Testis size,epididymis weight,and sperm competition in rhesus macaques

The intensity of sperm competition is often measured using the gonadosomatic index (testes/body weight). But sperm competition could be mediated more by size of the epididymis than by size of the testicles, and little information is available on the relationship between testicular and epididymal size. We found that both organs were positively correlated in size among male rhesus macaques. Body weight accounted for over 70% of the variance in testicle size and volumetric estimates of testicle size accurately reflected testicle weight. We conclude that methods for ascertaining testicle size are accurate, but the covariation in size between testicles and epididymis will hamper understanding of the physiological mechanisms involved in sperm competition in primates. © 1993 Wiley-Liss, Inc.     

A ten-month study of endogenous testosterone levels and behaviour in outdoor-living female rhesus monkeys (Macaca mulatta)

Endogenous testosterone levels were measured in association with sexual, aggressive, and social/affiliative behaviors in 11 outdoor-housed female rhesus monkeys over a ten-month period. Several behaviors (sex directed toward the male, sex received from the male, aggression directed toward the male, submission directed toward the male, submission directed toward the female, and groom another female) were significantly (p<0.05) positively correlated with testosterone in from one to five females. No trends were strong enough across all females to suggest that any of these correlations have species-wide significance. Factor analysis revealed clearcut clusters of behaviors, but elevations in testosterone were not strongly associated with any of these clusters. It is concluded that endogenous testosterone levels have little measurable effect on overt behavior in female rhesus monkeys.     

The genetic structure of a primate species: Rhesus macaques and other Cercopithecine monkeys

Among rhesus macaques (Macaca mulatta)and other cercopithecine monkeys, social groups occupying adjacent home ranges (i.e., members of the same local population) exchange individuals and genes and thus exhibit marked genetic similarities. To assess the degree to which this pattern extends beyond the local population, the genetic structure of M. mulattaand six other primate species was determined using Nei’s (1973) gene-diversity analysis. The genetic similarities seen among social groups in the Dunga Gali population of M. mulatta (Melnick et al.,1984a) can be seen over the entire species range. Comparison of these results with the structures of other similarly organized primate species indicates that (1) the average social group contains most of its local population’s genetic diversity, (2) the average local population contains the majority of the genetic diversity found in the region to which it belongs, and (3) the proportion of species gene diversity found in the average regional population varies substantially between species. Genetic homogeneity within local and regional populations is probably the product of gene flow. The application of a number of analytical models of selection and gene flow strongly suggests that gene flow, genetic drift, and zoogeography offer a more parsimonious and plausible explanation for interspecific variation in regional differentiation than does stabilizing selection.     

Rhesus monkey (Macaca mulatta) complex learning skills reassessed

Results from three experiments on basic learning and transfer in rhesus monkeys (Macaca mulatta) are reported in which fully automated testing paradigms, afforded by the Language Research Center's Computerized Test System (LRC-CTS), were employed. Performance levels for discrimination learning set, transfer index, and mediational-learning testing were uniformly higher than was predicted from the literature, in contrast to previous reports of compromised learning under similar conditions (automated apparatus, planimetric stimuli, spatial discontiguity between stimuli and response loci). Analyses reveal relatively advanced learning set performance, transfer-index ratios, and positive transfer of learning even at stringent criterion levels. Moreover, the data suggest that rhesus monkeys tested in these experiments exhibit mediational instead of associative learning strategies, as do great apes and in contrast to previous reports of rhesus learning. We argue that the LRC-CTS enhances learning by nonhuman primate subjects, obviating those factors, reported in the literature from experiments in which manual or other automated systems were employed, that compromise learning.     

