Data from: Pace-of-life in a social insect: behavioral syndromes in ants shift along a climatic gradient

Behavioral syndromes are correlations between behavioral traits, but their selective advantage under different environmental conditions is not well understood. Here, we used the pace-of-life hypothesis to predict how behavioral syndromes could vary along climatic gradients. This hypothesis states that populations experiencing different ecological conditions should differ in suites of physiological characteristics associated with behavioral and life-history traits. We examined the persistence of behavioral syndromes at multiple levels in the ant Temnothorax longispinosus along a climatic gradient in north-eastern USA. “Across populations”, we predicted that proactive phenotypes, which show higher activity, aggression and exploration, are more likely to persist in warmer climates. “Within populations”, we expected positive associations among proactive behaviors to be more pronounced at warmer sites. Additionally, we measured colony productivity to test whether deviation from the population-level syndrome influences their success, and whether such deviations could vary among populations. Behavioral syndromes clearly occurred across populations, with colonies from warmer environments exhibiting more exploration and foraging but slightly less aggressiveness than colonies from colder sites. However, the presence of behavioral syndromes within sites was population-specific. Positive associations between foraging, exploration and aggression, albeit rarely found, were more pronounced at the warmest sites, whereas negative associations were more common at colder sites. Furthermore, colonies from colder environments showed higher syndrome deviations than colonies from warmer environments, which may be linked to resource limitation and may also negatively affect colony productivity. This study partially corroborates the pace-of-life hypothesis and yields insights into the adaptive value of behavioral syndromes along climatic gradients.

行为综合征（behavioral syndromes）指不同行为性状间的相关性，但目前学界对其在不同环境条件下的选择优势尚未得到充分阐释。本研究借助生活节奏假说（pace-of-life hypothesis），预测行为综合征将沿气候梯度发生变化。该假说提出，处于不同生态条件下的种群，其与行为及生活史性状相关的一系列生理特征应存在显著差异。我们以美国东北部气候梯度分布的蚁类Temnothorax longispinosus为研究对象，从多个层面探究行为综合征的存续特征：在种群间维度，我们预测展现出更高活跃度、攻击性与探索欲的主动型表型（proactive phenotypes）更易在温暖气候环境中存续；在种群内维度，我们预期温暖生境中主动型行为间的正相关关联会更为显著。此外，我们测定了蚁群生产力，以验证偏离种群水平行为综合征的程度是否会影响蚁群生存成功率，以及这类偏离程度是否会因种群不同而存在差异。研究结果显示，种群间确实存在行为综合征：相较于来自寒冷生境的蚁群，温暖环境中的蚁群展现出更强的探索与觅食行为，但攻击性略低。但生境内部的行为综合征存在与否具有种群特异性。尽管较为少见，但觅食、探索与攻击性间的正相关关联在最温暖的生境中最为显著；而寒冷生境中则更易出现负相关关联。此外，寒冷环境的蚁群的行为综合征偏离程度显著高于温暖环境的蚁群，这一现象或与资源限制相关，且可能对蚁群生产力产生负面影响。本研究部分验证了生活节奏假说，并为理解行为综合征沿气候梯度的适应性价值提供了新的学术见解。