Multiple studies have shown that women’s likelihood of receiving research funding is lower than that of their male colleagues. Thus far, all research on this gender gap in academia has focused on ...post-PhD academics, making it difficult to discern whether the female disadvantages in number of publications, previous grants, maternity leave, and h-indexes are at the root of the gender gap in received funding, or whether it is due to a more fundamental gender bias in academia. Therefore, we investigated whether female university students are already disadvantaged in receiving their first grant in their scientific career. We analysed data on applications (
N
= 2651) from 1995 to 2018 to the Leiden University International Study Fund (LISF), a fund dedicated to support students to study or conduct research abroad. We found that men and women applied equally often to the LISF. However, women had a lower success rate, which seemed to only get worse over recent years. Furthermore, male and female applications were assessed to be equal in quality when gender-related information was removed from them. The current study demonstrates that the factors that were assumed to contribute the most to the gender gap in more senior academics (e.g. previous grants, h-index) do not explain it fully: even when those factors do not yet play a role, such as in our student sample, women were found to have lower success rates than men. This underscores the importance of attacking gender biases at its roots.
Experimental studies on traditions in animals have focused almost entirely on the initial transmission phase in captive populations. We conducted an open diffusion field experiment with 13 groups of ...wild common marmosets, Callithrix jacchus. Seven groups contained individuals that were already familiar with the task (‘push or pull’ box) and thus served as potential models for naïve individuals. Additionally, in four groups one individual was trained for one of the two possible techniques and in two control groups no skilled individuals were present. First, we investigated whether experienced individuals would remember how to solve the task even after 2 years without exposure and whether they would still prefer their learned technique. Second, we tested whether naïve individuals would learn socially from their skilled family members and, more importantly, whether they would use the same technique. Third, we conducted several test blocks to see whether the individual and/or group behaviour would persist over time. Our results show that wild common marmosets were able to memorize, learn socially and maintain preferences of foraging techniques. This field experiment thus reveals a promising approach to studying social learning in the wild and provides the basis for long-term studies on tradition formation.
•We show all key components of behavioural traditions in free-living primates.•Wild marmosets maintained a foraging technique for over 2 years without exposure.•Naïve individuals adopted the technique from their skilled family members.•They preserved their learned foraging variants for at least 9 months.
Oxytocin is involved in a broad array of social behaviours. While saliva has been used regularly to investigate the role of oxytocin in social behaviour of mammal species, so far, to our knowledge, ...no-one has tried to measure its homolog, mesotocin, in birds' saliva. Therefore, in this study we measured salivary mesotocin in common ravens (Corvus corax), and subsequently explored its link to three aspects of raven sociality. We trained ravens (n = 13) to voluntarily provide saliva samples and analysed salivary mesotocin with a commercial oxytocin enzyme-immunoassay kit, also suitable for mesotocin. After testing parallelism and recovery, we investigated the effect of bonding status, sex and season on mesotocin levels. We found that mesotocin was significantly more likely to be detected in samples taken during the breeding season (spring) than during the mating season (winter). In those samples in which mesotocin was detected, concentrations were also significantly higher during the breeding than during the mating season. In contrast, bonding status and sex were not found to relate to mesotocin detectability and concentrations. The seasonal differences in mesotocin correspond to behavioral patterns known to be associated with mesotocin/oxytocin, with ravens showing much more aggression during the mating season while being more tolerant of conspecifics in the breeding season. We show for the first time that saliva samples can be useful for the non-invasive determination of hormone levels in birds. However, the rate of successfully analysed samples was very low, and collection and analysis methods will benefit from further improvements.
•Ravens were trained to provide saliva samples voluntarily.•Salivary mesotocin levels were determined with an enzyme-immunoassay (EIA).•Mesotocin was more likely to be detected in the breeding than in the mating season.•Ravens' mesotocin levels were higher in the breeding than in the mating season.
Behavioral responses to novelty, including fear and subsequent avoidance of novel stimuli, i.e., neophobia, determine how animals interact with their environment. Neophobia aids in navigating risk ...and impacts on adaptability and survival. There is variation within and between individuals and species; however, lack of large-scale, comparative studies critically limits investigation of the socio-ecological drivers of neophobia. In this study, we tested responses to novel objects and food (alongside familiar food) versus a baseline (familiar food alone) in 10 corvid species (241 subjects) across 10 labs worldwide. There were species differences in the latency to touch familiar food in the novel object and novel food conditions relative to the baseline. Four of seven socio-ecological factors influenced object neophobia: (1) use of urban habitat (versus not), (2) territorial pair versus family group sociality, (3) large versus small maximum flock size, and (4) moderate versus specialized caching (whereas range, hunting live animals, and genus did not), while only maximum flock size influenced food neophobia. We found that, overall, individuals were temporally and contextually repeatable (i.e., consistent) in their novelty responses in all conditions, indicating neophobia is a stable behavioral trait. With this study, we have established a network of corvid researchers, demonstrating potential for further collaboration to explore the evolution of cognition in corvids and other bird species. These novel findings enable us, for the first time in corvids, to identify the socio-ecological correlates of neophobia and grant insight into specific elements that drive higher neophobic responses in this avian family group.
Display omitted
•Neophobia, i.e., fear of novel stimuli, impacts adaptability, and survival•Individual and species-level variation found in object and food neophobia in corvids•Urban habitat, adult sociality, max flock size, and caching influenced object neophobia•Large-scale collaborative study identified socio-ecological correlates of neophobia
Neophobia (novelty responses) impacts survival, with inter- and intra-species variation. In 10 corvid (crow family) species (241 subjects), Miller et al.’s multi-lab collaboration found individual temporal and contextual repeatability and species differences and identified socio-ecological drivers (urban habitat, sociality, flock size, caching) of neophobia.
