Nishikawa Michiko, Nishino Hiroshi, Misaka Yuko, Kubota Maiko, Tsuji Eriko, Satoji Yuji, Ozaki Mamiko, Yokohari Fumio
Department of Earth System Science, Fukuoka University, Fukuoka 814-0180, Japan.
Zoolog Sci. 2008 Feb;25(2):195-204. doi: 10.2108/zsj.25.195.
The carpenter ant, a social hymenopteran, has a highly elaborated antennal chemosensory system that is used for chemical communication in social life. The glomeruli in the antennal lobe are the first relay stations where sensory neurons synapse onto interneurons. The system is functionally and structurally similar to the olfactory bulbs of vertebrates. Using three-dimensional reconstruction of glomeruli and subsequent morphometric analyses, we found sexual dimorphism of the antennal lobe glomeruli in carpenter ants, Camponotus japonicus. Female workers and unmated queens had about 430 glomeruli, the highest number reported so far in ants. Males had a sexually dimorphic macroglomerulus and about 215 ordinary glomeruli. This appeared to result from a greatly reduced number of glomeruli in the postero-medial region of the antennal lobe compared with that in females. On the other hand, sexually isomorphic glomeruli were identifiable in the dorsal region of the antennal lobe. For example, large, uniquely shaped glomeruli located at the dorso-central margin of the antennal lobe were detected in all society members. The great sexual dimorphism seen in the ordinary glomeruli of the antennal lobe may reflect gender-specific tasks in chemical communications rather than different reproductive roles.
木匠蚁是一种群居膜翅目昆虫，拥有高度发达的触角化学感应系统，用于社交生活中的化学通讯。触角叶中的小球体是感觉神经元与中间神经元突触连接的首个中继站。该系统在功能和结构上与脊椎动物的嗅球相似。通过对小球体进行三维重建并随后进行形态计量分析，我们发现日本弓背蚁触角叶小球体存在性别二态性。雌性工蚁和未交配的蚁后约有430个小球体，这是迄今为止在蚂蚁中报道的最高数量。雄性有一个性别二态性的大球体和大约215个普通小球体。这似乎是由于触角叶后内侧区域的小球体数量与雌性相比大幅减少所致。另一方面，在触角叶的背侧区域可识别出性别同形的小球体。例如，在所有社会成员中都检测到位于触角叶背中央边缘的大型、形状独特的小球体。触角叶普通小球体中明显的巨大性别二态性可能反映了化学通讯中特定性别的任务，而非不同的生殖角色。
