胸熊蜂亚属Thoracobombus 3个种的形态比较

Comparison on the morphology of 3 species of subgenus Thoracobombus (Hymenoptera: Apidae: Bombus)

对熊蜂属(Bombus)胸熊蜂亚属(Thoracobombus)3个种的外部形态及雄性外生殖器特征进行比较,并采集整体及局部特征图.结果表明:3种熊蜂在体型大小、触角第4节及毛色等方面存在明显差异,如黑足熊蜂(B.atripes)与仿熊蜂(B.imitator)触角第4节长均大于宽,而兴熊蜂(B.impetuosus)宽大于长;阳茎瓣末端、阳茎基腹铗内钩、生殖刺突内钩差异明显,如黑足熊蜂生殖刺突具两内钩,仿熊蜂与兴熊蜂仅具一内钩.进一步对工蜂20个形态指标进行系统测量和分析得出:中单眼与右单眼距离、肘脉指数和跗节指数在3种熊蜂之间差异均不显著;黑足熊蜂中单眼半径(0.161±0.010)mm与仿熊蜂(0.152±0.020)mm差异不显著,但两者均与兴熊蜂(0.127±0.011)mm差异显著;其余16个指标差异均显著,特征大小表现为黑足熊蜂>仿熊蜂>兴熊蜂.

The morphology and male genitalia of three species of Thoracobombus Dalla Torre, 1880, Bombus atripes Smith, 1852, Bombus imitator Pittioni, 1949 and Bombus impetuosus Smith, 1871, were described and compared. The results showed that the three species varied significantly in size, color and the 4 th antenna. For instance, the length of the 4 th antenna is longer than its width for B.atripes and B.imitator but the opposite for B.impetuosus. For male genitalia, they also varied distinctly in penis valve, volsella and gonostylus, i.e., there are two inner hooks in the gonostylus of B.atripes, while there is only one inner hook in the gonostylus of B.imitator and B.impetuosus. Moreover, 20 morphological indexes were subject to analysis of variance. There are no significant differences in the distance between middle and right ocellus, cubital index and tarsus index among three species;there is no significant difference in the radius of median ocellus between B.atripes(0.161±0.010) mm and B.imitator(0.152±0.020) mm, but they are significantly different from that of B.impetuousus(0.127±0.011) mm. Apart from these, other 16 indexes can be used as distinguish features for identification, whose sizes is followed by B.atripes, B.imitator and B.impetuousus in a descending order.