Comparative chromosome painting in Aotus reveals a highly derived evolution

The genus Aotus represents a highly diverse group with an especially intricate taxonomy. No standard cytogenetic nomenclature for the genus has yet been established. So far, cytogenetic studies have characterized 18 different karyotypes with diploid numbers ranging from 46 to 58 chromosomes. By combining G-banding comparisons and molecular cytogenetic techniques, we were able to describe the most likely pattern of chromosome evolution and phylogenetic position of two Aotus karyomorphs (KMs) from Venezuela: Aotus nancymai (KM3, 2n=54) and Aotus sp. (KM9, 2n=50). All of the proposed Platyrrhini ancestral associations (2/16, 3/21, 5/7, 8/18, 10/16, 14/15) were found in the Aotus KMs studied, except 2/16 and 10/16. In addition, some derived chromosomal associations were also detected in both KMs (1/3, 1/16, 2/12, 2/20, 3/14, 4/15, 5/15, 7/11, 9/15, 9/17, 10/11, and 10/22). Although some of these associations have been found in other New World monkeys, our results suggest that Aotus species have undergone a highly derived chromosomal evolution. The homologies between these two Aotus KMs and human chromosomes were established, indicating that KM3 has a more derived karyotype than KM9 with respect to the ancestral Platyrrhini karyotype.     

Use of spatial, visual, and olfactory information during foraging in wild nocturnal and diurnal anthropoids: A field experiment comparing Aotus, Callicebus, and Saguinus

Early in their evolution, the ancestors of anthropoid primates radiated from a nocturnal to a diurnal niche. Foraging during the night differs from foraging during the day in terms of the availability of light and color cues, and in the movement of odor molecules through the canopy. In this study, we compared the ability of nocturnal and diurnal New World monkeys to use perceptual cues (i.e., the sight or smell of food) and spatial information (place predictability) in within-patch foraging decisions. An experimental field study was conducted on wild groups of night monkeys (Aotus nigriceps), tamarins (Saguinus imperator imperator and S. fuscicollis weddelli), and titi monkeys (Callicebus cupreus) at the Zoobotanical Park/UFAC, Rio Branco, Brazil. Our research design included the construction of feeding stations located in the home range of the study groups. Each feeding station consisted of eight visually identical feeding platforms located in a circular arrangement. In all test settings, two platforms at each feeding station contained a food reward (banana), and the remaining six platforms contained a sham reward (yellow plastic or inaccessible banana). In the night-monkey experiments, each feeding platform was illuminated by a 40-W red bulb to aid the researcher in observing their behavior. When the location of reward sites was predictable over time, individuals in all four species successfully relocated food rewards based solely on spatial information. Each species was also successful in using visual information to distinguish real from sham food rewards. However, only night monkeys and one group of emperor tamarins used olfactory information alone to locate food rewards. Overall, the species' performances did not clearly differentiate Aotus from diurnal New World primates in these experiments.     

Home range structure and inter-group competition for land of Japanese macaques in evergreen and deciduous forests

The per capita home range area of Japanese macaques,Macaca fuscata, is significantly smaller in evergreen forest than in deciduous forest, though a corresponding difference in food resource utilization patterns has never been described. The present study compared the home range utilization pattern of Japanese macaques living in two habitats: the Yakushima population inhabits an evergreen forest, while the Kinkazan population inhabits a deciduous forest. We found that in the Yakushima population, (1) food density was higher; (2) inter-feeding bout sites distance was shorter; (3) daily travel distance was shorter; (4) home range size was smaller; and (5) the unit value of the main home range was higher, than in the Kinkazan population. Yakushima groups utilized a small home range area intensively, compared to Kinkazan groups. We also found that a Yakushima group shared 24% of its main home range with neighboring groups, though a Kinkazan group shared only 10% with other groups. It is supposed that food distribution affects daily ranging pattern, and ultimately the social relationships between groups in Japanese macaques.     

