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Andrena rudbeckiae Robertson, 1891
Pterandrena rudbeckiae (Robertson, 1891)

Life   Insecta   Hymenoptera   Apoidea   Andrenidae   Andrena
Subgenus: Callandrena_sensu_lato

Andrena rudbeckiae, -male, -face 2012-06-12-14.22.37
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Andrena rudbeckiae, -male, -face 2012-06-12-14.22.37

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Andrena rudbeckiae, -male, -back 2012-06-12-14.14.55
© Copyright source/photographer · 9
Andrena rudbeckiae, -male, -back 2012-06-12-14.14.55
Andrena rudbeckiae, -male, -face 2012-06-12-14.22.37
© Copyright source/photographer · 9
Andrena rudbeckiae, -male, -face 2012-06-12-14.22.37

Andrena rudbeckiae, -male, -side 2012-06-12-14.30.05
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Andrena rudbeckiae, -male, -side 2012-06-12-14.30.05
Andrena rudbeckiae, Barcode of Life Data System
Barcode of Life Data Systems · 1
Andrena rudbeckiae, Barcode of Life Data System

Andrena rudbeckiae, male, face
© Rebekah Andrus Nelson · 1
Andrena rudbeckiae, male, face
Andrena rudbeckiae, female, face
© Copyright source/photographer · 1
Andrena rudbeckiae, female, face

Andrena rudbeckiae, male, sternal plates 7 and 8
© Copyright source/photographer · 1
Andrena rudbeckiae, male, sternal plates 7 and 8
Reprinted with permission of the University of Nebraska State Museum from:
LaBerge, W. E. 1967. A revision of the bees of the genus Andrena of the Western Hemisphere. Part I. Callandrena (Hymenoptera: Andrenidae). Bulletin of the University of Nebraska State Museum 7: 1-316.

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This is a large, relatively poorly known species occurring throughout, much of eastern United States. It is related closely to A. melliventris. Both sexes of rudbeckiae differ from melliventris by lacking the tendency toward red integument, the wing membranes being moderately infumate, the vestiture being largely white, and the face above the antennal fossae being punctate, not rugulose. The females lack yellow on the clypeus or this is reduced to a small subapical, ill-formed macula.

FEMALE. MEASUREMENTS AND RATIOS. N = 20; length, 13.0-15.0 mm; width, 4.0-5.5 mm; wing length, M = 4.85 0.231 mm; FL/FW, M = 1.04 0.003; FOVL/FOVW, M = 2.68 0.059.

INTEGUMENTAL COLOR. Black except as follows: clypeus often with small subapical median yellow macula of variable size but never more than one-tenth area of clypeus; flagellar segments 4-10 reddish beneath; tegula occasionally rufescent; wing membranes moderately infumate, brown; veins dark brown to reddish-brown; terga with apical areas hyaline, yellowish towards apices and rufescent basad; sterna broadly hyaline apically, rufescent basally in part; distitarsi dark rufescent; tibial spurs yellow.

STRUCTURE. Scape distinctly longer than flagellar segments 1-3; flagellar segments as in melliventris. Eyes about three times as long as broad, inner margins converging slightly towards mandibles. Malar space, mandibles and subgenal coronet as in melliventris. Galea strongly curved down at sides, dorsal surface with outer two-fifths thickened, sclerotized, strongly punctate, weakly shagreened, moderately shiny, inner three-fifths almost membranous, hyaline but brownish, dulled by fine tessellation. Maxillary palpus short, not exceeding tip of galea, segments in ratio of about 1.5:1.6:1.2:1.0:0.8:1.0. Labral palpus short, flattened, first segment slightly curved, not much broader apically than basally, segments in ratio of about 4.0:1.0:0.6:0.8. Labral process as in melliventris. Clypeus evenly rounded, protruding beyond lower ends of eyes by no more than one-third its median length or less, with moderate-sized, round punctures separated by one-half to one puncture width except sparser along narrow midline, surface moderately dulled by regular reticular shagreening. Supraclypeal area as in melliventris. Genal area equals width of eye in profile or slightly less, sculptured as in melliventris. Vertex as in melliventris. Face above antennal fossae dulled by crowded punctures and tessellation, without longitudinal rugulae. Facial fovea as in melliventris but separated from lateral ocellus by almost one ocellar diameter.

