Primate communities vary in their level of redundancy, or overlap, in seed dispersal function, which could be due to body size, degree of frugivory or intraspecific variation, among other factors. In this study, we quantified redundancy in seed dispersal among three sympatric primate species: Lagothrix lagothricha, Alouatta seniculus and Sapajus apella in gallery forests in Meta, Colombia. We compared the median seed width dispersed and the number and species richness of large (≥5.9 mm wide) and very large (>7.5 mm wide) seeds per faecal sample. The medium-sized, highly folivorous A. seniculus mostly dispersed large seeds, the larger, highly frugivorous L. lagothricha dispersed very large and small seeds, and the smaller, partially frugivorous S. apella dispersed the smallest seeds. However, for L. lagothricha and S. apella, we did not find the expected results that adults disperse larger seeds than juveniles. Across species, there is complementarity in seed dispersal in relation to seed size, with L. lagothricha being unique in its contribution to the dispersal of very large seeds both in terms of quantity and richness.

Stereotypies are frequently associated with sub-optimal captive environments and are used as welfare indicators. However, susceptibility to stereotypy can vary across individuals of the same group. As such, identifying which individuals are more susceptible to this behaviour may be helpful in managing this issue. We have investigated which sex-age class of semi-captive capuchin monkeys (Sapajus spp) is more susceptible to stereotypic behaviours and evaluated whether or not they are also more affected by the social factors that typically influence and increase allostatic load. To accomplish this, we used instantaneous sampling to collect data on a group of capuchins kept on an island in an urban park in São Paulo, Brazil. We found that sub-adult males were the only sex-age class to display stereotypic behaviours and they all displayed pacing. Furthermore, 33% of sub-adult males also exhibited a second stereotypic behaviour associated with their pacing. Compared to the other sex-age classes, sub-adult males had a higher participation in social conflicts and experienced higher social isolation. Sub-adult males also demonstrated a lower level of positive social interactions. All of these factors typically increase allostatic load. We suggest that distal causation of the observed pacing behaviour would be the ecological/evolutionary need of sub-adult males to disperse from their natal group and that the proximal causation would relate to the high allostatic load from social sources. We recommend that managers of zoos and other facilities monitor changes in the social composition of captive groups and evaluate individuals’ age so that necessary alterations may be made, where appropriate, to reduce allostatic load and generate better welfare at individual and group levels.

Ovarian biopsies from five health adult monkeys were collected by exploratory laparotomy. Preantral follicles (primordial, primary, and secondary) were classified as normal or degenerated and submitted to morphometric analysis in which granulosa cell counts and the areas of follicles, oocytes, and oocyte nuclei were measured. Ovarian fragments were also immunolabelled for the quantitative analysis of VEGFA and CD31 protein expression in the ovarian tissue and in the preantral follicles. In total, 213 preantral follicles was examined for morphometry and morphological classification. From this total, 20 (9.4%) were follicles enclosing two or more oocytes, i.e. multi-oocyte follicles (MOFs). From the 193 follicles enclosing only one oocyte, 46.3% were classified as primordial, 24,1% as transition, 23.3% as primary, and 6.3% as secondary follicles. The mean number of granulosa cells surrounding primordial, transition, primary, and secondary follicles was 9.2, 12.1, 18.7, and 45.3, respectively. Increase in oocyte diameter was observed from primary to secondary follicles, while the oocyte nucleus increased only when follicles reached the secondary stage. The expression of CD31 was strong in vessels, corpus luteum, and in normal oocytes and granulosa cells from preantral follicles at all developmental stages. Likewise, VEGFA expression was observed in vessels and preantral follicles (granulosa cells, the oocyte and the oocyte nucleus). We characterized the morphology, and morphometry and expression of angiogenic factors in normal and atretic preantral follicles from Sapajus apella. This description can support the analysis of follicular quality and survival after procedures such as transplantation and cryopreservation.

