Bold Individuals Research Articles

Identifying personality traits and their potential application to the management of captive forest musk deer (Moschus berezovskii)

Since the 1950s musk deer (Moschidae) are kept in captivity for the production of musk, a glandular secretion used in Chinese traditional medicine and as an ingredient in cosmetics. Most recently, forest musk deer (Moschus berezovskii) raised in captivity were reintroduced to augment depleted wild populations. The most prominent behavioral and social characteristics of musk deer are anxiety, a timid, solitary lifestyle and territoriality, making musk deer difficult to breed. Individual differences in the personality of captive male musk deer could allow breeders to sort bold individuals that are suitable for commercial farming from those with a shy and more timid personality suitable for reintroduction. We attempted to identify what behavioral variables and what novel stimulus tests are the most effective to characterize whether an individual is bold or shy. To measure boldness in 31 adult males, we used a two-step approach: i) using a Principal Component Analysis to identify reference behaviors that are indicative of either a shy or a bold personality, and ii) to establish individual boldness scores based on those reference behaviors and compare them between four novel stimuli. We obtained two ‘bold PCs’ with high axis loadings from behaviors that are typical for curiosity, territorial marking or that represent the ordinary daily activity of a ruminant, as well as three ‘shy PCs’ that received high axis loadings from behaviors that are typical for anti-predator responses, intimidation or displacement behavior.Although all tested stimuli were verified suitable, the unfamiliar human being was the strongest stimulus to test boldness, followed by leopard feces, a beach ball and a leopard dummy. Using cluster analysis, nearly three quarter of tested individuals were identified as shy, while only one quarter was classified as bold. Previous studies on poultry and domestic ungulates, demonstrated that through continued selective breeding for boldness, the overall personality in the population is driven towards a calm temperament in the majority of the individuals. This might be beneficial for musk production but will have adverse effects on successful reintroductions due to reduced individual fitness and domestication effects.

Personality composition determines social learning pathways within shoaling fish.

In shaping how individuals explore their environment and interact with others, personality may mediate both individual and social learning. Yet increasing evidence indicates that personality expression is contingent on social context, suggesting that group personality composition may be key in determining how individuals learn about their environment. Here, we used recovery latency following simulated predator attacks to identify Trinidadian guppies (Poecilia reticulata) that acted in a consistently bold or shy manner. We then employed network-based diffusion analysis to track the spread of a novel foraging behaviour through groups containing different proportions of bold and shy fish. Informed associates promoted learning to a greater extent in bold individuals, but only within groups composed predominately of bold fish. As the proportion of shy fish within groups increased, bold individuals instead emerged as especially effective demonstrators that facilitated learning in others. Individuals were also more likely to learn overall within shy-dominated groups than in bold-dominated ones. We demonstrate that whether and how individuals learn is conditional on group personality composition, indicating that selection may favour traits enabling individuals to better match their behavioural phenotype to their social environment.

An individual's propensity to disperse is dependent on the behavioral type of its peers but not its own behavioral type.

Intraspecific differences in the dispersal propensity of animals have been linked to interindividual variation in inherent tendencies (i.e., personality or behavioral type) that influence multiple aspects of an individual's behavior. Studies linking dispersal propensity and personality often (1) focus on defining behavioral tendencies with a single behavioral trait rather than multiple, (2) do not recognize that invertebrates may have behavioral tendencies that influence dispersal, and (3) do not consider how the behavioral type of other individuals affects the dispersal propensity of an individual. We documented multiple foraging behaviors of an aquatic predatory insect (Notonecta irrorata) and found that Notonecta individuals differ in their inherent behavioral tendency (i.e., degree of boldness); all foraging behaviors were correlated such that riskier behaviors were exhibited by the same individuals. We conducted an experiment in which we varied which behavioral types of Notonecta were placed in outdoor pools (passive, bold or both types present) and quantified how long it took for individuals to disperse. Passive and bold individuals had a similar propensity to disperse but the dispersal propensity of each behavioral type was influenced by the behavioral type of other conspecifics present in the pool. Our work reveals that (1) invertebrates have inherent behavioral tendencies that vary among individuals but these tendencies do not necessarily impact all of the behavior displayed by the individual (i.e., impact foraging but not dispersal) and (2) the inherent behavioral tendency of other individuals with which an animal co-occurs can affect habitat patch dynamics such as predation, competition, or colonization.

