Vocalization during copulation behavior in greater horseshoe bats, Rhinolophus ferrumequinum

Vocal communication plays an important role for individual recognition and male-female interaction during mating in greater horseshoe bats,especially in respect to mate fidelity,which ensures that the bats can maintain a stable social organization.Few studies,however,have addressed the calling behavior during copulating in bats.Here,we initially report the copulation vocalizations and behaviors of both male and female greater horseshoe bats.During copulation,the male assumed a dorsal position and arched his back,arming around the female using his feet and thumbs.The male repeatedly produced very short constant frequency(SCF) syllables with high intensity and repetition rate(male 1:16.48±4.8 ms,male 2:17.79±4.03 ms) when he tried to insert the penis into the female,and then long syllables(male 1:42.08±12.67 ms,male 2:43.02±11.44 ms) after penile insertion.The female bats sometime refused the male bats in the early phase of copulations as emitting noise bursts and broad-band vocalizations,but kept silence during actual copulation.We also found that the SCF copulation calls of one male remained stable peak frequencies on different copulation days although its echolocation call frequency varied each day.Moreover,different male individuals maintained their own "private frequency" in the SCF copulation calls.Therefore,we predicted that the SCF copulation calls may serve as an indicator for female greater horseshoe bats to recognize the mating males in order to maintain mate fidelity because horseshoe bats exhibit sexual segregation before mating.Our results stipulate further studies on mating system and copulation strategies in polygynous bats.Such work may also aid in promoting the preservation of greater horseshoe bats.     

A possible neuronal basis for Doppler-shift compensation in echo-locating horseshoe bats

The auditory system of the horseshoe bat is finely tuned to the bat's individual vocalization frequency. To compensate for flight-induced Doppler shifts in the echo frequency, the horseshoe bat adjusts the frequency of its echo-location call to maintain the echo frequency within the narrow range to which its auditory system is best tuned. In this report I describe neurons in the midbrain tegmentum of the horseshoe bat, with properties that strongly indicate their involvement in this Doppler-shift compensation. The activity of these neurons was influenced by both sound emission and auditory stimuli. Neuronal discharges in response to vocalization, however, differed from those in response to purely auditory stimuli that mimicked the bat call. When an auditory stimulus was temporally locked to a preceding vocalization, the response was dependent on the time delay between the two. This delay-sensitivity completely disappeared when vocalizations were simulated acoustically. Only those vocalization and 'echo' parameters were encoded that occur in Doppler-shift compensation. In conclusion, I suggest a model for the regulation of the vocalization frequency through auditory feedback.     

Harmonic-hopping in Wallacea's bats

Evolutionary divergence between species is facilitated by ecological shifts, and divergence is particularly rapid when such shifts also promote assortative mating. Horseshoe bats are a diverse Old World family (Rhinolophidae) that have undergone a rapid radiation in the past 5 million years. These insectivorous bats use a predominantly pure-tone echolocation call matched to an auditory fovea (an over-representation of the pure-tone frequency in the cochlea and inferior colliculus) to detect the minute changes in echo amplitude and frequency generated when an insect flutters its wings. The emitted signal is the accentuated second harmonic of a series in which the fundamental and remaining harmonics are filtered out. Here we show that three distinct, sympatric size morphs of the large-eared horseshoe bat (Rhinolophus philippinensis) echolocate at different harmonics of the same fundamental frequency. These morphs have undergone recent genetic divergence, and this process has occurred in parallel more than once. We suggest that switching harmonics creates a discontinuity in the bats' perception of available prey that can initiate disruptive selection. Moreover, because call frequency in horseshoe bats has a dual function in resource acquisition and communication, ecological selection on frequency might lead to assortative mating and ultimately reproductive isolation and speciation, regardless of external barriers to gene flow.     

城门洞形及马蹄形过水隧洞的临界水流

针对水利工程上常用的城门洞形及马蹄形过水隧洞,利用临界流方程,给出了旨在用于临界流分析的断面参数Ｚ和水力指数Ｍ 的计算公式和表示水深与Ｚ以及Ｍ 之间的关系曲线。计算曲线表明,若隧洞的高宽相等,在水深比小于１．４ 时, Ｍ 值的变化范围很小,而当水深比达到１．９０时,两种隧洞具有近似的临界流特征。分析和计算还表明,圆顶隧洞在水深无限接近洞顶时不可能出现临界流状态,但洞内水位较高时,其临界流的波状水面可较早地引起封顶水流。所提供的公式和曲线可为隧洞的水力设计所参考。     

对匹配问题的总结与探讨

本文对著名匹配问题的一些结论作了进一步讨论 ,对结论与 n的关系作了强调 ;并用古典概型的方法 ,导出一个递推公式 ;给出了匹配问题的一个古典解法     

短尾猴的社会理毛对交配选择的作用

本文报道了作者在安徽黄山对一群野生短尾猴１９８７—１９８８年度交配期和非交配期社会理毛行为的研究结果。用随机观察法（Ａｄｌｉｂ．ｓａｍｐｌｉｎｇ）获得的数据表明，交配活动影响异性之间的社会理毛。除成年雌体组与亚成年雄体组的理毛外，其余异性组之间，在交配期的理毛高于理论预测值。在短尾猴，交配期异性个体之间的社会理毛与交配选择有关。     

Foraging strategies in the greater horseshoe bat （Rhinolophus f errumequinum ）on Lepidoptera in summer

Abstract The diet of the bat Rhinolophus ferrumequinum was studied at the Zhi＇an Village of Ji＇an City in China, from June to August 2004. The bats were trained in a laboratory （volume： 9×4×4 m^3）. Foraging strategies of the bat were observed at night and prey remains were collected and identified. The results showed that the diet consisted mainly of Lepidoptera in summer, including 11 families, more than 30 species of moths, such as Noctuidae （36.6% by number）,Sphingidae （24.1%）, Geometridae （13.4%） and Limacodidae （9.5%）. The length of culled wings ranged from 10--40 mm （97.7%）. Pearson correlation analysis showed that the bat R.ferrumequinum foraged their prey selectively, but not opportunistically. From field studies, two ways were observed in which the bats retrieved their prey including aerial hawking during peak active period of the insects and flycatching during the insects＇ non-peak activity period. The bats never gleaned prey from the ground, though they appeared to be well able to detect fluttering moths on the ground.     

