Extracted from: Roberts, 1973. Bees of Northwester America: AGAPOSTEMON. Agricultural Experimental Station. Oregon State University.
Diagnosis. The male of this species has a bright metallic green head and thorax; the metasoma is black and yellow banded, with metallic tints apically. The male of A. angelicus may be distinguished from males of A. coloradinus and A. virescens by the presence of yellow on its last two visible sterna (fifth and sixth), from males of A. melliventris by the presence
of an apical black stripe on the posterior surface of its hind tibia
(Figs. 4, 6), and from males of A. texanus and A. femoratus by the lack of a medial brown or black stripe on the anterior surface of its hind tibia (Figs. 3-5). Agapostemon texanus may lack the anterior tibial stripe, but such specimens also lack the posterior stripe present in A. angelicus.
The female of A. angelicus has a bright metallic green head, thorax,
and metasoma. It may be distinguished from females of most other species
by the presence of two sizes of punctures on its scutum (Figs. 14-15).
The females of A. texanus are similarly colored and also have two sizes of
scutal punctures. Thus, females of A. texanus and A. angelicus cannot be distinguished by morphological features.
Distribution. Although common only in the and regions of the
southwestern United States and northern Mexico, males of A. angelica:
have been found as far north as west-central North Dakota, as far south
as northern Durango (Mexico), as far east as central Iowa, and as far
west as southwestern California (Fig. 18).
Distribution. Although common only in the and regions of the
southwestern United States and northern Mexico, males of A. angelica:
have been found as far north as west-central North Dakota, as far south
as northern Durango (Mexico), as far east as central Iowa, and as far
west as southwestern California (Fig. 18).
In the Northwest A. angelicus has been collected only in northern
Utah, southeastern Oregon, and in the Snake River Valley of Idaho. It
may also occur in northern Nevada.
In the Northwest A. angelicus has been collected only in northern
Utah, southeastern Oregon, and in the Snake River Valley of Idaho. It
may also occur in northern Nevada.
This species ranges from below sea level in Death Valley, California,
to 12,000 feet (3,658 m) on Mt. Evans, Colorado, where timberline is
11,700 feet. The recorded altitudinal range of this species surpasses that
of almost all other North American bees.
In the southern portion of its range (Arizona) males of this species
have been collected from April through November. Further north in
Kansas males of A. angelicus have been collected from June through
October.
Biology. Little is known of the biology of this species, but it is probably
similar to the biology of its close relative, A. te.ranus. Agapostemon
angelicus has been observed (Linslev, 1962) sleeping on the dried flower
heads of a clump of Heterotheca suhaxillaris (Compositae) in southeastern
Arizona. Numerous males and occasional females were seen on
these plants on 26 of 28 consecutive nights. The females always slept
alone, but the males tolerated each other's presence and as many as six
could be seen crowded onto one flower head. Grasping the plant with
their legs, the males slept with their bodies extended, wings folded, and
antennae held forward and pressed together or only slightly divergent.
The author has observed the males of this species sleeping atop sunflowers
(Helianthus sp.) in a pasture in eastern Colorado, in a manner
similar to that noted by Linsley (1962). Both flowers and hers were
covered with a heavy dew. As the morning was cold, the bees did not
dry off and fly until about nine o'clock.
This species, like most bees, normally forages from about 9 a.m. to
noon when the weather is warm and sunny. However, it is obvious that
the females are able to adapt their foraging period to the availability of a
locally abundant pollen source. Agapostemon angelicus females have
been reported (Linslev and Hurd, 1959) gathering pollen from the afternoon-
flowering R1entzelia pumila (Loasaceae) at sunset (5:40 p.m. ).
The same species has been reported (Linslev, 1960) collecting pollen
from the matinal flowering Curcurhita foetidissima at 5:35 a.m. when the
Distribution. Although common only in the and regions of the
southwestern United States and northern Mexico, males of A. angelica:
have been found as far north as west-central North Dakota, as far south
as northern Durango (Mexico), as far east as central Iowa, and as far
west as southwestern California (Fig. 18).
In the Northwest A. angelicus has been collected only in northern
Utah, southeastern Oregon, and in the Snake River Valley of Idaho. It
may also occur in northern Nevada.
This species ranges from below sea level in Death Valley, California,
to 12,000 feet (3,658 m) on Mt. Evans, Colorado, where timberline is
11,700 feet. The recorded altitudinal range of this species surpasses that
of almost all other North American bees.
In the southern portion of its range (Arizona) males of this species
have been collected from April through November. Further north in
Kansas males of A. angelicus have been collected from June through
October.
air temperature was 52-54° F (11.1-12.2° C) and a heavy overcast was
threatening rain.
