雄性布氏田鼠对不同熟悉程度和动情状态下雌鼠气味的辨别

通过雄性布氏田鼠（Microtus brandti)对配偶和陌生雌鼠气味的辨别实验发现：（1）雌鼠动情状况对雄鼠气味行为反应的影响,当配偶雌鼠处于动情期时,被试雄鼠对动情陌生雌鼠巢垫物的溴闻和舔舐的持续时间都明显多于对非动情陌生雌鼠巢垫物的嗅闻和舔舐时间,而其他行为没有明显判别当配偶雌鼠处于非动情期时,雄鼠对动情的和非动情的陌生雌鼠的气味行为反应都没有明显判别当陌生雌鼠处于动情期时,被试雄鼠对动情配偶气味的嗅闻时间明显多于对非动情配偶的嗅闻时间,而其他行为反应没有明显差异;当陌生雌鼠处于非动情期时,被试雄鼠对动情配偶雌鼠巢垫物的嗅闻时间,挖掘频次,舔舐频次和时间都明显多于对非动情配偶气味的嗅闻,而且雄鼠在动情配偶气味周围搔扒体侧行为的发生频次和持续时间也多于在非动情配偶气味周围的搔扒行为;（2）熟悉性对雄鼠气味行为反应的影响,当配偶雌鼠和陌生雌鼠都处于动情期或都处于非动情期时,被试雄鼠对陌生雌鼠气味的探究行为（嗅问、挖掘和舔噬）和搔扒体侧行为明显多于对配偶雌鼠气味的探究;雄鼠访问陌生雌鼠气味源箱的频次和在其中的停留时间也都多于访问配偶雌鼠气味源箱的频次和停留时间;当配偶雌鼠处于动情期而陌生雌鼠处于非动情期时,被试雄鼠对配偶气味的嗅闻,挖掘和自身修饰行为明显多于对陌生雌鼠气味的行为反应,进入配偶气味源箱中的访问频次也多于进入陌生雌鼠气味源箱的访问频次。结果说明：雌鼠与被试雄鼠的熟悉程度和雌鼠的动情状况直接影响雄性布氏田鼠的社会探究和气味选择行为,即雄鼠偏好并选择动情雌鼠和陌生雌鼠,雄性布氏田鼠对雌鼠气味的行为反应也表现出田鼠属动物典型的多配制种类特征。     

布氏田鼠在不同光周期下对陌生个体尿液和粪便的气味辨别

研究了成年布氏田鼠在10min内,对不同光照周期下（长光照：LD;短光照：SD）陌生雌／雄个体尿液和粪便两种单一个体气味源的气味行为反应,实验发现：所有雌雄被试鼠对LD气味源比SD气味源表现出更多的嗅闻行为。LD和SD被试鼠对同性／异性尿液气味的嗅闻行为没有表现出明显的差别,但LD被试雄鼠对陌生雌鼠粪便的嗅闻频次显多于SD被试雄鼠,从嗅闻行为特征量（嗅闻行为占所有行为的百分比）来看,所有LD和SD被试雌,雄鼠对尿液的嗅 明显多于粪便,除SD粪便气味外,被试鼠对异性气味源的嗅闻明显多于同性,实验结果表明：作为两种个体气味源,尿液和粪便都带有季节性信息,而且是具有性别特性的。异性的个体气味源比同性的个体气味源更具吸引力;长光照动物的个体气味比短光照动物的气味更具吸引力。     

雌性布氏田鼠对雄鼠气味的辨别

通过雌性布氏田导其配偶和陌生雄鼠气味的辨别实验,以及无交配经历的成年雌鼠对社会等级不同的陌生雄鼠气的辨别实验发现,有生育经历的雌鼠对陌生雄鼠气味的探究行为明显多于对配偶气味的控究,但雌鼠在配偶雄鼠气味周围的停留时间、自身修饰行为和何处行为的发生频次和持续地陌生雄鼠,没有交配经历的雌鼠对处于从鼠地位的雄性个体气味探究行为多于对优势雄性的控究,而其他行为表现没有明显差异。表明,雌性布氏田鼠可以利用气味     

