ID GUIDE TO WILD BEES
OF THE NATIONAL BUTTERFLY CENTER

Mission, Texas

A female Megachile (Litomegachile leafcutter - (c) Copyright 2019 Paua Sharp

LEAFCUTTER BEES
Megachile
 

LEAFCUTTER  BEES
Genus Megachile
 

LEAFCUTTER BEES:  The name leafcutter derives from female leafcutter bees' practice of using their sharp-edged mandibles to cut leaves and flower petals, for transport back to their nests.  The bees use these materials to line the walls of their nests.

 

Leafcutters, like most of the wild bees in this guide, are solitary.  They do not form colonies like honey bees or live in  structured societies governed by queen bees and maintained by workers and drones.  Instead, leafcutter bees construct individual nests.  They tunnel into dead twigs, rotted trees or the ground, and carve out areas known as brood cells.  They deposit eggs in the cells and provision them with pollen stores for the bees' offspring to eat when they hatch.  
 

Female leafcutters have large, toothed mandibles; the number of teeth and sharp edges on their mandibles vary from species to species.  Those with more formidable mandibles cut leaves, and those with simpler ones trim more delicate materials such as flower petals. According to Charles D. Michener, author of the 953-page The Bees of the World, the pieces leafcutters snip from plant parts tend to be nearly uniform in shape -- oval for constructing the bases and walls of their egg cells and circular for covering cell openings.  

 

Leafcutter bees are easily identified by their unique shape and the way that they carry pollen. They have wide, somewhat flattened abdomens that taper abruptly at the ends and broad, sculpted-looking heads.  Female leafcutters carry pollen in a distinctive way -- on sticky hairs called scopae located on the undersides of the bees' abdomens, rather than on their legs.  The bees' scopal hairs range in color:  they may be white, pale or golden brown, black or even bright orange.

 

Male leafcutters lack scopal hairs and sometimes differ significantly in appearance from their female counterparts. Males tend to be smaller and to have hairier faces than females.  In some species, such as the Zaptlana, Policaris and Megachile sidalceae leafcutters shown below on this page, males' front legs may sport long hairs or be enlarged and brightly colored.

Leafcutter species range in size and general attributes.  Some are larger than honey bees, and some are so small they elude notice by the casual observer.  Some are black; others are smoky-gray or black with pale stripes.  Some specialize in gathering pollen from a narrow range of wildflowers, and others are generalists.  

 

Leafcutter bees are important pollinators of an extensive gamut of commercial crops, including alfalfa, carrots, onions, blueberries and cranberries, among many others.  Wild leafcutters are also responsible for pollinating a prodigious range of wildflowers and garden flowers.

Leafcutter bees are preyed upon by cuckoo leafcutter bees, shown on the next page of this guide. 

National Butterfly Center Notable Species:  

In September 2018, while surveying native bees at the National Butterfly Center, photographers Paula Sharp and Ross Eatman discovered a red-legged leafcutter species new to the United States.  This leafcutter, Megachile cf. toluca, is shown here.  

Other notable leafcutters found at the NBC include the Zaptlana leafcutter (Megachile zaptlana)a species rarely seen within the United States, outside of Texas; and the Chichimeca leafcutter (Megachile chicimeca), a small species endemic to the Lower Rio Grande Valley and to Mexico.
 

 

Resin Bees:   

The leafcutter genus Megachile includes bees known by the common name "resin bees".  This name derives from the fact the they scrape and collect sticky resins from plants, which the bees use to seal the entrances of their nests.  Resin bees generally resemble leafcutters:  resin bees carry pollen under their abdomens, and they have large jaws equipped with teeth (but without cutting edges).  Typically, resin bees have narrow bodies and are often pollen specialists.  In the New World, resin bees in the genus
Megachile all belong to the subgenus Chelostomoides. The slender resin bee shown here, Megachile exilis, is an example of this subgenus.

Species Identification: 

Different species of leafcutter and resin bees are often told apart by minute traits difficult to see without a macro lens.  These include such features as the number of teeth and cutting blades on the bee's jaws; the shape of the tip of the bee's abdomen; the arrangement of bands of pale hairs on the abdomen; the length of the vertex (the space between the bee's eyes and the back of the head); the relative lengths of the segments of the bee's antennae; (on females) the color of the bee's scopal hairs; and (on males) whether bee's forelegs are enlarged or proportionate in size to the rest of the leg.  A bee's size, geographical location and the kind of plant it forages on may aid in identifying a given species as well.

