Ant Colonies Do Not Trade-Off Reproduction against Maintenance.
Ant Colonies Do Not Trade-Off Reproduction against Maintenance.
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DOI：
10.1371/journal.pone.0137969
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发表时间：
2015
期刊：
影响因子：
3.7
通讯作者：
Heinze J
中科院分区：
文献类型：
--
作者：
Kramer BH;Schrempf A;Scheuerlein A;Heinze J
个体如何分配资源用于维持和繁殖的问题是生活史理论的核心问题之一。然而，在机构一级用于维持的资源分配只能间接衡量。这在群居昆虫群体中是不同的，它是一个“超有机体”，工蜂代表索马，蜂王代表殖民地的生殖细胞系。在这里，我们调查维护和繁殖之间是否存在权衡两个层次的生物组织，皇后和殖民地，通过以下单皇后殖民地的蚂蚁obscurior在整个生命周期的女王。我们的研究结果表明，维护和繁殖是正相关的殖民地的水平，我们证实了早期的研究结果，发现没有权衡个人（女王）的水平。我们将这一意想不到的结果归因于一个正反馈循环的存在，其中对维护（工人）的投资增加了实验室条件下的资源获取率。尽管食物是随意提供的，但蜂群之间生产力的变化表明，只有在有足够的工蚁的情况下，资源才能被殖民地利用并投资于额外的维护和繁殖。在我们的研究中，人均和殖民地生产力之间的关系与该领域进行的其他研究吻合得很好，其中人均生产力的下降和殖民地生产力的稳定与殖民地之间的竞争导致的密度依赖效应有关。这表明，在我们的实验室研究中缺乏权衡在自然条件下也可能是普遍的，导致维护，（=生长）和繁殖的正相关。在这方面，昆虫群体类似于无限生长的有机体。
The question on how individuals allocate resources into maintenance and reproduction is one of the central questions in life history theory. Yet, resource allocation into maintenance on the organismic level can only be measured indirectly. This is different in a social insect colony, a “superorganism” where workers represent the soma and the queen the germ line of the colony. Here, we investigate whether trade-offs exist between maintenance and reproduction on two levels of biological organization, queens and colonies, by following single-queen colonies of the ant Cardiocondyla obscurior throughout the entire lifespan of the queen. Our results show that maintenance and reproduction are positively correlated on the colony level, and we confirm results of an earlier study that found no trade-off on the individual (queen) level. We attribute this unexpected outcome to the existence of a positive feedback loop where investment into maintenance (workers) increases the rate of resource acquisition under laboratory conditions. Even though food was provided ad libitum, variation in productivity among the colonies suggests that resources can only be utilized and invested into additional maintenance and reproduction by the colony if enough workers are available. The resulting relationship between per-capita and colony productivity in our study fits well with other studies conducted in the field, where decreasing per-capita productivity and the leveling off of colony productivity have been linked to density dependent effects due to competition among colonies. This suggests that the absence of trade-offs in our laboratory study might also be prevalent under natural conditions, leading to a positive association of maintenance, (= growth) and reproduction. In this respect, insect colonies resemble indeterminate growing organisms.