Blue monkey (Cercopithecus mitis stuhlmanni) predation on galagos

Two cases of predation on galagos by free-ranging blue monkeys (Cercopithecus mitis stuhlmanni) are described.C. mitis is only the second species of the genusCercopithecus known to prey on mammals. “Wadging,” the intermixing and chewing of leaves with meat, is reported for the first time in a primate other than the chimpanzee (Pan troglodytes). Meat-sharing was not observed inC. mitis.     

A Spontaneous Bronchogenic Carcinoma in a Sykes Monkey (Cercopithecus mitis stuhlmani)

A male blue monkey (Cercopithecus mitis stuhlmani), a subspecies of the Sykes group, was purchased from a commercial trapper as an adult in July 1978 and kept at the Institute of Primate Research, Kenya, for 2 years. The animal developed acute respiratory distress and died. Small nodular foci were found in the lung at necropsy and diagnosed as bronchogenic carcinoma on histopathology.     

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.     

Predation by squirrel monkeys and double-toothed kites on tent-making bats

Central American squirrel monkeys (Saimiri oerstedi) appear to recognize the modified leaves that phyllostomid bats utilize for diurnal roost sites. The monkeys visually and manually search these bat tents for both bats and insects. Adult males are the most successful at capturing bats. Nonvolant juvenile bats are more vulnerable to monkey predation than are adults. Bats that escape monkey predation frequently are captured by doubletoothed kites (Harpagus bidentatus) that tend foraging troops of monkeys. Predation by squirrel monkeys, coupled with that of double-toothed kites, may be a significant source of mortality for tent-making bats.     

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.     

Predation by vervet monkeys in an outdoor enclosure: The effect of age,rank, and kinship on prey capture and consumption

Sixty-one instances of vertebrate predation have been directly observed or inferred from remains in a captive colony of vervet monkeys (Cercopithecus aethiops sabaeus)over a 6-year period. Vertebrate prey included 33 rodents,27 birds, and 1 frog. Prey capturing was performed predominantly by juvenile males and females, independent of rank. Avian prey were highly preferred: all 27 birds were eaten completely, while only 1 of 33 rodents was consumed completely and 5 others partially. Prey consumption was related to age-sex class, rank, and kinship. All age-sex classes were observed to consume avian prey, but juvenile males and females predominated. Seventy-six percent of all animals noted consuming avian prey were members of the alpha matriline in their group. When two or more animals were observed cofeeding on the same preferred prey item, they were generally members of the same kinship group.     

A case of patas-vervet hybrid in captivity

A female patas monkey (Erythrocebus patas) housed with two males of different species, Hamadryas baboon (Papio hamadryas), and vervet monkey (Cercopithecus aethiops pigerythrus), gave birth to a female offspring in a semi-open enclosure on June 11, 1975. Karyological analyses and electrophoretic examinations were carried out in order to determine the real father of the hybrid. From the results of these observations it was concluded that the father of the hybrid individual wasCercopithecus aethiops. Additionally, somatometric and hematological investigations were performed.     

Social responses to the traumatic injury of a juvenile spider monkey (Ateles geoffroyi)

The behavioural development of a juvenile male spider monkey (Ateles geoffroyi) preceding and subsequent to a traumatic injury resulting in the loss of his tail, was documented over a nine-month period in Santa Rosa National Park, Costa Rica. The juvenile became heavily reliant on his mother, who readily provided compensatory care, including nursing the juvenile even though he had previously been weaned. In comparison to another juvenile male spider monkey of similar age, the development of the injured animal was severely retarded and even five months after the accident, the juvenile was still nursing and being carried by his mother. As injuries may be relatively common among primates it is suggested that the provision of compensatory care is an important trait in many primate species.     

Spit it out: Monkeys disperse the unorthodox and toxic seeds of Clivia miniata (Amaryllidaceae)

Seeds of many Amaryllidaceae are unorthodox (recalcitrant) and toxic, and cannot survive ingestion, yet are packaged in brightly colored fruits suggestive of zoochory. Seed dispersal and germination of the understory amaryllid, Clivia miniata, were investigated in KwaZulu‐Natal, South Africa. Motion‐activated cameras revealed that samango monkeys (Cercopithecus mitis labiatus) are the primary disperser of C. miniata seeds. They eat the mesocarp and, to a lesser extent, the exocarp, and spit the large (13 mm diameter) seeds whole and cleaned onto the forest floor. Most seeds were dispersed farther than 1 m from the parent. Experimental removal of the fruit pulp had a small positive effect on the rate of seed germination, but did not affect subsequent seedling growth rates. The main advantages of monkey dispersal of Clivia seeds appear to be short‐distance dispersal away from the dense foliage of clumped parent plants and occasional long‐distance dispersal through cheek‐pouching behavior.     

