Reproductive biology of Sykes and blue monkeys (Cercopithecus mitis)

Thirty-five live births were recorded over a 5-year period from three subspecies of the mitis (Sykes and blue) monkey (Cercopithecus mitis) maintained outdoors in single-male harem breeding groups. There was no indication of birth seasonality. Females of one subspecies, C. m. kolbi, were individually caged, and basic reproductive parameters were monitored. A menstrual cycle length of 31.9 ± 6.0 days was recorded, and there were a large number of irregular cycles. Within individuals, mean progesterone and estrogen concentrations during the luteal phase of the cycle ranged from 5.5 to 10.7 nmol/liter and from 542 to 829 pmol/liter, respectively. Attempts at timed matings were unsuccessful. It is concluded that the mitis monkey is slow to adapt reproductively to captivity and is, therefore, not especially well-suited for routine reproductive studies. However, it may prove valuable to elucidate some of the more complex factors controlling guenon reproduction.     

Feeding ecology and dietary differences between blue monkey (Cercopithecus mitis stuhlmanni Matschie) groups in logged and unlogged forest, Budongo Forest Reserve, Uganda

Several studies have investigated the effects of logging on primate population density, and attempted to relate density differences to changes in vegetation composition. As population density in some forest primates may be considerably influenced by dietary quality, it is important to understand how the effects of vegetation changes commonly associated with logging influence primate feeding ecology. Results are presented from a study carried out in the Budongo Forest Reserve in Uganda to investigate differences in blue monkey (Cercopithecus mitis stuhlmanni) feeding ecology in forest blocks with different logging history. Dietary composition differed between logged and unlogged forest, with a higher proportion of unripe fruit consumed in logged forest. By contrast, the proportion of young leaves, invertebrates and seeds in the diet was higher in unlogged forest. Variations in the intake of fruit was also higher in unlogged forest, but feeding patterns on other dietary items were more selective. These differences in diet reflect differences in availability of different categories of food items, as determined by tree species composition, abundance and plant phenological patterns. The observed differences between feeding ecology in logged and unlogged forest are discussed in relation to primate feeding ecology and habitat composition in Budongo.     

Brief report: Normal hematology values of Sykes monkeys (Cercopithecus mitis albogularis)

Hematologic values are presented for the Sykes monkey (Cercopithecus mitis albogularis). The values are, in general, similar to published findings for other primate species. Elevated hemoglobin, possibly caused by high altitude, was noted. Significant differences of several values between males and females are discussed.     

Reproduction in the vervet monkey (Cercopithecus aethiops): I. Testicular volume,testosterone, and seasonality

To test whether the male could contribute to the birth peak seen in both wild and captive vervets, testicular volume and peripheral testosterone concentration were measured monthly in nine adults throughout a 14-month period. Volume was an average of 15% greater during the months of June to September, the period of natural breeding activity in the wild, than at other times of the year. Testosterone concentration rose throughout the time period but did not correlate with testicular volume. Quarterly biopsies of the right testis in animals either used for or withheld from breeding revealed the presence of spermatozoa and the existence of spermatogenesis throughout the year. There was no correlation of testicular volume with breeding status or biopsy. If these results from individually caged animals are representative of group-caged and wild animals, then such small seasonal changes are unlikely to affect year-round breeding. Therefore, a physiological contribution by the male to natural birth peaks seen in the wild and captivity is not readily apparent.     

