SHARP-EATMAN
NATURE
PHOTOGRAPHY
ID GUIDE TO WILD BEES
OF THE NATIONAL BUTTERFLY CENTER
Mission, Texas
LEAFCUTTER BEES
Megachile
Sida Leafcutter Bee
Megachile (Pseudocentron) sidalceae
Family: Megachilidae
Size: 15 mm (male)
Associated flora at NBC:
Whitebrush
(Aloysia gratissima)
Plant family: Verbenaceae
When seen:
June 2019
A male Megachile sidalceae
A male Megachile sidalacea on whitebrush. Note the yellow stripe on the front tibia -- a distinguishing trait of leafcutters of the subgenus Peudocentron.
Note also that the lower segments (the basitarsi and tarsi) of all of the bees' legs are predominantly pale.
Close-up of middle leg and foreleg; the foreleg tibia is rimmed with a yellow band. The middle leg lacks a tibial spur.
Dorsal view of bee.
A male Megachile sidalceae
This leafcutter is named for Sidalcea, a genus of flowering mallows known by the common name Sida. Nonetheless, Megachile sidalceae is a generalist pollinator found on a range of other flora, such as milkweeds, buckwheat, and aster-family and pea-family plants. At the NBC, this species appears on whitebrush, a local native of the verbena family.
ID tips: These bees are large for leafcutters - 15 mm (3/5 inch). Most notably, male bees of the subgenus Pseudocentron have a distinctive yellow bar on the back rim of each upper front leg. The male Megachile sidalceae has an additional trait that aids greatly in its identification: the lower segments of all of the bee's legs are yellowish-white.
Silver-tailed petalcutter
Megachile (Megachile) montivaga
Family: Megachilidae
Size: 12 mm (female)
Associated flora at NBC:
Yellow prickly poppy
(Argemone aenea)
Plant family: Papaveraceae
When seen: June 2019
A female silver-tailed petalcutter inside a yellow prickly poppy. The bee has a slender, parallel-sided abdomen with narrow bands of white hairs on the first five segments (T1 - T5).
Lateral view of female Megachile montivaga inside a prickly poppy
The female bee's mandibles lack cutting edges, and the rim of the clypeus is relatively straight (and lacks a tubercule). The mandibles have 4 teeth.
Dorsal view of the female bee's vertex and thorax
The tip of the female silver-tailed petalcutter's abdomen (T-6) is concave in profile. The bee's scopal hairs are pale-orange to bright orange.
A female Megachile montivaga trimming prickly poppy petals for use in lining her nest
A female 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 (Megachile). Leafcutters of this subgenus vary fairly widely in behavior and physical shape. Silver-tailed petal-cutters in particular have slender abdomens and carry the distinction of using flowers rather than leaves to line the walls of their nests. 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. 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
Family: Megachilidae
Size: 11-12 mm (male)
Associated flora at NBC:
Blanketflower
(Gaillardia pulchella)
Plant family: Asteraceae
When seen:
March 2019
A male parallel leafcutter: dense light yellowish-brown hairs cover the bee's face and thorax.
The forelegs of the male parallel leafcutter are simple, rather than being enlarged like those of the subgenus Sayapis leafcutters shown above on this guide page.
Face of a male parallel leafcutter
Lateral view of a female Megachile parallela.
Dorsal view of a female Megachile parallela
Face of a female Megachile parallela:
A male parallel leafcutter bee (Megachile parallela)
A female parallel leafcutter bee (Megachile parallela)
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. These include the following. (1) On females, the tip of the sixth abdominal segment (T6) is upturned and appears partly bare. (2) The female's scopal hairs on S6 extend only part-way toward the tip, so that the back end of S6 is relatively hairless. (3) Both male and female Megachile (Argyropile) have 4-toothed mandibles; 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 an 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 Asteraceae such as gaillardia and sunflower.
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:
June-Nov. 2018-2013
A female chichimeca leafcutter bee (Megachile chicimeca)
A female chichimeca leafcutter: note the (1) tufts of white hair near the bases of the bee's wings; and (2) the dense band of white hair rimming the back of the thorax. (3) Note also that the bee's forewings are dusky toward the outer hind edges. These traits help identify this bee in the field.