The structure and functioning of the brain are lateralized—the right hemisphere processes unexpected stimuli and controls spontaneous behavior, while the left deals with familiar stimuli and routine ...responses. Hemispheric dominance, the predisposition of an individual using one hemisphere over the other, may lead to behavioral differences; particularly, an individual may be programed to act in a certain way concerning hemispheric dominance. Hand preference is a robust estimator of hemispheric dominance in primates, as each hemisphere controls the opposing side of the body. Studies have found links between hand preference and the exhibition of behaviors in contexts such as exploring and manipulating objects. However, little is known whether hand preference predicts behavioral variations in other ecologically relevant contexts like predation. We investigated the relationship between hand preference and behavioral responses to two types of predator models in captive Barbary macaques (Macaca sylvanus) (n = 22). Besides, a nonpredator novel object was included as control. We found 91% of the macaques to be lateralized with no group‐level bias. A higher rate of tension and focus (behavioral response) behavior was found in predator contexts than in the novel object condition. Unlike their right‐hand counterparts, individuals with a strong left‐hand preference elicited frequent focus and tension behavior toward the predator models. Additionally, the behavioral response varied with predator type. We also found an interaction effect between hand preference and predator type. Our study suggests that hand preference can reliably predict behavioral variations in the context of potential predation. While these results are consistent with lateralized brain function, indicating lateralization a neural mechanism of behavioral variation, the interaction effect between hand preference and predator type elucidates the importance of context‐specificity when investigating laterality noninvasively. Future research on other nonhuman primates using the current framework may provide insights into the evolution of laterality and underlying behavioral predispositions.
Hand preference predicts behavioral in Barbary macaques.
Research highlights
Hand preference is an indicator of hemispheric dominance, especially in nonhuman primates.
We investigated the relationship between hand preference and behavioral response in captive Barbary macaques using an ecologically relevant context.
Our findings suggest a potential role of brain lateralization in behavioral predisposition using a noninvasive framework.
The investigation of prosocial behavior is of particular interest from an evolutionary perspective. Comparisons of prosociality across non-human animal species have, however, so far largely focused ...on primates, and their interpretation is hampered by the diversity of paradigms and procedures used. Here, we present the first systematic comparison of prosocial behavior across multiple species in a taxonomic group outside the primate order, namely the bird family Corvidae. We measured prosociality in eight corvid species, which vary in the expression of cooperative breeding and colonial nesting. We show that cooperative breeding is positively associated with prosocial behavior across species. Also, colonial nesting is associated with a stronger propensity for prosocial behavior, but only in males. The combined results of our study strongly suggest that both cooperative breeding and colonial nesting, which may both rely on heightened social tolerance at the nest, are likely evolutionary pathways to prosocial behavior in corvids.
Animals of diverse taxa show different conditional mating strategies: they adjust their behaviour according to social and environmental situations, which may bring diverse (fitness) advantages for an ...individual. Especially in primates, mating is often associated with other social behaviours, such as grooming. Here, we study Barbary macaque postcopulatory grooming: we investigate for the first time whether males and females modify their grooming initiations after mating depending to the type of copulation (i.e. with or without ejaculation) and female lactation state. Our results show that males and females adjust grooming initiations conditional on copulation type, with males initiating grooming after copulations with ejaculation and females after non-ejaculatory mating. Moreover, lactating females tend to start grooming the males they just mated with more than vice versa, whereas there is no such a difference for grooming initiations after copulations with non-lactating females. These data indicate that Baibary macaques show post-mating grooming strategies that vary depending on the type of copulation that occurred and in dependence of female reproductive state. These grooming initiation patterns may reflect sex-specific mating interests and potentially serve to increase fitness: females, in particular lactating females, may benefit from initiating grooming to secure protection for themselves and their offspring and reduce harassment. Males may profit from grooming females after ejaculatory copulation by keeping them from mating with another male and thus potentially decreasing sperm competition.
Recent studies indicate that yawning evolved as a brain cooling mechanism. Given that larger brains have greater thermolytic needs and brain temperature is determined in part by heat production from ...neuronal activity, it was hypothesized that animals with larger brains and more neurons would yawn longer to produce comparable cooling effects. To test this, we performed the largest study on yawning ever conducted, analyzing 1291 yawns from 101 species (55 mammals; 46 birds). Phylogenetically controlled analyses revealed robust positive correlations between yawn duration and (1) brain mass, (2) total neuron number, and (3) cortical/pallial neuron number in both mammals and birds, which cannot be attributed solely to allometric scaling rules. These relationships were similar across clades, though mammals exhibited considerably longer yawns than birds of comparable brain and body mass. These findings provide further evidence suggesting that yawning is a thermoregulatory adaptation that has been conserved across amniote evolution.
Time-activity budget, i.e., how a population or an individual divides their day into various behaviours and activities, is an important ecological aspect. Existing research primarily focused on ...group-level time-activity budgets, while individual variations have only been reported recently. However, little is known about how consistent inter-individual differences or personalities influence time-activity budgets. We examined the personalities of lion-tailed macaques (Macaca silenus) and investigated their influence on individual time-activity budgets. The resulting personality traits, namely persistence, sociability, affiliation, and anxiety, were used to predict the three broad categories of the time-activity budget—food-related, active, and resting behaviours. We found that persistence and sociability positively predicted the time spent being active. Food-related behaviours were positively predicted by persistence, while anxiety was found to influence them negatively. The time spent resting was negatively predicted by persistence. We did not find an effect of affiliation on the time-activity budgets. We discuss these findings in light of the ecology of lion-tailed macaques. Our study highlights the importance of a novel approach that uses animal personality traits as predictors of individual time-activity budgets and offers insights regarding the use of personality assessments in conservation and welfare activities.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
PDF
