山西十二种鼠巢结构的观察

鼠巢随着鼠种的不同而有差异。但是多建筑在地下或隐蔽的地方,难以看到。研究鼠巢的目的就在于阐明其生物学中的某些专门性的问题,为植保工作者依据鼠巢特点,识别鼠种消灭鼠害提供资料。 我们于1963—1965年先后在桑干河,滹沱     

利用转录组数据分析高原鼢鼠和裸鼹鼠基因的趋同进化

地下鼠由于长期适应于地下洞道生活,在诸多生物学特征上都产生了一定的趋同进化现象,但目前尚未在分子水平分析其趋同进化特征。本研究利用高通量测序数据,从氨基酸位点变化和基因表达量水平,分析两种亲缘关系较远的地下鼠--高原鼢鼠和裸鼹鼠的趋同进化。氨基酸位点变化分析显示,两种地下鼠的54 个基因都存在至少一个理论趋同进化位点,其中13 个基因可以找到相对明确的表型功能注释。基因表达量分析显示,两种地下鼠在转录组水平的总体表达模式上存在趋同效应;有103 个基因在两种地下鼠脑中的表达量是作为对照的地上鼠(小鼠、豚鼠)表达量的3 倍以上,其中有20 个基因可以找到相对明确的表型功能注释。本研究的结果表明,高原鼢鼠和裸鼹鼠为了适应地下生活方式,在氨基酸序列和基因表达量水平上都产生了一定程度的趋同进化。其中,低氧适应相关基因(氧运输、氧代谢、DNA 修复等)是地下鼠进化适应的最重要组成部分,挖掘器官(尤其是肌肉)功能相关基因的重要性次之,能量代谢及平衡相关基因也是地下鼠适应性进化的关键要素。     

高原鼠兔和中华鼢鼠气体代谢的研究

本项研究试图通过对青海农牧区的两种主要害鼠:高原鼠兔(Ochotona curzoniae Hodgson)和中华鼢鼠(Myospalax fontanierii Milne-Edwards)气体代谢的测定,比较在高海拔、气候寒冷、缺氧的环境条件下,地面鼠和地下鼠的代谢适应性及与此相联系的某些血液值的特征。     

高原鼢鼠种群能量动态的研究 Ⅱ.每日能量收支模型的探讨

本文根据近年来国内外有关地下鼠种群能学研究的进展,结合地下鼠能量代谢的特点,提出了一个以平均每日代谢率为基础的估计地下鼠个体每日能量收支的经验模型。文中以高原鼢鼠为例,通过一系列的参数估计,采用本文提出的模型,计算出个体在春季的每日能收支为202.27千焦耳;日挖掘活动时间为2.61小时,相当于巢外总活动时间的80％;掘土价达57.93千焦耳/日。本文提出的模型避免了直接观测个体日挖掘活动时间这一仍难解决的问题,并把动物的能量需要同环境质量结合在一起,用定量的方式描述它们之间的关系,这不仅有助于地下鼠种群能学的研究,而且为探讨地下鼠的生境选择奠定了基础。     

甘肃鼢鼠的求偶和交配行为

甘肃鼢鼠 (Ｍｙｏｓｐａｌａｘｃａｎｓｕｓ)主要分布在我国黄土高原地区 ,该鼠的繁殖生态学已有许多报道[1～3] 。其繁殖行为尚未见报道。国内外已对高原鼢鼠 (Ｍｙｏｓｐａｌａｘｂａｉｌｅｙｉ)、裸瞎鼠 (Ｈｅｔｅｒｏｃｅｐｈａｌｕｓｇｌａｂｅｒ)、鼹形鼠 (Ｓｐａｌａｘｅｈｒｅｎｂｅｒｇｉ)和囊鼠 (Ｔｈｏｍｏｍｙｓｂｏｔｔａｅ)等地下鼠的繁殖行为作了研究[4～8] 。由于甘肃鼢鼠营严格的地下生活 ,在野外其繁殖行为无法观察。本文对室内甘肃鼢鼠的求偶行为和交配行为进行初步观察 ,将结果予以报道。1　材料和方法实验用成年甘肃鼢…     

