Nomada bethunei Cockerell

Droege, Sam, Rightmyer, Molly G., Sheffield, Cory S. & Brady, Seán G., 2010, New synonymies in the bee genus Nomada from North America (Hymenoptera: Apidae), Zootaxa 2661, pp. 1-32 : 6-7

Nomada bethunei Cockerell

Figures 4–6, 15, 16 , 21

Nomada bethunei Cockerell 1903: 607 [Holotype: U.S. National Museum of Natural History, ♂; label data: “Cana [ Canada] 2174 [ Baker collection No. 2,174]// N. M. 3// TYPE No. 13159 U.S. N.M. [red label]// Nomada bethunei Ckll TYPE // USNM ENT 0 0 533894 [yellow barcode label]”].

Nomada (Xanthidium) pseudops Cockerell 1905: 189 –190 [Holotype: University of Colorado, Boulder, Ψ, label data: “Collected by S. Graenicher, [ USA] Milwaukee, Wis [Wisconsin], 6-8-03 [8 June 1903]// Holotype [red label]// Type 1. pseudops, Ckll // FROM COLLS UNIV OF COLO MUSEUM [blue label]// UCMC 0 0 0 0 107 [barcode label]”] new synonymy.

Diagnosis. Nomada bethunei has more prominent yellow and red integument than in many other species, particularly in the males ( Figs. 5, 6). Females are differentiated by the following combination of characters: face with integument color pattern grading from red near the vertex to orange-yellow near the mandible except for restricted black regions immediately surrounding the ocelli and between the antennal bases ( Fig. 4); preoccipital margin carinate on gena; mesoscutum with integument more than fifty percent red ( Fig. 5); posterior surface of propodeum midlaterally with large yellow maculation extending from ventral margin dorsally, either joining or not joining yellow maculation laterally on propodeal triangle (Fig. 21); hind tibia with four to eight short, thick, red, spine-like hairs that line the outer apical margin (these hairs often difficult to detect as they are shorter than the surrounding white hairs) ( Fig. 15 ); for specimens from the eastern part of the species’ distribution, the scutellum is red; the propodeal triangle is red with two round, yellow, lateral spots; and T2–T3 have transverse yellow maculations that are clearly medially-interrupted (specimens from the midwestern part of the species’ distribution with the scutellum yellow to orange, propodeal triangle with a lateral, quadrate, yellow maculation; and T2–T3 each with a solid, or rarely medially-interrupted, transverse maculation). Nomada bethunei is similar to N. augustiana , but can be differentiated from that species by the long, white, spine-like hairs on the outer apical margin of the hind tibia that clearly extend beyond the surrounding white hairs in N. augustiana ( Fig. 13 ). It is also similar to N. obliterata , but in that species there are only two submarginal cells on the forewing (rarely three, but in such cases, usually only one wing with three cells), and the hind tibia has usually three to four, relatively long, stout setae on the outer apical margin, these setae clearly bent posteriorly at their apical tips. Finally, N. armatella differs from N. bethunei by the presence of long, thin, white or transparent, stout, spine-like hairs on the outer apical margin of the hind tibia. Males of N. bethunei are among the few species of Nomada , of this sex, with greater than fifty percent red on the integument of the mesoscutum ( Fig. 6). Males are differentiated from N. articulata Smith and N. australis Mitchell by the lack of a small spine present on the posterior surface (when the antennae is projected dorsally) of the third flagellar segment in both those species; it is separated from all other species by the combination of extensive red integument on the mesoscutum and by the very short, spine-like hairs on the outer apical margin of the hind tibia: these hairs are white, clear, or pinkish and are difficult to see among the surrounding white hairs in this region ( Fig. 16 ) (often most visible when the specimen is inverted and the tibia is examined from underneath). Other species have stout spine-like hairs on the hind tibia that project beyond or are level with the surrounding white hairs in this area.

Molecular results. We obtained DNA barcoding data from four female specimens and one male specimen ( Table 1) that were morphologically similar to the two holotypes representing each gender. The sequences from all five specimens were completely identical (0% sequence divergence), even though they were sampled from several different localities (e.g., Ontario, Connecticut, New York), further supporting the synonymy of N. pseudops with N. bethunei .

Variation. Both males and females have greater amounts of yellow on the propodeum and metasoma in the Midwest than the East. The metasomal terga have transverse yellow maculations that vary from mediallyinterrupted to complete.

Distribution. Nomada pseudops , as previously understood, is an uncommon, northern species, flying in late spring (most specimens from late May to Early June). Mitchell lists Michigan and Ohio for N. bethunei and Wisconsin to Massachusetts under N. pseudops . Based on Mitchell’s records and personal observation, N. bethunei ranges from Virginia north to Massachusetts, west to Kansas and Ontario.

Material examined. We examined 23 specimens from ON, CT, NY, NJ, VA, MI, PA, IA, WI, KS, and IL (Appendix).

Comments. Nomada bethunei , while uncommon, appears to be regularly collected throughout its range.

Figures

FIGURES 13 – 18. Outer apical surface of hind tibia. Figs. 13, 14. Nomada augustiana. Fig. 13. Female holotype. Fig. 14. Male. Figs. 15, 16. Nomada bethunei. Fig. 15 Female. Fig. 16. Male. Figs. 17, 18. Nomada fragariae. Fig. 17. Female. Fig. 18. Male.