The leafcutter species shown here, found at the National Butterfly Center in 2018-2019, belong to 9 different subgenera and vary significantly in basic characteristics and appearance.  The hallmark traits of each species are noted below.

Toluca leafcutter - Megachile cf toluca - (c) copyright 2018 Paula Sharp

This male leafcutter bee, Megachile cf. toluca, is the first of its kind to be documented in the United States.  The bee was found at the National Butterfly Center in September 2018. 

Leafcutter bee - Megachile zaptlana - (c) Copyright 2018 Paula Sharp

A female Zaptlana leafcutter bee, with white scopal hairs under her abdomen

General traits of leafcutter and resin bees

Megachile exilis; (c) Copyright 2018 Paula Sharp

A male  resin bee, balancing upside down by gripping a stem with its jaws

TAXONOMY OF LEAFCUTTER AND RESIN BEES

Order:   Hymenoptera

Family:   Megachilidae

Subfamily:   Megachilinae

Tribe:  Megachilini

Genus:   Megachile

Species shown on this page:  


    Megachile (Aryropile) parallela (Parallel Leafcutter)

    Megachile (Chelostomoides) exilis (Slender resin bee)
    Megachile (Litomegachile) brevis (Common little leafcutter)

    Megachile (Litomegachile) leafcutter (possibly coquilletti)

    Megachile (Megachile) montivaga (Silver-tailed petal-cutter)   
    Megachile (Megachiloides) leafcutter

    Megachile (Neochelynia) chichimeca (Chichimeca leafcutter)

    Megachile (Pseudocentron) sidalceae
    Megachile (Sayapis) inimica (Hostile leafcutter)

    Megachile (Sayapis) policaris (Policaris leafcutter)
    Megachile (Sayapis) zaptlana (Zaptlana leafcutter)
    Megachile  (Tylomegachile) cf.
toluca

Three of the leafcutter species  below – Megachile chichimeca, M. zaptlana and M. toluca, were first described by American entomologist E. T. Cresson in an 1878 article titled “Descriptions of New North American Hymenoptera in the Collection of the American Entomological Society”.  In this work, Cresson catalogued 38 species of leafcutters, nearly half of which came from Mexico and were unknown in published annals of entomology. Most of the Mexican specimens, including M. chichimeca, M. zaptlana and M. toluca, had been collected by the Swiss entomologist Adrien Louis Jean de Sumichast during expeditions he had made in Mexico earlier in the 19th Century.

More than 20 years before, Sumichrist had traveled from Europe to Mexico on an insect-collecting trip with fellow Swiss entomologist Louis Frederic De Saussure. After a year, Saussure had returned to Switzerland, citing the difficulties of travel and the political unrest that gripped Mexico after the Mexican-American War.  Sumichrast opted to stay behind.  He married a Mexican woman and remained in Mexico until his death in 1882.  For nearly thirty years, he journeyed through the Mexican states of Veracruz, Puebla, Mexico, Oaxaca and Chiapas, collecting insects.  In 1878, when Cresson undertook the task of cataloguing new American Entomological Society species, 55 of his bee specimens, spanning more than a dozen genera, came from Sumichrast.

Cresson liked to christen Mexican bees after ancient Meso-American civilzations and Aztec place names.  Thus, the leafcutters he catalogued in 1878 bear such names as  Megachile azteca, M. chichimeca, M. montezuma,  M. tuxtla, M. zapoteca, M. toluca, M. tuxtla, and M. zaptlana.  The chichimeca leafcutter shown here derives its name from a semi-nomadic people that occupied north central Mexico at the time of the Conquest.  Toluca is the name of the highland valley where the ancient Aztec ruins of Calixtlahuaca are situated.  Zaptlana in all probability relates to the Kingdom of Zapotlan, the site of various pre-Columbian civilizations before being overtaken by the conquistadors in the 1500s.

