Bristow C M
Department or Entomology, Michigan State University, 48824, East Lansing, MI, USA.
Oecologia. 1991 Sep;87(4):514-521. doi: 10.1007/BF00320414.
Oleander aphids, (Aphis nerii), which are sporadically tended by ants, were used as a moded system to examine whether host plant factors associated with feeding site influenced the formation of ant-aphid associations. Seasonal patterns of host plant utilization and association with attendant ants were examined through bi-weekly censuses of the aphid population feeding on thirty ornamental oleander plands (Nerium oleander) in northern California in 1985 and 1986. Colonies occurred on both developing and senescing plant terminals, including leaf tips, floral structures, and pods. Aphids preferentially colonized leaf terminals early in the season, but showed no preference for feeding site during later periods. Argentine ants (Iridomyrmex humilis) occasionally tended aphid colonies. Colonies on floral tips were three to four times more likely to attract ants than colonies on leaf tips, even though the latter frequently contained more aphids. Ants showed a positive recruitment response to colonies on floral tips, with a significant correlation between colony size and number of ants. There was no recruitment response to colonies on leaf tips. These patterns were reproducible over two years despite large fluctuations in both aphid population density and ant activity. In a laboratory bioassay of aphid palatability, the generalist predator,Hippodamia convergens, took significantly more aphids reared on floral tips compared to those reared on leaf tips. The patterns reported here support the hypothesis that tritrophic factors may be important in modifying higher level arthropod mutualisms.
夹竹桃蚜（Aphis nerii）偶尔会受到蚂蚁的照料，它被用作一个模型系统来研究与取食部位相关的寄主植物因素是否会影响蚂蚁与蚜虫关联的形成。通过在1985年和1986年对加利福尼亚北部30株观赏夹竹桃（Nerium oleander）上取食的蚜虫种群进行每两周一次的普查，研究了寄主植物利用的季节性模式以及与伴随蚂蚁的关联。虫群出现在发育中的和衰老的植物顶端，包括叶尖、花结构和豆荚。蚜虫在季节早期优先在叶尖定殖，但在后期对取食部位没有偏好。阿根廷蚁（Iridomyrmex humilis）偶尔照料蚜虫群体。花尖上的虫群比叶尖上的虫群吸引蚂蚁的可能性高3至4倍，尽管叶尖上的蚜虫通常更多。蚂蚁对花尖上的虫群表现出积极的招募反应，虫群大小与蚂蚁数量之间存在显著相关性。对叶尖上的虫群没有招募反应。尽管蚜虫种群密度和蚂蚁活动都有很大波动，但这些模式在两年内是可重复的。在一项关于蚜虫适口性的实验室生物测定中，多食性捕食者——会聚七星瓢虫（Hippodamia convergens）取食花尖上饲养的蚜虫的数量显著多于叶尖上饲养的蚜虫。这里报道的模式支持了这样一种假设，即三级营养因素可能在改变更高层次的节肢动物互利共生关系中很重要。
