Effects of tourist pressure on the follicular cycles and reproductive behavior in female barbary macaques (macaca sylvanus)

Die Studie beschäftigte sich mit den Auswirkungen des Tourismus auf die Reproduktionsphysiologie und das Sexualverhalten weiblicher Berberaffen (Macaca sylvanus). Die Daten hierfür wurden in einer Fokusgruppe der Population in Gibraltar, die häufig von Touristen besucht wird erhoben. Verhaltensdaten in Form von Fokusprotokollen und ad lib. Daten wurden täglich gesammelt, Hormonprofile mittels Urinproben erstellt. Die Studie wurde an sieben Fokusweibchen durchgeführt. Die Reproduktionsphysiologie der Weibchen konnte nur teilweise ausreichend untersucht werden. Aufgrund von Probenmangel war es nicht möglich, Zyklusphasen der Fokustiere nachzuvollziehen. Für vier Weibchen konnten jedoch mögliche Ovulationszeitpunkte eruiert werden. Diese wurden mit dem Sexualverhalten einige Tage vor beziehungsweise nach dem möglichen Ovulationszeitpunkt korreliert und interpretiert. Es zeigte sich, dass weibliche Berberaffen ihr Verhalten teilweise an die Touristensituation anpassen. Hierbei spielt jedoch auch der jeweilige Rang des Weibchens eine Rolle. Generell interagierten höherrangige Weibchen öfter mit Touristen als niederrangige. Allgemein wurde sowohl soziales, agonistisches wie sexuelles Verhalten in Anwesenheit von Touristen weniger oft gezeigt. Es konnten jedoch keine signifikanten Ergebnisse gewonnen werden. Eine Analyse der Stresslevels der Weibchen zeigte keinen klaren Zusammenhang mit der Frequenz der Touristeninteraktionen. Mittelrangige und das dominante Weibchen zeigten die höchsten Stresslevels.In the course of the present study effects of tourist pressure on Barbary macaque females’ reproductive physiology and sexual behavior were analyzed. The study was conducted on the Rock of Gibraltar in one focal group, frequently visited by tourists. Data collection was done over one reproductive season. Behavioral data were gained via focal protocols and collection of ad lib data. Endocrine profiles were evaluated from urine samples. Daily observations and urine sampling concentrated on seven focal females. The reproductive physiology of the female Barbary macaques was monitored. Due to lack of samples it was not possible to distinguish the different cycle phases of the females. For four focals however, time points of possible ovulations respectively of follicular genesis could be evaluated. These time points were linked with the corresponding sexual behaviors occurring within the following and previous days. It was shown that sexual initiative and male interest increased during this period. Female sexual behavior was partly affected by tourist presence. Mainly high ranking females adapted their behavior to the tourist situation and ceased being sexually active when tourists were at the site. Generally dominant females interacted more with tourists than their lower ranking peers. Overall social, agonistic and reproductive behavior was shown less in the presence of tourists, although no significant results could be gained. Stress analyses revealed that average cortisol levels and tourist interaction rates showed no clear connection. Rank might influence stress rates. Middle ranking and dominant females expressed highest stress levels

Measurement of salivary cortisol in two New World primate species

Funding: R.S. was supported by the Austrian Science Fund (FWF, Young Independent Researcher Group (YIRG) grant; Grant Number ZK 66) and ERC Grant 230604 SOMACCA (to W. Tecumseh Fitch).Glucocorticoids (GCs) are mammalian steroid hormones involved in a variety of physiological processes, including metabolism, the immune response, and cardiovascular functions. Due to their link to the physiological stress response, GC measurement is a valuable tool for conservation and welfare assessment in animal populations. GC levels can be measured from different matrices, such as urine and feces. Moreover, especially in captive settings, measuring GCs from saliva samples proved particularly useful as those samples can be collected non-invasively and easily from trained animals. Salivary GC levels can be measured using a variety of analytical methods, such as enzyme immunoassays. However, it is crucial to validate the analytical method for each specific application and species when using a new matrix. Using high-pressure liquid chromatography and a cortisol enzyme immunoassay, we show that the main glucocorticoids secreted in the saliva of squirrel monkeys and brown capuchin monkeys are cortisol and cortisone. Our biological validation found the expected salivary cortisol level to decline throughout the day. Our findings support the reliability of salivary cortisol measurements and their potential to be used as a valid tool in research and welfare assessment for these non-human primates.Publisher PDFPeer reviewe