甘肃鼢鼠的震动通讯

听觉通讯是兽类一种重要的通讯方式 ,尤其是鼢鼠 ,因其营地下独居生活 ,视觉退化 ,个体间通讯主要依赖听觉和嗅觉。Ｈｅｔｈ和Ｒａｄｏ分别在室内人工模拟洞道和野外自然洞道中采集到了鼹形鼠(Ｓｐａｌａｘｅｈｒｅｎｂｅｒｇｉ)用头敲击洞壁产生的震动波信号 ,首先发现地下鼠的震动通讯方式[1,2 ] 。甘肃鼢鼠 (Ｍｙｏｓｐａｌａｘｃａｎｓｕｓ)生活在与鼹形鼠相似的地下环境中 ,是否也同样存在震动通讯方式 ?为此 ,作者在室内利用人工模拟洞道对甘肃鼢鼠震动通讯进行了初步研究。1　材料与方法　　实验用甘肃鼢鼠捕自陕西省富县 ,室内单笼…     

地下鼠视觉系统对昼夜节律调节研究进展

地下鼠由于其特殊的生活环境,视觉系统表现出明显的退化和进化镶嵌的特征:视觉器官退化,由视觉诱导产生行为反应的脑区及视觉投射严重退化,但是有关感受光周期的"非成像"视觉通路结构高度发达.即与成像和运动知觉有关的结构退化,有助于感受光周期的结构却选择性地保留.很多研究表明地下鼠的视觉系统依然保留有感知光周期节律并产生与外界昼夜循环同步的生理功能.与光周期有关的季节性繁殖、内分泌、行为活动以及体温变化等也表现出相应节律性.本文对地下鼠昼夜节律研究现状进行了综述,旨在对地下鼠的适应性进化特征加以补充,有助于开展地下啮齿类视觉系统功能的研究,更进一步阐明生物进化与环境的关系.     

高原鼢鼠对其同类粪尿和尿道球腺的感受性

高原鼢鼠(Myospalax baileyi)是我国西北农牧区的主要害鼠之一,营地下生活;非繁殖季节独居。由于具特殊的生活方式,眼睛和耳壳均有明显退化。了解地下鼠在繁殖期间的通讯方式,对于防治鼠害有实际意义。     

鼹形田鼠的洞系结构及杀灭方法

鼹形田鼠 (Ellobius Talpinus)是我国蒙新区比较广泛分布的鼠种之一。主要栖息于山地草原和荒漠草原。营昼夜活动。以植物的根、根茎为主要食物。对草场和农田的危害,一是挖洞直接啮食、损伤牧草和农作物的根系;二是通过推到地面的大量土堆覆盖植被。在农作区引起缺苗断垅;在草场引起植被成分改变,草场退化,影响草场生产力。目前国内对其生活习性研究,尚乏报道,加之该鼠营特殊的地下生活方式,所采用的杀灭方法和杀灭效果,远不及防治其他鼠种有效。     

高原鼢鼠四肢骨的进化适应性分析

通过对比分析了高寒草甸生态系统的高原鼢鼠(Myospalax baileyi)、高原鼠兔(Ochotona curzoniae)及根田鼠(Microtus oeconomus)的四肢骨,结果表明,地下啮齿动物高原鼢鼠的四肢骨比地面种类高原鼠兔和根田鼠的对应骨骼粗壮,显示其较强的挖掘能力。与挖掘效率相关的尺骨挖掘动力臂系数,高原鼢鼠为0.3617,而高原鼠兔和根田鼠不到0.17。高原鼢鼠与其他两物种的四肢骨重量分布也明显不同:高原鼢鼠的前肢骨重量超过后肢骨,而高原鼠兔及根田鼠则正好相反;高原鼠兔及根田鼠的桡尺骨重量在四肢骨中最低,而高原鼢鼠的桡尺骨重量在四肢骨中则最高。这些特征反映了地下啮齿动物为了适应地下生活方式,其四肢骨骼系统已经发生了显著变化,这对于研究地下啮齿动物的进化适应性问题具有重要意义。     

