Intra-colony odor variability can disturb ants’ ability to discriminate against intruders. The evolutionary relevance of this phenomenon can be revealed by studies on colonies of slave-making ants in which the parasite, and not the host, is subject to selection pressures associated with living in a mixed colony. We examined how the European facultative slave-making species Formica sanguinea and its F. fusca slaves perform in discriminating ants from alien colonies. Results of behavioral assays showed that slave-maker ants respond with hostility to conspecific individuals from alien colonies but are relatively tolerant to alien slaves. Furthermore, the behavior of slaves indicated a limited ability to discriminate ants from alien parasitic colonies. The subdivision of colony fragments into mixed and species-separated groups demonstrated that contact with the parasite is necessary for F. fusca slaves to be re-accepted by former nestmates after a period of separation from the stock colony. The results presented in this paper are consistent with the following hypotheses: (1) F. sanguinea ants, as opposed to their slaves, are adapted to discriminate alien individuals in the conditions of odor variability found in a mixed-species colony, (2) the recognition of slaves by F. sanguinea ants involves a dedicated adaptive mechanism that prevents aggression toward them, (3) the odor of slaves is strongly influenced by the parasite with beneficial effect on the colony integrity.

中文翻译：

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兼性奴隶制蚂蚁及其奴隶的辨别能力

菌落内气味的变化会干扰蚂蚁区分入侵者的能力。这种现象的进化相关性可以通过对奴隶制蚂蚁群体的研究来揭示，其中寄生虫，而不是宿主，受到与生活在混合群体中相关的选择压力的影响。我们研究了欧洲兼性奴隶制造物种 Formica sanguinea 及其 F. fusca 奴隶如何区分来自外来殖民地的蚂蚁。行为分析的结果表明，奴隶制造者蚂蚁对来自外星殖民地的同种个体表现出敌意，但对外星奴隶相对宽容。此外，奴隶的行为表明区分蚂蚁与外来寄生菌落的能力有限。将菌落碎片细分为混合的和物种分离的组表明，与寄生虫的接触对于 F. fusca 奴隶在与种群分离一段时间后重新被前同窝者重新接受是必要的。本文中提出的结果与以下假设一致：(1) F. sanguinea 蚂蚁与其奴隶相反，适应于在混合物种群落中发现的气味可变性条件下区分外星个体，(2) F. sanguinea 蚂蚁对奴隶的识别涉及一种专门的适应机制，可以防止对它们的攻击，(3) 奴隶的气味受到寄生虫的强烈影响，对群体完整性产生有益影响。在与原种殖民地分离一段时间后，fusca 奴隶将被前同居者重新接受。本文中提出的结果与以下假设一致：(1) F. sanguinea 蚂蚁与其奴隶相反，适应于在混合物种群落中发现的气味可变性条件下区分外星个体，(2) F. sanguinea 蚂蚁对奴隶的识别涉及一种专门的适应机制，可以防止对它们的攻击，(3) 奴隶的气味受到寄生虫的强烈影响，对群体完整性产生有益影响。fusca 奴隶在与原种殖民地分离一段时间后被前同居者重新接受。本文中提出的结果与以下假设一致：(1) F. sanguinea 蚂蚁与其奴隶相反，适应于在混合物种群落中发现的气味可变性条件下区分外星个体，(2) F. sanguinea 蚂蚁对奴隶的识别涉及一种专门的适应机制，可以防止对它们的攻击，(3) 奴隶的气味受到寄生虫的强烈影响，对群体完整性产生有益影响。