Chichimeca Leafcutter Bee
Megachile (Neochelynia) chichimeca

Family:  Megachilidae

Size: 10 mm (female); 7-8 mm (male)

Food plant at NBC:  

Low croton

(Croton humilis)
Plant family:  Euphorbiaceae

Texas ebony
(Ebenopsis ebano)
Plant family:  Fabaceae

When seen:

November 2018, June 2019   

Megachile chichimeca; (c) Copyriught 2018 Paula Shar

A female chichimeca leafcutter bee

Chichimeca Leafcutter (Megacile chichimeca) - (c) Copyright 2018 Paula Sharp

A male chichimeca leafcutter bee

Megachile chichimeca is endemic to Mexico and was first catalogued in 1898 as a Mexican species.  Since that time, Megachile chichimeca has been documented in regions as far-flung as Brazil, British Guiana and Guatemala.  In 1917, while on a road trip through southern Texas in 1917, entomologist Wilmatte Cockerell encountered a chichimeca leafcutter in Port Isabel, Texas, located 80 miles from the modern-day National Buttterfly Center.  

 

According to Texas bee expert Jack Neff, Megachile chichimeca is a common leafcutter species in southern border areas of Texas.  At the National Butterfly Center, Megachile chichimeca is a frequent visitor to croton during the fall.  Chicimeca leafcutters are generalist pollinators known to feed on a very broad range of plants, including, among others, those in the dogbane, borage and pea families.  

Hallmark traits of the species Megachile chichimecas are:  it is small and slender; there are prominent tufts of white hairs located near the base of the bee’s wings; the back edge of the bee’s thorax is fringed with white hairs; the bee's wings are dusky near the back edges; the female bee's clypeus (the face part above the jaws) has a bump on the middle of the bottom edge; and the scopal hairs on the female bee's abdomen are white toward the front and rust-colored toward the back.

Entomologist Charles Michneer placed this leafcutter species in the subgenus Neochelynia in his voluminous The Bees of the World.  According to Michener, a distinctive trait of  male bees of this subgenus is that the middle tooth of each 3-toothed jaw of the male bee is jagged, with two corners, so that it almost appears to be two separate teeth.  This trait is apparent on the male bee shown in the photo strip at left.  The female bee shown here has four teeth on each jaw.

Food plant at NBC:  
Texas snout bean

(Rhynchosia senna var. texana)

Plant family:  Fabaceae

 

When seen:

September 2018

Toluca Leafcutter Bee
Megachile (Tylomegachile) cf. toluca
(tentative ID)

Family:  Megachilidae

Size:  10 mm (male)

Leafcutter Bee - Megachile (Tylocmegachile) cf. Toluca - (c) 2018 Paula Sharp.  Registered copyright.

A male Megachile cf. toluca leafcutter bee

This red-legged leafcutter, tentatively identified as a toluca leafcutter, or as Megachile (Tylomegachile) cf. toluca, is a rare find.  Its appearance at the National Butterfly Center in September 2018 entails the first sighting of this species, or any member of its subgenus Tylomegachile, within the United States.  The leafcutter was identified by world bee authority Dr. John S. Ascher of the National University of SIngapore.  Jack Neff, Director of the Central Texas Melittological Institute, collaborated in the identification. 

The abbreviation "cf." in the Latin species name Megachile cf. toluca means "compare to," or "resembles".  It is the hope of this website's authors that more specimens of this bee species, both male and female, will appear at the National Butterfly Center and thus allow for supplementary identification and behavioral information.  It is notable nonetheless that the first published description of the Toluca leafcutter, written in 1878 by entomologist E. T. Cresson, appears to fit the bee shown here to a tee. 

 

Cresson described the male Megachile toluca as follows:  it has a short, robust black body, and a head broader than its thorax.  The bee’s face, cheeks and thorax are covered with long, dense, pale to yellowish hair.   Its legs are red, with some black on the top segments (called the coxa and trochanter).  The male Toluca leafcutter's wings are faintly dusky on the tips.  The bases of the fifth and sixth segments of the male bee’s abdomen sport dense, tawny hairs.

In the 2008 edition of his opus The Bees of the World, Charles Michener wrote that bees of the subgenus Tylomegachile ranged from Argentina to the Mexican border states of Sonora and Tamaulipas.  Michener noted that on males of this subgenus, the sixth abdominal segment (T-6) has two "rather large submedian teeth" on its outer rim, a trait exhibited by the male bee showcased here (as shown in the photo strip at left).

