Dianthidium dubium Schwarz, 1928
Dianthidium dubium dilectum Timberlake, 1948; Dianthidium consimile mccrackenae Timberlake, 1943; Dianthidium plenum convictorum Timberlake, 1943; Dianthidium dubium mccrackenae Timberlake, 1943; Dianthidium (Dianthidium) dubium dilectum Timberlake, 1948, valid subspecies; Dianthidium (Dianthidium) dubium mccrackenae Timberlake, 1943, valid subspecies
Life   Insecta   Hymenoptera   Apoidea   Megachilidae   Dianthidium
Subgenus: Dianthidium

http://www.discoverlife.org/nh/id/20q/Dianthidium_female.xml ---> https://www.discoverlife.org/nh/id/20q/Dianthidium_female.xml
Dianthidium dubium, female, T1, AA, mtg
© Kimberly Huntzinger, 2007 · 1
Dianthidium dubium, female, T1, AA, mtg

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Dianthidium dubium, female, T6, A, mtg
© Kimberly Huntzinger, 2007 · 1
Dianthidium dubium, female, T6, A, mtg
Dianthidium dubium, male, T1
© Kimberly Huntzinger, 2007 · 1
Dianthidium dubium, male, T1

Dianthidium dubium, male, T7
© Kimberly Huntzinger, 2007 · 1
Dianthidium dubium, male, T7
Dianthidium dubium, male, T1black
© Kimberly Huntzinger, 2007 · 1
Dianthidium dubium, male, T1black
Extracted from THE POLLEN-COLLECTING BEES OF THE ANTHIDIINI OF CALIFORNIA (Hymenoptera: Megachilidae) by Grigarick A., A. (1968).

The male of Dianthidium dubium has a prominent tridentate tergum VII (fig. 138) similar to that of pudicum, plenum, marshi of California and parkeri of the southwestern states. This character places it in the pudicum group of Timberlake (1943). The com¬bination of the shape of the narrow tip of the penis valve of the genitalia (fig. 140) and the rounded sternum VI (fig. 139) of the males separates it from the closest related species, plenum and pudicum. The females of these species are not as easily distinguished, but a combination of the curved and double cutting edge of the mandible of dubium and the presence of a longitudinal carina on tergum VI of dubium and plenum will separate them.

Dianthidium dubium dilectum
The markings of D. dubium dilectum are usually bright yellow and extensive on a black background; some specimens from Monterey County, however, are somewhat pale and show a reduction of maculations. The apex of the penis valve of dilectum is more pointed than that of the other two subspecies; and
the mandible of the female has a double cutting edge common to dubium dubium but not dubium mccrac-kenae. The distribution of dilectum is primarily montane, extending up the mountains of southern California and Coast Range as far north as Mt Diablo in Contra Costa County. It is possible that future collections may show it to extend southward into Baja Califor¬nia. The species is well represented in most collec¬tions; 148 males and 96 females have been recorded. A nest of a single cell of gravel and resin on a leaf (Tanbark Flat, Los Angeles Co., VI-23-52, CIS) was determined by P. H. Timberlake to belong to D. dubium dilectum. He also assigned a series of nests collected on exposed clay shales (upper Sulfur Creek, Santa Clara Co., IX-14-48, CIS) to the same sub¬species. The insects reared from these latter nests were reported by Hurd and Linsley (1950) as fol¬lows: Amobia (Pachyophthalmus) floridensis (Town-send), Chrysis (Chrysis) coerulans Fabricius, Sapyga nevadica Cresson, Stenodynerus cochisensis (Vie-reck), and Toxophora pellucida Coquillett. A sum¬mary of host plant visitations by dilectum shows eight families to be represented, with the majority occur¬ring in the families Compositae, Hydrophyllaceae, and Polygonaceae.

Dianthidium dubium dubium
D. dubium dubium is black with a color pattern varying from cream to yellow. It also shows reddish-brown bands on the metasomal terga of both sexes. These bands are adjacent to the impunctate marginal bands and readily separate it from the other two subspecies, dilectum and mccrackenae. D. dubium dubium is the more frequently collected subspecies of this species, and a total of 266 males and 118 females have been examined. It has a well-defined distribution that appears to be nearly limited to the slopes of the ranges bordering the Great Valley except in the north. Its southernmost limit on the west is San Francisco Bay and on the east, the Teha-chapi Mountains. Little is known of the biology of dubium dubium except that the nests are made of resin and gravel and are constructed externally on vegetation or rocks. This subspecies has been found on host plants in seven families with the collections being most numer¬ous on the Compositae, Labiatae, and Leguminosae.

Dianthidium dubium mccrackenae
D. dubium mccrackenae is black with pale yellow to cream markings. The penis valve shows very slight differences from that of the other subspecies, but it is readily distinguished as dubium. The mandi¬ble of the female of mccrackenae does not possess the double cutting edge present in the two other sub¬species. The single cutting edge of mccrackenae may not be as curved (in profile) as in dubium and dilec-tum and has been confused with plenum, which has a straight cutting edge. The female does agree with dubium in other respects. The distribution of mccrac&enae is limited to the east side of the Sierra Nevada in Inyo and Mono counties. This subspecies is known from the collec¬tions of 17 males and 15 females from five localities.

Scientific source:

Supported by

Hosts · map
FamilyScientific name @ source (records)
Asteraceae  Achillea millefolium @ BBSL__GRIG (1); BBSL__BERK (1)

Centromadia fitchii @ UCRC_ENT (1)

Corethrogyne @ UCRC_ENT (1)

Eclipta prostrata @ UCRC_ENT (4)

Encelia sp @ BBSL__KWC (2)

Ericameria arborescens @ UCRC_ENT (2)

Stephanomeria cichoriacea @ UCRC_ENT (4)
Boraginaceae  Eriodictyon crassifolium @ UCRC_ENT (4)

Eriodictyon trichocalyx @ UCRC_ENT (5)

Nama parryi @ UCRC_ENT (1)

Phacelia ramosissima @ UCRC_ENT (3)
Convolvulaceae  Calystegia sp @ BBSL (2)

Ipomoea sp @ BBSL (1)
Fabaceae  Acmispon glaber @ UCRC_ENT (2)

Lotus heermannii @ BBSL__KWC (2)

Lotus nevadensis @ UCRC_ENT (1)

Lotus purshianus @ UCRC_ENT (1)

Lotus sp @ BBSL__KWC (1); BBSL__PUB (2)

Trifolium @ UCRC_ENT (1)
Hydrophyllaceae  Eriodictyon sp @ BBSL (2)

Eriodictyon trichocalyx @ BBSL (1)

Phacelia sp @ BBSL__KWC (3); BBSL (6)
Lamiaceae  Salvia sp @ BBSL (1)

Stachys ajugoides @ UCRC_ENT (1)

Stachys albens @ UCRC_ENT (6)

Trichostema lanceolatum @ UCRC_ENT (3)
Liliaceae  Zigadenus sp @ BBSL (1)
Lythraceae  Lythrum californicum @ UCRC_ENT (1)
Polygonaceae  Eriogonum fasciculatum @ UCRC_ENT (3)

Eriogonum sp @ BBSL (1)
Scrophulariaceae  Penstemon centranthifolius @ BBSL__KWC (1)

Penstemon sp @ BBSL__PUB (1)
_  Withheld @ BBSL__PINN (9); BBSL (217); BBSL__YOSE (67)

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Updated: 2019-02-17 14:02:39 gmt
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