The mandibles of the female chichimeca leafcutter are 4-toothed. Note the small tubercule in the middle of the female bee's clypeus (the face part above the mandibles. On either side of the tubercule are jagged crenulations.
Lateral view of a female Megachile chichimeca
A male chichimeca leafcutter bee
A male chichimeca leafcutter
Dorsal view of male bee
Close-up of vertex and thorax
Megachile chichimeca is native 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, Wilmatte Cockerell encountered a chichimeca leafcutter in Port Isabel (Cameron Co.) and recorded it in her publication Collecting Bees in Southern Texas.
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 chichimeca are: it is small and slender; there are prominent tufts of white hairs located near the bases 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 rear outer 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 D. Michener 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 mandible 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 here. The female Megachile chichimeca has four teeth on each mandible.
Associated flora 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)
A male Megachile cf. toluca Megachile toluca
A male Megachile (Tylomegachile) cf. toluca. This bee has striking red legs, a relatively unusual trait for a leafcutter found in Texas. The bee's face, cheeks and thorax are covered with dense yellowish hairs.
Head of the male Megachile (Tylomegachile) cf. toluca. The bee's mandibles have three teeth each.
Dorsal view of the male Megachile cf. toluca. Note the tawny hairs on the bee's thorax.
The underside of the bee: note the black coxae and trochanters (top segments) of the bee's otherwise red legs.
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 John L. Neff in collaboration with Dr. John Ascher and Hadel Go.
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 accompanying photo strip).
LEAFCUTTER BEES
Genus Megachile
The name leafcutter derives from female leafcutter bees' practice of using their sharp-edged mandibles to cut leaves and flower petals. The bees employ these materials to partition and line 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, female leafcutters tunnel into dead twigs, cavities in wood or the ground, and construct individual nests. The bees deposit their eggs in cell chambers and provision them with pollen stores for the leacutter 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.
Leafcutters are easily identified by the way they carry pollen and their unique shape. They have wide, somewhat flattened abdomens that taper abruptly at the ends and broad, sculpted-looking heads. Female leafcutters carry pollen in a way characteristic of all bees of their family, Megachilidae --- on sticky scopal hairs (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 rust-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 Megachile policaris, M. sidalceae and M. zaptlana (shown below), 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 broad 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, a red-legged leafcutter species new to the United States, appeared at the National Butterfly Center. 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". Such bees scrape and collect sticky resins from plants, for use in sealing nest entrances. 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 bees 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 15 leafcutter species shown here, found in the Lower Rio Grande Valley in 2018-2023, belong to 9 different subgenera and vary significantly in basic characteristics and appearance. The hallmark traits of each species are noted below.
A female Zaptlana leafcutter bee, with white scopal hairs under her abdomen
GENERAL TRAITS OF LEAFCUTTER BEES
Leafcutter bees tend to have long dark abdomens banded with pale hairs. Their legs are usually black. Leafcutter bees have large jaws, visible even to the naked eye. The bees use their jaws to trim pieces of leaves from plants.
Some leafcutters have red or partly-red legs. The hairs banding their abdomens may be yellowish.
Some leafcutters, such as the silver-tailed leafcutter (Megachile montivaga) shown here, trim flower petals rather than leaves, for use in lining their nests.
Leafcutter bees have large mandibles that enable them to cut off plant parts in order to build nests with them. The mandibles have both teeth and cutting edges. On this bee, the cutting edges are visible between the top teeth and the ones directly below them.
Petal-cutter bees, like the one shown here, lack cutting edges on their mandibles, presumably because petals are easier to trim than leaves.
This is a resin bee in the same genus as leafcutter bees (Megachile). The mandibles of resin bees have teeth but lack cutting edges.