Predation by the grey leaf monkey (Presbytis hosei) on the contents of a Bird's nest at Mt. Kinabalu Park,Sabah

An adult male grey leaf monkey (Presbytis hosei) was observed in Mt. Kinabalu Park, Sabah, Malaysia, raiding the nest of a grey-throated babbler (Stachyris nigriceps). The monkey removed from the nest and ate at least two eggs and perhaps one young hatchling. This incident appears to be the first reported case of anyPresbytis spp. consuming animal prey.     

Selective mortality of a coral reef damselfish: role of predator–competitor synergisms

Phenotypic variability within cohorts of juvenile organisms can serve as the basis for selective mortality. Previous studies have demonstrated the important role that predators play in this process but not the impact of competitors on selective predation. We use a combination of lab and field studies to evaluate the effect of the presence of adult competitor damselfish (Dascyllus aruanus and Pomacentrus moluccensis; family Pomacentridae) on the selective mortality of newly-arrived (settled) lemon damselfish (P. moluccensis) by resident predator fishes (Pseudochromis fuscus Pseudochromidae and Cheilodipterus quinquelineatus Apogonidae). Lab trials consisted of mesocosm experiments in which the behaviour, mortality, and physiological condition (measured as lipid content) of surviving P. moluccensis settlers from each of three treatments: (1) predators absent, (2) predators present, and (3) predators and competitors present, were compared. The field study involved stocking newly settled P. moluccensis on natural bommies (patch reefs) which had either been subject to a partial removal of resident fish (predators and competitors) or left alone. Results indicated there was very strong condition-based selective mortality in both the lab and field trials. In both cases there was a strong positive relationship between mortality and the lipid content of surviving fish; implying low-condition fish were selectively removed. The mesocosm trials indicated that the strength of mortality as well as condition selectivity was higher when competitors were present than when they were absent. Behavioural observations in the mesocosm study suggest that attention by juvenile P. moluccensis to the movements and occasional chases of the competitors (especially D. aruanus) reduced their vigilance to the predators. These results suggest the important and interactive roles which condition of newly settled reef fish and interspecific competition can play in the outcomes of post-settlement predation. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Reciprocity and partner preference in grooming of female blue monkeys

Grooming among adult and older juvenile females in a wild group of blue monkeys (Cercopithecus mitis stuhlmanni) is analyzed and related to agonistic behavior. Both grooming and agonistic behavior were less frequent than would be expected in baboon and macaque groups. Fair shares of grooming were given and taken, both within and between interactions, in amost dyads, and all females were seen to groom with at least half the others. The reciprovity of grooming was its most outstanding feature. There was no evidence that grooming was preferentially directed at kin. Frequent grooming partnerships fell into two clusters, one of which ranked higher than the other. We suggest that grooming throughout the group helps to establish a coherent team of females which effectively, defends its territory in daily encounters at the boundaries with neighboring groups.     

The Shrimp Caridina nilotica in Lake Victoria (East Africa), Before and After the Nile Perch Increase

The shrimp Caridina nilotica is a major prey of the introduced Nile perch in Lake Victoria. In spite of heavy predation, the density of shrimps increased after the Nile perch boom and the concomitant disappearance of the haplochromine cichlids. In the same period, the mean size of gravid shrimps and the size at first maturity declined. This seems to indicate an increased predation pressure on adult shrimps. Before the Nile perch upsurge, specialised shrimp eaters and piscivores, among the haplochromine cichlids, only took adult shrimps, whereas we assume that most haplochromines used to include juvenile shrimps into their diet. Another important predator on adult shrimps was Bagrus docmak. The combined density of predators on adult shrimps in the pre-Nile perch era was estimated at 10 kg ha⁻¹ and the potential predators on juveniles were estimated at 170 kg ha⁻¹. After the Nile perch upsurge, only Nile perch up to 10 cm TL and Rastrineobola argentea fed on juvenile shrimps (ca. 36 kg ha⁻¹) and Nile perch from 10 to 50 cm TL (ca. 13 kg ha⁻¹) fed on adults. These rough estimates of the biomass of predators on shrimps before and after the Nile perch upsurge indicate a reduced predation pressure on juvenile shrimps. The disappearance of the haplochromines may have released competition with small Nile perch for juvenile shrimps, thus enhancing the recruitment of Nile perch.     