Using multilayer network analysis to explore the temporal dynamics of collective behavior.

Social organisms often show collective behaviors such as group foraging or movement. Collective behaviors can emerge from interactions between group members and may depend on the behavior of key individuals. When social interactions change over time, collective behaviors may change because these behaviors emerge from interactions among individuals. Despite the importance of, and growing interest in, the temporal dynamics of social interactions, it is not clear how to quantify changes in interactions over time or measure their stability. Furthermore, the temporal scale at which we should observe changes in social networks to detect biologically meaningful changes is not always apparent. Here we use multilayer network analysis to quantify temporal dynamics of social networks of the social spider Stegodyphus dumicola and determine how these dynamics relate to individual and group behaviors. We found that social interactions changed over time at a constant rate. Variation in both network structure and the identity of a keystone individual was not related to the mean or variance of the collective prey attack speed. Individuals that maintained a large and stable number of connections, despite changes in network structure, were the boldest individuals in the group. Therefore, social interactions and boldness are linked across time, but group collective behavior is not influenced by the stability of the social network. Our work demonstrates that dynamic social networks can be modeled in a multilayer framework. This approach may reveal biologically important temporal changes to social structure in other systems.

The impact of personality, morphotype and shore height on temperature-mediated behavioural responses in the beadlet anemone Actinia equina.

Between-individual variation in behavioural phenotype, termed personality, is an important determinant of how populations cope with acute environmental fluctuation related to climate change. Personality in the beadlet sea anemone Actinia equina is linked to genetically distinct morphotypes, which are associated with different heights on the shore. In the intertidal zone, high-shore environments experience more environmental fluctuation due to longer periods of exposure, and animals adapted to live in these environments are predicted to deal more effectively with environmental perturbation than their low-shore counterparts. We collected beadlet anemones of two different morphotypes from three different shore heights. We investigated variation in two behaviours at three different temperatures and in a temporal control treatment where the temperature was not changed: startle response time, the time it took an anemone to re-extend its tentacles after a threatening stimulus, and immersion response time, the time to re-extend tentacles after simulated tidal immersion. These behaviours reflect risk-taking and allow individuals to be categorized as bold, shy or intermediate based upon response times. Both behaviours showed significant changes as the temperature increased. For immersion response, the morphotype associated with the low-shore-lengthened response times at high temperatures. For startle response, all animals lengthened their response times at high temperatures but animals collected from the low-shore lengthened theirs to the greatest degree. At the individual level, although control individuals exhibited temporal changes in their response times, a clear effect of temperature was present in both behaviours. Shy and bold individuals became more intermediate at higher temperatures in immersion response (this effect was present to a lesser degree in control individuals), while intermediate individuals raised their response times at higher temperatures for startle response. Given that prolonged tentacle retraction reduces foraging opportunities and can negatively impact respiratory efficiency, our data suggest that some individuals within a single population of A.equina, particularly those associated with the lower shore, may exhibit less effective behavioural responses to temperature shifts than others. These findings demonstrate that acute temperature changes influence risk-taking, and could have profound short and long-term implications for survival in the face of climate change.

Bolder and Brighter? Exploring Correlations Between Personality and Cognitive Abilities Among Individuals Within a Population of Wild Zebrafish, Danio rerio.