The efficiency of in vitro fertilization (IVF) depends on the viability of spermatozoa. For capuchin monkeys (Cebus apella), in vitro capacitation of spermatozoa is challenging because of their unique seminal coagulum. Motile spermatozoa can be obtained after liquefaction of the semen coagulum in coconut water-based solution. The objective of the present study was to establish an optimal in vitro maturation (IVM) protocol for capuchin monkeys and to observe the effect of follicle stimulating hormone (FSH) and luteinising hormone (LH) on IVF and parthenogenetic activation (PA) of oocytes collected from unstimulated females. We assessed spermatozoa quality after recovery from seminal coagulum using the solution ACP-118® as an extender. Oocytes were matured in vitro for 36 or 40 h and subjected to IVF or PA by applying ionomycin combined either with 6-dimethylaminopurine (6-DMAP) or roscovitine. In total, 87% of oocytes reached metaphase II (MII) after 40 IVM and 4-cell embryo production was obtained after IVF and parthenogenesis using ionomycin/6-DMAP. ACP-118® was used successfully to harvest viable spermatozoa from semen coagulum and in the preservation of spermatozoa, which were able to fertilize oocytes in vitro.

Terrestrial locomotion requires that animals maintain postural stability against the flexing force of gravity. To counteract volume/area relationships that limit muscle force and may compromise stability, larger animals increase the effective mechanical advantage of their extensor musculature by walking on more extended limbs and showing allometric increases in extensor muscle lever arm lengths. Assuming these size-related principles are uniform, similar adaptations should characterize ontogenetic increases in size. Previous research on non-primate mammals has shown, however, that extensor muscle mechanical advantage is greater early in ontogeny and decreases with negative allometry during growth. This study extended this work by investigating patterns of relative elbow lever arm growth in two capuchin monkeys, Cebus albifrons and Cebus apella. Unlike previously studied mammals, growing capuchin monkeys face unique anatomical constraints, including relatively long limb bones and positively allometric limb growth. These constraints could augment the flexing torque of gravity at the limb joints and require compensatory increases in extensor muscle mechanical advantage as size increases through growth. Forearm length and the length of elbow extensor and flexor muscle lever arms were measured in longitudinal radiographic series of growing capuchin monkeys. In contrast to other mammals, all lengths scaled to body mass with positive allometry. Anatomical mechanical advantage (lever arm length/forelimb length) scaled with negative allometry, however, matching the non-primate mammalian trend. Greater muscle mechanical advantage during early locomotion may help young mammals overcome relatively weak extensor muscles and other growth-related limits on locomotor performance. Additional data on ontogenetic changes in gait dynamics and musculoskeletal growth are required to validate this hypothesis.

The pattern of home-range use by seven groups of tufted capuchin monkeys Cebus apella nigritus is described in the Iguazú National Park, Argentina, during 1991–94. The seasonal changes in home-range use by one of these groups between August 1997 and December 1998, are correlated with changes in food distribution and availability. Fruit availability was estimated with fruit traps, and the abundance and distribution of food was experimentally changed within the home range of one group by using feeding platforms filled with bananas. Average home-range size is 161 ± 77 ha (range = 81–293 ha, n = 7). There is a positive relationship between the number of females per group and home-range size. Neighbouring groups have partially overlapping home ranges and aggressive relationships. Fruit abundance is scarce during the winter and peaks during the spring and early summer. The pattern of home-range use by the main study group of capuchins was consistent with the hypothesis that fruit distribution and availability is the most important factor affecting the spatial use of their range. This is evidenced by the changes in range size and in range use as the distribution and abundance of their main fruit sources change seasonally. Range use shifted dramatically during the experimental phase of this study; the capuchins reduced their range and most frequently visited the areas where the feeding platforms were located. For most populations of frugivorous monkeys, fruit distribution and availability are the main factors that determine the pattern of home-range use. However, in some populations the availability of water sources and sleeping sites can have some effect on range use. For capuchin monkeys in particular, within-species variation in home-range size, degree of range overlap and interactions between neighbouring groups are large and do not serve to characterize any species of Cebus monkeys.