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Human aging is accompanied by a decrease in social activity and a narrowing in social networks. Studies in nonhuman primates may provide valuable comparative insights in which way aging impacts social life, in the absence of cultural conventions and an awareness of a limited lifetime. For female Barbary macaques at "La Forêt des Singes" in Rocamadour, France, we previously reported an age-associated decrease in active grooming time and network size. Here, we aimed to extend these findings by investigating in which way physical decline, spatial proximity, and aggression vary with age in female Barbary macaques. We analyzed >1,200 hr of focal observations for 46 females aged 5-29 years. As expected, older females engaged less frequently in challenging locomotor activity, such as climbing or running, than younger ones. The previously reported decrease in grooming time was not due to shorter grooming bout duration. Instead, active grooming bouts lasted even longer, which discounts the idea that manual fatigue explains the shift in grooming pattern. We found that older females tended to be spatially reclusive and that they were less frequently the targets of aggression. Although older females showed aggressive behaviors at similar rates as younger females, the proportion of low-level aggression (i.e., threats) increased with age. We suggest that these threats are not simply a signal of dominance, but also function to deter approaches by others. Overall, these findings are in line with the idea that older females aim to avoid potentially negative interactions, specifically if these are costly. In sum, these findings support the idea that shifts in female Barbary macaques' grooming activity, do not simply result from physical deterioration, but are instead due to a higher selectivity in the choice of social partners., (© 2017 Wiley Periodicals, Inc.)

Nonhuman primates are an important experimental model for the development of targeted biological therapeutics because of their immunological closeness to humans. However, there are very few antibody reagents relevant for delineating the different immune cell subsets based on nonhuman primate antigens directly or with cross-reactivity to those in humans. Here, we report specific expression of HLA-DR, PD-1, and CD123 on different circulating immune cell subsets in the peripheral blood that included T cells (CD3+), T cells subsets (CD4+ and CD8+), B cells (CD20+), natural killer (NK) cells (CD3–CD16+), and natural killer T cells (CD3+CD16+) along with different monocyte subsets in squirrel monkey (Saimiri sciureus). We established cross-reactivity of commercial mouse antihuman monoclonal antibodies (mAbs), with these various immune cell surface markers. These findings should aid further future comprehensive understanding of the immune parameters and identification of new biomarkers to significantly improve SQM as a model for biomedical studies. [ABSTRACT FROM AUTHOR]

Motion‐sensitive cameras are popular as non‐invasive monitoring tools, and several methods have been developed to estimate population densities from camera data. These methods frequently rely on auxiliary movement data including the distance traveled by an individual in a day and the proportion of the day that an animal spends moving when individual recognition is not possible. The estimation of these movement parameters is time‐consuming, which could limit the applicability of cameras to estimate population density. To investigate the relevance of measuring movement parameters for the target population, we monitored 54 wildlife populations of red deer (Cervus elaphus), fallow deer (Dama dama), roe deer (Capreolus capreolus), wild boar (Sus scrofa), and red fox (Vulpes vulpes) in different seasons through Europe with cameras. We estimated 91‐day ranges and activity levels. We fitted mixed models for day range and activity level as response variables to assess if the inter‐population variability in movement was explained by a set of a priori relevant geographical, environmental, biological, and management predictors. We then explored the bias in density estimates obtained in 25 independent populations when using predicted movement data. There was high intra‐species variation in day range and activity level among species and populations. Only species explained a small proportion of this variability; other predictor variables did not. We observed bias in densities when predicting the day range and activity for independent populations. Considering the intra‐species variability in movement parameters and the consequent unacceptable bias in density estimates, we recommend that monitoring and conservation programs estimate movement parameters for the target population and survey populations from camera data for more accurate density estimates. While this increases the handling time needed to estimate densities, it is worth the cost because of the reliability of camera‐based methodologies to estimate needed movement parameters. [ABSTRACT FROM AUTHOR]

Social and emotional cues from faces and voices are highly relevant and have been reliably demonstrated to attract attention involuntarily. However, there are mixed findings as to which degree associating emotional valence to faces occurs automatically. In the present study, we tested whether inherently neutral faces gain additional relevance by being conditioned with either positive, negative, or neutral vocal affect bursts. During learning, participants performed a gender‐matching task on face‐voice pairs without explicit emotion judgments of the voices. In the test session on a subsequent day, only the previously associated faces were presented and had to be categorized regarding gender. We analyzed event‐related potentials (ERPs), pupil diameter, and response times (RTs) of N = 32 subjects. Emotion effects were found in auditory ERPs and RTs during the learning session, suggesting that task‐irrelevant emotion was automatically processed. However, ERPs time‐locked to the conditioned faces were mainly modulated by the task‐relevant information, that is, the gender congruence of the face and voice, but not by emotion. Importantly, these ERP and RT effects of learned congruence were not limited to learning but extended to the test session, that is, after removing the auditory stimuli. These findings indicate successful associative learning in our paradigm, but it did not extend to the task‐irrelevant dimension of emotional relevance. Therefore, cross‐modal associations of emotional relevance may not be completely automatic, even though the emotion was processed in the voice. This study provides new evidence for the transfer of affective processing to affective learning and complements previous research on the preferential processing of emotional stimuli. Our findings indicate that only task‐relevant stimulus features were robustly learned, although the task‐irrelevant emotional meaning of the same stimulus influenced online processing and behavior during learning. [ABSTRACT FROM AUTHOR]

Aging brings about notable changes in sociality, with an increasing focus on essential partners in both humans and nonhuman primates. Several studies have shown that older nonhuman primates have fewer social partners and shift their types of interactions. The majority of these studies, however, involved only female individuals. Much less is known about the trajectory of social aging in males. We collected 2180 h of focal observation data in a large age-heterogeneous sample of 34 male and 50 female Barbary macaques (Macaca sylvanus; age range 5-30 years) living in two social groups at the outdoor enclosure at La Forêt des Singes in Rocamadour (France). To track age-related changes in social engagement of both sexes, we used classical behavioral and social network analysis to measure age-related variation in the number of partners, the frequency of affiliative interactions, and the position in the social network (eigenvector centrality and local clustering coefficient). We found that females were more central in most social network metrics than males, that is, had more social partners and were more engaged in affiliative interactions than males. We did not find notable sex differences with age: both sexes showed a similar decline in social activity and energy-demanding activities like jumping or running. Our results thereby extend our knowledge of older nonhuman primates' social life and emphasize that age can have a similar impact on female and male social behavior., (© 2021 The Authors. American Journal of Primatology Published by Wiley Periodicals LLC.)

