【作者】 孙俊华；

【导师】 张洪海；

【作者基本信息】 曲阜师范大学 ， 动物学， 2006， 硕士

【摘要】 本研究以分布于鲁中南山地丘陵的黑线姬鼠(Apodemus agrarius)为研究对象,利用黄鼬(Mustelia siberica)肛腺模拟田鼠天敌的气味源,系统研究了黑线姬鼠在长期黄鼬气味影响下体重和激素水平以及繁殖行为的改变等。主要研究结论如下: 1.利用Agilent1100型高效液相色谱-质谱联用仪,1,2-苯并-3,4-二氢咔唑-9-乙基肼基甲酸酯作为柱前衍生化试剂,对四种类固醇化合物的衍生化和色谱分离条件进行了优化选择。借助在线的柱后质谱方法进行了衍生物的定性鉴定。建立了快速、灵敏地测定黑线姬鼠粪便中类固醇的方法,测定结果满意。 2.雌雄黑线姬鼠在21天黄鼬气味处理下体重都明显下降,但是雌体反应更迅速。单因素方差分析表明雄性黑线姬鼠的体重显著下降[F(1,49)=7.65,P=0.008],与处理前相比在第14天(P=0.016)和第21天(P=0.031)显著下降;雌性黑线姬鼠的体重也显著下降[F(4,36)=2.881,P=0.036],而与处理前相比在第7天就开始持续下降(day7,P=0.003;day14,P=0.006;day21,P=0.01)。 3.捕食风险条件下雌性黑线姬鼠内分泌反应更强烈,低的孕酮水平以及高的皮质醇水平可能是雌性黑线姬鼠繁殖抑制的生理因素。单因素方差分析表明雄性黑线姬鼠的皮质酮水平在第21天比处理前显著升高[F(1,39)=6.923;P=0.013],而皮质醇[F(4,35)=1.35,P=0.27]和睾酮[F(4,35)=0.424,P=0.79]没有变化。在21天的长期气味处理下雌性黑线姬鼠的皮质酮水平在第7天显著升高(P=0.004,LSD post hoc tests),皮质醇水平发生显著改变[F(1,39)=5.84,P=0.021],第14天(P=0.037)和第21天(P=0.032)显著高于气味处理前水平;孕酮水平在21天的气味处理下显著下降[F(4,35)=2.87,P=0.037],第21天(P=0.002)比处理前水平显著下降。 4.捕食风险条件下雌性黑线姬鼠繁殖行为的反应更敏感。可能是繁殖价不等。黄鼬气味处理下雄性黑线姬鼠的修饰行为(Z=2.38,P=0.015)和探究行为(Z=2.42,P=0.015)频次显著低于对照组;在繁殖交配期交配行为频次更多还原

【Abstract】 Predation is one of the strongest selective pressures. Mustelid odors have been shown to suppress breeding in voles from cyclic populations. The mechanism behind the suppression is unknown. Predation risk has been shown to alter animal behavior in several ways based on genotypic responses and/or phenotypic flexibility of individual’s feeding behavior or habitat use. In most studies, predation risk reduced the general activity and feeding of prey individual. Breeding activities, such as mate-searching, copulation and egg-laying and parental activity, can also increase an individual’s susceptibility to predation. Despite numerous studies on other taxonomic groups and behavioral traits, little is known about the effects of predation on mating behavior of higher verebrates, especially mammals. One more possible mechanism for breeding suppression is a physiological one based on hormonal changes caused by predation risk. However, relatively few studies on physiological and psychological stress have worked with predators.Measuring steroid hormone metabolites in fecal samples has become a widely appreciated technique, because it has been proved to be a powerful noninvasive tool that provides important information about an animal’s endocrine status (adrenocortical activity and reproductive status). Measurement of these hormones in fecal extracts by high-performance liquid chromatography (HPLC) was validated using chemical derivatization, mass spectrometry.The objectives of the present study were (1) to develop a method for assessment of fecal glucocorticoids (specifically cortisol and corticosterone) as ameasure of stress in rodent, specifically striped field mice (Apodemus agrarius), and (2) to discuss the mechanism for breeding suppression based on hormonal changes caused by predation risk, and (3)to investigate the possible change in the mating behavior between experimental and control groups and to examine whether paired mice show intersexual differences in their response to predation risk. The main results of this are as follow.1. A simple and sensitive method for the determination of steroid compounds extracted from mice feces using 1, 2-benzo-3, 4-dihydrocarbazole-9-ethyl-carbonylhydazine (BCEC) as pre-column derivatization reagent by high-performance liquid chromatography in combination with a gradient elution with fluorescence detection and mass spectrometric identification has been developed. Studies on derivatization conditions indicate that steroid compounds react with BCEC at 65 °C within a two-hour period in the presence of trichloroacetic acid (TCA) catalyst with acetonitrile as reaction co-solvent to give the corresponding sensitive fluorescence derivatives. The fluorescence excitation and emission wavelengths are set at A. ex 333 and ^ em390nm, respectively. The identification of steroid derivatives is performed under APCI source in positive-ion mode. Correlation coefficients for steroid derivatives are >0.9999, and detection limits (at signal-to-noise ratio of 3:1) are 47.3—71.2 finol. The established method is sensitive and reproducible for the determination of steroid compounds from real samples with satisfactory results.2. The weights of both females and males differed significantly between during the days of stress treatment, but females were more frangibility. Males lost weight under predator odor significantly on dayl4 (P=0.016) and day21 (P=0.031) contrast to baseline, while female mice body mass began to decrease significantly on day7, lasted to day21 (day7, P=0.003;day 14, P=0.006;day21, P=0.01).3. Our data suggest that there is difference in mechanism between male and female mice to adjust endocrine responses to predator odor. A one-way ANOVA revealed that long-term predator odor (21 day) treatment did not altercortisol[F(4,35)=1.35,P=0.27] and testosterone[F(4,35)= 0.424,P=0.79] levels in male striped field mice, but corticosterone level on day21 was higher than that of baselines [F (l,39)=6.923;P=0.013]. Cortisol levels in female mice were significantly higher that those of baselines [F (1, 39) =5.84, P=0.021];LSD post hoc tests indicated that average cortisol level in individuals on baselines was significantly lower than that of dayl4 (P=0.037), and individuals on day21 (P=0.032). Long-term stress treatment did not alter corticosterone levels in female mice [F (4, 35) =2.39, P=0.069], but LSD post hoc tests indicated that average corticosterone level in individuals on day7 was significantly higher than that of baselines (P=0.004). One-way ANOVA analyses revealed that long-term predator odor treatment restrained female mice from secreting progesterone [F (4, 35) =2.87, P=0.037], LSD post hoc tests indicated that average progesterone level in individuals on day21 was significantly lower than that of baselines (P=0.002).4. Our results suggest that under predator odor treatment female behavior have most changed. This difference in the reaction between the sexes is in accordance with predictions for a situation where reproductive costs are divided unequally between the two sexes. Predation risk simulated by odor decreased the investigating (Z=2.38, P=0.015), self-grooming behavior (Z=2.42, P=0.015) and mating behavior (Z=2.83, P=0.004) of the experimental male mice compared to control ones, and the accumulated time of investigating (Z=2.38, P=0.017), self-grooming behavior (Z=2.08, P=0.037) and mating behavior (Z=3.36, P=0.0007) were significant decreased. While the general activity, chasing, aggressive behavior and the accumulated time were not observed significant differences. Under predator odor treatment, the self-grooming, investigating, aggressive, solciation walk and lordosis behavior frequencies and accumulated times were significantly decreased.更多还原