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Andrena mojavensis Linsley & MacSwain, 1955
Andrena (Melandrena) mojavensis Linsley and MacSwain, 1955

Life   Insecta   Hymenoptera   Apoidea   Andrenidae   Andrena
Subgenus: Onagrandrena




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Overview
Text used courtesy of the Illinois Natural History Survey from: LaBerge, W. E., Thorp, R. W., 2005. A revision of the bees of the genus Andrena of the Western Hemisphere. Part XIV. Subgenus Onagrandrena. Illinois Natural History Survey Bulletin 37: 1-63.

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Andrena mojavensis is a large bee closely related to rubrotincta. The female of mojavensis has the mesoscutum and scutellum shiny. The male of mojavensis also has a shiny mesoscutum and scutellum and has a distinct subapical mandibular tooth.

FEMALE: MEASUREMENTS AND RATIOS. N = 20; length, 13-14 mm; width, 3-4 mm; WL, M = 4.50 0.081 mm; FL/FW, M = 1.01 0.005; FOVL/FOVW, M = 2.96 0.041.

DIAGNOSIS. Vestiture dark brown to black; wing membranes hyaline, veins dark reddish brown to dark brown; metasomal terga piceous, not metallic. Galeae as in oenotherae; labral process and vertex as in rubrotincta. Clypeus sculptured as in rubrotincta. Vertex and ocelli as in rubrotincta. Pronotum with humeral angle and lateral ridge. Mesoscutum and scutellum punctate as in rubrotincta but surfaces shiny, shagreening delicate and largely peripheral, if present. Propodeum and mesepisterna sculptured as in rubrotincta. Terga 2-4 with apical areas sculptured as in rubrotincta but apical impunctate rim broader, often equal to half of apical area and punctures smaller and sparser; basal areas with punctures sparse and minute, separated mostly by three to five puncture widths; surfaces shiny. Thoracic hairs and pollen-collecting hairs as in rubrotincta.

MALE: MEASUREMENTS AND RATIOS. N = 20; length, 9-11 mm; width, 2-3 mm; WL, M = 3.85 0.279 mm; FL/FW, M = 1.00 0.004; FS1/FS2, M = 1.24 0.016.

DIAGNOSIS. Vestiture pale, yellowish or ochraceous, darker on face and thoracic dorsum, usually brown on vertex and along inner margins of eyes, occasionally some brown hairs on gena near outer margin of eye; wing membranes hyaline, veins reddish brown to dark brown; metasomal terga brown to black but apical areas hyaline, yellow to reddish brown. Galea as in oenotherae; labral process as in rubrotincta; mandibles decussate, with more or less distinct subapical tooth; clypeus, vertex, genal area and flagellar segments as in male of rubrotincta. Pronotum as in female. Mesoscutum and scutellum sculptured much as in female, surfaces shiny; propodeum and mesepisterna sculptured as in female. Terga 2-5 sculptured as in female terga 2-4 but apical areas with punctures minute and often barely visible. Metasomal tergum 2 with basal area hairs short, as in rubrotincta male; hind tibiae with hairs as in rubrotincta. Sterna 7 and 8 similar to those of rubrotincta but sternum 7 with denser hairs and sternum 8 with smaller apical lobes and dense vestiture (Figs. 61 and 62).

TYPE MATERIAL. The holotype female (CAS No. 6,704) of Andrena (O.) mojavensis was collected from Short Canyon, 6.5 mi. NW of Inyokern, Kern Co., California, April 13, 1954 from flowers of Camissonia campestris (as Oenothera dentata var. johnstonii) by James M. Linsley.

DISTRIBUTION. Andrena mojavensis is known to occur only in northeastern Kern County in California (Fig. 6). It has been collected from March 19 through April 26. In addition to the type material, a total of 470 females and 43 males were examined from localities listed below.

CALIFORNIA. KERN CO.: Brown (3 mi. W in Sand Canyon); Jawbone Canyon; Short Canyon (6.5 mi. NW of Inyokern); Walker Pass (1 mi. W).

NEST BIOLOGY. The following notes are from Linsley et al. (1964). Burrows of A. mojavensis are constructed in the coarse granitic sand of the upper slopes of Short Canyon and in the finer sand of the upper washes near these slopes. Those on the upper slopes penetrated to an underlying layer of decomposing granite at depths of 60 to 75 cm; in the finer sand of the washes and alluvial fans the only one found was 60 cm deep. They had vertical entrances and diameters averaging almost 8 mm. All were scattered over a wide area with no tendency toward aggregations."

FLORAL RECORDS. This species is an oligolege of species of Camissonia (primarily C. kernensis) and has been collected from flowers of plants listed below (including records I rom the literature).

Camissonia campestris, C. claviformis claviformis, C. kernensis, Coreopsis bigelovii, Cryptantha sp., Dithyrea californica.

Identification
A. (M.) mojavensis is the largest and most robust of the relatively clear-winged Melandrena. It is related to A. (M.) rubrotincta Linsley but it differs in the long pubescence of the metasoma, most of which is plumose, the smooth interpuncture areas of the posterior discal region of the mesoscutum, the distinct, elevated, impunctate median line of the clypeus, and the totally black pubescence (in rubrotincta the pubescence is wholly or largely brownish-black).


Female. Integument black, metasoma faintly tinted with reddish in a few paratypes; hairs black. Head with clypeus convex, shining, coarsely and subcontiguously punctured with a narrow, elevated, impunctate median line; labrum with process subtriangular, apex not produced, moderately elevated, elevation an inverted triangle; antennae with first flagellar segment about as long as second and third combined. Mesosoma with mesoscutum shining, finely and moderately densely punctured, punctures mostly one or two puncture widths apart, interspaces finely reticulate anteriorly and laterally, smooth postmedially; mesoscutellum with larger and slightly less dense punctures than mesoscutum; mesopleura a little more densely punctured than mesoscutum; propodeum finely granulate, punctate, basal enclosure well defined, surface very finely, irregularly rugulose; wings subhyaline, tinted with blackish; legs with scopa of posterior tibiae long and dense. Metasoma shining, clothed with numerous moderately long erect black hairs, hairs on posterior portion of second tergum simple, on anterior portion distinctly plumose, first four metasomal terga with an impunctate apical margin, which at middle occupies almost one-half of posterior depression, pubescence longer and denser toward lateral margin giving sinuous appearance to metasomal margins in dorsal aspect. Length approximately 14mm., anterior wing 10 mm.

Names
Scientific source:
References
Andrena (Melandrena) mojavensis Linsley and MacSwain, 1955, Pan-Pacific Ent., 31: 165, 171-172; Linsley, MacSwain, and Smith, 1955, Pan-Pacific Ent., 31: 173, 174, 176, 178, 179-181, 182, 183.

Andrena (Onagrandrena) mojavensis: Linsley and MacSwain, 1956, Pan-Pacific Ent., 32: 112; Linsley, MacSwain, and Raven, 1964, Univ. California Publ. Ent., 33: 65-67; Davis and LaBerge, 1975, Illinois Nat. Hist. Survey, Biol. Notes, No. 95, p.10.

Hosts · map
FamilyScientific name @ source (records)
Asteraceae  Baccharis @ BMEC_ENT (1)
Onagraceae  Camissonia claviformis @ BBSL (1)

Oenothera sp @ BBSL (1)

Oenothera @ BMEC_ENT (1)

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