Size,Site Fidelity,and Overlap of Home Ranges and Core Areas in the Socially Monogamous Owl Monkey (Aotus azarae) of Northern Argentina

In addition to environmental factors, social variables such as group size may play an important role in explaining primate ranging patterns. In this study we investigated range sizes, site fidelity, and range overlaps of owl monkeys (Aotus azarae) in Northern Argentina. We calculated the size of home range and core areas for 18 groups in our study area. For the six most intensively studied groups we tested whether precipitation as a crude proxy for food availability or group size had an influence on range size, assessed the degree of site fidelity by quantifying overlaps of annual ranges and core areas, and calculated the amount of range overlap between neighboring groups for each year. We used the kernel density estimation method to calculate home ranges as 90% kernel and core areas as 50% kernel. Home range size (mean ± SD) was 6.2 ha (± 1.8) and core area size 1.9 (± 0.6). Rainfall and group size were not statistically significant predictors of range sizes. Site fidelity was high, with a range overlap of 82% (± 11) between consecutive years. Neighboring groups overlapped over 48% (± 15) of the outer parts of their group ranges and 11% (± 15) of their core areas. We found no evidence that larger groups occupy larger areas than smaller groups, suggesting that food availability might be above a critical threshold for owl monkeys so that larger groups do not need to extend their foraging areas to meet their energy requirements. Our findings indicate that ranges remain stable over several years as groups visit the same locations of fruit trees within their range. We showed that owl monkeys exhibit a considerable degree of range overlap. However, we suggest that this range overlap might be spatial rather than temporal, which maximizes access to clumped feeding resources in overlapping areas that are used at distinct times, while excluding other males from access to females in exclusively used areas.     

Adaptation of a strain of Plasmodium vivax from India to New World monkeys, chimpanzees, and anopheline mosquitoes.

A strain of Plasmodium vivax from India was adapted to develop in splenectomized Saimiri boliviensis, Aotus lemurinus griseimembra, A vociferans, A. nancymai, A. azarae boliviensis, hybrid Aotus monkeys, and splenectomized chimpanzees. Infections were induced via the inoculation of sporozoites dissected from the salivary glands of Anopheles stephensi and An. dirus mosquitoes to 12 Aotus and 8 Saimiri monkeys; transmission via the bites of infected An. stephensi was made to 1 Aotus monkey and 1 chimpanzee. The intravenous passage of infected erythrocytes was made to 9 Aotus monkeys and 4 chimpanzees. Gametocytes in 13 Aotus monkeys and 4 chimpanzees were infectious to mosquitoes. Infection rates were markedly higher in mosquitoes fed on chimpanzees. PCR studies on 10 monkeys injected with sporozoites revealed the presence of parasites before their detection by microscopic examination. The India VII strain of P. vivax develops in Aotus and Saimiri monkeys and chimpanzees following the injection of parasitized erythrocytes, or sporozoites, or both. The transmission rate via sporozoites to New World monkeys of approximately 50% may be too low for the testing of sporozoite vaccines or drugs directed against the exoerythrocytic stages. However, the strain is highly infectious to commonly available laboratory-maintained anopheline mosquitoes. Mosquito infection is especially high when feedings are made with gametocytes from splenectomized chimpanzees.     

Functional and structural similarity of V gamma 9V delta 2 T cells in humans and Aotus monkeys, a primate infection model for Plasmodium falciparum malaria.

Gammadelta T cells are implicated to play crucial roles during early immune responses to pathogens. A subset of human gammadelta T cells carrying the Vgamma9Vdelta2 TCR recognize small, phosphorylated nonpeptidic Ags. However, the precise role of these cells and the ligands recognized in human immune responses against pathogens remains unclear because of the lack of suitable animal models. We have analyzed the reactivity of spleen cells of the New World monkey Aotus nancymaae against isopentenyl pyrophosphate (IPP), a phosphorylated microbial metabolite selectively activating Vgamma9Vdelta2 T cells. Spleen cells were stimulated by IPP and the expanding cell population expressed the Vgamma9 TCR. TRGV-J and TRDV-D-J rearrangements expressed by IPP-stimulated cells of Aotus were analyzed by RT-PCR and DNA sequencing. The TRGV-J and TRDV-D-J rearrangements expressed by IPP-stimulated Aotus and human gammadelta T cells were similar with respect to 1) TCR gene segment usage, 2) a high degree of germline sequence homology of the TCR gene segments used, and 3) the diversity of the CDR3 regions. Phylogenetic analysis of human, Pan troglodytes, and A. nancymaae TRGV gene segments showed that the interspecies differences are smaller than the intraspecies differences with TRGV9 gene segments located on a distinct clade of the phylogenetic tree. The structural and functional conservation of Vgamma9Vdelta2 T cells in A. nancymaae and humans implicates a functionally important and evolutionary conserved mechanism of recognition of phosphorylated microbial metabolites.     

