Data from: Life-history strategy and behavioral type: risk-tolerance reflects growth rate and energy allocation in ant colonies

Despite the recent interest in animal personality and behavioral syndromes, there is a paucity of explanations for why distinct behavioral traits should evolve to correlate. We investigate whether such correlations across apparently distinct behavioral traits may be explained by variation in life history strategy among individual ant colonies. Life history theory predicts that the way in which individuals allocate energy towards somatic maintenance or reproduction drives several distinct traits in physiology, morphology, and energy use; it also predicts that an individual's willingness to engage in risky behaviors should depend on reproductive strategy. We use Temnothorax ants, which have been shown to exhibit ‘personalities’ and a syndrome that may reflect risk tolerance at the colony level. We measure colonies' relative investment in growth rate (new workers produced) compared to reproductive effort (males and queens produced). Comparing sterile worker production to reproductive alate production provides a direct measure of how colonies are investing their energy, analogous to investment in growth versus reproduction in a unitary organism. Consistently with this idea, we found that behavioral type of ant colonies was associated with their life history strategy: risk-tolerant colonies grew faster and invested more in reproduction, whereas risk-averse colonies had lower growth rate but invested relatively more in workers. This provides evidence that behavioral syndromes can be a consequence of life-history strategy variation, linking the two fields and supporting the use of an integrative approach.尽管学界近年来对动物个性与行为综合征（behavioral syndromes）的研究热度持续攀升，但针对为何不同行为性状会演化出相关性的合理解释仍较为匮乏。本研究旨在探究表观上截然不同的行为性状间的相关性，是否可通过单个蚁群间生活史策略（life history strategy）的差异加以解释。生活史理论（life history theory）预测，个体分配能量用于体细胞维持或繁殖的模式，会驱动生理、形态及能量利用方面的多项差异化性状；该理论同时指出，个体参与风险行为的意愿取决于其繁殖策略。本研究以扁胸切叶蚁属（Temnothorax）蚂蚁为研究对象，该类群已被证实存在“个性”特征，且其行为综合征可反映蚁群层面的风险耐受能力。我们量化了蚁群在生长速率（即新工蚁产出量）与繁殖投入（即雄蚁与处女蜂王产出量）两方面的相对资源分配。相较于单体生物的生长与繁殖资源分配模式，对比不育工蚁产出与具翅繁殖型个体产出，可直接反映蚁群的能量投资策略。本研究结果与该假说一致：蚁群的行为类型与其生活史策略显著相关——风险耐受型蚁群生长速率更快，且对繁殖的投入更高；而风险规避型蚁群生长速率较慢，但对工蚁的相对投入更高。该研究结果证实，行为综合征可源于生活史策略的差异，这一发现将两个研究领域联系起来，并为整合性研究方法的应用提供了支持。