Acomprehensive study on invasive aliea species and supercolonies of ants

在对北海道石kari海岸上的一个超级蚁群Formica yessensis的研究中，我们证实了一种化学感觉器的存在，这种感觉器是以前在一种系统发育上接近的蚂蚁Camponotus japonica的工蚁中发现的。尽管感觉器对巢友的碳氢化合物也有反应，但对其他工蜂的碳氢化合物的反应要弱得多，这表明该器官保留了识别巢友的功能。在超级蚁群内，感觉器官的反应与所分析巢穴的地理距离显著相关，表明即使没有任何攻击行为的巢穴之间也存在少量的对抗关系。对室外观察所得的工蚁行为数据进行数学分析，表明超群蚁巢间存在拮抗关系。此外，微卫星DNA分析表明，超级群体内部的亲缘关系与不同群体之间的亲缘关系一样低。巢内亲缘关系虽略高，但标准差较高，说明巢内配偶既有亲缘关系，也有非亲缘关系的工蜂和蚁后。这些结果表明亲缘选择不是维持超级群体的重要因素。可能，更重要的因素之一是强风，它经常把飞蝇吹到海里，因此为交配后的蚁后提供了有利条件，它们放弃飞行，进入母巢或邻近的巢穴。海边沙丘上相对均匀的生境可能是石kari海岸一夫多妻制发展和内部对抗减少的另一个关键因素。

In this research on Formica yessensis which exhibits a supercolony on the coast of Ishikari, Hokkaido, We confirmed the presence of a chemosensory sensillum which was previously discovered in workers of a phylogenetically close ant Camponotus japonica. Whereas the sensillum responded even to hydrocarbons of nestmates, the response was less intense than that to hydrocarbons of workers from other colonies, indicating that this organ of F. yessensis retains the function of nestmate recognition. Within the supercolony, the response of the sensillum was significantly correlated with the geographic distance of the analyzed nests, suggesting that there is a little antagonistic relationship even between the nests which do not show any aggressive behaviors. The presence of the antagonistic relationship between the supercolonial nests was also suggested by a mathematical analysis of the behavioral data which was obtained in the outdoor observation of F. yessensis workers. Moreover, the analysis of microsatellite DNA demonstrated that the kin relatedness within the supercolony was as low as that between different colonies. Although the intranidal kin relatedness was a little higher, the standard deviation was high, indicating that the nestmates were composed not only of kins but also of non-related workers and queens. These results suggest that the kin selection is not an important factor to maintain the supercolony. Probably, one of more important factors is the strong wind which often blows flying alates to the sea and accordingly offers advantages to the post-mating queens which abandon the flight and enter the natal or neighboring nests. The relatively homogeneous habitat on seaside dune may be another key factor which facilitated the development of polygyny and the reduction of internidal antagonism on the Ishikari Coast.