Leafcutter  Bee Species of the National Butterfly Center

Zaptlana Leafcutter Bee
Megachile (Sayapis) zaptlana

Family:  Megachilidae
Size:  12-13 mm

Associated plants at NBC:  
Carpet vervain

(Verbena bracteata)

Whitebrush

(Alyosia gratissima)
Plant family:  Verbenaceae

Low croton

(Croton humilis)
Plant  family:  Euphorbiaceae

When seen:

September 2018,

June-July 2019 

Zapatlana Leafcutter Bee - Megachile zapatlana

A female Zaptlana leafcutter

Zapatlana Leafcutter Bee - Megachile zapatlana - (C) Copyright 2018 Paula Sharp

A male Zaptlana leafcutter

Male and female Zaptlana leafcutters show marked sexual dimorphism. 

The male Zaptlana leafcutter has striking forelegs with lower segments (tarsi) that are greatly enlarged, pale yellowish- green and fringed with white and rust-colored hairs. The  forelegs' upper segments are black with orange markings.  Females lack such traits.

Such sexual dimorphism is not unusual in the leafcutter world.  In many other leafcutter species -- such as Megachile policaris and Megachile sidalceae shown below -- male bees have expanded and colorful forelegs. 

Zaptlana leafcutters are found in Mexico and throughout Central and South America.  Within the United States, this species has been documented principally in southern Texas.  At the National Butterfly Center, Zaptlana leafcutters can be found  from June through early fall

Policaris Leafcutter Bee
Megachile (Sayapis) policaris


Size: 14 (female); 13 mm (male)

Food plant at NBC:  

Skeleton-leaf Goldeneye

(Viguiera stenoloba)

Texas thistle
(Cirsium texanum)

Plant family:  Asteraceae

When seen:

March - April  2019 

Megachile policaris leafcutter bee - (c) Copyright 2019 Paula Sharp

A female Megachile policaris  leafcutter

Megachile policaris leafcutter bee - (c) Copyright 2019 Paula Sharp

A male Megachile policaris  leafcutter

Like the Zaptlana leafcutter above and the hostile leafcutter below, the Policaris leafcutter belongs to the subgenus Sayapis.  Bees of this subgenus have long, slender parallel-sided bodies that enable them to move easily through narrow tunnels.  

ID tip:  The male Policaris leafcutter bee's middle leg has extensive orange coloration on the femur and tibia (the two top segments visible to the eye).  This trait helps distinguish this bee from the other two male leafcutter species with expanded forelegs shown on this page. The male Zaptlana leafcutter, shown above, has middle legs that are mostly dark.  The male Megachile sidalceae leafcutter shown below has middle legs that are white on the bottom segments.

Hostile Leafcutter Bee

Megachile (Sayapis) inimica inimica

Size:  14 mm (female)

Associated plant at NBC:  
Resinbush / Skeleton-leaf Goldeneye

(Viguiera stenoloba)

Plant Family:  Asteraceae

When seen:

April 2019  

Megachile inimica hostile leafcutter - (c) Copyright 2019 Paula Sharp

A female hostile leafcutter

Jaws of a female hostile leafcutter bee

Hostile Leafcutter - Megachile inimica - (c) Copyright 2019 Paula Sharp

According to the entomologist Karl Krombein, hostile leafcutters employ inventive masonry skills to construct their tubular nests.  The bees form cell partitions between the egg chambers of their nests by combining circular leaf-cuttings with layers of sand and small pebbles.

There are two subspecies of hostile leafcutters in North America – the more southerly variety Megachile inimica inimica  (shown here), and Megachile inimica sayi, found in more northern areas.  These subspecies are identical except for their coloring – the legs of Megachile inimica sayi are black and the bee's abdominal bands and scopal hairs are white; Megachile inimica inimica leafcutters have red legs, and their abdominal bands and scopae tend to be yellowish.

