Bernasconi G, Keller L
Abteilung Verhaltensökologie, Ethologische Station Hasli, University of Berne, Switzerland
Anim Behav. 1999 Feb;57(2):371-377. doi: 10.1006/anbe.1998.0955.
In many ant species, including the fire ant Solenopsis invicta, queens can found their colonies alone or in associations of two or more. Colonies founded by associations produce a larger worker brood, have higher survival and mature earlier than colonies founded by solitary queens. However, cofoundresses almost invariably fight after the eclosion of the first workers. As a result, only one queen survives and monopolizes the colony's future reproductive output. Queen mortality also occurs before worker eclosion, but neither the causes (e.g. starvation, conflict), nor the factors (e.g. social environment) potentially affecting its occurrence, have been investigated. We analysed the effect of social environment and queen body mass on early mortality by keeping queens (1) solitarily, (2) within associations of four queens of the same initial mass, and (3) within associations of four queens of random initial mass. Mortality was higher for queens within associations than for solitary queens. Within associations of equally heavy queens, mortality significantly increased with the queens' body mass. In contrast, mortality of solitary queens did not significantly depend on body mass. Early mortality was significantly more frequent in associations of queens of random initial mass than in associations of equally heavy queens. Altogether these results demonstrate that queen phenotype differentially affects early queen mortality depending on the social environment, and suggest that reproductive competition rather than starvation is the main cause of mortality in multiple-queen associations. Copyright 1999 The Association for the Study of Animal Behaviour.
在许多蚁种中，包括火蚁入侵红火蚁（Solenopsis invicta），蚁后可以单独建立蚁群，也可以两个或更多蚁后联合建群。由多个蚁后联合建立的蚁群产生的工蚁幼虫更多，存活率更高，且比由单个蚁后建立的蚁群成熟得更早。然而，共同建群的蚁后在第一批工蚁羽化后几乎总会发生争斗。结果，只有一只蚁后存活下来并垄断蚁群未来的繁殖产出。蚁后死亡也会发生在工蚁羽化之前，但死亡的原因（如饥饿、冲突）以及可能影响其发生的因素（如社会环境）均未得到研究。我们通过将蚁后（1）单独饲养、（2）置于由四只初始体重相同的蚁后组成的群体中以及（3）置于由四只初始体重随机的蚁后组成的群体中，分析了社会环境和蚁后体重对早期死亡率的影响。群体中的蚁后死亡率高于单独饲养的蚁后。在体重相同的蚁后群体中，死亡率随蚁后体重显著增加。相比之下，单独饲养的蚁后死亡率并不显著取决于体重。初始体重随机的蚁后群体中的早期死亡率显著高于体重相同的蚁后群体。总之，这些结果表明，蚁后表型根据社会环境对早期蚁后死亡率有不同影响，并表明繁殖竞争而非饥饿是多蚁后群体中死亡率的主要原因。版权所有1999动物行为研究协会。