雄性等级对布氏田鼠雌性选择的影响

利用监控录像以及特定行为记录的方法,研究了雄性等级对布氏田鼠气味选择和个体选择的影响。结果表明不论是气味选择还是个体选择,雌鼠动情状态不影响对雄鼠的选择频次,但是动情雌鼠在自我修饰行为频次上高于非动情雌鼠。此外,在气味和个体选择的优先权方面,动情雌鼠更多的优先选择优势雄鼠的气味和个体并与之交配,而非动情雌鼠更多的先选择从属雄鼠的气味和个体。总之,不论是气味选择还是个体选择,布氏田鼠不仅受到被选择雄鼠的地位影响,还与雌鼠的生理状态有关。     

棕色田鼠探究行为对同种个体气味源反应格局的分析

通过观察非动情期的棕色田鼠对麻醉的同种个体身体气味源的探究行为 ,包括雄鼠对麻醉雄鼠和雌鼠的嗅闻、雌鼠对麻醉雄鼠和雌鼠的嗅闻 ,分析了棕色田鼠在社会探究中对不同气味源的反应格局。结果表明 ,棕色田鼠对同种个体肛殖区和面部的嗅闻频次及嗅闻持续时间最多 (P <0 0 5 ) ;对背部、腹部、肋部嗅闻的频次和持续时间较少。在对同一部位的嗅闻中 ,在嗅闻频次上 ,雄鼠对雄鼠的嗅闻、雌鼠对雌鼠的嗅闻以及雌鼠对雄鼠的嗅闻都显著多于雄鼠对雌鼠的嗅闻 (P <0 0 5 ) ;在嗅闻时间上 ,性别组合对同一部位的探究行为没有显著影响 ,但气味源与性别组合有交互作用 (P <0 0 5 ) ,影响探究行为。这些结果说明棕色田鼠的肛殖区和面部是重要的气味源 ,而且在对同一气味源的探究中存在性别差异。但在非动情期 ,异性间的探究并不总是高于同性间的探究     

不育雄性对布氏田鼠气味选择和个体选择的影响

在Y型迷宫中进行了动情雌性布氏田鼠对结扎不育雄鼠及正常雄鼠气味和个体的选择实验。气味选择实验以动物的巢垫物为气味源,个体选择直接采用结扎雄性和正常雄性作为被选择个体。记录雌性布氏田鼠对选择源的选择频次以及停留时间。结果表明,无论在气味选择或是个体选择中,动情雌性布氏田鼠在选择频次和停留时间上都具有显的正相关性,而且都没有明显表现出对某—气味或个体选择上的偏好。激素测定结扎不育后雄鼠血清中的睾酮和皮质醇含量有听升高．但这种变化没有对雌性布氏田鼠的选择产生影响。     

雌性根田鼠断奶后对亲本尿气味的记忆

为研究亲子分开后雌性根田鼠对亲本气味的记忆持续时间，分别在未分开（20日龄）、分开10 d（30日龄）、20 d（40日龄）、30 d（50日龄）、40 d（60日龄）时，以新鲜尿作气味源，在行为观察箱中记录雌性根田鼠对不同气味源的行为响应模式，结果表明：(1) 未分开时，雌鼠遭遇父本气味时自我修饰的频次极显著高于陌生雄鼠气味，在分开10 d时，雌鼠接近父本气味的频次显著多于接近陌生雄鼠气味的频次，其对前者反标记显著少于后者；(2)分开20 d后，雌鼠对父本和陌生雄鼠气味的行为响应无明显差异；(3) 未分窝时，雌性根田鼠幼仔对母本和陌生雌鼠气味的行为响应无差异；（4）分开10—40 d时，雌性根田鼠对母本和陌生雌鼠气味表现出不同的行为响应模式。以上结果表明，在亲子分开10 d时，雌鼠仍能识别父本和陌生雄鼠的气味；分开20 d后，雌鼠不再能够识别父本和陌生雄鼠的气味；在亲子分开40 d时，雌鼠仍能识别母本和陌生雌鼠的气味。因此，雌鼠对父本气味的嗅觉记忆时间可以持续到亲子分开10—20 d之间；而对母本气味的嗅觉记忆时间则可以持续到亲子分开40 d以上。     