Juvenile survival of a planktonic insect: effects of food limitation and predation

• 1 An experiment was conducted to investigate potential impacts of food limitation and copepod predation on juvenile survival of Chaoborus purtctipennis. We tested the hypotheses that: (i) juvenile survival of Chaoborus is influenced more by copepod predation than by starvation in a productive environment, and (ii) food limitation and predation interact to affect survival.
• 2 Effects of food concentration (approximately 800, 1400 and 2300 microzooplankton 1-^?1) and predator density (0, 1 and 2 Mesocydops edax 1-^?1) on Chaoborus development and survival were evaluated using a 3 × 3 factorial design. Jars containing lake water, the appropriate food and predator treatments, and two Chaoborus (<12h old) were rotated on a plankton wheel at 25°C. Survival and developmental stage were monitored daily until all individuals had either died or moulted to instar II.
• 3 Predation by Mesocydops was the major source of mortality, causing 87.5% of Chaoborus deaths over all treatments. Chaoborus mortality was significantly higher in treatments with Mesocydops (67–100%) than in predator-free treatment (0–13%).
• 4 Development time was significantly longer in the low-density food treatment than in the highest food treatment.
• 5 No significant interaction between food limitation and predation was detected.
• 6 These results suggest that predation by copepods may limit recruitment of juvenile Chaoborus in productive lakes.

     

Variation in plant stem density and its effects on foraging success of juvenile bluegill sunfish

Synopsis Juvenile bluegill sunfish, Lepomis macrochirus, are known to use beds of aquatic vegetation as a refuge from predators. This study examines the effects of increasing plant stem density on juvenile bluegill foraging. Three stem densities (100, 250 and 500 stems m⁻²), varying in their refuge potential for bluegills from predators, were tested. Results demonstrate that stem densities chosen as a refuge from predation (i.e. 500 stems m⁻²) significantly reduced bluegill foraging success and increased time required to capture prey. Therefore, juvenile bluegills seeking safety in vegetation may be faced with a trade-off between foraging success and effective refuge from predation when choosing among plant stem densities.     

Diet of samango monkeys (Cercopithecus mitis erythrarchus) in the Cape Vidal dune forest, South Africa

The samango monkey ( Cercopithecus mitis erythrarchus Peters, 1852) is the southernmost representative of the widely-distributed polytypic Cercopithecus mitis species-group. At Cape Vidal (28 S) climatic seasonality causes significant seasonal fluctutation in food abundance. There are, however, no congeneric competitors, and few arboreal frugivores (birds, bats). In spite of seasonality of food abundance at Cape Vidal, samango monkeys maintain a high quality diet, dominated by fruit (51.7%), throughout the year. To a large extent this is made possible by their broad dietary tolerances and the effect of competitive release on food choice. Seasonal insect abundance does, however, place serious constraints on the availability of readily-digestible protein and the acquisition of protein-rich foods must be seen as the critically limiting factor in the dietary behaviour of the samango monkey. Adaptation of gut morphology and symbiotic microflora permit samangos to supplement the diet with large amounts of protein-rich foliar and floral items. Where necessary, even large quantities of less palatable items, such as unripe fruits and mature leaves, may be ingested. Although insects form a small part of the diet a larger variety, than used by equatorial C. mitis populations, are included in the diet. Given that there are no congeneric competitors, nor are the monkeys particularly food stressed, I suggest that the diet of the samango monkey at Cape Vidal most closely reflects the intrinsic food choices of the C. mitis species-group.     

Hb bali (Macaca) β80 (EF 4) Asn→Lys: The first hemoglobin variant found in the crab-eating monkey (Macaca fascicularis) on Bali Island,Indonesia

A variant hemoglobin due to structural change in the β chain was found in the central part of Bali island, Indonesia, during field studies on the genetic variation of the Indonesian crabeating monkey (Macaca fascicularis), and was named Hb Bali (Macaca). Structural analysis yielded the following results. (1) The amino acid sequence of the normal β chain of the crab-eating monkey coincided with that of the Japanese monkey (M. fuscata) and the pig-tailed monkey (M. nemestrina). (2) Asn at the 80th position from the amino terminal of the β chain was substituted by Lys in Hb Bali. This substitution appeared to have little harmful effect on the carrier, since the hematological characteristics of the heterozygous carriers were not different from those of normal individuals.     