Sida Leafcutter Bee

Megachile (Pseudocentron) sidalceae

Family:  Megachilidae

Size:  15 mm  (male)

Associated plant at NBC:  
Whitebrush

(Aloysia gratissima)

Plant family:  Verbenaceae

When seen: 
June 2019  

Megachle sidalceae - (c) Copyright 2019 Paula Sharp

Male bee 

Megachle sidalceae - (c) Copyright 2019 Paula Sharp

The Megachile sidacaleae leafcutter is named for Sidalcae, a genus of flowering mallows known by the common name Sida.  Nonetheless, this leafcutter is a generalist pollinator found on a range of other plants, such as milkweeds, aster-family and pea family plants and buckwheat.   At the NBC, this species appears on whitebrush, a local native of the verbena family.

ID tip:    This bee belongs to the leafcutter subgenus Pseudocentron.  Male bees of this subgenus have a distinctive yellow bar on the back rim of each upper front leg. The male Megachile sidalceae leafcutter specifically also has these distinctive traits:  (1) The bottom segments of the bee's' back and middle legs are white.  (2) The bees are large for leafcutters - 15 mm (3/5 inch).  The first two of these traits is shown in the photo strip at left.

Silver-tailed petalcutter

Megachile (Megachile) montivaga

Family:  Megachilidae

Size:  12 mm  (female)

Associated plant at NBC:  

Yellow prickly poppy
(Argemone aenea)

Plant family:  Papaveraceae 

When seen: June 2019  

Megachile montivaga leafcutter bee - (c) Copyright 2019 Paula Sharp

Female bee trimming prickly poppy  petals for use in lining her nest

Megachile motivaga - (c) Copyright 2019 Paula Sharp

A female bee Megachile montivaga inside a prickly poppy

Megachile montivaga is a rarely seen leafcutter bee whose Latin name translates to the mysterious and enticing "mountain-wanderer".  In English, however, this bee's common name is "silver-tailed petal-cutter". 

 

This pretty bee belongs to the subgenus Megachile.  Leafcutters of this subgenus vary fairly widely in behavior and physical shape.  Silver-tailed petal-cutter bees in particular have slender abdomens and carry the distinction of using flowers rather than leaves to line the walls of their tunnels.  According to a 1985 study by entomologists Sheffield, Ratti, Packer and Griswold, this trait is unique among leafcutters of the Megachile (Megachile) subgenus. 

 

Silver-tailed petal-cutters usually construct nests in the ground, but they also build them in the hollowed-out piths of old stems. These bees are generalist pollinators, but they tend to favor flowers with delicate, broad petals such as evening primrose and clarkia.  The bee shown here was found trimming the petals of a prickly poppy.

Parallel Leafcutter

Megachile (Argyropile) parallela


Size:  11-12 mm  (male)

Associated plant at NBC:  
Blanketflower 

(Gaillardia pulchella)

Plant family:  Asteraceae

When seen: 

March 2019  

Detailed Photographs: 

Parallel Leafcutter - Megachile parallela - (c) Copyright 2019 Paula Sharp

A male parallel leafcutter bee

Parallel Leafcutter - Megachile parallela - (c) Copyright 2019 Paula Sharp

A male parallel leafcutter bee on gaillardia

A mere seven species of bees occupy the subgenus Argyropile.  Most occur in the western and central United States, ranging from Canada to the Texas border and then southward to Chiapas, Mexico.  Some subgenus Argopyle leafcutters have been found in Florida and North Carolina.

According to entomologist Theodore B. Mitchell, a handful of minute traits help define this subgenus.  Among others, these include the following:  (1) On females, the tip of the sixth abdominal segment  is upturned and appears partly bare.  The scopal hairs on S6 (the sixth segment of the sternum or underside of the abdomen) extend only part-way toward the tip, so that the back end of S6 is relatively hairless.  (2) Both males and females have four teeth on each jaw; in species such as M. parallela, females have two cutting blades, between the 2nd and 3rd, and the 3rd and 4th teeth. 

 

The parallel leafcutter bee is a generalist pollinator that feeds on a broad array of plants, including those in the aster, mustard, pea and verbena families.  At the National Butterfly Center, parallel leafcutter bees are usually seen during the spring, on aster-family plants such as gaillardia and sunflower. 

