Unit of Social Ecology, CP 231, Université libre de Bruxelles, Bld du Triomphe, 1050 Brussels, Belgium.
J Insect Sci. 2010;10:3. doi: 10.1673/031.010.0301.
We investigated whether the physical castes of the dimorphic ant Pheidole pallidula (Nylander) (Hymenoptera: Formicidae), are involved in determining within-nest activities and how their social investment in everyday tasks is influenced by large changes in the colony's caste ratio. Although the large-headed majors are morphologically distinct from minors, they are similar in size, exhibit similar behavioral repertoires and carry out nearly the same tasks as minors. Changes, even large ones, in the colony's caste ratio have no significant effect on the repertoire size of either caste. Majors do not compensate for the depletion of minors by expanding their repertoire or increasing their activity level. Instead of being an idle stand-by caste as suggested for other Pheidole specie s, P. pallidula majors are nearly as totipotent as minors. Moreover, their performance rate of social behaviors is remarkably high and constant regardless of the colony caste ratio. Such high investment of the major caste helps the colony to keep social behaviors at a baseline even in colonies undergoing large demographic changes. Alternative schemes of social regulation in polymorphic ant species are discussed. A possible methodological bias accounting for between-species differences in the level of majors' specialization is described.
我们研究了二态蚁种双色树蚁（Pheidole pallidula）（膜翅目：蚁科）的物理型是否参与决定巢内活动，以及它们在日常任务中的社会投资如何受到蚁群型比率的巨大变化的影响。尽管大头兵蚁在形态上与小兵蚁明显不同，但它们在体型上相似，表现出相似的行为 repertoire，并执行与小兵蚁几乎相同的任务。即使蚁群型比率发生巨大变化，也不会对任何一种型的 repertoire size 产生显著影响。大头兵蚁不会通过扩大 repertoire 或增加活动水平来弥补小兵蚁的减少。与其他 Pheidole 物种不同，双色树蚁的大头兵蚁不是一种闲置的候补型，而是几乎与小兵蚁一样全能。此外，无论蚁群型比率如何，它们执行社会行为的表现率都非常高且保持不变。大头兵蚁的这种高投入有助于蚁群在经历巨大的人口变化时，将社会行为保持在基线水平。讨论了多态蚁种中替代的社会调节方案。描述了一种可能的方法学偏差，该偏差解释了大头兵蚁专业化水平的种间差异。
