IDENTIFICATION PAGE # 8


ID requests for November 15,  2019


WILD BEES OF THE NATIONAL BUTTERFLY CENTER
Mission, Texas

A female Exomalopsis mellipes

This species is distinguished from other Exomalopsis bees in part by the colors of its leg hairs and tegulae (where the wing joins the body). Note that some of the outer scopal hairs on the bee's hind legs are orange and dark-brown. The bee's tegulae are orange.

This is the rear view of the female bee.

The E. mellipes female's pale hair bands are set back from the rim of each segment, but join the rim as the hairbands descend the bee's sides.

View of the thorax and vertex (top of head) of a female Exomalopsis mellipes

An additional view of the bee's thorax and vertex

Face of the female Exomalopsis mellipes

The pits on the female Exomalopsis mellipes bee's clypeus are fairly evenly distributed. This minute trait helps differentiate this Exomalopsis species from others.

The only other reddish bee we've seen in the area is Diadasia tropicalis, but males of that species (like that shown below), do not have red tegulae or antennae

Male bee - Genus?

Family:  Apidae

Size: est 6-7 mm  (male)

Associated plant at NBC:  

Seaside goldenrod

(Solidago sempervirens)
Family:  Asteraceae

When seen:

October 2018

This male bee, found feeding on goldenrod, flew away before we could snag more photographs of it. 

​This is a small bee -- we estimated  its size at about 6-7 mm.  In addition to red tegulae, the bee has red femora and antennae (including the scapes) -- even part of the abdomen (S1) appears to be partly red.  ​We're completely stumped by this one.  Is it a male Exomalopsis mellipes? 

February 8 response form Jack Neff:  " Your red bee is presumably a male of Exomalopsis mellipes which is a fairly robust species with red legs and metasoma.  All the North American Diadasia (Dasiapis) - (ochracea, olivacea and tropicalis) are little tan bees whose males have a pale yellow clypeus and mandibles and usually a yellow labrum while in the females the yellow maculation is limited to the mandibles.  Diadasia ochracea is by far the most common member of this group so having common male tropicalis and female ochracea sounds like you have one of the two, but not both.  Not all specialists recognize tropicalis but it and ochracea can be distinguished by the color of the integument of the hind femora (red/reddish in tropicalis - the usual tan in ochracea) and the punctation of the center of the scutum (sparse or near absent in ochracea, dense in tropicalis).  The map of ochracea in the Snelling paper is a bit misleading as it omits its distribution in the US.  Diadasia ochracea is actually widespread in Texas and occurs in the Valley.

The other male Exomalopsis has the orange hair of the hind legs and is what is commonly called birkmanni.  Timberlake suggested it might be only a subspecies of solani and I tend to think it is only a color variant of solani as I have not found the genitalic differences Timberlake mentions.  You could use either name."

 

A male Snow's Exomalopsis (Exomalopsis snowi)

As is true of male bees generally, male Exomalopsis bees do not gather pollen and thus lack scopal hairs on their legs.

Male Exomalopsis snowi bees have thick pale hairs covering their faces.

Rear view of the abdomen of a male Exomalopsis snowi

The front segments of the male bee's abdomen

Wing of a male Exomalopsis snowi bee

These are photographs of a bee identified last fall as a male Exomalopsis snowi.  This bee measured 7mm.  It does not have red antennae, and its eyes are blue-gray rather than green

Exomalopsis birkmanni?   male

Family:  Apidae

Size:  9 mm  (male)

Associated plant at NBC:  

Texas sage

(Leucophyllum frutescens)
Family:  Scrophulariaceae

When seen:

October 2018

Male Exomalopsis found on cenizo, together with female Exomalopsis birkmanni. The male bee has only light-colored hairs on its legs.

Rear view of male bee

Alternate view of abdomen: the male bee's abdomen is covered with pale, long, fairly dense hairs.

Sternum

WJPEG-Exomalopsis-M-NBC-%23306cenizo-293

A large number of male bees like this were found mobbing a Texas sage bush where female Exomalopsis birkmanni with bright orange hind legs were feeding.  (This is the same bush where we found the bee you identified earlier as a female E. birkmanni, shown below.)  The hairs on the male bee's bottom leg segments are yellowish-orange.  The hairs on the abdomen are long, pale and dense. 