A male slender resin bee
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 (Chelostomoides) prosopidis (Mesquite resin bee)
Megachile (Chelostomoides) texensis (Texan resin bee)
Megachile (Leptorachis) petulans) (Petulant leafcutter)
Megachile (Litomegachile) brevis (Common little leafcutter)
Megachile (Litomegachile) leafcutter (possibly coquilletti)
Megachile (Megachile) montivaga (Silver-tailed petal-cutter)
Megachile (Neochelynia) chichimeca (Chichimeca leafcutter)
Megachile (Pseudocentron) sidalceae (Sida leafcutter)
Megachile (Sayapis) frugalis (frugal leafcutter)
Megachile (Sayapis) inimica inimica (Hostile leafcutter)
Megachile (Sayapis) policaris (Policaris leafcutter)
Megachile (Sayapis) zaptlana (Zaptlana leafcutter)
Megachile (Tylomegachile) cf. toluca (Toluca leafcutter)
Leafcutter Species of the National Butterfly Center & Lower Rio Grande Valley
Associated flora at NBC:
Carpet vervain
(Verbena bracteata)
Whitebrush
(Alyosia gratissima)
Plant family: Verbenaceae
Low croton
(Croton humilis)
Plant family: Euphorbiaceae
Honey mesquite
(Prosopis glandulosa)
Plant family: Fabaceae
When seen:
June - Oct. 2019-2023
This species is common in
Cameron, Hidalgo & Starr Counties.
Zaptlana Leafcutter Bee
Megachile (Sayapis) zaptlana
Family: Megachilidae
Size: 12-13 mm
A female Megachile zaptlana: the scopal hairs on the bee's sternum are predominantly pale.
This is a close-up of pollen-collecting hairs (scopae) underneath the female bee's abdomen.
A female Megachile zaptlana
A male Megachile zaptlana
A male Megachile zaptlana: this species shows considerable sexual dimorphism. The male bee's front basitarsi are enlarged, have orange and pale markings and sport brushes of pale hair.
Head of a male Zaptlana leafcutter bee: the male bee's face is thickly covered by pale hairs, which partly obscure its mandibles. Male leafcutters of the subgenus Sayapis have 3-toothed mandibles.
Male and female Zaptlana leafcutters show marked sexual dimorphism. The male Zaptlana leafcutter has striking forelegs with lower segments 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. It is a common species in the Lower Rio Grande Valley.
Policaris Leafcutter Bee
Megachile (Sayapis) policaris
Family: Megachilidae
Size: 14 mm (female); 13 mm (male)
Associated flora at NBC:
Resinbush
(Viguiera stenoloba)
Texas thistle
(Cirsium texanum)
Plant family: Asteraceae
When seen:
March - April 2019 - 2023
This female Megachile policaris is a large (13-14 mm), black bee with an abdomen banded by white hairs; white scopae under its abdomen; and dark wings.
Dorsal view of vertex and thorax of female Megachile policaris
A male Megachile policaris
Megachile policarismales have dilated, thmb-shaped, orange-and-pale forelegs.
A female Megachile policaris
A male Megachile policaris
Like the Zaptlana leafcutter above and the hostile leafcutter below, Megachile policaris belongs to the subgenus Sayapis. Bees of this subgenus have long, slender, parallel-sided bodies that enable them to move easily through narrow tunnels. This leafcutter's name derives from the Latin policaris or "of the thumb," a reference to the thumb-shaped , enlarged foreleg of the male bee.
ID tip: The middle leg of the male Megachile policaris has extensive orange coloration on the femur and tibia. 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
Family: Megachilidae
Size: 14 mm (female)
Associated flora at NBC:
Resinbush
(Viguiera stenoloba)
Plant Family: Asteraceae
When seen:
April 2019
A female hostile leafcutter (Megachile inimica inimica)
A female Megachile inimica inimica
Female hostile leafcutters of the Lower Rio Grande Valley are striking, because they have brightly-colored red legs, and yellowish hairs on their faces and bodies.
The female Megachile inimica inimica has a narrow, long, parallel-sided abdomen, a trait of leafcutter bees of the subgenus Sayapis.
The bee's jaws are pitted and ornately carved. The clypeus (the face-part above the jaws) has a distinctive margin.
Mandibles of a female hostile leafcutter
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 (both male and female) have red legs, and their abdominal bands and scopae tend to be yellowish. The male bee (not shown here) has partly-pale expanded forelegs.