Pronotum normal, with small punctures above separated by puncture width or less and scattered or absent laterally, surface reticularly shagreened above, tessellate laterally. Mesoscutum, scutellum, and metanotum with crowded, moderate-sized, shallow punctures separated by mere ridges, surface opaque, shagreened. Propodeum as in melliventris but enclosure with basal third or so roughened by weak, irregular, anastomizing rugulae masked by the coarse tessellation. Mesepisternum and metepisternum as in melliventris. Wing venation as in melliventris. Middle basitarsus expanded as in melliventris. Tibial spurs and claws normal.

Metasomal terga 1-4 with apical area punctures of same size as basal area punctures, separated mostly by one-half to one punctures width, becoming sparser in basal halves of terga, surfaces opaque, finely tessellate. Pygidial plate as in melliventris. Sterna 2-5 with narrow apical area impunctate, apical halves of basal areas with coarse punctures separated mostly by two to four puncture widths, largely impunctate in basal halves, surfaces moderately dulled by coarse reticular shagreening.

VESTITURE. Head white, on vertex often ochraceous to pale ochraceous. Thorax white below to pale ochraceous or white above, dorsum of thorax with hairs short, erect, plumose, but not mat-like nor obscuring surfaces appreciably. Terga 1-4 with long, weak, plumose, apical hairs forming weak fasciae often more or less interrupted medially, basally with abundant, long, erect, barbed hairs. Terga 5-6 with long hairs yellowish medially to white laterally. Sterna 2-5 with long, erect to suberect, white to ochraceous, sparse hairs, with a simple row of longer hairs along base of hyaline apical area. Propodeal corbicula as in melliventris. Trochanteral flocculus complete, sparse. Tibial scopal hairs of moderate length, highly plumose throughout. Leg hairs white except inner surfaces tarsi yellow and middle and hind tibiae with outer surfaces ochraceous at least in part.

MALE. MEASUREMENTS AND RATIOS. N = 16; length, 11.0-13.0 mm; width, 3.5-4.5 mm; wing length, M = 4.48 0.058 mm; FL/FW, M = 1.08 0.009; FS1/FS2, M = 2.44 0.052.

INTEGUMENTAL COLOR. Black except as follows: clypeus yellow except apical margin and triangular maculae below and mesad of tentorial pits brown to reddish-brown; parocular areas yellow to level of tentorial pits, occasionally yellow area smaller, rarely larger; flagellum slightly rufescent below, especially segments 4-11; tegulae testaceous, reddish-brown, or piceous; wing membranes moderately infumate, brown, veins dark brown to reddish-brown; terga 1-5 as in female but terga 1 and 2 occasionally slightly rufescent basally; sterna as in female; legs as in female.

STRUCTURE. Antennae as in melliventris. Eyes distinctly less than three limes as long as broad, converging towards mandibles. Malar space, galea, mandible and labral process as in female. Maxillary palpus as in female but segments in ratio of about 1.1:1.4:1.0:0.9:0.6:0.9. Labial palpus as in female but ratio of about 2.6:1.0:0.4:0.9. Clypeus as in female but punctures slightly coarser and median longitudinal line of sparse punctures less evident. Supraclypeal area as in female. Genal area slightly broader than eye in profile, sculptured as in female but shinier. Vertex and face above antennal fossae as in female but vertex with punctures more abundant laterally. Pronotum as in female. Dorsum of thorax as in female but scutellum and posteromedian area of mesoscutum with punctures more discrete, separated by about one-halt a puncture width, surfaces moderately shiny, shagreening fine. Propodeum as in female but lateral surface with more abundant punctures and dulled by regular, coarse tessellation. Episternal surfaces as in female but mesepisternum with punctures slightly more abundant. Wings as in female.

Metasomal terga as in female but terga 5 and 6 similar to 4 but with punctures more abundant and punctures everywhere coarser, although not spaced closer. Sterna 2-5 as in female but punctures more crowded near apical areas. Sternum 6 with broad, shallow, almost V-shaped, apical emargination and apex moderately reflexed especially laterally.

Genital capsule and sterna 7 and 8 similar to those of melliventris, note the shorter neck region of sternum 7.

VESTITURE. Generally white. Tergal banding as in female but weaker. Sterna 2-5 with apical bands of erect hairs more evident than in female and hairs generally ochraceous. Legs white except tarsi and tibiae ochraceous, inner surfaces distitarsi yellow.

TYPE MATERIAL. Lectotype male and lectoallotype female, here designated, plus ten paratype females, were taken by Charles Robertson, June 12 and 23, 1886, Carlinville, Illinois, on flowers of Rudbeckia hirta (INHS). The lectotype male was taken in copula with the lectoallotype female.

