本文以分布于鲁西南山区的黑线仓鼠雄体为对象,通过测定重复遭遇战(repeated encounters)对黑线仓鼠体重、生理指标等参数的作用,以期阐明社群冲突(social conflict)对黑线仓鼠生理状态的影响。研究结果表明:在4周的重复遭遇战过程中,参与冲突个体的体重增长率略有降低,但未达到显著水平;粪便肾上腺皮质激素(GCs)含量呈现波动性变化,在整个遭遇战过程中,优势个体与从属个体的GCs含量交替显著升高,与冲突时间及个体社群地位均有关;优势个体保持较高的睾酮水平,利于其增强攻击行为和获得优势地位;从属组雄体的肾上腺显著增大,但生殖腺间差异不显著;HPA轴对HPG轴具有显著的抑制效应,肾上腺分泌的皮质醇可显著抑制个体的睾酮分泌,二者呈显著的负相关关系。这些数据表明,黑线仓鼠雄体可通过斗殴行为建立明确的优势一从属关系,睾酮可促进个体优势地位的形成并受到肾上腺皮质醇抑制;HPA轴对HPG轴的抑制未能在器官指数方面得到证实。从属个体受到胁迫,对优势雄性黑线仓鼠野外生存和繁殖有重要意义。
We examined the body mass and physiological states related to solitary lifestyle and dominant-subordinate relationships in male striped hamsters ( Cricetulus barabensis). Wild adult hamsters were captured from farmland in mountainous areas in southwest of Shandong province and caged singly in the laboratory during the breeding season. The experimen- tal hamsters were subjected to 4 weeks staged dyadic encounters, and the faeces were collected every day for 28 consecutive days by pairing two unfamiliar and weight-matched males in a neutral arena. In order to determine dominant or subordinate status, aggressive behavior, defense, social and nonsocial behaviors were quantified every day. Animals were then necropsled and their physiological and reproductive state assessed. Our results suggested that 1 ) an increase of body mass could not be depressed by social conflict of male hamsters ; 2) adrenal gland index of subordinate animals increased significantly ; 3 ) the concentration of faecal GCs was related to the social conflict' s time and an individual' s social status ; 4) the dominant individual maintained a high testosterone level, which favored its aggressive behavior and facillitated the dominant status ; 5 ) the cortisol suppressed testosterone secretion within all treatment groups caused the testosterone to fall to the low level. These data show that formation of dominance-subordinate relationships could be determined by aggressive behavior; testosterone level improved the formation of dominance of males, but this was in turn depressed by cortisol level. Organ index data suggested that the HPA axis did not suppress the HPG axis. Subordinate animals were stressed, which benefited survival and reproduction of dominant male hamsters in the field.