Proliferative response of peripheral blood lymphocytes to mitogens in the owl monkey Aotus nancymae

The new world primate Aotus sp. has been recommended by the World Health Organization as a model for evaluation of malaria vaccine candidates, given its susceptibility to experimental infection with the human malaria parasites Plasmodium falciparum and P. vivax. The present study examined the in vitro proliferative response of peripheral blood mononuclear cells (PBMCs) isolated from Aotus monkeys, utilizing a wide range of mitogens. Results presented herein demonstrate that the in vitro proliferative response of PBMCs from the Aotus sp. is quite variable from monkey to monkey for each of the mitogens assessed. PBMCs from the Aotus monkey exhibited a delayed kinetic proliferative response and, particularly, a different sensitivity to proliferation in response to various concentrations of Phytohemagglutinin-P and favin lectins, the phorbol ester Phorbol myristate acetate and the calcium ionophore ionomycin. Altogether, our findings are consistent with the conclusion that the in vitro proliferative response of PBMCs from the Aotus differ in their activation requirements compared with PBMCs from humans.     

Long-term changes in the winter home ranges of Japanese monkeys in the Shiga heights

In the home ranges of the monkeys, the densely utilized food sites (densely utilized sites of food resources ofWada andTokida, 1981) varied over a period of ten years. The Shiga B₂ troop changed both its densely utilized food sites and the kinds of tree mostly eaten within the same home range, whereas the Shiga C troop transferred to a new home range. The home range transition of the C troop was influenced by both food deficiencies and the existence of the B₂ troop. Based on these facts, it can be said that two types of long-term home range utilization were distinguishable.     

Ranging patterns and habitat use of Sulawesi Tonkean macaques (Macaca tonkeana) in a human-modified habitat

The goal of this study was to investigate the ecological flexibility of Tonkean macaques (Macaca tonkeana) by examining how they respond to human-induced habitat alteration. To do so, I observed movement patterns, forest strata use, microhabitat use, and home range use in two groups that occupied habitats with different levels of human alteration and habitat quality in Lore Lindu National Park, Sulawesi, Indonesia. The group occupying the heavily altered habitat (Anca) spent a significantly greater proportion of time traveling on the ground than the group in minimally altered habitat (CH), and significantly more time than expected in microhabitats within their range that were characterized by greater alteration (e.g., agroforestry areas). There was no significant difference between the two groups in daily path length, despite differences in group size. The Anca group exhibited a greater home range area per individual than the CH group, and utilized a more limited area within their home range with greater intensity, relative to the CH group. Tonkean macaques therefore show considerable flexibility in response to anthropogenic disturbance by adjusting their use of forest strata to facilitate travel and increase foraging opportunities and by intensively using particular areas within their home range where known resources are present and predictably available.     

Habitat utilization by wintering Japanese monkeys (macaca fuscata fuscata) in the Shiga heights

The detailed habitat utilization of the Shiga B₂ troop was studied in winter. The following results were obtained. (1) The roosting site distribution was limited to the Yokoyugawa valley. (2) The measured home range size was 1.99 km², which was greater than the 1.23 km² of larger population size of the Shiga C troop. (3) The daily travel distance ranged from 0 to 1,825 m (mean 646 m). (4) The pendulum cycle of troop movement is composed of two types: wandering and tripping. The daily travel distance in tripping was much longer than that in wandering. (5) The utilization rate of the home range was assessed according to the total length of the travelling course per grid square. Highly utilized areas in the home range were found along the Yokoyugawa valley without using areas far from the valley. (6) Diurnal activity was influenced by climate, although it was difficult to establish any clear daily rhythm. (7) The food items amounted to 39 species. (8) Distribution of densely utilized sites of food resources almost coincided with those of resting sites. (9) The reasons for the use of the complete home range by the B₂ were also discussed.     