雌性根田鼠断奶后对亲本尿气味的记忆

为研究亲子分开后雌性根田鼠对亲本气味的记忆持续时间,分别在未分开(20日龄)、分开10d(30日龄)、20d(40日龄)、30d(50日龄)、40d(60日龄)时,以新鲜尿作气味源,在行为观察箱中记录雌性根田鼠对不同气味源的行为响应模式,结果表明(1)未分开时,雌鼠遭遇父本气味时自我修饰的频次极显著高于陌生雄鼠气味,在分开10d时,雌鼠接近父本气味的频次显著多于接近陌生雄鼠气味的频次,其对前者反标记显著少于后者;(2)分开20d后,雌鼠对父本和陌生雄鼠气味的行为响应无明显差异;(3)未分窝时,雌性根田鼠幼仔对母本和陌生雌鼠气味的行为响应无差异;(4)分开10—40d时,雌性根田鼠对母本和陌生雌鼠气味表现出不同的行为响应模式。以上结果表明,在亲子分开10d时,雌鼠仍能识别父本和陌生雄鼠的气味;分开20d后,雌鼠不再能够识别父本和陌生雄鼠的气味;在亲子分开40d时,雌鼠仍能识别母本和陌生雌鼠的气味。因此,雌鼠对父本气味的嗅觉记忆时间可以持续到亲子分开10—20d之间;而对母本气味的嗅觉记忆时间则可以持续到亲子分开40d以上。     

雄性柴达木根田鼠断奶后对亲本尿气味的记忆

为了研究亲子分开后雄性柴达木根田鼠(Microtus limnophylus)对亲本尿气味的记忆持续时间,分别在未分开(20日龄),以及分开10d(30日龄)、20d(40日龄)、30d(50日龄)、40d(60日龄)时,以新鲜尿作为气味源,在行为观察箱中记录雄性柴达木根田鼠对不同气味源的行为响应模式.结果表明:(1)未分开时,雄鼠对父本气味的接近频次显著高于陌生雄鼠气味;分开10d时,雄鼠对父本气味的访问时间显著多于对陌生雄鼠气味的访问时间;分开20d时,雄鼠对陌生雄鼠气味的接近潜伏期极显著短于父本,对陌生雄鼠气味的访问时间极显著长于父本,其遭遇父鼠气味时的自我修饰频次显著少于陌生雄鼠气味.(2)分开30d后,雄鼠对父本和陌生雄鼠气味的行为响应没有明显差异.以上结果表明,在亲子分开20d时,雄鼠仍能识别父本与陌生雄鼠的气味;在分开30d后,雄鼠不再能够识别父本与陌生雄鼠的气味.(3)在未分窝时,雄性柴达木根田鼠幼仔对母本和陌生雌鼠气味的行为响应没有任何差异.(4)在分开10d时,雄性柴达木根田鼠对母本和陌生雌鼠气味表现出不同的行为响应模式;分开20～40d时,雄鼠对母本与陌生雌鼠气味的行为响应没有任何差异.以上结果表明,在亲子分开10d时,雄鼠仍能识别母本与陌生雌鼠的气味;在分开20d后,雄鼠不再能够识别母本与陌生雌鼠的气味.因此,雄鼠对父本气味的嗅觉记忆时间可以持续到亲子分开20～30d之间;其对母本气味的嗅觉记忆时间可以持续到亲子分开10d时.     

成年布氏田鼠对个体气味信号的识别与记忆

将配对饲养的成年雌雄布氏田鼠分离, 通过分开单独饲养12 h , 1 d、2 d、3 d、5 d 和7 d 后雌、雄鼠对原配偶异性和陌生异性气味信号的选择实验, 探讨布氏田鼠对气味信号的识别和记忆。实验表明: 在分离12 h 和1 d 后, 雄鼠对陌生雌性气味的选择和探究行为显著多于对熟悉雌鼠气味, 而雌鼠对两种气味并未表现显著的探究差异; 布氏田鼠对气味信号的记忆维持的强度和时间随个体不同而产生差异, 雄鼠在分离后12 h、1d、2 d 中对陌生雌鼠气味均表现出差异明显的探究行为, 而后, 各项探究行为的差异均不明显。雌鼠探究行为变化比较缓慢。据此推测雄鼠对气味的记忆维持在2 d 左右。     

Seasonal Changes in Scents and Responses to them in Meadow Voles: Evidence for the Co-evolution of Signals and Response Mechanisms