Event‐related potential studies using affective words have indicated that selective attention to valence can increase affective discrimination at early perceptual stages. This effect most likely relies on neural associations between perceptual features of a stimulus and its affective value. Similar to words, emotional expressions in human faces are linked to specific visual elements. Therefore, selectively attending to a given emotion should allow for the preactivation of neural networks coding for the emotion and associated first‐order visual elements, leading to enhanced early processing of faces expressing the attended emotion. To investigate this, we employed an expression detection task (N = 65). Fearful, happy, and neutral faces were randomly presented in three blocks while participants were instructed to respond only to one predefined target level of expression in each block. Reaction times were the fastest for happy target faces, which was accompanied by an increased occipital P1 for happy compared with fearful faces. The N170 yielded an arousal effect (emotional > neutral) while both components were not modulated by target status. In contrast, the early posterior negativity (EPN) arousal effect tended to be larger for target compared with nontarget faces. The late positive potential (LPP) revealed large effects of status and expression as well as an interaction driven by an increased LPP specifically for nontarget fearful faces. These findings tentatively indicate that selective attention to facial affect may enhance early emotional processing (EPN) even though further research is needed. Moreover, late controlled processing of facial emotions appears to involve a negativity bias. Recent research suggests that selective attention to emotional stimuli can improve affective discrimination at early perceptual stages. Using emotional faces, we find indications that selective attention to facial affect might boost emotional processing during the EPN time window. Additionally, late controlled processing of facial emotions appears to involve a negativity bias and the increased allocation of resources toward attended (relative to unattended) faces. [ABSTRACT FROM AUTHOR]

Estimation of changes in abundances and densities is essential for the research, management, and conservation of animal populations. Recently, technological advances have facilitated the surveillance of animal populations through the adoption of passive sensors, such as camera traps (CT). Several methods, including the random encounter model (REM), have been developed for estimating densities of unmarked populations but require additional information. Hierarchical abundance models, such as the N‐mixture model (NMM), can estimate abundances without performing additional fieldwork but do not explicitly estimate the area effectively sampled. This obscures the interpretation of its densities and requires its users to focus on relative measures of abundance instead. Hence, the main objective of our study is to evaluate if REM and NMM yield consistent results qualitatively. Therefore, we compare relative trends: (i) between species, (ii) between years and (iii) across years obtained from annual density/abundance estimates of three species (fox, wild boar and red deer) in central Spain monitored by a camera trapping network for five consecutive winter periods. We reveal that NMM and REM provided density estimates in the same order of magnitude for wild boar, but not for foxes and red deer. Assuming a Poisson detection process in the NMM was important to control for inflation of abundance estimates for frequently detected species. Both methods consistently ranked density/abundance across species (between species trend), but did not always agree on relative ranks of yearly estimates within a single population (between years trend), nor on its linear population trends across years (across years trend). Our results suggest that relative trends are generally consistent when the range of variability is large, but can become inconsistent when the range of variability is smaller. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Applied Ecology is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Social relationships among animals emerge from interactions in multiple ecological and social situations. However, we seldom ask how each situation contributes to the global structure of a population, and whether different situations contribute different information about social relationships and the position of individuals within the social fabric. Griffon vultures (Gyps fulvus) interact socially in multiple situations, including communal roosting, joint flights, and co‐feeding. These social interactions can influence population‐level outcomes, such as disease transmission and information sharing that determine survival and response to changes. We examined the unique contribution of each social and ecological situation to the social structure of the population and individuals' positions within the overall social network using high‐resolution GPS tracking. We found that the number of individuals each vulture interacted with (degree) was best predicted by diurnal interactions—both during flights and on the ground (such as when feeding). However, the strength of social bonds, that is, the number of interactions an individual had (strength), was best predicted by interactions on the ground—both during the day (e.g., while feeding) and at night (e.g., while roosting) but not by interactions while flying. Thus, social situations differ in their impact on the relationships that individuals form. By incorporating the ecological situations in which social interactions occur we gain a more complete view of how social relationships are formed and which situations are important for different types of interactions. [ABSTRACT FROM AUTHOR]

The steepness of dominance hierarchies provides information about the degree of competition within animal social groups and is thus an important concept in socioecology. The currently most widely used metrics to quantify steepness are based on David's scores (DS) derived from dominance interaction networks. One serious drawback of these DS‐based metrics is that they are biased, that is, network density systematically decreases steepness values.We provide a novel approach to estimate steepness based on Elo‐ratings, implemented in a Bayesian framework (STEER: Steepness estimation with Elo‐rating). We evaluate and validate its performance by means of experimentation on empirical and artificial datasets and compare its performance to that of several other steepness estimators.STEER has two key advantages. First, it is unbiased, precise and more robust to data density than DS‐based steepness. Second, it provides explicit probability distributions of the estimated steepness coefficient, which allows uncertainty assessment. In addition, it relies on the same underlying concept and is on the same scale as the original measure, and thus allows comparison to existing published results.STEER provides a considerable improvement over existing methods to estimate dominance hierarchy steepness. We demonstrate its application with an example comparing within‐ and between species variation in steepness in a comparative analysis and present guidelines on how to use it. The R package EloSteepness allows convenient numeric and graphical assessment of the new steepness measure. [ABSTRACT FROM AUTHOR]