Megachile (Litomegachile) Leafcutter

Megachile (Litomegachile)
Megachile coquilletti
  (tentative species ID)

 

Size: 13-14 mm (female)

Associated plant at NBC:  
Texas thistle 

(Cirsium texanum)

Plant Family:  Asteraceae

April 2019  

Associated plant at NBC:  
Texas thistle 

(Cirsium texanum)

Plant Family:  Asteraceae

April 2019  

Associated plant at NBC:  
Texas thistle 

(Cirsium texanum)

Plant Family:  Asteraceae

April 2019  

A female Megachile (Litomegachile leafcutter - (c) Copyright 2019 Paua Sharp

A female leafcutter bee of the subgenus Litomegachile (possibly coquilletti)

The subgenus Megachile (Litomegachile)  is found throughout the United States and ranges as far north as Canada and as far south as Oaxaca, Mexico.  At least 7 species of Megachile (Litomegachile) leafcutters are found in Texas:  Megachile brevis, M. coquilletti, M. gentilis, M mendica, M. onobrychidis, M. snowi and M. texana.

 

The female Megachile (Litomegachile) leafcutter bee shown at left is typical of its subgenus:  Megachile (Litomegachile) leafcutters are  medium-sized bees with relatively broad abdomens; dark heads and thoraxes partly covered with pale hairs; and abdomens banded with pale hair. The tip of the abdomen of the typical female Megachile (Litomegachile) leafcutter looks concave in profile (although in M. mendica, the profile is flat).  Female bees have 4 teeth on each mandible, with cutting edges between the 2nd and 3rd and the 3rd and 4th teeth; male Megachile (Litomegachile) leafcutters have 3 teeth on each jaw.

Bees of this subgenus tend to be generalist pollinators.  At the National Butterfly Center, Megachile (Litomegachile) leafcutters can be seen frequently in the spring and summer, flexing the ends of their abdomens upward into the air, in a characteristic leafcutter pose like the bee shown above.  These bees often buzz noisily as they pollinate flowers.  

The female bee shown here has been tentatively identified as the species Megachile coquiletti.  Distinguishing features  of female Megachile conquilletti are its relatively large size; the black hairs on its scutellum (at the back of the thorax); and the presence of a groove near the base of the 5th abdominal segment in particular (as well as the 2nd through 4th segments) .  Most hairs on the bee's abdomen are white, but on the 6th segment (T6 & S6), the hairs are principally black.

Associated plant at NBC:  
Tenaza 

(Havardia pallens)

Plant family:   Fabaceae

When seen: 
Late June & early July 2019  

Common Little Leafcutter

Megachile (Litomegachile) brevis

Family:  Megachilidae

Size:  12 mm  (male)

Megachle brevis - (c) Copyright 2019 Paula Sharp

A male common little leafcutter bee

Megachle brevis - (c) Copyright 2019 Paula Sharp

Male Megachile brevis bee drinking nectar from Tenaza tree blossoms

A female common little leafcutter bee

Megachile brevis, known as the common little leafcutter bee, is in fact among the most common leafcutter species in North America; it is found from coast to  coast, from Florida through Canada.

 

According to entomologist Charles D. Michener’s The Social Biology of the Bees, while most solitary bees produce only one generation annually, common little leafcutters produce a succession of generations each year, so that , except in spring, all life stages of the bee, including larvae and pupae, can be found at any time during warmer months.

 

The Discover Life database records common little leafcutters as feeding on a broad range of flowers, including asters, yarrow, clover and caneberries. Michener wrote, in The Bees of the World,  that common little leafcutters collect pollen from whitish, blue, purple and pink flowers of various families, but rarely collect from yellow Asteraceae-family flowers such as sunflowers.  The male bee shown here was feeding on white-flowered tenaza trees; the female was collecting pollen from purple hyssop.

 

Identification Information.   Megachile brevis  is very similar to two other leafcutters of the subgenus Litomegachile -- Megachile mendica and Megachile texana.  The common little leafcutter can be distinguished from these in part because it is generally smaller -- its Latin name, brevis, means "small" or "short".  Other traits aid in distinguishing Megachile brevis from these two species.  (1) Female common little leafcutters have white scopal hairs; M. mendica females usually have orange-yellow scopal hairs; M. texana females have black scopal hairs under the 6th segments of their abdomens.  (2)  The abdominal bands of female common little leafcutters are white on the sides on the 2nd through 5th segments; on M. texana, dark bristles intermingle with pale hairs.  (3) Entomologist Charles Robertson noted that on male common little leafcutters, the 6th abdominal segment has two median teeth like those of a circular saw,” a trait that helps differentiate it from M. mendica.

