红火蚁对新入侵龙眼园和荒草地蚂蚁类群多样性的影响

于2007年7月至2008年2月期间在增城龙眼园及周边的荒草地人工移殖1蚁巢及10蚁巢红火蚁,并采用陷阱法和诱饵诱集法调查研究红火蚁对新入侵龙眼园区和荒草地区蚂蚁类群多样性的影响。结果表明,在荫蔽、少干扰的龙眼园和杂草茂密、少干扰的未割草区,红火蚁难以成功定殖,对这两种生境蚂蚁类群的多样性几乎没有影响;在红火蚁成功定殖的1蚁巢割草区和10蚁巢割草区,红火蚁以这两种密度入侵对蚂蚁类群多样性的影响程度不同。在1蚁巢割草区,红火蚁入侵后5个月期间,由于其数量占蚂蚁个体总数的比例很少,对蚂蚁类群多样性的影响很小;在红火蚁成功定殖5个月后,第6—7个月其工蚁所占比例增加,蚂蚁类群个体数和优势度下降,多样性和均匀度增加;第8—9个月其工蚁所占比例继续增加,而蚂蚁个体数、多样性和均匀度下降,优势度增加。在10蚁巢割草区,红火蚁入侵后,蚂蚁类群个体数、多样性和均匀度下降,优势度增加。红火蚁入侵对1蚁巢割草区和10蚁巢割草区蚂蚁物种数的影响较小。

Influence of the red imported fire ant, Solenopsis invicta Buren (Hymenoptera: Formiciddae) on the diversity of ant communities in a newly infested longan orchard and grass areas nearby

The impacts of red imported fire ant invasion on the diversity of ant communities in longan orchards and grasslands were studied with pitfall and bait traps from July 2007 through February 2008, in Zengcheng, Guangzhou. Different number of the fire ant colonies were moved into the two types of the habitats and kept for observation. Fire ants did not establish their colonies in the high\|shade longan orchards and un\|mowed grass areas. However, they did establish in areas with mowed grass. The impacts of fire ants on the diversity of the ant community were dependent on the densities of colonies moved into the grasslands. When one fire ant colony was set in 300 m2 of mowed grass, the abundance of ants and predominant indices of the ant community decreased, while the diversity and evenness indices increased after 6-7 months. However, the abundance of ants and the diversity and evenness indices decreased, and predominant indices increased after the fire ant colonies colonized the area for 8-9 months. When up to 10 colonies were introduced per 300 m2, and were allowed to establish for 5 months, the abundance, diversity indices and evenness indices decreased, and the predominant indices increased.