Numerous different objects are simultaneously visible in a person's visual field, competing for attention. This competition has been shown to affect eye‐movements and early neural responses toward stimuli, while the role of a stimulus' emotional meaning for mechanisms of overt attention shifts under competition is unclear. The current study combined EEG and eye‐tracking to investigate effects of competition and emotional content on overt shifts of attention to human face stimuli. Competition prolonged the latency of the P1 component and of saccades, while faces showing emotional expressions elicited an early posterior negativity (EPN). Remarkably, the emotion‐related modulation of the EPN was attenuated when two stimuli were competing for attention compared to non‐competition. In contrast, no interaction effects of emotional expression and competition were observed on other event‐related potentials. This finding indicates that competition can decelerate attention shifts in general and also diminish the emotion‐driven attention capture, measured through the smaller effects of emotional expression on EPN amplitude. Reduction of the brain's responsiveness to emotional content in the presence of distractors contradicts models that postulate fully automatic processing of emotions. The current study investigated overt attention to emotional faces using coregistered eye‐tracking and EEG, measuring whether emotional expressions affect early and late Event‐related Potentials. It shows that emotion effects are attenuated and delayed when several targets are competing for attention, providing evidence that cortical processing of emotion is not automatic but is influenced by distractors. [ABSTRACT FROM AUTHOR]

Population density estimates are important for wildlife conservation and management. Several camera trapping‐based methods for estimating densities have been developed, one of which, the random encounter model (REM), has been widely applied due to its practical advantages such as no need for species‐specific study design. Nevertheless, most of the studies in which REM has been assessed against referenced methods have sampled one population, precluding evaluation of the circumstances under which REM does or does not perform well. At this point, a review of all REM assessments could be useful to provide an overview of method reliability and highlight the main factors determining REM performance. Here we used a combination of literature review and empirical study to compare the performance of REM with independent methods. We reviewed 34 studies where REM was applied to 45 species, reporting 77 REM‐reference density comparisons; and we also sampled 13 populations (ungulates and lagomorphs) in which we assessed REM performance against independent densities. The results suggested that appropriate procedures to estimate REM parameters (namely day range, detection zone and encounter rate) are mandatory to obtain unbiased densities. Deficient estimates of day range and encounter rate lead to an overestimation of density, while deficient estimates of detection zone conducted to underestimations. Finally, the precision achieved by REM was lower than reference methods, mainly because of the high levels of spatial aggregation observed in natural populations. In this situation, simulation‐based results suggest that c. 60 camera placements should be sampled to achieve acceptable precision (i.e. coefficient of variation below 0.20). The wide range of situations and scenarios included in this study allow us to conclude that REM is a reliable method for estimating wildlife population density when using appropriate estimates of REM parameters and sampling designs. Overall, these results pave the way to wider application of REM for monitoring terrestrial mammals. [ABSTRACT FROM AUTHOR]

Comparative study of the social systems of macaques has revealed correlated variations between species in multiple social traits such as the asymmetry of dominance relationships, preferential treatment of kin, patterns of aggression and reconciliation, modes of socialization, and access to food resources. Macaques can be classified on a scale of four categories of social styles, ranging from the least to the most tolerant species. This led to the development of the covariation framework, which addresses the constraints responsible for the linkages between social traits, and their consequences on the evolution of primate social systems. Decades of research have provided a wealth of information that supports, complements, expands, or challenges the covariation framework. In this article, I review this body of knowledge and consider covariation in its two aspects, that is, as a pattern and as a hypothesis. I first consider the extent to which social styles can be invariant, the strength of correlations between traits, and the possible extension of the framework to nonhuman primates other than macaques. I then discuss how to formulate hypotheses, identify sources of linkage between traits, make predictions about the effects of social constraints, assess the tolerance dimension of social styles, and consider the breaking of linkages between traits. Whereas socioecological studies aim to understand how adaptation to the ecological environment determines the shape of social systems, the covariation framework is a complementary research program that seeks to unravel the internal processes that restrict or channel change in social behavior. [ABSTRACT FROM AUTHOR]

In the last decade, two hypotheses, one on the evolution of animal vocal communication in general and the other on the origins of human language, have gained ground. The first hypothesis argues that the complexity of communication co‐evolved with the complexity of sociality. Species forming larger groups with complex social networks have more elaborate vocal repertoires. The second hypothesis posits that the core of communication is represented not only by what can be expressed by an isolated caller, but also by the way that vocal interactions are structured, language being above all a social act. Primitive forms of conversational rules based on a vocal turn‐taking principle are thought to exist in primates. To support and bring together these hypotheses, more comparative studies of socially diverse species at different levels of the primate phylogeny are needed. However, the majority of available studies focus on monkeys, primates that are distant from the human lineage. Great apes represent excellent candidates for such comparative studies because of their phylogenetic proximity to humans and their varied social lives. We propose that studying vocal turn‐taking in apes could address several major gaps regarding the social relevance of vocal turn‐taking and the evolutionary trajectory of this behaviour among anthropoids. Indeed, how the social structure of a species may influence the vocal interaction patterns observed among group members remains an open question. We gathered data from the literature as well as original unpublished data (where absent in the literature) on four great ape species: chimpanzees Pan troglodytes, bonobos Pan paniscus, western lowland gorillas Gorilla gorilla gorilla and Bornean orang‐utans Pongo pygmaeus. We found no clear‐cut relationship between classical social complexity metrics (e.g. number of group members, interaction rates) and vocal complexity parameters (e.g. repertoire size, call rates). Nevertheless, the nature of the society (i.e. group composition, diversity and valence of social bonds) and the type of vocal interaction patterns (isolated calling, call overlap, turn‐taking‐based vocal exchanges) do appear to be related. Isolated calling is the main vocal pattern found in the species with the smallest social networks (orang‐utan), while the other species show vocal interactions that are structured according to temporal rules. A high proportion of overlapping vocalisations is found in the most competitive species (chimpanzee), while vocal turn‐taking predominates in more tolerant bonobos and gorillas. Also, preferentially interacting individuals and call types used to interact are not randomly distributed. Vocal overlap ('chorusing') and vocal exchange ('conversing') appear as possible social strategies used to advertise/strengthen social bonds. Our analyses highlight that: (i) vocal turn‐taking is also observed in non‐human great apes, revealing universal rules for conversing that may be deeply rooted in the primate lineage; (ii) vocal interaction patterns match the species' social lifestyle; (iii) although limited to four species here, adopting a targeted comparative approach could help to identify the multiple and subtle factors underlying social and vocal complexity. We believe that vocal interaction patterns form the basis of a promising field of investigation that may ultimately improve our understanding of the socially driven evolution of communication. [ABSTRACT FROM AUTHOR]

