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.尽管当前学界对动物个性（animal personality）与行为综合征（behavioral syndromes）的研究兴趣与日俱增，但针对为何不同的行为性状会演化出相关性，现有解释仍十分匮乏。本研究旨在探究：上述看似迥异的行为性状间的相关性，是否可通过单个蚁群的生活史策略（life history strategy）差异加以解释。生活史理论预测，个体将能量分配于体细胞维持或繁殖的方式，会驱动生理学、形态学及能量利用模式中的多项差异化性状；同时该理论还指出，个体参与风险行为的意愿应与其繁殖策略息息相关。本研究以盘腹蚁属（Temnothorax）蚂蚁为研究对象，已有研究表明该类群蚁群展现出“个性”特征，且存在可反映群体层面风险耐受度的行为综合征。我们对比测定了蚁群在生长速率（即新增工蚁产出）与繁殖投入（即雄性生殖蚁与处女蚁后产出）两方面的相对投资情况。将不育工蚁产出与生殖型有翅成虫产出进行对比，可直接衡量蚁群的能量分配模式，这与单体生物（unitary organism）在生长与繁殖间的能量投资策略具有类比性。与该假说一致，我们发现蚁群的行为类型与其生活史策略紧密相关：耐受风险的蚁群生长速率更快，且在繁殖上投入更多资源；而规避风险的蚁群生长速率较低，但相对更多地投入工蚁培育。本研究结果证实，行为综合征可源于生活史策略的差异，这为连接动物个性与生活史理论两大研究领域提供了证据，并支持采用整合式研究方法的可行性。