Extracted from: Roberts, 1972. The University of Kansas Science Bulletin.
Agapostemon angelicus Cockerell 1924. Type 9, California Academy of Sciences.
I have seen the type in San Francisco and it is from Pond Island Bay,
Angel de la Guarda Island in the Gulf of California, Mexico. As the males
of A. texanns are rare relative to those of A. angelicus in this region, it
seems reasonable and expedient to consider this type to be conspecific with
those males which differ in genitalia and color pattern from those of A.
texanns.
Distribution. All males of A. angelicus have been found well within
the range of the males of A. texanns. Owing to this sympatry and my in-
ability to distinguish between females of A. texanns and A. angelicus, I have
here considered the distribution of males and disregarded females.
Although common only in the arid regions of the southwestern United
States and northern Mexico, males of A. angelicus have been found as far
north as west-central North Dakota, as far south as northern Durango
(Mexico), as far east as central Iowa, and as far west as southwestern California. This species ranges from below sea level in Death Valley,
California, to 12,000 ft. (3,658 m) on Mount Evans (timberline is at 11,700
ft.) in Colorado. The altitudinal range of A. angelicas is as astounding as
the latitudinal range of A. texanus. In Arizona males of A. angelicas have
been collected from April through November; in Kansas from June through
October; and in Mexico from June through October. (Map, Fig. 20.)
Albeit uncommon, A. angelicas does occur in the Great Plains, where
it is found together with A. texanus in the gallery forests of the tributaries
of the Missouri and Mississippi Rivers. This habitat is the "Northern
Floodplain Forest" of Popalas, Salix, and Ulmas (no. 98 in Appendix A).
While not as diverse as those of A. texanas, its habitats are numerous (39
of the 116 given by A. W. Kiichler 1964— cf. Appendix A).
Diagnosis. The male may be distinguished from many other species by
its toothed hind femora, the apical stylus on its gonostylus, and the lack of
a low medial ridge on the apical half of its last visible sternum; and from
A. texanus by the shorter apical stylus with swollen base and enlarged apex
on its gonostylus, and by the presence of a posterior stripe and absence of
an anterior stripe on its hind tibia. The female may be distinguished from
most other species by its bright metallic green to blue metasomal terga, its
almost hyaline wings, and by the presence of two distinct sizes of
mesoscutal punctures.
I have labeled females of A. angelicas as "Agapostemon texanas or A.
angelicas" because I am unable to separate them from A. texanas. Sand-
house (1936) claimed that these species differ in the punctation of the
mesoscutum and in the color of the pubescence. After having examined
many thousands of females of these species I am forced to conclude that
the variation within A. texanas nearly encompasses the range of variation
within A. angelicas, thus invalidating the characters used by Sandhouse.
It is probably true that the modes of A. angelicas characters differ from those
of A. texanas but this cannot be demonstrated without positively identified
females of both species. If one were able to positively identify A. angelicas
females, perhaps by means of rearing, it might be possible to utilize a
discriminant function to distinguish between females of the two species.
Owing to the occurrence of A. texanas males within the range of A.
angelicas males, I was unable to obtain females which were indisputably
A. angelicas. Even if one were to find an area where only A. angelicas
occurred, one could not be sure that differences between these females and
females of A. texanas were not simply geographic variations.
Variation. Basing the probable identity of females on the relative
abundance of males, it would seem that most females of A. angelicas have
a slightly shinier mesoscutum and whiter pubescence than most of those of
A. texanas. Like the males, the females of A. angelicas probably average slightly smaller than those of A. texanus, but the variation within each
species is far greater than any difference between them. In both males and
females of A. angelicas the metallic coloration is the same green as that of
the sympatric A. texanus. The most noticeably variable character of A.
angelicits is the amount of melanic pigmentation on the fore coxae of
males, which range in color from yellow to brown-black, but intra-locality
variation is far greater than inter-locality variation.
Description
male (Figs. 73-74, 164, 181)
Males as in A. texanus but only about 85% as large with whiter
pubescence on the mesonotum and metanotum; with dark stripe present
posteriorly and absent anteriorly on its hind tibia (Fig. 164) ; with apical
stylus on its gonostylus shorter, swollen basally, and larger apically; with
medial plate on its gonostylus smaller; and with basal stylus on its
gonostylus broader and blunt apically (Fig. 181).
female (Figs. 67-68)
As in A. texanus but always green and probably smaller with shinier
mesoscutum and whiter pubescence.
|