A preliminary study on the social relationships in a semi-free ranging colony of sun-tailed monkeys (Cercopithecus solatus), a species recently discovered in Gabon

In 1984, a species of guenon endemic to Gabon was discovered: the sun-tailed monkey (Cercopithecus solatus). This species is difficult to locate and observe in the wild, and hence to date has been little studied. The Centre International de Recherches Médicales de Franceville (CIRMF), Gabon, houses the world’s only breeding colony ofC. solatus, on which eco-ethological investigations can be carried out in a semi-free ranging environment. The data reported here present the first results of observations on the social relationships of this colony and support the scant field observations available on this species, showing a basic social unit of one adult male and several females with their offspring. The resident male systematically repulses any second adult male in proximity to the group. A clear hierarchy exists among the females, with mature female offspring eventually acquiring a rank just below that of their mother.     

Mixed-species primate groups in the kibale forest: Ecological constraints on association

Five species of diurnal primates in the Kibale Forest of western Uganda— red colobus (Colobus badius),black- and- white colobus (Colobus guereza),redtail monkeys (Cercopithecus ascanius),blue monkeys (Cercopithecus mitis),mangabeys (Cercocebus albigena)-often associate in mixed- species groups that vary in size and composition from day to day. Across this range of species, we found no consistent effect of association on feeding rate. In addition, there is no systematic difference between the species- specific individual feeding rates when animals were in mixed- species groups feeding in a specific tree on one day and when individuals of one of the same species were feeding in the same individual tree on a subsequent day. If associating in a mixed- species group lowers the risk of predation, one might expect that the number of vigilant events would decrease in mixed- species groups. However, the only species to exhibit a consistent decrease in vigilant behavior when in association was the red colobus. Redtail monkeys were more vigilant when in association. We predicted that the density and distribution of food resources would both constrain the frequency of association and the size of mixed- species groups. Based on 22 months of data on food resources and bimonthly censuses, we found no relationship between the frequency of association (except mangabeys) or mean mixed- species group size and the density and distribution of food resources for all species. Finally, we examined the behavior of the monkeys in and out of association before and after the playback of a crowned hawk eagle call (Spizaetus coronatus),a known predator. When more species were in association, the amount of time they spent being vigilant following the playback was greater and the response more intense than when fewer species were in association or when the group was alone. The results of this study illustrate that the nature of the costs and benefits of polyspecific associations for these different monkey species are complex and vary from species to species.     

Predation on mammals by chimpanzees in the montane forest of Kahuzi, Zaire

The rate of predation on mammals by chimpanzees was determined from carcasses and from fecal specimens found on fresh trails during a 16-month period in the montane forest of Kahuzi-Biega National Park, Zaire. A unit-group of semi-habituated chimpanzees, composed of 22 – 23 individuals including 8 adult or adolescent males, appeared to kill about 18 – 30 mammalian prey (16 – 28Cercopithecus monkeys) per year, if the multiple kills by chimpanzees were not considered. A juvenile l'Hoest's monkey was recorded for the first time as the prey of chimpanzees in this study. Predation occurred in the late dry and the early rainy seasons, when the diversity of ripe fruits was the highest during the year. The Kahuzi chimpanzees tended to kill mammals less frequently but to killCercopithecus monkeys more frequently than chimpanzees in other habitats. The absence of red colobus monkeys, which are the most frequent prey in Gombe, Mahale, and Tai, might be responsible for the low predation rate. However, the estimated rate of predation onCercopithecus monkeys is the highest record among various chimpanzee habitats. At least 11 – 18% of theCercopithecus population seemed to be lost annually as a result of being killed by chimpanzees. Chimpanzees may be the most important predators on these monkeys in the absence of leopards at Kahuzi. The examination of fecal samples and carcasses suggested that adult (probably male) or adolescent chimpanzees tended to eat juvenile or subadult monkeys most frequently, as is also seen for chimpanzees in Gombe, Mahale, and Tai.