Relatively little is known about the mechanisms of communication during the non-breeding season in species that are seasonal breeders. Previous work with meadow voles, Microtus pennsylvanicus, housed under long photoperiods, has shown that they prefer the odors of opposite-sex conspecifics. In this paper, we investigated the effects of short photoperiod on preferences for sex-specific odors and the production of such odors. Short-photoperiod females preferred anogenital and fecal scents of other short-photoperiod females over those of males, but did not show sexual preferences for three other scents. Short-photoperiod males did not exhibit sexual preferences for any of the odors. Furthermore, scents from short-photoperiod voles did not elicit sex-specific preferences in long-photoperiod voles, and scents from long-photoperiod voles did not elicit preferences from short-photoperiod voles. These and previous results indicate that both the odors and responses to odors change seasonally and that long-photoperiod voles respond selectively to scents from long-photoperiod voles and short-photoperiod voles respond selectively to scents from short-photoperiod voles. Taken together, these results suggest the co-evolution of seasonal changes in scents and in perceptual or other response mechanisms.     

Preferences for salivary odor cues by female hamsters

There is a growing body of data which indicates that saliva may function as a chemosignal in mammals. The salience of this cue in hamsters is investigated. Twelve females were tested in a four-choice olfactorium to determine whether the subjects could differentiate and demonstrate a preference for salivary cues as a function of the dominance status of the stimulus donors and the subjects estrous state. Clear differences in responding were found for estrous as opposed to diestrous females. Estrous females detected and exhibited a preference for male stimuli on the basis of entry and approach measures. Subjects were also found to exhibit sniffing preferences for male odors and possible an avoidance of female odors relative to the saline control. Estrous females appeared to be unable to distinguish between dominant and subordinate males.     

Olfactory preferences, scent marking, and "proceptivity" in female hamsters

Two appetitive sexual behaviors of female hamsters, attraction to odors of males and vaginal scent marking, were investigated and the correlations of each to reproductive states were determined. Both estrous and diestrous females were more attracted to the odors of intact males than to the odors of females or castrated males; this differential attraction was more pronounced for estrous females. Lactating females, but not pregnant females, were also preferentially attracted to odors of intact males. Thus, odors alone provided sufficient information to allow sexual discrimination by females, and estrous, diestrous, and lactating females were preferentially attracted to odors of intact males whereas pregnant females were not. Reproductive condition had no influence on responses to odors of castrated males or diestrous females. Vaginal scent marking was strongly influenced by reproductive state: Marking frequency was low in estrous, pregnant, and early lactation females, but high in late lactation and diestrous females, suggesting a function of advertisement of approaching receptivity. Thus sexual preferences based on olfactory cues and vaginal scent-marking frequency differed in their relationships to reproductive conditions. It is suggested that in other species such relationships between appetitive sexual behaviors and reproductive condition will depend on the species social organization, ecological niche, and taxonomic group, and consequently that the concept of preceptive behaviors should be broadened to include all appetitive sexual behaviors of females, not just those that are correlated with the hormonal state characterizing estrus.     

Regulation of sexual odor preference by sex steroids in the posterodorsal medial amygdala in female rats

Our previous study in male rats demonstrated that bilateral administration of flutamide, an androgen receptor (AR) antagonist, into the posterodorsal medial amygdala (MePD) increased the time sniffing male odors to as high as that sniffing estrous odors, eliminating the preference for estrous odors over male odors. This made us speculate that under blockade of AR in the MePD, testosterone-derived estrogen acting on the same brain region arouses interest in male odors which is otherwise suppressed by concomitant action of androgen. In cyclic female rats, endogenous androgen has been thought to be involved in inhibitory regulation of estrogen-activated sexual behavior. Thus, in the present study, we investigated the possibility that in female rats the arousal of interest in male odors is also normally regulated by both estrogen and androgen acting on the MePD, as predicted by our previous study in male rats. Implantation of either the estrogen receptor blocker tamoxifen (TX) or a non-aromatizable androgen 5α-dihydrotestosterone (DHT) into the MePD of ovariectomized, estrogen-primed female rats eliminated preference for male odors over estrous odors by significantly decreasing the time sniffing male odors to as low as that sniffing estrous odors. The subsequent odor discrimination tests confirmed that the DHT and TX administration did not impair the ability to discriminate between male and estrous odors. These results suggest that in estrous female rats estrogen action in the MePD plays critical roles in the expression of the preference for male odors while androgen action in the same brain region interferes with the estrogen action.     

