predominantly yellow legs. 

Associated plants at NBC: 


(Chromolaena odorata)

Common sunflower
(Helianthus annuus)

Mexican hat
(Ratibida columnifera)

Family:  Asteraceae

Honey mesquite
(Prosopis glandulosa)

Family:  Fabaceae

When seen at NBC:

Feb. - Nov. 2018-2020

Texas Agapostemon
Agapostemon texanus

Family:  Halictidae

Size:  10 mm (male); 11 mm (female)

Agapostemon texanus - (c) Copyright 2018 Paula Sharp

A female Texas Agapostemon (Agapostemon texanus) 

Agapostemon texanus - (c) Copyright 2018 Paula Sharp

A male Texas Agapostemon (Agapostemon texanus) 

Agapostemon texanus is uncommon in the Lower Rio Grande Valley.  Although it is a generalist pollinator, it is most likely to be found in the Valley in association with sunflowers and other large-flowered Asteraceae.  This species is widespread throughout the United States, and ranges from Canada to Panama.

The female Agapostemon texanus is entirely iridescent green, without bands or pale facial markings.  Males have black abdomens banded by yellow stripes.  

Females are easily differentiated from Agapostemon tyleri and Agapostemon melliventris by their uniformly green coloring.  Males are best identified by the black markings on their legs, as shown in the accompanying photo strip.   Females cannot be differentiated with the naked eye from the nearly identifical female Agapostemon angelicus.

Tyler's Agapostemon

Agapostemon tyleri

Family:  Halictidae

Size:  9-10 mm (female)

           8-9 (male)

Associated plants:

Leucophyllum frutescens

Family:   Scrophulariaceae

Texas olive

Cordia boissieri

Family:   Acanthaceae

When and where seen: 

June 17, 2021
Campos Viejo Ranch

Rio Grande City (Starr Co.)

Agapostemon tyleri; Copyright 2023 Sharp-Eaatman Nature Photography

A female Tyler's agapostemon (Agapostemon tyleri)

Agapostemon tyleri; Copyright 2023 Sharp-Eaatman Nature Photography

A male Tyler's  agapostemon

Agapostemon tyleri is an uncommon species in the Valley.  This species is found principally  in high-altitude regions of Mexico and in desert areas of southern Arizona, New Mexico and west Texas.  The bees shown here were found in Starr County, the westernmost county of the Lower Rio Grande Valley.

Both the male and female Agapostemon tyleri have iridescent green thoraxes and banded black abdomens.  On females, the abdominal bands are formed by short white hairs.  On males, the bands are pale yellow and part of the integument (exoskeleton) of the abdomen.  Females’ legs are dark and covered with pale hairs; males legs’ are predominantly yellow, with some black markings on the upper segments.  The female bee’s face is predominantly iridescent green, with a dark band rimming the bottom edge of the clypeus.  The male bee's face is also iridescent green; its clypeus is rimmed with yellow.  

The male bee can be best identified by these traits:  the first yellow band on its abdomen is interrupted, and its sternum is entirely black.  Traits that help differentiate the female Agapostemon tyleri from other South Texas Agapostemon include:  its black-and-white striped abdomen, the lack of yellow on its clypeus, its size, its dark tegulae and its light-colored, transparent wings.

CITE THIS PAGE:  Sharp, Paula and Ross Eatman.  "Agapostemon."  Wild Bees of the National Butterfly Center of Mission, Texas. 15 Jan. 2019,  Accessed [day/month/year guide accessed].

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