Frugal Leafcutter Bee
Megachile (Sayapis) frugalis
Family: Megachilidae
Size: 13 mm (female)
10.5 mm (male)
Associated flora:
Coastal lazydaisy
Aphanostephus skirrhobasis
Family: Asteraceae
Shrubby blue salvia
Salvia ballotiflora
Family: Laminaceae
When and where seen:
June 2 & June 9, 2021
El Mesteno Ranch
Puerto Rico (Hidalgo Co.)
A female frugal leafcutter bee
Dorsal view of female bee: the frugal leafcutter's abdomen is narrow and parallel-side (a trait typical of the subgenus Sayapis).
Face of female bee: female frugal leafcutters have 4 teeth in each mandible, with a beveled edge between the second and third tooth (traits of the leafcutter subgenus Sayapis).
A female frugal leafcutter (Megachile frugalis)
A male frugal leafcutter
A male frugal leafcutter: this is a medium-sized black bee with fringes of long white hair on its rear forelegs and a dark abdomen banded by pale hairs.
Male frugal leafcutters lack the expanded and colorful forelegs seen on some other regional members of the subgenus Sayapis (such as Megachile zaptlana and policaris shown above).
Dorsal view of male Megachile frugalis
Frugal leafcutters are broad generalist pollinators that range from the west to the east coast of the United States, and as far south as Costa Rica. This species It is nonetheless uncommon in the Lower Rio Grande Valley: ogher members of the subgenus Sayapis, particularly Megachile zaptlana and M. policaris, are far more abundant.
This is a medium-sized black leafcutter. Males lack the colorful and expanded forelegs characteristic of Megahile zaptlana, M. policaris an m. inimica. The legs of male frugal leafcutters are black, with a fringe of flamboyant white hairs. Both male and female Megachile frugalis have distinctive black hairs on the clypeus, most easily seen in profile, that aid greatly in identifying the species (with the aid of magnification). The bees' forewings are dark on the outer edges, a trait visible in the field.
Megachile (Litomegachile) Leafcutter
Megachile (Litomegachile) cf. coquilletti
Family: Megachilidae
Size: 13-14 mm (female)
Associated flora at NBC:
Texas thistle
(Cirsium texanum)
Plant Family: Asteraceae
April 2019
A female Megachile (Litomegachile) with her abdomen tip raised in the air. This behavior is characteristic of bees of the subgenus Litomegachile. This female bee has been identified tentatively as Megachile coquilletti.
Lateral view of female bee: this leafcutter was found feeding on a Texas thistle. The dark hairs on the bee's scutellum (the back part of the thorax) are a distinctive trait of female Megachile coquilletti.
Face of female bee
Close-up of 4-toothed jaws, each with two cutting edges.
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 leafcutter of the subgenus Litomegachile (possibly Megachile 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 leafcutter bee shown here, tentatively identified as Megachile coquilletti, is typical of its subgenus: Megachile (Litomegachile) 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) looks concave in profile (although in M. mendica, the profile is flat). Female bees have 4-toothed mandibles, with cutting edges between the 2nd and 3rd and the 3rd and 4th teeth; male Megachile (Litomegachile) have 3-toothed mandibles.
Bees of this subgenus tend to be generalist pollinators. At the National Butterfly Center, Megachile (Litomegachile) can be seen frequently in the spring and summer, flexing the ends of their abdomens upward into the air, in a characteristic Megachile (Litomegachile) pose like the bee shown above. These bees often buzz noisily as they pollinate flowers.
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 flora at NBC:
Tenaza
(Havardia pallens)
Plant family: Fabaceae
When seen:
Late June & early July 2019
Common Little Leafcutter
Megachile (Litomegachile) brevis
Family: Megachilidae
Size: 7-9 mm (male)
9-12 mm (female)
A male common little leafcutter resting on the blossoms of a tenaza tree in early summer. Male bees of this kind mobbed the blossoms of tenaza trees in June and July 2019 at the NBC.
A male common little leafcutter bee negotiating a tenaza blossom
The underside of the male bee is covered with copious, woolly hair.