Enzootic simian piroplasm (Entopolypoides macaci ) in wild-caught Kenyan non-human primates

Background Three species of non‐human primates comprising African green monkeys (AGMs), (Cercopithecus aethiops, n = 89), Syke’s monkeys (Cercopithecus mitis, n = 60) and olive baboons (Papio cynocephalus anubis, n = 30), were screened for Entopolypoides macaci. Methods Observation of blood smears prepared from these animals revealed E. macaci infection rate of 42.7% in AGMs, 35% in Syke’s monkeys and 33.3% in baboons. Results Gender infection rate was 38.2% in females and 29% in males. Statistically, there was no significant difference in infection rates between the monkey species and sexes (P > 0.05). Subsequent indirect immuno fluorescent antibody test supported the morphological appearance of E. macaci observed by microscopy. Sera from infected animals reacted positively (1:625) with E. macaci antigen, but not to Babesia bigemina or B. bovis antigen at 1:125 titer. Conclusion This study has revealed high prevalence of E. macaci infection in all three widely distributed Kenyan non‐human primates. With the continued use of these animals as models for human parasitic diseases, the presence of this highly enzootic parasite should be noted.     

Rank,relationships, and responses to intruders among adult male vervet monkeys

We examined the influences of dyadic relationships among captive adult male vervet monkeys (Cercopithecus aethiops sabaeus) on behavior directed toward caged “intruder” males placed inside subjects' enclosures. Subjects were all 9 adult male residents from three stable social groups, each of which contained 3 adult males, at least 3 adult females, and their immature offspring. Every male was observed in two 3-hour sessions, each time with one of the 2 other adult males from his group. Observation sessions consisted of six consecutive 30-min stages in which group composition and the presence of the intruder were manipulated. All groups exhibited a stable, linear male dominance hierarchy prior to and throughout the study. In each group, there was one pair of males, when together, in which each member exhibited higher rates of intruder-directed approach and aggressive behaviors than when either animal was paired with the third male of his social group. Such pairs were also distinguished by high levels of within-pair agonistic interactions. The higher-ranking member of each dyad was the most aggressive male toward the intruder in his social group, although only one of these animals was the dominant male of his group. Mutual facilitation of aggression against intruding males is interpreted as cooperative behavior benefitting both males by increasing the likelihood of repelling a potential competitor for resident females. Such cooperation provides further evidence in nonhuman primates for cohesive male-male dyads between animals whose social interactions are characterized by agonism. © 1993 Wiley-Liss, Inc.     

ABH Salivary antigens in populations of vervet monkeys(Cercopithecus aithiops) from Kenya

Blood and saliva samples were collected from 330 vervet monkeys living in 30 troops in central and southern Kenya. The saliva samples were tested for the presence of human-type ABH antigens by standard agglutinationinhibition tests. This population of vervets is the first in which the O phenotype has been found to occur. The gene frequencies in the overall population are as follows: A, 0.74; B, 0.21; and O, 0.05. The serum samples were tested for the presence of agglutinins having specificities like those of human anti-A and anti-B. Ten percent of the vervets have anomalous combinations of salivary antigens and serum agglutinins. The nature of the anomalies is described and a hypothesis presented to account for these observations.     

Group extinction and fusion in free-ranging vervet monkeys

Three cases of group fusion were observed among vervet monkeys in Amboseli National Park, Kenya, during the 1984 drought. In all cases, group fusion involved the migration of at least two females into a small neighboring group. Following migration, the females' natal groups ceased to exist. Although migrants initially assumed low ranks, none received high rates of aggression, and two rose in rank 6 months after their arrival. Migrant females appeared to employ a number of “strategies,” including grooming, allomothering, participation in intergroup encounters, and the formation of coalitions against males and each other to hasten integration. Results suggest that the causes of male and female migration differ fundamentally, and that group fusion occurs primarily in response to the inability of small groups of females to compete successfully with other groups for resources.     

De Brazza's monkeys (Cercopithecus neglectus) in Kenya: Census,distribution, and conservation

The population of De Brazza's monkeys (Cercopithecus neglectus) in Kenya, East Africa, was surveyed from May to September of 1983 to estimate its numbers, distribution, and conservation status. A small number of De Brazza's monkeys are protected within Saiwa National Park; however, the vast majority of the population is endangered because they are restricted to small, isolated pockets of forests amid expanding farmland within the Trans-Nzoia area of western Kenya. A few animals are found on the slopes of Mt. Elgon and on the Cherangani Hills, although these areas offer little protection. The pressures now facing this population are loss of habitat, reproductive isolation, and a decline in numbers as the result of being killed, either as a food source or as agricultural pests. If the current situation continues and no attempt is made to conserve the remaining De Brazza's monkeys, the species faces almost certain extinction in Kenya.     