地下啮齿动物视觉系统的形态结构与机能进化

感觉系统的适应进化机制一直是动物行为学研究的焦点。生活在特殊环境中的动物,其感觉系统在进化过程中表现出的显著差异更是引人注目。由于适应地下黑暗生活环境,地下啮齿动物感觉系统在各个组织水平都表现出进化和退化镶嵌的形态特征,其视觉系统表现得最为突出：视觉器官退化,有关图象分析结构、由视觉诱导产生行为反应的脑区及视觉投射严重退化,有关感受光周期的“非成像” 视觉通路结构高度发达。本文综述了地下啮齿动物视觉系统的结构、功能、进化与发育等方面的研究进展,旨在阐明地下啮齿动物视觉系统的特点,有助于开展地下啮齿动物视觉系统适应进化机制的研究。     

地下鼠生物学特征及其在生态系统中的作用

地下鼠生活型、行为、种群结构的特殊性,决定了此类动物对植被、土壤及生态系统作用的多样性。地下挖能改变土壤的物理环境,导致土壤类型、发育速率、营养可利用性、微地形等的变化。地下啃食直接影响植物的形态、丰富度、种间竞争、植被类型和物种多样性、生物是及群落组成构成等,植物对植食性动物的防御策略具有更明显的化学防卫特性。地下鼠与其他植食性动物种间竞争、空间利用等关系密切,是食肉动物重要的食物资源。地下鼠对生态系统生产力、空间异质性、营养结构和循环、碳素储存以及微量气体释放等生物地球化学过程均能产生影响,显示出有别于地面植食性动物的重要性和不可替代性。     

Comparative respiratory strategies of subterranean and fossorial octodontid rodents to cope with hypoxic and hypercapnic atmospheres

Subterranean rodents construct large and complex burrows and spend most of their lives underground, while fossorial species construct simpler burrows and are more active above ground. An important constraint faced by subterranean mammals is the chronic hypoxia and hypercapnia of the burrow atmosphere. The traits, regarded as “adaptations of rodents to hypoxia and hypercapnia”, have been evaluated in only a few subterranean species. In addition, well-studied subterranean taxa are very divergent to their sister groups, making it difficult to assess the adaptive path leading to subterranean life. The closely related sister genera Octodon and Spalacopus of Neotropical rodents offer a unique opportunity to trace the evolution of physiological mechanisms. We studied the ventilatory responses of selected octodontid rodents to selective pressures imposed by the subterranean niche under the working hypothesis that life underground, in hypoxic and hypercapnic conditions, promotes convergent physiological changes. To perform this study we used the following species: Spalacopus cyanus (the subterranean coruros) and Octodon degus (the fossorial degus) from central Chile. Ventilatory tidal volume and respiratory frequency were measured in non-anaesthetized spontaneously breathing animals. Acute hypoxic challenges (O₂ 1–15%) and hypercapnia (CO₂ 10%) were induced to study respiratory strategies using non-invasive whole body pletismography techniques. Our results show that coruros have a larger ventilatory response to acute hypoxia as than degus. On the other hand, hypercapnic respiratory responses in coruros seem to be attenuated when compared to those in degus. Our results suggest that coruros and degus have different respiratory strategies to survive in the hypoxic and hypercapnic atmospheres present in their burrows.     

Acoustic signals of a solitary subterranean rodent Ctenomys talarum (Rodentia: Ctenomyidae): physical characteristics and behavioural correlates

The purpose of this study was to analyse and describe vocalizations of a solitary subterranean rodent, Ctenomys talarum. In adult C. talarum five different sounds (four true vocalizations and one mechanical sound) were recorded during different behavioural contexts. Using data from the laboratory and literature, we classified these vocalizations as territorial, distress, and mating calls. We found that the vocalization range in C. talarum is shifted towards low frequencies, which transmit better in underground burrows and match well the hearing range described for other species of subterranean rodents. These low-frequency vocalizations, also found in other non-related subterranean rodents, may reflect an adaptation to the acoustic conditions of the habitat. Electronic Publication     

Functional morphology of the ear in fossorial rodents, Microtus arvalis and Arvicola terrestris