Chimpanzee intellect:Personality, performance, and motivation with touchscreen tasks

Human intellect is characterized by intercorrelated psychological domains, including intelligence, academic performance and personality. Higher openness is associated with higher intelligence and better academic performance, yet high performance among individuals is itself attributable to intelligence, not openness. High conscientiousness individuals, although not necessarily more intelligent, are better performers. Work with other species is not as extensive, yet animals display similar relationships between exploration- and persistence-related personality traits and performance on cognitive tasks. However, previous studies linking cognition and personality have not tracked learning, performance and dropout over time—three crucial elements of cognitive performance. We conducted three participatory experiments with touchscreen cognitive tasks among 19 zoo-housed chimpanzees, whose personalities were assessed 3 years prior to the study. Performance and participation were recorded across experiments. High conscientiousness chimpanzees participated more, dropped out less and performed better, but their performance could be explained by their experience with the task. High openness chimpanzees tended to be more interested, perform better and continue to participate when not rewarded with food. Our results demonstrate that chimpanzees, like humans, possess broad intellectual capacities that are affected by their personalities

Salivary cortisol reaction norms in zoo-housed great apes : diurnal slopes and intercepts as indicators of stress response quality

SIMPLE SUMMARY: Changes in cortisol fluctuations are used for stress monitoring. Methodologically, this is straight forward, because sample collection is simple and analytical methods advanced, but since cortisol is primarily a hormone that facilitates energy allocation, the interpretation of these measures is often complex. Acute elevations in cortisol levels are not per se bad, but may constitute an adaptive coping mechanism. Likewise, low cortisol levels do not always indicate the absence of a stressor. To distinguish between stress response qualities, a more fine-grained analyses of cortisol fluctuations is warranted. Cortisol excretion follows a diurnal pattern with high levels in the morning, decreasing throughout the day. Two regression coefficients describe this curve: the intercept (the constant with which levels change throughout the day) and the slope (curve steepness and direction). We assessed salivary cortisol intercepts and slopes in zoo-housed apes on routine days, enrichment days, and in the new ape house. While cortisol excretion increased on enrichment days, the daily decline of cortisol levels was not affected. The move to the new house seemingly was a major stressor as cortisol levels increased slightly and the circadian cortisol decrease was impaired. The combination of intercept and slope measures can differentiate between stress responses, thereby constituting a useful tool for stress monitoring. ABSTRACT: Monitoring changes in cortisol levels is a widespread tool for measuring individuals’ stress responses. However, an acute increase in cortisol levels does not necessarily denote an individual in distress, as increases in cortisol can be elicited by all factors that signal the need to mobilize energy. Nor are low levels of cortisol indicative for a relaxed, healthy individual. Therefore, a more fine-grained description of cortisol patterns is warranted in order to distinguish between cortisol fluctuations associated with different stress response qualities. In most species, cortisol shows a distinct diurnal pattern. Using a reaction norm approach, cortisol levels across the day can be described by the two regression coefficients: the intercept and the slope of the curve. We measured immunoreactive salivary cortisol in three zoo-housed ape species under three conditions (routine days, enrichment days, and after the move to a new house). We examined salivary cortisol intercepts (SCI) and salivary cortisol slopes (SCS) of the diurnal curves. SCI and SCS were independent from each other. SCI was highest on enrichment days and lowest on routine days. SCS was steep on routine days and blunted after the move. Only SCI was species-specific. Our study provides evidence that combining SCI and SCS measures allows us to differentiate between types of stress responses, thereby constituting a useful tool for welfare assessment

Plasma testosterone and androstenedione levels follow the same sex-specific patterns in the two Pan species

