Department of Chemical & Biological Sciences, Mount Royal University, 4825 Mount Royal Gate, S.W., Calgary, Alberta, Canada.
J Insect Sci. 2010;10:109. doi: 10.1673/031.010.10901.
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.
密切相关的熊蜂物种的分类地位往往不清楚。使用遗传（酶电泳）和形态计量分析研究了两个指名亚种，即熊蜂 melanopygus Nylander（膜翅目：蜜蜂科）和熊蜂 edwardsii Cresson（膜翅目：蜜蜂科）之间的关系。这两个分类群在腹部第二节和第三节的颜色上存在差异，B. melanopygus 为赤褐色，而 B. edwardsii 为黑色。B. edwardsii 分布于加利福尼亚州全境，而 B. melanopygus 则从俄勒冈州向北延伸至阿拉斯加和加拿大。它们仅在俄勒冈州南部和加利福尼亚州北部同域分布。当 Owen 和 Plowright（1980）从同域采集的蜂王饲养的殖民地中发现，堆的颜色是由于一个单一的、双等位基因的孟德尔基因，红色（R）等位基因对黑色（r）是显性的，这引起了人们对这些分类群的分类地位的质疑。这里表明，无论是来自加利福尼亚州、俄勒冈州还是艾伯塔省的所有分类群，都具有相同的电泳图谱，并且不能通过翅膀形态计量学可靠地区分。这强烈支持了 B. melanopygus 和 B. edwardsii 是同一种的结论，应该将它们合并为一个名称 B. melanopygus。因此，存在一个从北到南的基因频率梯度，在大约 600 公里的距离内，红色等位基因完全被黑色等位基因取代。