Functionally relevant features and parameters of the outer, middle, and inner ear were studied morphologically and morphometrically in two species of voles, smaller Microtus arvalis and larger Arvicola terrestris. The findings in these fossorial (i.e., burrowing) rodents with components of surface activity were compared with respective findings reported for taxonomically related muroid rodents representing the same size classes but different eco-morphotypes: obligate subterranean rodents (Ellobius talpinus and Spalax ehrenbergi superspecies) and generalized rodents (Mus domesticus and Rattus norvegicus). The ear in voles was characterized by traits reported for subterranean rodents. The eardrum was round, without a distinct pars flaccida, and had an area of 5.4 mm2 in M. arvalis and 9 mm2 in A. terrestris. The middle ear exhibited reduced goniale, enlarged incus nearly parallel to the manubrium of the malleus. The malleus-incus lever ratio amounted to 2.1 (M. arvalis) and 2.0 (A. terrestris). The malleus-incus complex weighed about 0.8 mg in both vole species. The stapedial footplate had an area of 0.3 mm2 in M. arvalis and 0.4 mm2 in A. terrestris. The cochlea had 2.3 coils in both vole species; the basilar membrane was 8.5 mm and 10.5 mm long in M. arvalis and A. terrestris, respectively. There were on average 1,030 (M. arvalis) and 1,220 (A. terrestris) inner hair cells, and 3,760 (M. arvalis) and 4,250 (A. terrestris) outer hair cells in the organ of Corti. In quantitative terms, all these (as well as some further) traits and parameters were intermediate (related to body size) between those reported for generalized rodents on the one hand and subterranean ones on the other. The sound transmission system of the ear seems to be best tuned to frequencies of about 8-16 kHz with a high-frequency cut-off at about 50-60 kHz. The ear of A. terrestris seems to be tuned to somewhat lower frequencies than that in M. arvalis. In this aspect as well as regarding hearing sensitivity (as judged from the mechanical transmission parameters), voles can be considered intermediate not only in their lifestyle but also in their hearing abilities between the subterranean rodents (mole-vole and blind mole-rat) and the surface dwellers (house mouse and Norway rat).     

Hearing in coruros (<Emphasis Type="Italic">Spalacopus cyanus</Emphasis>): special audiogram features of a subterranean rodent

Learning curves and behavioural audiograms of subterranean, socially living coruros (Spalacopus cyanus) were obtained using a positive reinforcement conditioning procedure. The individually varying audiograms revealed best hearing at frequencies between 1.25 and 1.6 kHz, which corresponds with the common pattern established in subterranean rodents studied so far. However, the broad hearing range covering frequencies at least between 0.25 and 20 kHz coupled with the high sensitivity (average minimum 7 dB) that is found in coruros are atypical features for audiograms of subterranean rodents, which usually show restricted high-frequency hearing ranges and very poor sensitivity. Hearing at low frequencies (peaks at frequencies <1 kHz), which may be related to sound transmission in underground burrows, and high sensitivity at 1.25/1.6 kHz are discussed in relation to vocalization. In addition to these peaks, a third peak at 8 kHz—probably a plesiomorphic feature of mammals—may be of significance in aboveground communication.     

The impact of digging on craniodental morphology and integration

The relationship between the form and function of the skull has been the subject of a great deal of research, much of which has concentrated on the impact of feeding on skull shape. However, there are a number of other behaviours that can influence craniodental morphology. Previous work has shown that subterranean rodents that use their incisors to dig (chisel‐tooth digging) have a constrained cranial shape, which is probably driven by a necessity to create high bite forces at wide gapes. Chisel‐tooth‐digging rodents also have an upper incisor root that is displaced further back into the cranium compared with other rodents. This study quantified cranial shape and upper incisors of a phylogenetically diverse sample of rodents to determine if chisel‐tooth‐digging rodents differ in craniodental morphology. The study showed that the crania of chisel‐tooth‐digging rodents shared a similar place in morphospace, but a strong phylogenetic signal within the sample meant that this grouping was nonsignificant. It was also found that the curvature of the upper incisor in chisel‐tooth diggers was significantly larger than in other rodents. Interestingly, most subterranean rodents in the sample (both chisel‐tooth and scratch diggers) had upper incisors that were better able to resist bending than those of terrestrial rodents, presumably due to their similar diets of tough plant materials. Finally, the incisor variables and cranial shape were not found to covary consistently in this sample, highlighting the complex relationship between a species’ evolutionary history and functional morphology.     

