重复遭遇战对雌性黑线仓鼠生理状态的影响

以独居型啮齿动物——黑线仓鼠(Cricetulus barabensis)为对象,主要测定了与优势-从属关系有关的体重、生理状态和粪便激素变化规律相关的参数。野生成年仓鼠捕获于鲁西南山区农田并于实验室内单独饲养。按照陌生和体重匹配的原则配对,实验动物在中立竞技场中每天进行15 m in的遭遇战并收集粪便,连续28 d。以攻击行为、防御行为、社会行为、非社会行为确定个体的优势-从属地位。用于实验的动物共33只。行为实验结束后,将动物解剖,确定其繁殖及生理状态。结果表明:4周重复遭遇战期间,(1)优势雌体体重显著增加;(2)肾上腺指数显著降低;(3)雌体肾上腺指数与卵巢指数无显著的相关关系;(4)雌体粪便皮质醇及雌二醇含量随时间表现出明显的波动,但优势与从属个体间差异不显著;(5)优势雌体的粪便雌二醇含量与皮质醇含量呈显著的正相关关系。研究结果提示,重复遭遇战未影响雌体的存活及潜在繁殖能力,这可能与黑线仓鼠的独居生活方式有关。

Effects of repeated encounters on physiological status in female striped hamsters (Cricetulus barabensis)

Striped hamsters (Cricetulus barabensis), living in a solitary lifestyle in the field, exhibited marked dominant subordinate relationship among individuals, and, for females, the body mass, physiological status and faecal hormones level were related to lifestyle and inter-individual relationships. Total 87 adult female hamsters were captured from cropland of a mountainous area in southwest of Shandong province, and all experimental animals were individually housed in cages for 6 months. Animals were given free access to commercial food pellets and water throughout the holding period. Based on matching in body mass, every two unfamiliar female hamsters were given an encounter within arena for 15 min. The faeces of each experimental hamster were collected every day for 28 consecutive days. In order to determine the dominant-subordinate relationships of animals, aggressive behavior, defense, social behaviors and nonsocial behaviors among individuals were quantified everyday. Thirty three female hamsters were tested, and were then autopsied at the end of investigation, and the physiological and reproductive status was checked. Our results showed that (1) during chronic social conflicts, body mass of dominant female hamsters increased significantly; (2) adrenal gland index of dominants decreased significantly; (3) ovary index did not correlated with adrenal gland index in both dominant and subordinate individuals; (4) the faecal cortisol and estradiol concentrations of female fluctuated significantly with time lapse, but the difference was insignificantly between dominant and subordinate females; (5) the faecal cortisol level correlated positively and significantly with estradiol level of dominant females. Our data implied that repeated encounters did not affect the survival and potential reproduction capabilities of female hamsters, which might be attributed to the solitary lifestyle of this species.