Medium and large‐sized mammals of Jorgo‐Wato Protected Forest have not yet been documented though the forest established before four decades. Hence, this study aims to document medium and large mammals and the behavioral responses of selected mammals toward anthropogenic activities in the study area. The study was conducted from February 2015 to June 2016, encompassing the wet and dry seasons. Data were collected mainly through camera traps, indirect and direct evidence. The study revealed about 23 medium and large‐sized mammals that belong to seven orders namely Bovidae, Carnivora, Primates, Rodentia, Tubulidentata, Lagomorpha, and Hyracoidea. Papio anubis, C. guereza, and C. aethiops were the most abundant large mammals in JWPF. Because of high anthropogenic activities, African buffalo shifted its activity period from diurnal into crepuscular and nocturnal. African buffalo traveled longer distances during the wet season (mean = 14.33 km, SD = 1.25 km) than during the dry season (mean = 9.00 km, SD = 2.16 km). This could be due to the fact that the local people were less likely to go to the forest for resource exploitation during the wet season as they are fully engaged in agricultural activities. However, low agricultural activities during the dry season allow the local people to extract resources and involve in bushmeat hunting which could limit the movement of mammals to their refugia. African buffalo preferred to rest on and adjacent to a gravel road (22.1%) in the forest, followed by on open rocky hilltops (14.7%) at night time, but rest in the bottomland thicket vegetation during the dry daytime. Regardless of high human pressure in the area, this study has revealed a good number of medium and large‐sized mammals that could be used as baseline information to design a sound conservation and management action plan of large mammals and their habitat in Jorgo‐Wato Protected Forest. [ABSTRACT FROM AUTHOR]

Despite the strong interest in connecting social complexity and cognitive ability, there remains considerable debate about how to best quantify both cognitive performance and social complexity. Measuring group and brain size are clearly not sufficient and recent attention has been placed on the use of rigorous, increasingly challenging cognitive tasks and studying the quality, not merely the number of social interactions. Here we used two cichlid fishes from Lake Tanganyika, one cooperative breeder and one biparental species, in a cross‐fostering experiment, to investigate the links between social complexity and cognition. While controlling for parental cues, individual fish grew up either in a socially homogenous group with only conspecifics or in a mixed and diverse social group with hetero‐ as well as conspecifics and then were tested for learning abilities as subadults. To quantify differences in learning, we first employed a discrimination learning task followed by a reversal learning task that requires behavioral flexibility, as previous associations are forgotten and new associations forged. We found that individuals growing up in a more diverse social environment learned faster and made fewer mistakes in the discrimination learning task, but this ability did not transfer to the reversal learning task. Irrespective of the early social experiences, the cooperatively breeding, and thus the more social of the two cichlid species, learnt the color discrimination more quickly and made significantly fewer errors. These results provide a first demonstration of a possible association between cognitive performance and social complexity in cichlid fishes. [ABSTRACT FROM AUTHOR]

Prior affective and social knowledge about other individuals has been shown to modulate perception of their faces and gaze‐related attentional processes. However, it remains unclear whether emotionally charged knowledge acquired through interactive social learning also modulates face processing and attentional control. Thus, the aim of this study was to test whether affective knowledge induced through social interactions in a naturalistic exchange game can influence early stages of face processing and attentional shifts in a subsequent gaze‐cueing task. As indicated by self‐reported ratings, the game was successful in inducing valenced affective knowledge towards positive and negative players. In the subsequent task, in which the locations of future targets were cued by the gaze of the game players, we observed enhanced early neural activity (larger amplitude of the P1 component) in response to a photograph of the negative player. This indicates that negative affective knowledge about an individual indeed modulates very early stages of the processing of this individual's face. Our study contributes to the existing literature by providing further evidence for the saliency of interactive social exchange paradigms that are used to induce affective knowledge. Moreover, it extends the previous research by presenting a very early modulation of perception by socially learned affective knowledge. Importantly, it also offers increased ecological validity of the findings due to the use of naturalistic social exchange in the study design. This research complements previous evidence that experimentally induced socio‐affective knowledge about other individuals, modulates processing of their faces, and shows that negative (but not positive) affect enhances very early face processing (the P1). Importantly, we provide an effective affect induction tool—an interactive social exchange game—which offers increased social ecological validity in experimental settings. [ABSTRACT FROM AUTHOR]

Event‐related potentials (ERPs) are increasingly used as neurophysiological markers of perceptual and cognitive processes conveying risk for psychopathology. However, little is known about the reliability of ERP components during childhood, a time of substantial brain maturation. In the present study, we examine the early visual ERP components (P1, N170, VPP), frequently examined as indicators of attentional bias, for 110 children at kindergarten (T1) and first grade (T2). Children performed a Go/Nogo task at both time points, with exact stimuli changed to reduce habituation. All components showed increases in absolute amplitude and the P1 and VPP also showed decreases in latency. Retest reliability across time was good to very good for amplitude measures (Pearson rs ranging from.54 for N170 to.69 for P1) and low to very good for latencies (rs from.34 for P1 to.60 for N170), despite the change in visual stimuli. Although there was some evidence of moderation by sex, early visual ERP components appear to be a reliable measure of individual differences in attention processing in middle childhood. This has implications for the use of early visual ERP components as trait‐like markers for individual differences in perceptual processes in developmental research. [ABSTRACT FROM AUTHOR]