The Vanishing De Brazza's Monkey (Cercopithecus neglectus Schlegel) in Kenya

We conducted a trail survey of De Brazza's monkey (Cercopithecus neglectus) on Mt. Elgon and the Cherangani Hills between October 1994 and February 1995. The objectives were to assess the status and distribution of the species and its habitats and to formulate recommendations on its conservation. We counted a total of 49 monkeys: 3 groups and 6 lone individuals near Kimothon River (Mt. Elgon) and 4 groups and 6 lone individuals at Kapolet Forest Reserve and its environs (Cherangani Hills). The mean group size is 6.6. Wanton habitat destruction was evident in all the forest habitats. The species now inhabits unprotected remnant strips of riverine forest. Furthermore, the Kapolet Forest Reserve offers little or no protection to De Brazza's monkeys or their habitat. Translocation of the monkeys from unprotected areas to a protected habitat is recommended as an urgent conservation measure to save the De Brazza's population in Mt. Elgon and the Cherangani areas of Kenya.     

中老年食蟹猴群体自发型糖尿病的筛选

筛选440只中老年偏胖食蟹猴群体中自发糖尿病个体,并探讨食蟹猴群体中糖尿病粗筛的方法。以调查基础血糖值为基础,推断疑似糖尿病血糖值,后经OGTT(口服糖耐量)和尿检结果验证该血糖值是否准确。结果显示中老年偏胖食蟹猴群体血糖值为(3.88±0.98)mmol/L,其中56只食蟹猴血糖值大于5.0mmol/L,被初步定为糖尿病个体。这些个体全部糖耐量异常,且36只(69.23%)出现尿糖阳性,证明血糖值大于5.0mmol/L可作为本群体食蟹猴糖尿病的粗筛标准。由于针对中老年偏胖食蟹猴群体,患病率为12.72%(56/440),高于我国糖尿病患病率(9.7%)。虽然该实验的糖尿病血糖指标并不适用于所有食蟹猴群体,但是该筛选的流程简单快捷,对动物损伤小,可适用于大群体糖尿病的筛选。     

IL-10 is up regulated in early and transitional stages in vervet monkeys experimentally infected with Trypanosoma brucei rhodesiense

IL-10 has been suggested as a possible parameter for human African trypanosomiasis stage determination. However, conclusive experimental studies have not been carried out to evaluate this, which is a prerequisite before a potential test can be validated in humans for diagnostic purposes. We used the vervet monkey model of trypanosomiasis to scrutinize IL-10 in blood and cerebrospinal fluid (CSF). Five adult males were experimentally infected with T. b. rhodesiense. The infected animals became anemic and exhibited weight loss. Parasitemia was patent after 3 days and fluctuated around 3.7 × 10⁷ trypanosomes/ml throughout the experimental period. The total CSF white cell counts increased from pre-infection means around 3 cells/μl to a peak of 30 cells/μl, 42 days post-infection (DPI). IL-10 was not detectable (< 2 pg/ml) in serum prior to infection. IL-10 serum concentrations increased to 273 pg/ml 10 DPI coinciding with the first peak of parasitemia. Thereafter the levels declined to a mean value of 77 pg/ml 34 DPI followed by a significant rise to a second peak of 304 pg/ml (p < 0.008) 42 DPI. There was no detectable IL-10 in CSF. IL-10 synthesis is thus stimulated both in the early and transitional stages of experimental trypanosomiasis. That IL-10 is produced in early stage disease is an interesting finding unlikely to be detected in humans where it is difficult to determine the exact time of infection. The IL-10 peak observed on day 42 of infection might indicate onset of parasite neuroinvasion coinciding with a peak in white blood cell counts in the blood and CSF.