Extracted from THE POLLEN-COLLECTING BEES OF THE ANTHIDIINI OF CALIFORNIA (Hymenoptera: Megachilidae) by Grigarick A., A. (1968). |
Dianthidium parvum exhibits a number of morphological similarities to D. subparvum. The males are separated by the shape of tergum VII (fig. 153) in which the median lobe of parvum is narrower than that of subparvum (fig. 156). A number of differences are also present on the penis valve of the genitalia of these species (figs. 155, 158). The females of these species are not easily separated. It may be necessary to clear pollen from the scopa of sternum VI (fig. 188) to view the apical margin and surface
of the sternum. The posterior half of the ventral surŽface of this sternum is slightly convex on parvum whereas it is flat or slightly concave on subparvum.
Dianthidium parvum parvum
D. parvum parvum was described from a speciŽmen having pale yellow markings and is designated in this paper to include all populations with color varying from pale yellow to nearly white. About three-fourths of the specimens of this species have some form of reddish markings. The most common of these markings occur on the apical tergal margins, but the red color may become quite extensive and include the usual black area of the legs and meta-somal terga. The reddish background color occurs in association with the other color markings of yellow to white but is more extensive on the lighter speciŽmens and the most frequently observed on the males. The extent of the pale yellow to white pattern of p. parvum also shows considerable variation.
Seven males and three females of p. parvum have been observed from collections in California east of the Sierra Nevada and in the Colorado Desert. The biology of this sub-species is unknown. The few records of plant visitations are primarily from the Compositae.
Dianthidium parvum schwarzi
D. parvum schwarzi is characterized by full, bright-yellow maculations. The metasomal bands are usually wide and without emarginations, but the width of these bands is somewhat variable. The redŽdish markings discussed under p. parvum are also present on specimens of p. schwarzi but not as freŽquently. Representatives of both subspecies have been collected at Anza, Riverside Co., California.
D. parvum schwarzi is known from 92 males and 61 females collected mainly from the Peninsular and Transverse ranges of southern California, but it is also found in the foothills of the south coast range and in the San Joaquin Valley. The distribution and color pattern of parvum show a number of similarities to plutyurum. Plant visitations are recorded in 14 genera belonging to five families with 10 of the genera from the Compositae.
Updated: 2021-05-14 02:16:46 gmt