A dorsal view of a female common little leafcutter: note the broad body, typical of females of this species.
Female common little leafcutter bees have 4 teeth on each mandible. There are cutting blades between the 2nd and 3rd and the 3rd and 4th teeth.
This Megachile brevis was found outside of Texas. It is shown here as an example of a female of this species. Note the white scopal hairs under the bee's abdomen.
Close-up of the tip of the female bee's abdomen
A male common little leafcutter bee (Megachile brevis)
Male Megachile 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 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.
Petulant leafcutter
Megachile (Leptorachis) petulans
Family: Megachilidae
Size: 11-12 mm (female)
9-10 male
Associated flora:
Shrubby blue salvia
Salvia ballotiflora
Family: Laminaceae
When and where seen:
June 3, 2021
Falcon Park
Roma (Starr County)
A female petulant leafcutter (Megachile petulans)
A female Megachile petulans
Megachile petulans is a robustly-built leafcutter that stands out in the field because of its overall yellow-orange appearance: the hairs on the bee's head, thorax, and legs and the hairs banding its abdomen are all yellowish.
Frontal view of female bee
Closeup- of face: the female bee’s mandibles have four teeth in each jaw, with a cutting edge between the innermost and third tooth. Unlike the female parallel leafcutter, the petulant leafcutter lacks an additional cutting edge between the second and third teeth. This minute trait distinguishes the species.
A female petulant leafcutter
Megachile petulans is a solitary ground nester that uses pebbles and sand as well as resin, leaves and other plant debris when constructing its nests. A generalist pollinator, the petulant leafcutter is often found on plants of the aster, mint and pea families.
Megachile petulans is the only member of its subgenus that appears within the United States. The subgenus Leptorachis is neotropical. E.T. Cresson first described Megachile petulans in 1878 after examining a specimen found in Mexico -- the original name of the petulant leafcutter was the Mexican leafcutter (Megachile mexicana). The petulant leafcutter still occurs throughout most of Mexico, from its northern border to Yucatan. It has proven to have a broad range, however. It appears along the US-Mexican border as far west as Arizona, and it ranges through the central and eastern United States as far north as North Dakota and New England.
The petulant leafcutter is a relatively large, robustly-built leafcutter that stands out in the field because of the overall yellowish-orange appearance of the hairs on its head, body and legs. Megachile petulans is best distinguished from the similarly yellowish Megachile parallela, shown above, by differing traits of the bees' mandibles and the tips of their abdomens, as illustrated in the accompanying photo strip.
Resin Bee Species of the National Butterfly Center & Lower Rio Grande Valley
Associated flora at NBC:
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)
A female slender resin bee resting under a snout bean flower
Head of a female slender resin bee. The mandibles of female slender resin bees each have four teeth that lack cutting edges. The bottom rim of the female bee's clypeus (the face-part above the jaws) has a small tubercule (bump) in the middle; on either side of this are jagged edges.
Profile of a female slender resin bee's head
A male slender resin bee: male slender resin bees have distinctive red forelegs with expanded lower segments.
A closer view of a male bee's foreleg
male slender resin bees have 3-toothed mandibles. Their faces are covered with dense white hairs.
A female slender resin bee (Megachile exilis) on a Texas snout bean blossom
A male slender resin bee: the male bee's lower forelegs 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 mandibles 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.
Slender resin bees are often associated with plants of the pea family. They are, nonetheless, 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: As is typical of the subgenus Megachile (Chelostomoides), slender resin bees have narrow, parallel-sided black abdomens banded by stripes of pale hairs. The male slender resin bee has distinctive, enlarged and reddish forelegs. Other minute traits help distinguish males of this species as well. (1) The sixth segment of the male bee’s abdomen (T-6) has a distinct notch. (2) The clypeus rim of the male bee 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. Males have 3-toothed mandibles.
The female slender resin bee can be recognized by the following traits. (1) The female has 4-toothed jaws and a clypeus with a small tubercule in the middle, flanked by two jagged areas (shown in the accompanying photo strip). (2) 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.