Androgen receptor blockade in the posterodorsal medial amygdala impairs sexual odor preference in male rats

The present study was designed to investigate the role of androgen in the medial amygdala (MeA) in the expression of sexual odor preference in male rats. Gonadally intact, sexually experienced male rats received bilateral administration of flutamide, an androgen receptor (AR) blocker, aimed at either the posterior dorsal part (MePD) or the anterior dorsal part (MeAD) of the MeA through inner cannulae inserted into the implanted guide cannulae. Prior to flutamide administration, all subjects spent longer sniffing volatile odors from an estrous female than those from a sexually active male. Experiment 1 demonstrated that the preference for the female odors over the male odors was eliminated during flutamide administration into the MePD, but not into either the MeAD or outside MePD/MeAD. This elimination of the female-directed odor preference resulted from increase of time sniffing the male odors rather than decrease of time sniffing the estrous odors. In Experiment 2, odor discrimination tests confirmed that the flutamide administration into the MePD did not induce impairment in the ability of the subjects to discriminate the estrous odors from the male odors. These results demonstrated that activation of AR in the MePD plays a critical role in the expression of the preference for estrous odors over male odors. AR blockade, however, seemed to induce a preference for male odors rather than reduce the existing preference for estrous odors, suggesting a complicated regulation of sexual odor preference by sex steroids.     

Self-grooming induced by sexual chemical signals in male root voles (Microtus oeconomus Pallas)

Sniffing is one-way animals collect chemical signals, and many males self-groom when they encounter the odor of opposite-sex conspecifics. We tested the hypothesis that sexual chemical signals from females can induce self-grooming behavior in male root voles (Microtus oeconomus Pallas). Specifically, we investigated the sniffing pattern of male root voles in response to odors from the head, trunk, and tail areas of lactating and non-lactating females. The self-grooming behavior of males in response to female individual odorant stimuli was documented, and the relationship between self-grooming and sniffing of odors from the head, trunk, and tails areas were analyzed. Sniffing pattern results showed that males are most interested in odors from the head area, and more interested in odors from the tail as compared to the trunk area. Males displayed different sniffing and self-grooming behaviors when they were exposed to odors from lactating females as compared to non-lactating females. Males also spent more time sniffing and engaged in more sniffing behaviors in response to odors from the lactating females’ tail area as compared to the same odors from non-lactating females. Similarly, males spent more time self-grooming and engaged in more self-grooming behaviors in the presence of individual odors from lactating females as compared to individual odors from non-lactating females. Partial correlation analyses revealed that the frequency of self-grooming was significantly correlated with the frequency of tail area sniffs. Results from this experiment suggest that sexual attractiveness of lactating females is stronger than that of non-lactating females. Furthermore, the partial correlation analysis demonstrated that self-grooming in males is induced by odors from the tail area of females. Collectively, these results support the hypothesis that sexual chemical signals from females can induce self-grooming behavior in male root voles. Self-grooming may also reflect the groomer's sexual motivation and facilitate sexual interactions.     

雌性布氏田鼠对不同共居时间雄性气味的识别与记忆

啮齿动物的社会识别包括对化学信号的辨别、学习和记忆。田鼠属动物雌雄成年个体共居一定时间后,可以利用气味信号来识别配偶。本研究将成年雌雄布氏田鼠配对饲养12 h、18 h、24 h,确认发生交配行为形成配对关系后,分开单独饲养6 h,取配偶雄鼠和陌生雄鼠巢垫物作为个体气味,在气味选择箱中观察雌鼠对配偶雄鼠和陌生雄鼠气味信号的探究和选择行为,从而探讨不同共居时间雌性布氏田鼠对配偶气味信号的识别与记忆的影响。研究结果表明:共居时间影响雌性布氏田鼠对配偶气味的识别与记忆;共居时间越长,雌鼠在气味探究和选择时间上对配偶气味偏好越明显;共居24 h 后,雌性布氏田鼠能够识别出配偶雄鼠的气味信号并形成记忆,这样的记忆维持时间至少是6 h。