This is a bee identified last year as a female E. birkmanni

A female Exomalopsis birkmanni on Texas sage: to the naked eye, these bees closely resemble Exomalopsis solanum (shown above). The only visible difference is that E. bikmanni bees have bright orange scopal hairs on their legs and a bright orange tuft of hairs behind the thorax.

Note the brilliant orange scopal hairs onthis female bee's hind legs.

Profile view of bee

Dorsal view of female bee: The bee has a bare, somewhat shiny scutum with a rust-colored tuft of hair on its hind edge.

T1 and T2 are black and shiny. Pale hair bands rim the apical edges of T2, T3 and T4. T1 has some pale hair laterally on its rim. Sparse longish hairs stretch across of T2-T4 as well. This is the same hair pattern as that on the bee identified as Exomalopsis solani.

Tip of abdomen & pygidial plate

Face of female Exomalopsis birkmanni

Antenna of female bee: F1 is somewhat longer than F2.

This is one of the female Colletes bees we found feeding on t he same seaside goldenrod plants as the male bee you identified as Colletes birkmanni.  All of the female Colletes bees we're seeing on the goldenrod have the same rust-colored thorax hairs.  (The female Colletes birkmanni identified last year also had this trait.)  The females lack the specialized sternum hairs found on the male bee.  (Photos of last year's female and of this year's male are shown below the latest photos of this new female.)

Colletes birkmanni?

Family:  Colletidae

Size:  12 mm (female)

          8-10 mm (male)

Associated plants at NBC:  

Seaside goldenrod

(Solidago sempervirens)   
Plant Family: Asteraceae

When Seen:

November 2019

Colletes birkmanni cellophane bee - (c) Copyright 019 Paula Sharp

Female bee

Female Colletes bee on goldenrod, this November 2019

The bee has rust-red hair on its thorax, similar to that of the female Colletes birkmannie bee found last November at NBC

Female bee

Collees birkmanni cellophane bee - (c) Coopyright 2019 Paula Sharp

Female bee found a year ago, in November 2018

This is a female Birkmann's cellophane bee. Species identification of cellophane bees often hinges on such traits as size; geographic location; the color of hairs on a given bee's thorax and head; the narrowness vs. wideness of the basitarsus of the bee’s hind leg; and the appearance of the bands of pale hair on the bee's abdomen.

Note that the hind-leg basitarsus of this female Birkmann's cellophane bee is long and narrow (3 3/4 as long as it is broad). The yellow material on the bee's feet is pollinia (pollen clusters) from flowers. (The basitarsis is the second long segment from the top shown in this picture).

Both males and females of this species have pale rust-colored thorax hairs that are visible even to the naked eye.

Female Birkmann's cellophane bees, like the one shown here, also have pale orange hairs on the vertex (the area just behind the eyes, at the back of the head).

The female Birkmann's cellophane bee has white hairs on her face. The hairs are denser near the antennae. The flagellar segments of the antennae (the 3rd through uppermost segments) are broader than they are long.

The "malar space" is the distance from the bottom of a bee's compound eye to the mid-point of the jaw. On the female C. birkmanni, the malar space is 3/8 as long as it is broad. Note that there are some yellowish-orange hairs near the bee's jaw.

Male bee found a week ago, in October 2018

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etes-M-NBC-#305-Goldenrod-293A

A male Birkmann's cellophane bee

A male Birkmann's cellophane bee: All of the hair on the bee is light-colored.

Alternate view of bee

Face of male bee

Close-up of jaw and malar space

Close-up of antennae

bee on solidago

Rear view of bee's abdomen and hind legs

This is an unfortunately murky picture of the bee's wings. The image seems consistent with this being an Exomalopsis -- it shows a large stigma and a marginal cell whose tip is bent abruptly away from the wing margin. There appear to be 3 submarginal cells.

Diadasia tropicalis bee - (c) Copyright 2019 Paula Sharp