In most animals, males are considered more aggressive, in terms of frequency and intensity of aggressive behaviors, than their female peers. However, in several species this widespread male-biased aggression pattern is either extenuated, absent, or even sex-reversed. Studies investigating potential neuro-physiological mechanisms driving the selection for female aggression in these species have revealed an important, but not exclusive role of androgens in the expression of the observed sex-specific behavioral patterns. Two very closely related mammalian species that markedly differ in the expression and degree of sex-specific aggression are the two Pan species, where the chimpanzee societies are male-dominated while in bonobos sex-biased aggression patterns are alleviated. Using liquid chromatography–mass spectrometry (LC-MS) methods, we measured levels of plasma testosterone and androstenedione levels in male and female zoo-housed bonobos (N = 21; 12 females, 9 males) and chimpanzees (N = 41; 27 females, 14 males). Our results show comparable absolute and relative intersexual patterns of blood androgen levels in both species of Pan. Plasma testosterone levels were higher in males (bonobos: females: average 0.53 ± 0.30 ng/mL; males 6.70 ± 2.93 ng/mL; chimpanzees: females: average 0.40 ± 0.23 ng/mL; males 5.84 ± 3.63 ng/mL) and plasma androstenedione levels were higher in females of either species (bonobos: females: average 1.83 ± 0.87 ng/mL; males 1.13 ± 0.44 ng/mL; chimpanzees: females: average 1.84 ± 0.92 ng/mL; males 1.22 ± 0.55 ng/mL). The latter result speaks against a role of androstenedione in the mediation of heightened female aggression, as had been suggested based on studies in other mammal species where females are dominant and show high levels of female aggressivenes

Blood testosterone levels in sickness and in health : male chimpanzee testosterone levels decrease in face of an immune challenge

As an integral part of the immune response, testosterone secretion is inhibited when an individual is confronted with an immune challenge. Testosterone-mediated physiological, morphological, and behavioral traits are compromised at times of impaired health. Nevertheless, males of some species seem to maintain high levels of testosterone when confronted with an immune challenge, upholding competitive strength but compromising their immune response. It has been argued that this phenomenon will occur only in species living in social systems with high degrees of male-male competition over mating opportunities. Male chimpanzees contest over access to fertile females and dominants sire the majority of offspring. This male mating pattern makes chimpanzees a candidate species where we could expect males to maintain high testosterone levels, compromising their immune response, to ensure immediate reproductive success. We measured blood testosterone levels in male and female chimpanzees, who expressed clinical symptoms (symptomatic) or showed no evidence of clinical disease on assessment (asymptomatic). For females, we expected to find lower testosterone levels in symptomatic individuals than in asymptomatic subjects. In males, we would predict lower testosterone levels in symptomatic individuals than in asymptomatic males, if the immune response leads to a decrease in testosterone secretion. Alternatively, males could have equal levels of testosterone when symptomatic and asymptomatic, upholding competitive strength. Our results show that male chimpanzees exhibit lower levels of testosterone when confronted with an immune challenge than when being asymptomatic. This suggests that male testosterone secretion is suppressed as part of the immune response, which potentially increases survival and lifetime reproductive success. It will, however, negatively impact momentary competitive ability. Also, males may employ different mating strategies, some of which are less testosterone-driven (e.g., affiliative strategies). Consequently, in some individuals, the costs of maintaining high testosterone levels may not outweigh the potential gain in reproductive success

Data from: Chimpanzee intellect: personality, performance and motivation with touchscreen tasks

Human intellect is characterized by intercorrelated psychological domains, including intelligence, academic performance and personality. Higher openness is associated with higher intelligence and better academic performance, yet high performance among individuals is itself attributable to intelligence, not openness. High conscientiousness individuals, although not necessarily more intelligent, are better performers. Work with other species is not as extensive, yet animals display similar relationships between exploration- and persistence-related personality traits and performance on cognitive tasks. However, previous studies linking cognition and personality have not tracked learning, performance and dropout over time—three crucial elements of cognitive performance. We conducted three participatory experiments with touchscreen cognitive tasks among 19 zoo-housed chimpanzees, whose personalities were assessed 3 years prior to the study. Performance and participation were recorded across experiments. High conscientiousness chimpanzees participated more, dropped out less and performed better, but their performance could be explained by their experience with the task. High openness chimpanzees tended to be more interested, perform better and continue to participate when not rewarded with food. Our results demonstrate that chimpanzees, like humans, possess broad intellectual capacities that are affected by their personalities