促性腺激素诱导猕猴排卵周期中卵巢纤溶酶原激活因子与抑制因子的变化

在用 PMSG 和 hUG 诱导猕猴排卵过程中,我们研究了 pA 和它的抑制因子 PAI-1与排卵的关系。实验结果表明,由促性腺激素所诱导出的卵巢 tPA 活性的增加与排卵密切相关,在排卵前达到高峰,而排卵后明显下降;uPA 只在排卵后的颗粒细胞大量出现;PAI-1分泌高峰比 tPA 峰值早出现12—24小时;排卵来临时,tPA 的明显上升导致 PAl-1的空然下降。上述实验结果说明,卵巢中 tPA 和 PAI-1活性的这种平衡性的变化可能在排卵机制和维持卵巢的正常生理功能中起重要作用,而 uPA 或许与黄体形成的调节有某些关系。     

Skeptical responding in rhesus monkeys (Macaca mulatta)

Signalers that misinform sufficiently open may become devalued as sources of information; however, “skepticism” and any comparison involved in testing reliability entail a cost that involves delays and energy expenditure. Skepticism may be less costly though, if, as a rule, animals are not equally skeptical of the signals of all conspecifics. Animals with the ability to recognize individual conspecifics and to recall past encounters with them may have the capacity to restrict skepticism to subsets of animals that are most likely to benefit from deception. We played tape-recorded alarm calls of high- and low-ranking rhesus monkeys(Macaca mulatta) to their groups in a feeding context once daily over 8 consecutive days at the Yerkes Primate Center Field Station. Over the sequence of playbacks, response was greater to the calls of high-ranking monkeys, adult response patterns were different from those of juveniles, and for adults especially, decline in responsiveness was punctuated by partial resurgences of response. These differences may be the consequence of the adults’ more extensive histories of interaction with group members that, though generally reliable, vary with respect to the potential benefits of deceptive signaling.     

人胚DA能神经元移植于帕金森氏病猴模型的TH免疫细胞化学的研究

为了对人胚黑质ＤＡ神经元移植治疗ＰＤ人的临床应用作出客观评估,将８－１２周人胚黑质细胞移植到用ＭＰＴＰ诱发的偏侧ＰＤ猴新纹状体内。实验动物分别存活２个月、５个月和１年后,用ＴＨ免疫细胞化学方法对被移植的人胚ＤＡ细胞的存活和与宿主间的突触联系进行检查。在光镜下可见被移植侧的新纹状体内有ＴＨ阳性细胞,它们成小群散在分布,每小群有３－１０个细胞。ＴＨ阳性细胞的轴突延伸到整个新纹状体,树突呈现出正常发育过     

A circular waveguide irradiation system for nonhuman primates: design and dosimetry

A 275-MHz exposure system, consisting of a circular waveguide irradiator and a transparent plastic animal cage, has been developed to accommodate rhesus monkeys weighing up to 15 kg. The vertically oriented waveguide is composed primarily of stainless steel and is fitted with an inner cage fabricated from a tubular section of acrylic plastic. Circularly polarized electromagnetic energy at 275 MHz, either pulsed or continuous wave (CW), can be propagated from the removable top section of the waveguide. The cage is designed to function as the monkey's permanent home. It is fitted with a lever-actuated behavioral performance device on which the monkey responds according to a predetermined schedule to obtain a daily food ration. The system can be adapted to provide for the collection of metabolic and physiologic data as well. Dosimetric measurements were conducted with six rhesus monkeys weighing 3.0-7.2 kg and with a 4-kg model. The dosimetric results show that about one-third of the net incident energy is absorbed by a subject in this system at a normalized specific absorption rate (SAR) of 0.33 (W/kg)/(mW/cm2).     

Early agonistic experience and rank acquisition among free-ranging infant rhesus monkeys

Several aspects of agonistic experience are described for freeranging infant rhesus monkeys (Macaca mulatta)on Cayo Santiago. Even before infants are fully integrated with peers in rank dominance based on maternal ranks,infants of highranking mothers tend to be threatened less frequently by other members of the group and are less likely to be threatened by unfamiliar individuals than are infants of lowranking mothers. There is no evidence that fearful interactions between pairs of infants are related to their mother’s ranks before 22 weeks of age. However, an imperfect hierarchy can be constructed for infants between 27 and 30 weeks of age. At this age,infants of higherranking mothers are also more likely to receive protection when threatened than are infants of lowerranking mothers. When protected, their protectors are less likely to emit fearful gestures to the infants’ threatener. Close female relatives appear to play a large role in the protection of infants and may be more directly responsible for the differences described above than the mother, other relatives, or other highranking members of the group. It is suggested that more than one mechanism, including intervention by the mother and by close female relatives,may be important in rank acquisition among peers.