Natural regeneration of trees may provide a cost‐effective way to restore degraded tropical dry forests, but the factors predominantly affecting natural regeneration success are poorly understood. We performed a multifactor analysis of natural regeneration in an Afromontane forest in Northern Ethiopia. Inventory plots of 400 m2, each with a nested 9 m2 subplot, were systematically established. All trees larger than 5 cm DBH and natural regeneration were identified and recorded in the plots and subplots, respectively. Variables describing climate, topography, soil, vegetation, and indications of local human degradation were collected. Determinants of regeneration presence and abundance were analyzed using Hurdle negative binomial regressions. Sixty‐nine woody species were represented in the regeneration, with an average regeneration density (SE) of 14,700 (51) ha−1. The presence of regeneration was positively associated with canopy cover (p < 0.001), distance to the road network (p = 0.04), precipitation (p = 0.003) and tree species diversity (p = 0.03), and negatively with Northing (p = 0.003). The regeneration abundance was positively associated with soil quality (p = 0.001), canopy cover (p = 0.04), and precipitation (p = 0.01). Including the abundance of dominant species in the tree canopy and regeneration layers in the regression model did not affect the presence of natural regeneration, but it clearly affected regeneration abundance. In such a model, the regeneration abundance was positively associated with Euclea racemosa seedlings abundance and negatively associated with the basal area of Dodonaea angustifolia (p = 0.02) and Rhus natalensis (p = 0.04). In this model, forest degradation (p = 0.01) negatively affected the late‐successional species regeneration but not the regeneration of the drought‐resistant light‐demanding species. The low representation of late‐successional trees species in the natural regeneration calls for active restoration intervention. [ABSTRACT FROM AUTHOR]

In everyday life, faces with emotional expressions quickly attract attention and eye movements. To study the neural mechanisms of such emotion‐driven attention by means of event‐related brain potentials (ERPs), tasks that employ covert shifts of attention are commonly used, in which participants need to inhibit natural eye movements towards stimuli. It remains, however, unclear how shifts of attention to emotional faces with and without eye movements differ from each other. The current preregistered study aimed to investigate neural differences between covert and overt emotion‐driven attention. We combined eye tracking with measurements of ERPs to compare shifts of attention to faces with happy, angry, or neutral expressions when eye movements were either executed (go conditions) or withheld (no‐go conditions). Happy and angry faces led to larger EPN amplitudes, shorter latencies of the P1 component, and faster saccades, suggesting that emotional expressions significantly affected shifts of attention. Several ERPs (N170, EPN, LPC) were augmented in amplitude when attention was shifted with an eye movement, indicating an enhanced neural processing of faces if eye movements had to be executed together with a reallocation of attention. However, the modulation of ERPs by facial expressions did not differ between the go and no‐go conditions, suggesting that emotional content enhances both covert and overt shifts of attention. In summary, our results indicate that overt and covert attention shifts differ but are comparably affected by emotional content. During real‐life social interactions, covert and overt shifts of attention are flexibly used to attend to emotional stimuli. The current preregistered coregistration study of EEG and eye tracking is the first to demonstrate independent effects of emotional content and type of attention shift on eye‐movements and event‐related potentials to neutral and emotional faces. [ABSTRACT FROM AUTHOR]

Copyright of Methods in Ecology & Evolution is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The natural pedagogy hypothesis proposes that human infants preferentially attend to communicative signals from others, facilitating rapid cultural learning. In this view, sensitivity to such signals is a uniquely human adaptation and as such nonhuman animals should not produce or utilize these communicative signals. We test these evolutionary predictions by examining sensitivity to communicative cues in 206 rhesus monkeys (Macaca mulatta) using an expectancy looking time task modeled on prior work with infants. Monkeys observed a human actor who either made eye contact and vocalized to the monkey (social cue), or waved a fruit in front of her face and produced a tapping sound (nonsocial cue). The actor then either looked at an object (referential look) or looked toward empty space (look away). We found that, unlike human infants in analogous situations, rhesus monkeys looked longer at events following nonsocial cues, regardless of the demonstrator's subsequent looking behavior. Moreover younger and older monkeys showed similar patterns of responses across development. These results provide support for the natural pedagogy hypothesis, while also highlighting evolutionary changes in human sensitivity to communicative signals. [ABSTRACT FROM AUTHOR]

How social development in early‐life affects fitness remains poorly understood.Though there is growing evidence that early‐life relationships can affect fitness, little research has investigated how social positions develop or whether there are particularly important periods for social position development in an animal's life history. In long‐lived species in particular, understanding the lasting consequences of early‐life social environments requires detailed, long‐term datasets.Here we used a 25‐year dataset to test whether social positions held during early development predicted adult fitness. Specifically, we quantified social position using three social network metrics: degree, strength and betweenness. We determined the social position of each individual in three types of networks during each of three stages of ontogeny to test whether they predict annual reproductive success (ARS) or longevity among adult female spotted hyenas Crocuta crocuta.The social positions occupied by juvenile hyenas did predict their fitness, but the effects of social position on fitness measures differed between stages of early development. Network metrics when individuals were young adults better predicted ARS, but network metrics for younger animals, particularly when youngsters were confined to the communal den, better predicted longevity than did metrics assessed during other stages of development.Our study shows how multiple types of social bonds formed during multiple stages of social development predict lifetime fitness outcomes. We suggest that social bonds formed during specific phases of development may be more important than others when considering fitness outcomes. [ABSTRACT FROM AUTHOR]

Social groups take a myriad of forms, reflecting the countless different ways in which animals can interact and associate (Wilson, 2000). The Joint Special Feature in I Methods in Ecology and Evolution i and the I Journal of Animal Ecology i is a celebration of research by animal social network scientists, introducing novel methods and questions pertaining to Animal Social Network Analysis (ASNA). ANIMAL NETWORKS UNDER DIFFERENT ENVIRONMENTS Social structure represents the most plastic aspect of animal societies as individuals can, through social interactions, regulate conflicts (Aureli & de Waal, 2000), create affiliative bonds (De Waal & Roosmalen, 1979), cooperate (Seyfarth & Cheney, 2012), transmit information and learn (Hoppitt & Laland, 2013). [Extracted from the article]

