IDENTIFICATION PAGE # 7

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 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.

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

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 as a female Exomalopsis mellipes.

A male tropical Diadasia chimney bee on Rio Grande abutilon

A male tropical Diadasia chimney bee sleeping on Rio Grande abultilon

The bee's legs are reddish. Its clypeus (the face part above the jaws) is pale yellow; there is also a pale-yellow spot on the base of each jaw.

Face of male bee: the scapes of the bee's antennae are black.

Dorsal view of bee

The bee's abdomen is covered with pale gold-brown hairs of fairly uniform length.

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

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

Male bee in question

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.

These are photographs of a bee identified last fall as a female Exomalopsis mellipes