Wang Dawei, Wang Zhenlong, Zhang Jianxu, Zhang Jianjun, Zhang Zhibin
State Key Laboratory of Integrated Management of Pest Insects and Rodents in Agriculture, Institute of Zoology, Chinese Academy of Sciences, Datun Road, Chaoyang District, Beijing, 100101, China.
Physiol Behav. 2009 Jun 22;97(3-4):347-52. doi: 10.1016/j.physbeh.2009.03.002. Epub 2009 Mar 16.
Agonistic behavior is crucial for conspecific members to maintain a social hierarchy, optimum population density, and high fitness. It is known that agonistic behavior and social ranking often interact with hormones such as testosterone (T) and glucocorticoids (GCs). The challenge hypothesis states that T levels in males are promoted by the agonistic behaviors of other males and has been widely testified in many taxa of vertebrates, even in humans, but seldom attempted in rodents. Here, we examined how fecal T and corticosterone (CORT) concentrations changed during prolonged social conflict in male greater long-tailed hamsters (Tscheskia triton). Dyads were subjected to 5 min staged encounters daily for 15 days during which agonistic and social behaviors were recorded and fecal hormone concentrations were determined by radioimmunoassay. Our results showed that pairwise male hamsters developed overt and stable dominant-subordinate relationships rapidly and that the agonistic behavior decreased over the course of the experiment. Dominant males exhibited more frequent flank marking and locomotion and shorter latency to initial attack than their subordinate counterparts. Testosterone levels were significantly increased in both dominant and subordinate males during early encounters, but T and CORT levels were higher in subordinate males. After five encounters, we found no difference between hormone levels and behavior for all males, implying some kind of behavioral and physiological habituation. This complex pattern of hormonal change during social conflict is discussed and correlations between behavioral and physiological habituation are hypothesized.
攻击行为对于同种个体维持社会等级制度、最佳种群密度和高适应性至关重要。已知攻击行为和社会等级通常与睾酮（T）和糖皮质激素（GCs）等激素相互作用。挑战假说指出，雄性的T水平会因其他雄性的攻击行为而升高，这在许多脊椎动物类群中甚至在人类中都得到了广泛验证，但在啮齿动物中很少进行尝试。在此，我们研究了雄性大仓鼠（Tscheskia triton）在长期社会冲突期间粪便中T和皮质酮（CORT）浓度是如何变化的。将成对的大仓鼠每天进行5分钟的阶段性对抗，持续15天，在此期间记录攻击行为和社会行为，并通过放射免疫分析法测定粪便激素浓度。我们的结果表明，成对的雄性大仓鼠迅速建立起明显且稳定的优势-从属关系，并且在实验过程中攻击行为减少。优势雄性比从属雄性表现出更频繁的胁腹标记和活动，以及更短的首次攻击潜伏期。在早期对抗中，优势雄性和从属雄性的睾酮水平均显著升高，但从属雄性的T和CORT水平更高。经过五次对抗后，我们发现所有雄性的激素水平和行为之间没有差异，这意味着某种行为和生理习惯化。我们讨论了社会冲突期间这种复杂的激素变化模式，并对行为和生理习惯化之间的相关性进行了假设。