Texan Resin Bee
Megachile (Chelostomoides) texensis
Family: Megachilidae
Size: 9 - 10.5 mm (female)
8 - 10.5 mm (male)
Possible associated flora:
Guajillo
(Senegalia berlandieri)
Honey mesquite
(Prosopis glandulosa)
Plant family: Fabaceae
When and where seen:
April 26, 2021
Teniente Tract
Raymondville
(Hidlago Co. / WIllacy Co. border)
A female Megachile texensis: this is an imposing bee, with bulky mandibles and a hornlike protrusion on its face.
Dorsal view of the female Megachile texensis
Dorsal view of vertex & pointed protrusion on head of the female Megachile texensis
Face of female bee: on both males and females of this species, the tips of the mandibles are 3-toothed.
A female Texan resin bee (Megachile texensis)
The female Megachile texensis is a singular bee: It has bulky mandibles and a conical horn in the center of its face. Both female and male Megachile texensis have black heads and bodies and abdomens banded by pale hairs. Females' scopal hairs are mostly white, with black hairs near the tip. Males' legs are black; they lack the extensive red coloration and expanded forelegs of the two resin bee species shown above.
The Texas resin bee was first described in 1956 by the entomologist T. B. Mitchell, after he examined a single female found in Cameron County. The Texan resin bee, despite its name, is a subtropical species that ranges from Central America through Mexico. Within the United States, it appears principally and uncommonly in the Lower Rio Grande Valley.
The female Texan resin bee shown here was discovered in late April 2021, on the border of Hidalgo and Willacy Counties. The bee was flying low over the ground in a gas pipeline right-of-way covered with low scrub vegetation. The soil of the locale was sandy and strewn with wood debris. Few flowers were in bloom in the area, but a scrub woodland of honey mesquite and guajjillo trees lined the access way. Texan resin bees are associated with pea-family plants.
Associated plant:
Shrubby blue salvia
(Salvia ballotiflora)
Family: Laminaceae
When and where seen:
June 3, 2021
Falcon State Park
Roma (Starr Co.)
Mesquite resin bee
Megachile (Chelostomoides) prosopidis
Family: Megachilidae
Size: 12-13 mm (female)
10-11 mm (male)
A male mesquite resin bee (Megachile prosopidis)
A male mesquite resin bee: the primarily red coloration of the middle (as well as hind legs) of the male Megachile prosopidis sets it apart from other male resin bees of the Valley. (The middle and hind legs of the male Megachile exilis and M. texanum, e.g., are black.)
Long white hairs partially cover the sides of the bee's thorax. Note the tuft of white hair just in front of and below the reddish tegula: this is a distinctive trait of this species.
Dorsal view of the male bee's vertex and thorax: note also the two distinctive curved patches of white hairs on the front of the bee's scutum.
Profile of head: dense white hairs cover the male bee's face and cheeks.
The male mesquite resin bee somewhat resembles the male slender resin bee shown above. Both are black bees with partly-red and expanded forelegs, and abdomens banded by white hairs. Megachile prosopidis, however, is larger, has extensive red coloration on all legs; and has distinctive patches of hair on the thorax, as shown in the accompanying photo strip. The female bee, not shown here, has white scopal hairs on most of its sternum (S1-S5), and black scopal hairs on S6. Females can be told apart from similar resin bees of the Valley by their 5-toothed mandibles.
Megachile prosopidis ranges along the Mexican border, from Texas to southern California, and southward into Mexico. The male bee shown here appeared in an area covered by Tamaulipan thornscrub at Falcon State Park (Starr Co.) in June 2021.
Although this male bee was found drinking nectar from the mint-family plant shrubby blue sage, Megachile prosopidis is considered an oligolectic pollinator of plants of the family Fabaceae, particularly leguminous trees. Cockerell first described and named this species after examining female bees found feeding in part on honey mesquite (Prosopis glandulosa).
CITE THIS PAGE: Sharp, Paula and Ross Eatman. "Megachile." Wild Bees of the National Butterfly Center of Mission, Texas. 15 Jan. 2019, http://www.wildbeestexas.com. Accessed [day/month/year guide accessed].