Symmetry and horseshoe in the model of bouncing ball

By coordinate transformation, the map of bouncing ball has certain symmetry in the new coordinates, This symmetry is used to simplify the conditions which guarantee the existence of the compact, hyperbolic and invariant set and to find the same properties in symbolic dynamics. Based on the analysis, the lower bound of parameter beyond which the map possesses a hyperbolic horseshoe is estimated more precisely.     

二元互补序列偶集及其伴集

定义了非周期相关下二元互补序列偶集以及伴集的概念,提出了多种伴集的构造方法,并进行了理论证明.实例表明,利用这些方法可以得到大量的二元互补序列偶集以及伴集,与传统的互补序列集相比有更广阔的存在空间.     

Mate guarding as paternity insurance in Idaho ground squirrels

Following a copulation, males in many species of vertebrates (particularly birds) and invertebrates remain near the inseminated female and repel other suitors with displays or force. Guarding males must delay resumption of competitive mate searching, but they may insure their paternity by reducing possibilities for secondary matings and sperm competition. Among mammals, post-copulatory mate guarding has been reported in rodents, mongooses, ungulates and primates, including humans, but the effects of such behaviour on male reproductive success have not been determined genetically. I report here that mate guarding by male Idaho ground squirrels (Spermophilus brunneus) enhances a male's probability of paternity. Furthermore, an analysis based on game theory shows that mate guarding is an evolutionarily stable strategy for male S. brunneus, but not male Belding's ground squirrels (S. beldingi), which resume searching once copulation is completed.     

企业战略杠杆与核心能力的匹配关系

介绍了企业战略杠杆及核心能力的概念,建立了一个二者相互作用的模型.并讨论了企业在模型图上所处的不同位置分别应采取的对策.     

Evidence for echolocation in the oldest known bats

The earliest-known bats are represented by excellent fossil material, including virtually complete skeletons of Icaronycteris index from the early Eocene (50 Myr BP) of western Wyoming and Palaeochiropteryx tupaiodon from the middle Eocene (45 Myr BP) 'Grube Messel' of western Germany. These taxa have been closely allied with Recent Microchiroptera, a suborder of diverse bats noted for their powers of ultrasonic echolocation. A problem with this relationship is the alleged absence in the Eocene forms of specializations in the auditory region and other aspects of the skeletal system. It has been proposed, therefore, that the oldest bats are members of a group more primitive and possibly ancestral to the Microchiroptera and the visually oriented Megachiroptera. Previously undescribed specimens now show, however, that Icaronycteris and Palaeochiropteryx share special basicranial features with microchiropterans which suggest comparable refinement of ultrasonic echolocation. These results support the theory that a sophisticated sonar system was present in the earliest records of microchiropteran history.     

光电检测电路中的噪声匹配条件及工程近似估算方法

根据低噪声电路理论,应用解析方法推导出了光电探测器与前置放大器噪声匹配条件的理论修正表达式,并对工程近似估算光电检测电路噪声系数方法进行了讨论。     

Tavis-Cummings模型中的量子态平均保真度

运用全量子理论,研究了Tavis-Cummings模型中量子态平均保真度的演化特性,对原子和光场的初态以及两原子的关联程度对平均保真度的影响进行了研究.结果表明,原子、光场和系统的平均保真度依赖于初态时2个原子处在基态的几率以及光场处于真空态的几率;初态两原子在基态无关联,光场处于真空态,体系不失真.     

No cost of echolocation for bats in flight

Echolocation has evolved in relatively few animal species. One constraint may be the high cost of producing pulses, the echoes of which can be detected over useful distances. The energy cost of echolocation in a small (6 g) insectivorous bat, when hanging at rest, was recently measured at 0.067 Joules per pulse, implying a mean cost for echolocation in flight of 9.5 x basal metabolic rate (range 7 to 12x). Because flight is very costly, whether the costs of echolocation and flying are additive is an important question. We measured the energy costs of flight in two species of small echolocating Microchiroptera using a novel combination of respirometry and doubly-labelled water. Flight energy expenditure (adjusted for body mass) was not significantly different between echolocating bats and non-echolocating bats and birds. The low cost of echolocation for flying vertebrates may have been a significant factor favouring its evolution in these groups.     

Noise correlations improve response fidelity and stimulus encoding

Computation in the nervous system often relies on the integration of signals from parallel circuits with different functional properties. Correlated noise in these inputs can, in principle, have diverse and dramatic effects on the reliability of the resulting computations. Such theoretical predictions have rarely been tested experimentally because of a scarcity of preparations that permit measurement of both the covariation of a neuron's input signals and the effect on a cell's output of manipulating such covariation. Here we introduce a method to measure covariation of the excitatory and inhibitory inputs a cell receives. This method revealed strong correlated noise in the inputs to two types of retinal ganglion cell. Eliminating correlated noise without changing other input properties substantially decreased the accuracy with which a cell's spike outputs encoded light inputs. Thus, covariation of excitatory and inhibitory inputs can be a critical determinant of the reliability of neural coding and computation.