Megachile (Megachiloides) Leafcutter

Megachile (Megachilodies)

Size:  14  mm (female))

Associated plant at NBC:  


Shrubby blue sage

(Salvia ballotiflora)

Plant family:   Lamiaceae

When seen:  May 2019  

Associated plant at NBC:  


Shrubby blue sage

(Salvia ballotiflora)

Plant family:   Lamiaceae

When seen:  May 2019  

Megachile (Megachiloides) leafcuttter bee - (c) Copyright 2019 Paula Sharp

A female Megachile (Megachiloides) leafcutter bee

Leafcutter bees of the subgenus Megachiloides are often hefty – measuring up to 17 mm in length. Females have mandibles with three or four teeth and one cutting edge.  Male Megachile (Megachiloides) of some species have enlarged and pale front legs, and antennae with expanded top segments.

According to entomologist Charles D. Michener, leafcutters of the subgenus Megachiloides range from Canada to southern Mexico, and they tend to live in arid regions.  Many are oligolectic (specialist pollinators of particular species or genera of flowering plants).  Female bees of the kind shown here were observed feeding repeatedly but exclusively on shrubby blue salvia at the NBC in May 2019.

According to Jack Neff, President of the Central Texas Melittological Institute, Megachile (Megachiloides) leafcutters are largely undocumented in the Lower Rio Grande Valley.  Members of this subgenus found in Texas include:  Megachile deflexa, M. integra, M. instita, M. maurata, M. mucorosa, M. oenetherae, M. parksi and M. victoriana. 

Associated NBC plants:  


Texas snout bean

(Rhynchosia senna var. texana)

Climbing dalea

(Dalea scandens)

Plant family:  Fabaceae

Shrubby blue sage

(Salvia ballotiflora)

Plant family:  Laminacae

When seen:  
September 2018, April 2019  

Slender Resin Bee
Megachile (Chelostomoides) exilis

Family:  Megachilidae

Size: 11 mm (female); 10 mm (male)

Megachile exilis (female) - (c) 2018 Paula Sharp

A female slender resin bee (Megachile exilis) on a Texas snout bean blossom

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A male slender resin bee:  the male bee's forelegs are unusual:.  The bee's tarsi are dilated and reddish.

As noted in this guide page’s introduction, resin bees in the genus Megachile belong to the subgenus Chelostomodes. They differ from leafcutters by virtue of having jaws that lack cutting edges.  Rather than trim leaves or petals from plants, resin bees use plant saps, sometimes mixed with dirt or pebbles, to construct and seal their nests.  Resin bees usually nest in holes made by beetles or other insects in wood or pithy plant stems.  

At the National Butterfly Center, slender resin bees have been found on a single plant:  Texas snout bean, a member of the pea family.  Slender resin bees are often associated with plants of the pea family, but are generalist pollinators that have been documented feeding on a fairly broad range of plants -- among others, on milkweeds, dogbane, heathers, members of the aster family, calamint and salvias.

ID Info:  Slender resin bees of the species Megachile exilis have narrow, parallel-sided black abdomens banded by stripes of pale hairs. The male slender resin bee’s unusual, enlarged and reddish forelegs. Other minute traits help distingush males of this species as well.  Males have 3-toothed jaws.  The clypeus rim of the male bee also has a small tubercule in the middle and two larger ones on either side; these tend to be obscured by the dense white hairs on the male bee’s face. The sixth segment of the male bee’s abdomen (T-6) has a distinct notch.

The female slender resin bee has four-toothed jaws and a clypeus with a small tubercule in the middle, flanked by two jagged areas (shown in the photo strip at left). The scopal hairs on the underside of the female bee are white.  The sixth segment of the female bee’s abdomen (T-6) has dark hairs at the base and a turned-up rim. Viewed from below, the female bee's sixth abdominal segment (S-6) has a slight dip in the center.

Resin  Bee Species of the National Butterfly Center

Permissions and Copyright Information:   All images on this site are (c) Copyright 2018-2019 Paula Sharp and Ross Eatman.  All rights reserved. All photographs are protected by registered copyright.  Please contact Sharp-Eatman Nature Photography for written permission before using any of these images for any purpose. 

Last updated November 2019

 1-15-19