Genetic and morphometric evidence for the conspecific status of the bumble bees, Bombus melanopygus and Bombus edwardsii
1Department of Chemical & Biological Sciences, Mount Royal University, 4825 Mount Royal Gate, S.W., Calgary, Alberta, Canada, T3E 6K6
2Department of Biological Sciences, University of Calgary, 2500 University Drive, NW, Calgary, Alberta, Canada, T2N 1N4
3Department of Zoology, Ramsay Wright Zoological Laboratories, 25 Harbord Street, University of Toronto, Toronto, Ontario, Canada, M5S 1A1
4Present address: Whidden Environmental Ltd., 17 Covepark Bay, NE, Calgary, Alberta, Canada T3K 6K8
5Present address: 108 Ch. River, Cantley, Quebec, J8V 3A1
Abstract
The taxonomic status of closely related bumble bee species is often unclear. The relationship between the two nominate taxa, Bombus melanopygus Nylander (Hymenoptera: Apidae) and Bombus edwardsii Cresson (Hymenoptera: Apidae), was investigated using genetic (enzyme electrophoretic) and morphometric analyses. The taxa differ in the color of the abdominal terga two and three, being ferruginous in B. melanopygus and black in B. edwardsii. B. edwardsii occurs throughout California, while B. melanopygus extends north through Oregon, to Alaska and Canada. They are sympatric only in southern Oregon and northern California. The taxonomic status of these taxa was questioned when Owen and Plowright (1980) reared colonies from queens collected in the area of sympatry, and discovered that pile coloration was due to a single, biallelic Mendelian gene, with the red (R) allele dominant to the black (r). Here it is shown that all the taxa, whether from California, Oregon, or Alberta, have the same electrophoretic profile and cannot be reliably distinguished by wing morphometrics. This strongly supports the conclusion that B. melanopygus and B. edwardsii are conspecific and should be synonymized under the name B. melanopygus. Hence, there is a gene frequency cline running from north to south, where the red allele is completely replaced by the black allele over a distance of about 600 km.
Keywords: allozymes, color variation, taxonomy
Correspondence:
a*rowen@mtroyal.ca,
btwhidden@telus.net,
cchris@plowright.ca, *Corresponding author
Associate Editor: Eugene Hall was editor of this paper.
Received: 23 September 2008 | Accepted: 13 January 2009 | Published: 13 July 2010
Copyright: This is an open access paper. We use the Creative Commons Attribution 3.0 license that permits unrestricted use, provided that the paper is properly attributed.
ISSN: 1536-2442 | Volume 10, Number 109
Owen RE, Whidden TL, Plowright RC. 2010. Genetic and morphometric evidence for the conspecific status of the bumble bees, Bombus melanopygus and Bombus edwardsii. Journal of Insect Science 10:109, available online: insectscience.org/10.109
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