We provide an overview of the most commonly used social network measures in animal research for static networks or time‐aggregated networks.For each of these measures, we provide clear explanations as to what they measure, we describe their respective variants, we underline the necessity to consider these variants according to the research question addressed, and we indicate considerations that have not been taken so far.We provide a guideline indicating how to use them depending on the data collection protocol, the social system studied and the research question addressed. Finally, we inform about the existent gaps and remaining challenges in the use of several variants and provide future research directions. [ABSTRACT FROM AUTHOR]

Because of the nature of social interaction or association data, when testing hypotheses using social network data it is common for network studies to rely on permutations to control for confounding variables, and to not also control for them in the fitted statistical model. This can be a problem because it does not adjust for any bias in effect sizes generated by these confounding effects, and thus the effect sizes are not informative in the presence of confounding variables.We implemented two network simulation examples and analysed an empirical dataset to demonstrate how relying solely on permutations to control for confounding variables can result in highly biased effect size estimates of animal social preferences that are uninformative when quantifying differences in behaviour.Using these simulations, we show that this can sometimes even lead to effect sizes that have the wrong sign and are thus the effect size is not biologically interpretable. We demonstrate how this problem can be addressed by controlling for confounding variables in the statistical dyadic or nodal model.We recommend this approach should be adopted as standard practice in the statistical analysis of animal social network data. [ABSTRACT FROM AUTHOR]

Humans undergo robust ontogenetic shifts in the theory of mind capabilities. Are these developmental changes unique to human development or are they shared with other closely related non‐human species? To explore this issue, we tested the development of the theory of mind capacities in a population of 236 infant and juvenile rhesus macaques (Macaca mulatta). Using a looking‐time method, we examined what developing monkeys know about others' perceptions. Specifically, we tested whether younger monkeys predict that a person will reach for an object where she last saw it. Overall, we found a significant interaction between a monkey's age and performance on this task (p =.014). Juvenile monkeys (between two and 5 years of age) show a nonsignificant trend towards human infant‐like patterns of performance, looking longer during the unexpected condition as compared to the expected condition, though this difference is nonsignificant (p =.09). However, contrary to findings in human infants, infant rhesus macaques show a different trend. Infant monkeys on average look slightly longer on average during the expected condition than the unexpected condition, though this pattern was not significant (p =.06). Our developmental results in monkeys provide some hints about the development of the theory of mind capacities in non‐humans. First, young rhesus macaques appear to show some interest in the perception of other agents. Second, young rhesus seems able to make predictions based on the visual perspective of another agent, though the developmental pattern of this ability is not as clear nor as robust as in humans. As such, though an understanding of others' perceptions is early‐emerging in human infants, it may require more experience interacting with other social agents in our non‐human relatives. HIGHLIGHTS: We tested 236 infant and juvenile rhesus macaques on a visual perspective‐taking task designed to track the development of this cognitive ability. Previous work shows that adult monkeys perform similarly to human infants on the task, looking longer when the experimenter acts inconsistently with her visual perspective as compared to when she acts consistently. Although juvenile rhesus monkeys show an adult‐like pattern, infant monkeys show the opposite pattern, suggesting macaques may require experience to develop sophisticated visual perspective‐taking capacities. [ABSTRACT FROM AUTHOR]

In social species, network centralities of group members shape social transmission and other social phenomena. Different factors have been found to influence the measurement of social networks, such as data collection and observation methods. In this study, we collected data on adults and juveniles and examined the effect of data collection method (ad libitum sampling vs. focal animal sampling) and observation method (interaction—grooming; play—vs. association—arm‐length; 2 m; 5 m proximities—) on social networks in wild vervet monkeys. First, we showed using a bootstrapping method, that uncertainty of ad libitum grooming and play matrices were lesser than uncertainty of focal matrices. Nevertheless, grooming and play networks constructed from ad libitum and focal animal sampling were very similar and highly correlated. We improved the certainty of both grooming and play networks by pooling focal and ad libitum matrices. Second, we reported a high correlation between the proximity arm‐length network and the focal grooming one making an arm‐length proximity network a reasonable proxy for a grooming one in vervet monkeys. However, we did not find such a correlation between proximity networks and the play one. Studying the effects of methodological issues as data collection and observation methods can help improve understanding of what shapes social networks and which data collection method to choose to study sociality. HIGHLIGHTS: We compared social networks constructed through different data collection and observation methods in a wild primate species.We found that ad libitum networks were less uncertain than focal networks.Arm‐length proximity network can be used as a proxy for a grooming network but not for a play one. [ABSTRACT FROM AUTHOR]

To make adaptive behavioural decisions, animals must acquire and process information from their natural and social environment. Reducing uncertainty regarding the actions and goals of conspecifics is especially important for group‐living animals.Bats are often highly gregarious and use versatile social vocalizations to mediate social interactions. These social vocalizations encode a substantial amount of ecologically relevant information, such as individual identity, sex and kin. Decoding this information enables receivers to make informed decisions on resource allocation, mate choice, territorial defence and cooperation. Erroneous decisions on such crucial aspects of bats' social behaviour can be costly due to reduced reproductive success or survival.Increasingly complex social interactions require social vocalizations encoding more information which, in turn, could facilitate the evolution of even more complex social interactions. Evidence for the positive correlation of social and vocal complexity is available for several taxa but is currently very limited for bats.We conducted a phylogenetic comparative analysis to link the information content encoded in bats' social vocalizations to the complexity of their social lives, that is the level of uncertainty associated with assessing individual identity. We focused on three different vocalization types encoding individual signatures (pup isolation calls, adult contact calls and male‐specific vocalizations). Information content in bit (i.e. the number of binary decisions necessary to discriminate among N individuals) was used as an estimate of vocal complexity; relevant social group size (i.e. the number of conspecifics whose identity a receiver could confuse) was used as an estimate of social complexity.Our phylogenetic comparative analysis detected a positive relationship between the information content of vocalizations and the respective relevant social group size. This relationship suggests a positive feedback loop between social and vocal complexity for bat vocalizations and highlights the importance of vocal information for negotiating fitness‐relevant social decisions of bats.In conclusion, our work suggests that social complexity drives vocal complexity in bats. Future studies on other hitherto understudied taxa are necessary to establish a comprehensive theory on the multi‐faceted co‐evolution of sociality and communication in the animal kingdom. A free Plain Language Summary can be found within the Supporting Information of this article. [ABSTRACT FROM AUTHOR]