GEOGRAPHICAL VARIATION. Specimens of A. rudbeckiae from Texas, both male and female, differ from those from other regions by having the wings somewhat less infumate. The female Texas specimens average slightly smaller in size and have the vestiture generally paler, although one female from Bexar County, Texas, is as large or larger than average and has more ochraceous vestiture than usual. We do not believe that these differences justify recognizing a subspecies at this time, especially in view of the paucity of material.

DISTRIBUTION. This species is known from Minnesota south to Texas and from Colorado east to North Carolina (Fig. 7). It has been taken from May 5th through August 13th, but chiefly in June and early July. A total of 88 females and 53 males have been examined in addition to the type material. Localities are listed below for specimens examined and from published records.

COLORADO: Holyoke. ILLINOIS: Carlinville; Galena Junction; McHenry; Urbana. IOWA: Ames (4 miles S.); Bremer Co.; Dickinson Co.; Floyd Co.; Lyon Co. KANSAS: Baldwin; Baxter Springs (5 miles S.); Bourbon; Cherokee Co.; Coffeyville; Ellis Co.; Lawrence; Oswego; Parsons; Thomas Co. MICHIGAN: Gull Lake Biological Station, Kalamazoo Co. MINNESOTA: Wabasha (5 miles W.). MISSOURI: Colombia; Kirkwood; Smithton; Pettis Co.; Wheatland. NEBRASKA: Imperial (9 miles S.); Pine Ridge; Roscoe (4 miles E.), NORTH CAROLINA: Marion; Raleigh. OKLAHOMA: Blue; Hugo; Nowata (5 miles S.E.); Pawhuska, Pawnee Co. TEXAS: Brazos Co.; Camp Bullis, Bexar Co.; Cypress Mills, Blanco Co.; Fedor, Lee Co.; Goliad (10 miles E.); Kerr Co.: New Braunfels; Victoria; Waskom; Weser. WISCONSIN: Maiden Rock, Pierce Co.; Prescott, Pierce Co.

Flower Records. A. rudbeckiae is an oligolege of the Compositae and seems to prefer the genera Ratibida and Rudbeckia as sources of pollen. More than halt of the collections (11 out of 15 with floral data) available to the author were made from these two genera of plants. Robertson (1925, 1926) regarded this species as an oligolege of the genus Rudbeckia, as the specific name suggests. This species has been collected from flowers of the plants listed below (including published records).

Centaurea americana, Chrysopsis sp., Echinacea angustifolia, Gaillardia pulchella, Ratibida sp., R. coliianncris, R. columnifera, R. pinnata, Rudbeckia sp., R. hirta, R. lanceolata, R. triloba, Verbesina helianthioides.

Reprinted with permission from: Mitchell, T.B. 1960. Bees of the Eastern United States. North Carolina Agricultural Experiment Station Technical Bulletin No. 141.

FEMALE. Length 13 mm.; clypeus broadly convex, projecting slightly less than one-half below suborbital line, somewhat shining medially where the punctures are close, deep and well separated, becoming dull, with rather fine and quite dense punctures laterally, without a distinct median impunctate line; facial foveae rather broad above, filling most of space between eyes and ocelli, covered with ochraceous tomentum; space between margin of vertex and lateral ocelli only slightly less than distance between ocelli; cheeks broader than eyes, rounded posteriorly, deeply, finely and quite closely punctate; malar space distinct but quite short; basal segment of flagellum slightly longer than 2nd and 3rd combined; process of labrum broadly subtriangular, apex quite deeply emarginate; mandibles with a very slight, subbasal, inferior dilation; pubescence of head, thorax and legs entirely ochraceous, rather short and dense; thoracic integument dull, densely tessellate, punctures of scutum very fine, shallow and obscure, hardly visible, those on scutellum more deep and distinct, rather close, surface somewhat shining; pleura with shallow and obscure, well separated, barely visible punctures anteriorly; dorsal area of propodeum oblique, triangle densely tessellate, very narrowly substriate along basal margin; propodeal corbicula ochraceous, rather thin, poorly developed, without a distinct anterior fringe; trochanteral floccus rather well developed, whitish-ochraceous; hind tibiae broadened apically, apex not quite twice width of the rather broad basitarsi, scopa rather dense, hairs rather short, finely plumose, entirely ochraceous; front basitarsi nearly as broad as their tibiae, the mid basitarsi very broad, length less than three times the breadth and fully as broad as the tibiae; wings quite strongly and uniformly infuscated, 2nd submarginal cell somewhat shorter than 3rd, receiving 1st recurrent near middle; abdominal terga dull, densely tessellate, punctures very shallow but rather coarse. sparse on discs basally. becoming rather; lose toward depressed apical margins, these quite deep, rather narrow, becoming clear hyaline along rims, discal pubescence short, thin, erect, entirely pale, apical fasciae on terga 1-4 evident but thin and rather poorly developed, tergum 5 with an ochraceous apical fimbria.

