Anthophora curta Provancher, 1895

Orr, Michael C., Koch, Jonathan B., Griswold, Terry L. & Pitts, James P., 2014, Taxonomic utility of niche models in validating species concepts: A case study in Anthophora (Heliophila) (Hymenoptera: Apidae), Zootaxa 3846 (3), pp. 411-429 : 419-420

Anthophora curta Provancher, 1895

Anthophora curta Provancher, 1895: 173 (lectotype: female, Los Angeles, California, USA; Les Collections de l'Université Laval, Pavillon Louis-Jacques-Casault, Ste Foy, Québec, Canada) (Prior Lectotype Designation ( Sheffield & Perron, 2013))

Anthophora curta var. melanops Cockerell, 1926: 84 (holotype: male, 2 miles east of Oracle , Arizona, USA; California Academy of Sciences , San Francisco, California, USA) (New Synonym)

Anthophora curta var. ensenadensis Cockerell, 1941: 349 (holotype: male, Ensenada , Baja California, México; California Academy of Sciences, San Francisco, California, USA)

Diagnosis. Males of Anthophora curta are easily separated from all Nearctic species, other than A. squammulosa , by the apically truncate medial projection on T7. In other species, there is either a sharp pygidial plate or a pair of submedial projections. In addition to the distinctions in the key, A. curta males differ from A. squammulosa in the thickness of the longitudinal clypeal maculation, which typically only equals a third or less of the height of the clypeus in A. curta , but usually about half that height in A. squammulosa . Anthophora curta also typically lacks a supraclypeal maculation, while it is present in most specimens of A. squammulosa . The male genitalia are also distinct ( Fig. 3b–e ). The gonostylus is more robust in A. curta overall, and the poorly scleritized digit near the end of the gonostylus is attached for half or less its length, while in A. squammulosa it is attached for more than half its length. There are also differences in overall structure and tips of S7 and S8 ( Fig. 3c–d ).

Females of A. curta are separated from other species of Nearctic Anthophora (Heliophila) , save for A. squammulosa , by the unique combination of the following characters: basal bands of black setae on the metasomal terga; the lack of strongly curved or bent setae on the galea; the supraclypeal maculation either negligible or more often absent; the near-flat distal edge of the basitibial plate; the distinct presence of appressed, branched setae on T5; the very narrowly transparent apical rim of T4; and the relatively flat clypeus, which does not appear fully halfcircular in ventral view. From A. squammulosa , it is distinguished using the couplet above. In addition, the supraclypeal maculation is typically absent or weak in A. curta , and generally strong and distinct in A. squammulosa , although rarely such maculations are absent.

Geographical and ecoregion distribution. The geographical range of this species is quite broad ( Fig. 2 ). Although it is difficult to identify absolute limits of distribution, the absence of this species in Utah, except on its southern border, despite extensive collection efforts throughout the state, is likely telling of its northern boundary there. Its northern limits to the east are likely farther south, in New Mexico rather than Colorado. More collections are necessary in northern California, Nevada, and Oregon to discern the northern limits of the distribution of A. curta in these three states, although it at least reaches southern Washington. It is highly unlikely that A. curta ranges farther east than Texas, but its limits within the state are unclear. This species ranges south throughout the Baja Peninsula and much of northern Mexico. There are too few collections to be certain of its southernmost limit in Mexico, although it currently appears largely restricted to the Sonoran and Chihuahuan Deserts. Corresponding to its large geographical range, A. curta also inhabits a wide variety of ecoregions, based on 541 unique locations. This species’ range spans a total of six WWF biomes encompassing 27 ecoregions. Two-thirds of all collection events (65%) are from 10 ecoregions in the Deserts & Xeric Shrublands biome. Anthophora curta is also present in the Mediterranean Forests Woodlands, & Scrub biome, with 19% of collection events spread across three ecoregions. The remaining four biomes are primarily forest and grassland, accounting for 16% of all collection events (Temperate Conifer Forests; Temperate Grasslands, Savannas, & Shrublands; Tropical & Subtropical Coniferous Forests; and Tropical & Subtropical Dry Broadleaf Forests).

Phenology. In the Mojave Desert, 73% of collection events took place in the spring and early summer (March through June). A similar trend exists in the adjacent Sonoran Desert, with 73% of collection events during the same spring period. Contrastingly, in the Chihuahuan Desert, 62% of all collection events occurred during August through October. Additional collections during spring in the Chihuahuan Desert and fall of the Sonoran Desert are necessary to confirm the apparent phenological differences for A. curta . The phenology of A. curta in the Mojave and Sonoran Deserts appears similar to that of the Mediterranean ecoregions of California from the Mediterranean Forests, Woodlands, and Scrub biome and the Temperature Grasslands, Savannas, and Shrublands biome, with 71% of collections events in these ecoregions during the same spring period. Despite the trend, A. curta has been collected as late as November in the Arizona Mountains forests, California montane chaparral and woodlands, Chihuahuan Desert, and Sonoran Desert ecoregions.