Identification,cloning, and sequencing of different cytokine genes in four species of owl monkey

Non-human primates could prove to be suitable models for the study of infectious diseases such as malaria, tuberculosis, and hepatitis; the molecules of their immune systems are in the process of being fully characterized. Due to the relevance of cytokines in the modulation of the immune response, a molecular analysis of these proteins in non-human primates from the Aotus genus was carried out. Peripheral blood mononuclear cells from four species of Aotusmonkey were obtained and their mRNAs for interleukin-2 (IL-2), IL-4, IL-6, IL-10, interferon-gamma (IFN), and tumor necrosis factor (TNF)-alpha were characterized. This study shows a high degree of conservation between nucleotide and amino acid sequences of cytokines from different Aotus species and those from humans. The TNF-alpha molecules were identical in amino acid sequences for both.     

Range expansion as a response to increasing group size in the Yunnan snub-nosed monkey

The Yunnan snub-nosed monkey (Rhinopithecus bieti) is characterized by a larger home range and group size than other colobine species. We investigated variations in home range size of a free-ranging group of R. bieti from 1998 to 2007 in the Baimaxueshan National Nature Reserve in Yunnan, China. Group size increased from 160 to 450 over the 10 years. Results also showed a home range shift and yearly home range expansion, although this expansion was very limited. The study group covered a 33.78-km(2) area during the 10-year period, with some areas abandoned and others used repeatedly. The yearly home range increase stopped in 2004 and decreased thereafter. Despite increasing group size usually being coupled with larger yearly home range (>30 km(2)), the group confined itself within a relatively small and stable area (<18 km(2)) during 2005-2007, with a significant portion of their accessible home range discarded. Consequently, the study group showed the highest recorded population density among extant groups of R. bieti. Reasons why the group settled into a substantially smaller home range area remain unclear.     

Home range variation of two different-sized groups of golden snub-nosed monkeys(Rhinopithecus roxellana) in Shennongjia,China: implications for feeding competition

Knowledge on the home range size of a species or population is important for understanding its behavioral and social ecology and improving the effectiveness of conservation strategies. We studied the home range size of two different-sized groups of golden snub-nosed monkeys(Rhinopithecus roxellana) in Shennongjia, China. The larger group(236 individuals)had a home range of 22.5 km2 from September2007 to July 2008, whereas the smaller group(62 individuals) occupied a home range of 12.4 km2 from November 2008 to July 2009. Both groups exhibited considerable seasonal variation in their home range size, which was likely due to seasonal changes in food availability and distribution. The home range in any given season(winter, spring, summer, or winter+spring+summer) of the larger group was larger than that of the smaller group. As the two groups were studied in the same area, with the confounding effects of food availability thus minimized, the positive relationship between home range size and group size suggested that scramble feeding competition increased within the larger group.     

Do Forest Composition and Fruit Availability Predict Demographic Differences Among Groups of Territorial Owl Monkeys (Aotus azarai)?

Small-scale ecological variables, such as forest structure and resource availability, may affect primate groups at the scale of group home ranges, thereby influencing group demography and life-history traits. We evaluated the complete territories of 4 groups of owl monkeys (Aotus azarai), measuring and identifying all trees and lianas with a diameter at breast height ≥10 cm (n = 7485). We aimed to determine all food sources available to each of those groups and to relate food availability to group demographics. For analyses, we considered the core areas of the home range separately from the 80% home range. Our results showed that groups occupy territories that differ in size, species evenness, stem density, and food species’ stem abundances. The territories differed in the availability of fruits, flowers, and leaves, and most fruit sources were unevenly distributed in space. Differences among territories were more pronounced for the whole range than they were for the core areas. Despite marked differences among territories in structure and food availability, the number of births and age at natal dispersal were quite similar, but 1 group had a consistently lower group size. Our results suggest that owl monkey groups occupy territories of different structure and composition and food availability, yet ones that contain similar quantities of, mostly, dry season fruit sources. We propose that groups inhabit these territories to overcome food shortages safely during limiting periods, specifically the dry season, in this markedly seasonal forest. The occupancy and defense of territories with strict boundaries may therefore be associated with food resources available during limiting seasons that may be the ones influencing life history patterns and demographics.     