Day range (DR), the distance travelled by an individual during the day, is an important metric in movement ecology that recently gained interest by its relevance for estimating population density through the random encounter model (REM). Traditionally, DR has been estimated using GPS technology and considering raw straight‐line distances between consecutive locations, which is an underestimation of the true path distance. In this work, we tested the accuracy of a new approach based on camera‐trap data for the estimation of DR taking into account the animals' behaviour. For this purpose, we considered wild boar (Sus scrofa) as a model species. We tagged 18 individuals with telemetry devices and then monitored the population with camera‐traps (photo and video mode) to estimate the DR. In the case of telemetry, a straight‐line DR was estimated and rescaled with a tortuosity‐related correction factor. Using this camera‐trap data, we revisited the procedure described by Rowcliffe et al. (Remote Sens. Ecol. Conserv. , 2, 2016, 84) to estimate the DR from the speed and activity information obtained from camera‐trapsping. A new derivation of this approach was then developed, in which different animal behaviours were weighted to estimate the DR. The analysis showed no significant differences between the DR values obtained using telemetry data (corrected by the tortuosity‐related correction factor) and those attained with the weighted approach. However, the original approach used to estimate the DR based on camera‐trap data underestimated this parameter. The DR estimated with the weighted approach was 12.74 km·day−1 ± (se) 1.89. Here, we showed that animals' behaviour should be taken into account to estimate the DR when working with species that behave differently in front of cameras. These results may be relevant not only for REM, but also for movement ecology, disease dynamics and population monitoring methods. [ABSTRACT FROM AUTHOR]

Human aggression can be differentiated into reactive aggression (RA), displayed in face of a real or perceived threat and associated with high levels of anxiety, and proactive aggression (PA), displayed to achieve a certain goal and linked to lower anxiety levels. To study the origins of these aggression subtypes and their relation to anxiety, we tested if both subtypes can be distinguished in a nonhuman primate species, characterized their occurrence within the study group, and examined the link between aggression subtype and anxiety. Data were collected on 29 individuals of a semi-free ranging group of Barbary macaques (Macaca sylvanus) at Affenberg Salem, Germany, via focal animal (303 hr) and event sampling (1,222 agonistic events). Using a priori definitions, each aggressive event was classified as either reactive or proactive. We found both aggression types in our study population as well as individual differences in the proportion at which they occurred. The predominant use of one subtype of aggression was linked to the individual's dominance rank, age and sex, but not related to standard behavioral and physiological measures of anxiety. Our results suggest that reactive and proactive subtypes of aggression also exist in Barbary macaques, indicating a deeper evolutionary history of these aggression types observed in humans. [ABSTRACT FROM AUTHOR]

Abstract: The construction of rank hierarchies based on agonistic interactions between two individuals (“dyads”) is an important component in the characterization of the social structure of groups. To this end, winner‐loser matrices are typically created, which collapse the outcome of dyadic interactions over time, resulting in the loss of all information contained in the temporal domain. Methods that track changes in the outcome of dyadic interactions (such as “Elo‐ratings”) are receiving increasing interest. Critically, individual ratings are not just based on the succession of wins and losses, but depend on the values of start ratings and a shift coefficient. Recent studies improved existing methods by introducing a point estimation of these auxiliary parameters on the basis of a maximum likelihood (ML) approach. For a sound assessment of the rank hierarchies generated this way, we argue that measures of uncertainty of the estimates, as well as a quantification of the robustness of the methods, are also needed. We introduce a Bayesian inference (BI) approach using “partial pooling”, which rests on the assumption that all start ratings are samples from the same distribution. We compare the outcome of the ML approach to that of the BI approach using real‐world data. In addition, we simulate different scenarios to explore in which way the Elo‐rating responds to social events (such as rank changes), and low numbers of observations. Estimates of the start ratings based on “partial pooling” are more robust than those based on ML, also in scenarios where some individuals have only few observations. Our simulations show that assumed rank differences may fall well within the “uncertain” range, and that low sampling density, unbalanced designs, and coalitionary leaps involving several individuals within the hierarchy may yield unreliable results. Our results support the view that Elo‐rating can be a powerful tool in the analysis of social behaviour, when the data meet certain criteria. Assessing the uncertainty greatly aids in the interpretation of results. We advocate running simulation approaches to test how well Elo‐ratings reflect the (simulated) true structure and how sensitive the rating is to true changes in the hierarchy. [ABSTRACT FROM AUTHOR]

Continuous-time multistate survival models can be used to describe health-related processes over time. In the presence of interval-censored times for transitions between the living states, the likelihood is constructed using transition probabilities. Models can be specified using parametric or semiparametric shapes for the hazards. Semiparametric hazards can be fitted using P-splines and penalised maximum likelihood estimation. This paper presents a method to estimate flexible multistate models that allow for parametric and semiparametric hazard specifications. The estimation is based on a scoring algorithm. The method is illustrated with data from the English Longitudinal Study of Ageing. [ABSTRACT FROM AUTHOR]

The effects of aging on the social behavior of nonhuman primates is little understood, especially in New World monkeys. We studied the members of a colony of tufted capuchin monkeys (Sapajus sp.) in order to evaluate age related changes in their social behavior. We conducted observations on 25 subjects aged 4–36 years, living in captive social groups. We found that affiliative interactions (grooming and proximity) decreased with age, and that grooming was increasingly directed to a single preferred partner. Manipulation of objects in the environment also decreased with age, while locomotion and aggression showed no change. Overall, these results concur with previous findings on both human and nonhuman primates, and cast doubts on interpretations of age associated changes in human social behavior that rely of uniquely human advanced cognitive capacities. [ABSTRACT FROM AUTHOR]

