Department of Biology, Earlham College, Richmond, Indiana, United States of America.
PLoS One. 2011;6(8):e24011. doi: 10.1371/journal.pone.0024011. Epub 2011 Aug 23.
Eusocial species exhibit pronounced division of labor, most notably between reproductive and non-reproductive castes, but also within non-reproductive castes via morphological specialization and temporal polyethism. For species with distinct worker and queen castes, age-related differences in behavior among workers (e.g. within-nest tasks versus foraging) appear to result from physiological changes such as decreased lipid content. However, we know little about how labor is divided among individuals in species that lack a distinct queen caste. In this study, we investigated how fat storage varied among individuals in a species of ant (Dinoponera australis) that lacks a distinct queen caste and in which all individuals are morphologically similar and capable of reproduction (totipotent at birth). We distinguish between two hypotheses, 1) all individuals are physiologically similar, consistent with the possibility that any non-reproductive may eventually become reproductive, and 2) non-reproductive individuals vary in stored fat, similar to highly eusocial species, where depletion is associated with foraging and non-reproductives have lower lipid stores than reproducing individuals. Our data support the latter hypothesis. Location in the nest, the probability of foraging, and foraging effort, were all associated with decreased fat storage.
真社会性物种表现出明显的劳动分工，最显著的是在生殖和非生殖等级之间，但也在非生殖等级内通过形态特化和时间多态来实现。对于具有明显工蚁和蚁后的物种，工蚁之间与年龄相关的行为差异（例如巢内任务与觅食）似乎是由于生理变化引起的，例如脂质含量降低。然而，我们对于缺乏明显蚁后的物种中个体之间如何分工知之甚少。在这项研究中，我们研究了缺乏明显蚁后的蚂蚁物种（Dinoponera australis）中个体之间的脂肪储存如何变化，在这种蚂蚁中，所有个体在形态上相似且具有生殖能力（出生时具有全能性）。我们区分了两种假设，1）所有个体在生理上相似，这与任何非生殖个体都可能最终具有生殖能力的可能性一致，以及 2）非生殖个体在储存的脂肪量上存在差异，类似于高度真社会性物种，其中消耗与觅食有关，非生殖个体的脂质储存比生殖个体低。我们的数据支持后一种假设。巢内位置、觅食的可能性和觅食努力都与脂肪储存减少有关。