Floral hosts. Anthophora curta appears broadly polylectic due to the long list of plant associations: 61 plant genera from 17 families. Despite this, past authors have suggested that females use only Asteraceae pollen (Moldenke & Neff, 1974). Collated floral records support this (72% from Asteraceae ). The known floral hosts are as follows:

Amaranthaceae : Salsola sp. ; Asteraceae : Adenophyllum cooperi , Baccharis salicina , Bahia absinthifolia , Baileya multiradiata , B. pleniradiata , Bebbia juncea , B. juncea var. aspera , Bidens pilosa , Carduus tenuiflorus , Carthamus tinctorius , Centromadia pungens , Chaenactis glabriuscula , Chaetopappa ericoides , Chrysopsis sp. , Coreopsis sp. , Deinandra fasciculata , Dieteria canescens , Encelia californica , E. farinosa , E. frutescens , E. virginensis , Erigeron sp. , Gaillardia pinnatifida , G. pulchella , Grindelia sp. , Gutierrezia microcephala , G. sarothrae , Helianthus annuus , Hemizonia corymbosa ssp. macrocephala , Heterotheca subaxillaris ssp. latifolia , H. villosa , Hymenopappus filifolius , Hymenothrix wislizeni , Isocoma tenuisecta , Malacothrix sp. , Palafoxia arida , P. arida var. gigantea , Pectis papposa , Psilostrophe sp. , Symphyotrichum spathulatum , S. tenuifolium , Verbesina encelioides , Viguiera deltoidea ; Bignoniaceae : Chilopsis sp. ; Boraginaceae : Heliotropium sp. , Phacelia coerulea , P. distans , P. robusta ; Brassicaceae : Physaria sp. ; Cleomaceae : Cleomella sp. ; Convulvulaceae : Ipomoea sp. ; Fabaceae : Dalea lanata , D. lanata var. terminalis , D. leporina , Medicago sativa , Melilotus sp. , Parryella filifolia , Psoralidium lanceolatum , Psorothamnus emoryi , P. scoparius ; Loasaceae : Cevallia sinuata , Mentzelia multiflora ; Malvaceae : Melochia tomentosa , Sphaeralcea emoryi , S. grossulariifolia ; Nyctaginaceae : Allionia incarnata ; Papaveraceae : Argemone sp. ; Plantaginaceae : Penstemon centranthifolius ; Polemoniaceae : Eriastrum sp. , Gilia capitata , Ipomopsis congesta ssp. congesta ; Polygonaceae : Chorizanthe douglasii , Eriogonum gypsophilum , E. roseum , E. trichopes ; Rosaceae : Adenostoma sp. , Fallugia paradoxa ; Zygophyllaceae : Larrea sp.

Comments. Anthophora curta is more variable than most other species of the subgenus Heliophila , likely owing to its large distribution. This is only problematic in the females, given the ease of identification for the male of this species. In the female, the supraclypeus almost always lacks a light integumental marking. There are a few specimens in which there is a negligible dot of light integument centrally at the border with the clypeus. The extent of the apical bands of appressed setae of the metasomal terga is variable in both sexes, from narrow bands restricted to the apical rims to covering the majority of the terga. This character is more evident in females as the band variation is more constrained in males. The bands are generally narrower in California, while they are thicker eastward in eastern Arizona, New Mexico, and Texas. The synonyms A. curta var. melanops and A. curta var. ensenadensis were transferred to A. curta following examination of the types. Although A. curta var. ensenadensis was previously synonymized with A. curta , A. curta var. melanops and A. curta were synonymized with A. squammulosa at the same time ( Michener, 1951; Brooks, 1988). As such, this is a new synonymy for A. curta var. melanops .

Figures

FIGURE 2. Localities and environmental niche distributions modeling of Anthophora curta and A. squammulosa. Anthophora curta is symbolized by dark green circles and A. squammulosa by dark blue triangles. The areas with>0.30 habitat suitability index are shaded green for A. curta and blue for A. squammulosa, with darker areas indicating higher suitability. The species A. curta and A. squammulosa are seen to be disjunct in Sinaloa, Mexico.

FIGURE 3. The morphology of Anthophora curta and A. squammulosa, left and right respectively. a. The first submarginal cell of each lectotype. b. Dorsal view of the genital capsule. c. Sternite 7. d. Sternite 8. Wing images were taken at 100x magnification and genitalia images were taken at 150x magnification. Note that setae were removed from figures 3b-d to improve clarity of the structures.