Energetics in a solitary subterranean rodent, the silvery mole-rat, Heliophobius argenteocinereus, and allometry of RMR in African mole-rats (Bathyergidae)

Low resting metabolic rate (RMR) in subterranean rodents used to be considered as a physiological adaptation to cope with stresses of the belowground environment. In African mole-rats (Bathyergidae, Rodentia), RMR was reported to be independent of body mass. This deviation from a general mammalian pattern was considered a precondition for evolution of eusociality, occurring in some bathyergids. We measured metabolic rate and thermoregulation in the silvery mole-rat, Heliophobius argenteocinereus, the only bathyergid genus for which well-supported, comparable data were still missing. Low RMR (154.04 mL O(2) h(-1), which is 82% of the value predicted for a rodent) corresponds to the value expected in a subterranean rodent. Broad range of the thermoneutral zone (25-33 degrees C) and only slightly higher conductance (17.3 mL O(2) h(-1) degrees C(-1), i.e. 112.5% of that predicted for subterranean mammals) indicate that H. argenteocinereus is adapted to lower burrow temperatures rather than to high temperatures. Low RMR in this solitary species, as in other subterranean rodents in general, is probably associated particularly with high energetic cost of foraging. Our results combined with data on other mole-rats show clearly that RMR within the Bathyergidae is mass-dependent.     

Evolutionary association between subterranean lifestyle and female sociality in rodents

Subterranean rodents are a good model system to examine adaptive evolution of social organization. Life underground has been proposed either to favor solitariness or, to the contrary, to promote sociality. In concordance with the first idea, most specialized diggers are solitary. However, group-living in several unrelated subterranean rodent species and especially eusociality in two genera of African mole-rats, the Bathyergidae, seem to support the second hypothesis. Thus, none of the two models is fully consistent with empirical data. Here we apply the comparative phylogenetic method to test an evolutionary correlation between fossoriality and female social strategy (solitary breeding vs breeding in group). Both characters show very strong phylogenetic signal, and we found a significant correlation between them. Subterranean lifestyle is readily acquired under female sociality. By contrast, the transition to life underground is extremely unlikely under female solitariness. Thus, not only social behavior may be affected by ecological specialization as it is widely assumed, but it can itself restrain the range of possible specializations. The rates of transition from sociality to solitariness are equal under subterranean and surface-dwelling lifestyle. Sociality loss is irreversible in subterranean lineages, unlike surface-dwelling lineages. Based on the revealed transition rates we suggest that all lineages of subterranean rodents have gone through the stage of cooperation at the beginning of their evolutionary track, whereas group-living is selected against in highly specialized diggers. An odd pattern of distribution of sociality across and within truly subterranean taxa probably derives from the influence of extrinsic factors in combination with phylogenetic inertia.     

Home-Range Dynamics in a Solitary Subterranean Rodent

Despite an important role of subterranean rodents as ecosystem engineers, their belowground mobility is poorly documented. It is supposed that their underground burrow systems, once established, are relatively stable because of high-energy costs of digging. We chose the silvery mole-rat, Heliophobius argenteocinereus (Bathyergidae, Rodentia) from mesic Afrotropics as a representative of solitary subterranean rodents to investigate how, and how fast these rodents process their established burrow systems. We combined radio-tracking of individual animals with subsequent mapping of their burrow systems, and we developed a new method for assessing the rate of burrowing. Mole-rats continuously rebuilt their burrow systems; they excavated approx. 0.7 m of new tunnels per day and backfilled on average 64% of all tunnels. On average, every 32 d they established a new nest. They often completely backfilled newly excavated peripheral burrows, while other parts of their burrow systems were more permanent. Their home-ranges were dynamic and continuously shifted in space. Burrow system processing continued even in the advanced dry season, when soil is difficult to work.