Dieunomia heteropoda heteropoda (Say)

Gibbs, Jason, Dumesh, Sheila & Griswold, Terry L., 2014, Bees of the genera Dufourea and Dieunomia of Michigan (Hymenoptera: Apoidea: Halictidae), with a key to the Dufourea of eastern North America, Journal of Melittology 2014 (29), pp. 1-15 : 10-12

Dieunomia heteropoda heteropoda (Say)

( Figs. 21–22 )

Nomia (?) heteropoda Say, 1824: 349 (♂).

Andrena valida Say, 1837: 393 (♀).

Nomia heteropoda valida (Say) : Cockerell, 1934: 4 (synonymy).

Nomia heteropoda validescens Blair, 1935: 206 (♂).

Nomia heteropoda subvalida Blair, 1935:206 (♀).

Nomia (Dieunomia) heteropoda heteropoda (Say) : Michener, 1951: 1128 (catalog); Mitchell, 1960: 507 (♀ ♂ redescription); Hurd, 1979: 1945 (catalog); Moure & Hurd, 1987: 40 (catalog).

This is a highly distinctive species, which is unlikely to be mistaken for any other bee in the state. It can easily be recognized by its large size (> 17 mm), andreniform body shape, and dark body, pubescence, and wings ( Fig. 22 ). The first and third submarginal cells are approximately equal in length, and each are much longer than the second cell. A distinctive feature of the male is the enlarged metatibia ( Fig. 23 ), which is used to grasp the female during mating ( Wcislo & Buchmann, 1995).

This species has been collected from the following sites in southwest Michigan: Allegan Co.: 4.5 km south of Pullman, 17 July 2013 [ MSUC], 15 August 2013 [J.G. private collection]; Allegan State Game Area , T2 N R14 W Sec. 18, 2 August 2003 [ MSUC]; Berrien Co. : 4 km west of Berrien Springs [ MSUC]; Van Buren Co. : 4 km north by northwest of Almena 20 July 2011, 08 August 2011, 10 July 2012 [ MSUC] ( Fig. 24 ). Although this bee is very distinctive we do not know of any Michigan specimens preceding 2003. There is a single specimen deposited at the University of Guelph Insect Collection collected on 15 July 2007 at Black Oak Heritage Park (C. Sheffield, pers. comm.), which is part of the Ojibway Prairie Complex in Windsor , Ontario. This record suggests that D. heteropoda may be present in southern counties across the state of Michigan. It is possible that the lack of earlier records of this distinctive bee are due to a recent range extension, but the lack of thorough collection effort in the state makes this difficult to determine.

Dieunomia heteropoda is primarily an oligolege of Helianthus ( Hurd et al., 1980) . In Michigan, it has been collected from Helianthus , Ratibida pinnata (Vent.) Barnhart , Rudbeckia hirta , and Centaurea L. ( Asteraceae ). Females usually make solitary nests ( Parker et al., 1986; Wcislo, 1993), but may sometimes behave as communal nesters ( Wcislo, 1993; Wcislo & Engel, 1996).

Figures

Figure 24. Distribution map of Dufourea Lepeletier de Saint Fargeau and Dieunomia Cockerell of Michigan. Circle (○) Dufourea harveyi (Cockerell); solid triangle (▲) D. maura (Cresson); empty triangle (∆) D. monardae (Viereck); cross (+) D. novaeangliae (Robertson); and square (□) Dieunomia heteropoda (Say).

Figures 16–21. Male Dufourea harveyi (Cockerell) (16–18) and D. marginata (Cresson) (19–21). 16, 19. Clypea. 17, 20. Inner metatibial spurs. 21, 22. Metasomal sterna five and six. Modified from Dumesh & Sheffield (2012).

Figures 22–23. Lateral habitus of Dieunomia heteropoda (Say). 22. Female. 23. Male. Images courtesy of Laurence Packer.