MALE. Length 11 mm.; face with a pair of small yellow maculae adjacent to clypeal margin below; clypeus broadly convex, projecting about one-third below suborbital line, yellow, except for two small dark spots and the blackish apical rim, rather densely short pubescent, but surface visible, somewhat shining, closely and finely punctate; space between margin of vertex and lateral ocelli only slightly less than distance between ocelli; cheeks broader than eyes, rounded posteriorly, somewhat shining, closely and finely punctate; malar space distinct but very short; basal segment of flagellum subequal to 2nd and 3rd combined; process of labrum short, quite broad, rather broadly truncate and subemarginate apically; mandibles rather short, with a distinct, inner subapical tooth, overlapping about one-third; pubescence of head, thorax and legs entirely pale, tinged with ochraceous on vertex and dorsum of thorax, rather strongly ochraceous on the more apical leg segments; thoracic integument dull, densely tessellate, punctures of scutum fine and very obscure, quite close, surface uniformly dull, those on scutellum close and distinct, surface somewhat more shining; pleura with shallow, obscure but rather close punctures anteriorly; dorsal area of propodeum oblique, triangle densely tessellate, obscurely and very narrowly substriate along basal margin; basitarsi rather robust, but distinctly narrower than their respective tibiae; wings uniformly brownish-hyaline, 2nd submarginal cell considerably shorter than 3rd, receiving 1st recurrent near middle; abdominal terga dull, densely tessellate, punctures shallow but rather coarse, well separated on discs basally, but becoming quite close toward apical depressed areas which are quite abrupt, entirely reddish-hyaline, discal pubescence quite long and copious, erect, entirely pale, forming loose and thin, whitish, apical fasciae on terga 1-5; sternum 8 rather robust, gradually narrowed from base to the somewhat broadened and truncate apex, very slightly protuberant beneath near center, well covered with rather long, pale pubescence beneath; penis valves slender apically, gradually broadened toward base, quite deeply grooved on each side, gonocoxites broadly dilated apically, apical lobe considerably longer than broad, gonocoxal lobes quite narrowly and acutely produced, tips very narrowly rounded.

DISTRIBUTION. Illinois to Kansas, south to Texas and North Carolina, June to August.

FLOWER RECORDS. Collected on Rudbeckia lanceolata in North Carolina. Recorded by Robertson (1929) on Rudbeckia hirta, R. triloba and on Coreopsis palmata, Lepachys pinnata and Verbesina helianthoides.

Scientific source:

Andrena rudbeckiae Robertson, 1891, Transactions of the American Entomological Society, vol. 18, p. 56; Cockerell, 1899, Entomological News, vol. 10, p. 255; Graenicher, 1911, Bulletin of the Public Museum of Milwaukee, vol. 1, pp. 226, 286.

Pterandrena rudbeckiae: Robertson, 1902, Transactions of the American Entomological Society, vol. 28, p. 194; 1914, Entomological News, vol. 25, p. 70; 1925, Ecology, vol. 6, p. 426; 1926, Ecology, vol. 7, p. 379; 1929, Flowers and Insects, p. 10; Pearson, 1933, Ecology Monographs, vol. 3, p. 384.

Andrena (Pterandrena) rudbeckiae: Lanham, 1949, University of California Publications in Entomology, vol. 8, p. 200; Mitchell, 1960, North Carolina State Agricultural Experiment Station Technical Bulletin of the No. 141, pp. 149-151.

Supported by

Hosts · map
FamilyScientific name @ source (records)
Asteraceae  Heliopsis helianthoides @ B_AW (1)

Ratibida columnifera @ AMNH_BEE (1); B_AW (1)

Ratibida pinnata @ B_AW (3)

Rudbeckia hirta @ BBSL (2); B_AW (8); BBSL__LSAM (2)
Lamiaceae  Monarda fistulosa @ B_AW (1)

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Updated: 2023-09-29 17:36:47 gmt
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