Banding patterns of the chromosomes of two new karyotypes of the owl monkey, Aotus, captured in Panama.

Two new chromosome complements of Aotus trivirgatus griseimembra are described making a total of five different karyotypes observed in this subspecies inhabiting Panama and the northwestern part of Colombia, South America. Detailed comparisons of the G-banded chromosomes of these five karyotypes suggest that the polymorphism of chromosome numbers 56 and 55 in Panamanian Aotus and 54, 53, and 52 in Colombian Aotus stems primarily from a Robertsonian translocation mechanism involving pairs B13 and B14 (or A1). A second Robertsonian translocation mechanism involving pairs B28 and B29 (or A2) constitutes the karyotypic differences between the two chromosomal races.     

Home Range and Frugivory Patterns of Mountain Gorillas in Bwindi Impenetrable National Park,Uganda

Mountain, western, and Grauer's gorillas exhibit broad differences in ecological patterns with western gorillas eating more fruit and having larger home ranges than their largely folivorous counterparts in the Virunga Volcanoes. We studied the home range and frugivory patterns of one group of Gorilla beringei beringei in the little-studied population of Bwindi Impenetrable National Park, Uganda, to compare with other populations and to investigate whether there was any relationship between patterns of frugivory and home range size. During the 3-year study, the gorillas ate 16 species of fruit on 27% of observation days. There was high variability in frugivory among the 3 years and no consistent seasonal pattern. Annual home range size was ca. 21 km² for Years 1 and 2, and it increased dramatically to 40 km² in Year 3. Home range size varied considerable between months and seasons, but there is no clear relationship between occurrence of fruit-eating and home range size. The group exhibited more fruit-eating and a larger home range size those ofthe gorillas in the Virunga Volcanoes. Their home range size is comparable to that of western gorillas, though Bwindi gorillas consumed less fruit. Home range size and utilization by all gorillas probably depends on a complex relationship between the distribution and abundance of both fruit and herbaceous vegetation and social factors such as male mating tactics.     

Home range size and dispersion in the helmeted guineafowl (Numida meleagris galeata Pallas) of the Waza National Park, Cameroon

Field investigations of the home range size and emigration pattern of wild helmeted guineafowl ( Numida meleagris galeata Pallas) from 1992 to 1995 showed that home range size (±95% confidence limits (CL) ) varied with season from 3·6±1·5 km² for the dry seasons to 3·1±1·5 km² for the rainy seasons. Home range size varied depending on whether it was estimated with data for adult males, adult females or young birds, with a higher home range size for young birds, closely followed by adult males. Group size (±95%CL) varied by month, and was highest between March and April (47·0±8·1 birds/group) and lowest in August 9·0±5·1 birds/group). More young birds (±95%CL) (36·8±19·6%) dispersed than adult males (21·1±1·9%) or adult females (13·5±1·8%). There was a highly significant positive correlation between group size and the number of birds emigrating from the group. There was also a significant negative correlation between the weights of birds at tagging and the percentage that emigrated during the first year of study but not later. This is suggested to be linked to the high number of young birds emigrating, since they weigh relatively less than adults. The lack of correlation between body weight and number of birds emigrating a year or later after birds were tagged was thought to be due to the fact that birds tagged while young attained adult weight within a year.     

Home range of juvenile Atlantic salmon, Salmo salar, and brown trout, Salmo trutta, in a Norwegian stream

SUMMARY. 1. The sizes of home ranges of juvenile Atlantic salmon (age 1 +) and brown trout (age 2+ to 9+) in a Norwegian coastal stream were estimated by local movements of batch-marked fish from 12.5 and 25 m long sections. Only recoveries made in the release section and in up-and downstream neighbouring sections were considered.
2. There was no significant difference in the average percentage of recaptures of salmon and trout between 12.5 and 25 m sections; a stream area of about 40–50 m² defines the size of home range for stocks of both species.
3. The fraction of brown trout recaptured in release sections increased with increasing fish densities, indicating a smaller home range under these conditions.