The social relationships that individuals experience at different life stages have a non‐negligible influence on their lives, and this is particularly true for group living animals. The long lifespan of many primates makes it likely that these animals have various tactics of social interaction to adapt to complex changes in environmental or physical conditions. The different strategies used in social interaction by individuals at different life stages, and whether the position (central or peripheral) or role (initiator or recipient) of an individual in the group social network changes with age, are intriguing questions that remain to be investigated. We used social network analysis to examine age‐related differences in social interaction patterns, social roles, and social positions in three affiliative social networks (approach, allogrooming, and social play) in a group of wild rhesus macaques (Macaca mulatta). Our results showed that social interaction patterns of rhesus macaques differ between age classes in the following ways: i) young individuals tend to allocate social time to a high number of groupmates, older individuals prefer to focus on fewer, specific partners; ii) as they grow older, individuals tend to be recipients in approach interactions and initiators in grooming interactions; and iii) regardless of the different social interaction strategies, individuals of all ages occupy a central position in the group. These results reveal a possible key role played by immature individuals in group social communication, a little‐explored issue which deserves closer investigation in future research. [ABSTRACT FROM AUTHOR]

Social relationships play an important role in animal behavior. Bonds with kin provide indirect fitness benefits, and those with nonkin may furnish direct benefits. Adult male chimpanzees (Pan troglodytes) exhibit social bonds with maternal brothers as well as unrelated adult males, facilitating cooperative behavior, but it is unclear when these bonds develop. Prior studies suggest that social bonds emerge during adolescence. Alternatively, bonds may develop during adulthood when male chimpanzees can gain fitness benefits through alliances used to compete for dominance status. To investigate these possibilities and to determine who formed bonds, we studied the social relationships of adolescent and young adult male chimpanzees (N = 18) at Ngogo in Kibale National Park, Uganda. Adolescent male chimpanzees displayed social bonds with other males, and they did so as often as did young adult males. Adolescent and young adult males frequently joined subgroups with old males. They spent time in proximity to and grooming with old males, although they also did so with their age peers. Controlling for age and age difference, males formed strong association and proximity relationships with their maternal brothers and grooming relationships with their fathers. Grooming bonds between chimpanzee fathers and their adolescent and young adult sons have not been documented before and are unexpected because female chimpanzees mate with multiple males. How fathers recognize their sons and vice versa remains unclear but may be due to familiarity created by relationships earlier in development. Research Highlights: Adolescent male chimpanzees form social bonds with other males.Bonds were common between unrelated males, but frequent with maternal brothers, peers, old males, and fathers.Fathers may be important for male chimpanzees transitioning to adulthood. [ABSTRACT FROM AUTHOR]

Lepilemur mittermeieri, a little‐studied sportive lemur of north‐west Madagascar, endemic to the Ampasindava Peninsula, faces habitat loss through forest degradation and rapid fragmentation. Understanding its habitat requirement is the first step toward preservation of this threatened forest‐dependent species. In this study, we gathered data on the use of space and home range characteristics of L. mittermeieri. We studied individuals from early March to the end of June 2015 and 2016, in three sites of the Ampasindava peninsula. We radio‐tracked 15 individuals to obtain detailed information on the size and location of home ranges (around 450 hr of tracking). Direct observation and morphometric measurements provided additional data sets. Both kernel density estimation (KDE) and minimum convex polygon (MCP) methods yielded similar home range sizes (an average of 2.01 ha with KDE method and 1.96 ha with MCP method). We did not find differences in home range size between males and females, with respect to forest type or proximity to the forest edge. Home ranges overlapped and individuals showed low levels of territoriality. We highlighted a sexually‐dimorphic trait: males have longer upper canine than females. Our results constitute the first set of ecological information on Lepilemur mittermeieri and could be the basis for a conservation strategy for this endangered species with a very small distribution area. Research Highlights: First research on the home range characteristics and habitat use of 15 Lepilemur mittermeieri (4 females and 11 males) in three forested areas of the Ampasindava Peninsula, north‐west Madagascar.Main findings from the study of habitat use of Lepilemur mittermeieri include:Home range averaged size of 2.01 ha (kernel density estimation method)No difference in home range size between males and females or proximity to the forest edgeOverlapping home ranges and low levels of territorialityMorphometrics measured on 21 individuals:Sexual dimorphism: males have longer upper canineFirst data on habitat use and space requirements of Lepilemur mittermeieri provides essential information on some of the species basic needs. Such parameters are required for the evaluation of the species' conservation status. Lepilemur mittermeieri is mostly threatened by current and planned deforestation throughout the peninsula. [ABSTRACT FROM AUTHOR]

The diversity of great ape diets requires behavioral flexibility. Consequently, the exploration of potentially novel food sources is supposedly beneficial, but simultaneously, apes show high neophobia to prevent harmful and poisonous food intake. Social information, such as presence of group members or observations of non‐naïve, experienced individuals have been demonstrated to affect the acceptance of novel food items in primates. Sociality may have evolutionary effects on the response of apes to novel foods. Here we assess the social information hypothesis, which predicts that selection favors higher neophobia in species where social information is abundant. We report the results from 134 great apes housed in multiple facilities from four closely related species that naturally differ in their degree of sociality: Pongo pygmaeus, Pongo abelii, Pan troglodytes and Pan paniscus. We examined individuals' reactions to novel foods when alone, which enabled us to detect any inherent differences and revealed significant distinctions between species. Chimpanzees and bonobos, that are naturally exposed to higher amounts of social information, were less likely to consume novel foods alone (showed higher neophobia) than the two more solitary orangutan species. Chimpanzees were especially cautious and showed higher explorative behaviors before tasting novel food than other species. Age influenced neophobia as younger individuals of all species took longer to taste novel foods than adults did. Group living social Pan species show higher food neophobia than the solitary Pongo species. Immature apes (Pan‐ & Pongo spp) take longer at tasting novel food. Chimpanzees were more likely to taste novel food in a group setting than when tested alone. [ABSTRACT FROM AUTHOR]