Data from: Queen presence mediates the relationship between collective behavior and disease susceptibility in ant colonies

The success of social living can be explained, in part, by a group's ability to execute collective behaviors unachievable by solitary individuals. However, groups vary in their ability to execute these complex behaviors, often because they vary in their phenotypic composition. Group membership changes over time due to mortality or emigration, potentially leaving groups vulnerable to ecological challenges in times of flux. In some societies, the loss of important individuals (e.g., leaders, elites, queens) may have an especially detrimental effect on groups’ ability to deal with these challenges.
Here, we test whether the removal of queens in colonies of the acorn ant Temnothorax curvispinosus alters their ability to execute important collective behaviors and survive outbreaks of a generalist entomopathogen.
We employed a split-colony design where one half of a colony was maintained with its queen, while the other half was separated from the queen. We then tested these subcolonies’ performance in a series of collective behavior assays and finally exposed colonies to the entomopathogenic fungus Metarhizium robertsii by exposing two individuals from the colony and then sealing them back into the nest.
We found that queenright subcolonies outperformed their queenless counterparts in nearly all collective behaviors. Queenless subcolonies were also more vulnerable to mortality from disease. However, queenless groups that displayed more interactions with brood experienced greater survivorship, a trend not present in queenright subcolonies. Queenless subcolonies that engage in more brood interactions may have had more resources available to cope with two physiological challenges (ovarian development after queen loss and immune activation after pathogen exposure).
Our results indicate that queen presence can play an integral role in colony behavior, survivorship, and their relationship. They also suggest that interactions between workers and brood are integral to colonies survival. Overall, a social group's history of social reorganization may have strong consequences on their collective behaviors and their vulnerability to disease outbreaks.

社会生活的成功，在一定程度上可归因于群体具备执行单个个体无法完成的集体行为的能力。然而，不同群体执行此类复杂行为的能力存在差异，这往往源于其表型组成的不同。群体成员会因死亡或迁出随时间发生更替，这可能使群体在动荡时期难以应对生态挑战。在部分社会性类群中，重要个体（如首领、精英、蚁后）的流失，对群体应对这些挑战的能力可能造成尤为严重的损害。
本研究旨在检验，在橡子蚁（Temnothorax curvispinosus）的蚁群中移除蚁后，是否会改变其执行关键集体行为的能力，以及应对广谱昆虫病原微生物暴发的存活能力。
我们采用分群实验设计：将一个蚁群分为两部分，一半保留蚁后进行饲养，另一半则与蚁后分离。随后，我们通过一系列集体行为实验检测这些亚群的表现，最后通过将蚁群中的两只个体先接触昆虫病原真菌罗伯茨绿僵菌（Metarhizium robertsii），再将其放回蚁巢的方式，使整个蚁群暴露于该病原之下。
我们发现，保留蚁后的亚群在几乎所有集体行为测试中均优于无蚁后亚群。无蚁后亚群的疾病致死率也更高。不过，在无蚁后亚群中，与育幼群体（brood）互动更频繁的群体存活率更高，这一趋势在保留蚁后的亚群中并未出现。无蚁后亚群中，更多参与育幼互动的群体可能拥有更多资源，以应对两种生理挑战：蚁后缺失后的卵巢发育，以及病原暴露后的免疫激活。
我们的研究结果表明，蚁后的存在对蚁群的行为、存活率及其二者的关联均具有不可或缺的作用。同时还表明，工蚁与育幼群体的互动对蚁群存活至关重要。总体而言，社会群体的社会重组历程，可能对其集体行为及应对疾病暴发的脆弱性产生显著影响。