Within populations, individual differences in behavioral and cognitive traits are dependent on the habitat and specific contexts, such as the presence of a predator or other risks. The ability to show variable responses to changing conditions can be of immense survival advantage to organisms. We studied individual differences in specific personality traits, such as boldness, exploration, and spatial ability, and the effect of these traits on learning ability and memory in the presence of a predatory threat, among wild caught zebrafish (Danio rerio). Under laboratory conditions, individuals were trained to perform a simple navigation task, and their performance, exploration, boldness traits were measured, along with learning and memory abilities under two contexts (i.e., in the presence and absence of a predator). Our results revealed that fish showed a clear decline in emergence time, exploration time, and feeding latency over trials, indicative of learning, and further tests for memory also showed memory retention. While the presence of a predator increased emergence time and latencies for navigating, indicating declines in boldness and exploration, these were found to be correlated to different personalities among the individuals and dependent on their sex. While females tended to be bolder and learned the spatial task faster, they showed lower memory retention abilities than males. Personality traits were also found to affect cognitive abilities among individuals. In general, the presence of a predator decreased performance latencies. However, bolder individuals were less affected and emerged more quickly from the refuge chamber than shy individuals. Our results point to the complex interplay of ecological context along with inherent correlations across personality traits that decide the overall personality and cognitive responses among individuals even within populations. These findings thus highlight the importance of an inclusive approach that combines personality and cognition studies for understanding variations within populations.

Differences in prey personality mediate trophic cascades.

Functional trait approaches in ecology chiefly assume the mean trait value of a population adequately predicts the outcome of species interactions. Yet this assumption ignores substantial trait variation among individuals within a population, which can have a profound effect on community structure and function. We explored individual trait variation through the lens of animal personality to test whether among‐individual variation in prey behavior mediates trophic interactions. We quantified the structure of personalities within a population of generalist grasshoppers and examined, through a number of field and laboratory‐based experiments, how personality types could impact tri‐trophic interactions in a food chain. Unlike other studies of this nature, we used spatial habitat domains to evaluate how personality types mechanistically map to behaviors relevant in predator–prey dynamics and found shy and bold individuals differed in both their habitat use and foraging strategy under predation risk by a sit‐and‐wait spider predator. In the field‐based mesocosm portion of our study, we found experimental populations of personality types differed in their trophic impact, demonstrating that prey personality can mediate trophic cascades. We found no differences in respiration rates or body size between personality types used in the mesocosm experiment, indicating relative differences in trophic impact were not due to variation in prey physiology but rather variation in behavioral strategies. Our work demonstrates how embracing the complexity of individual trait variation can offer mechanistically richer understanding of the processes underlying trophic interactions.

Sand lizards Lacerta agilis with higher digit ratios are more likely to autotomy.

Digit ratio is a morphological feature regarded as a biomarker of the balance of sex hormones during early development. The exposure of embryos to a set of sex hormones and the mutual relations between those hormones cause the emergence of individual morphological and/or behavioural characteristics as well as differences between sexes. We have thus hypothesised that differences in one of these morphological traits-digit ratio-may be a proxy representing a tendency towards tail autotomy. The aim of this study is to investigate the digit ratio (2D:3D, 2D:4D, 3D:4D) of the sand lizard, Lacerta agilis, Lacertidae, a species characterised by well-developed sexual dimorphism, whereby females are larger than males. We also tested associations between patterns in digit ratio and caudal autotomy, a common defensive mechanism among lizards. To our knowledge, the relationship between a tendency towards autotomy and digit ratio pattern has never been researched. To date, studies on autotomy have mainly focused on the consequences, costs or evolutionary background of tail loss. Hence, researchers examined mostly the frequency of autotomy in the context of predatory pressure or habitat conditions, omitting an individual's behavioural tendency to shed its tail. However, behavioural traits can affect an individual's exposure to predator attack and consequently the need to use an anti-predator strategy. Thus, following this logic, dropping the tail may be the result of the lizard's intraspecific personality characteristics, resulting from the effect of hormones on behaviour or innate traits. Therefore, we suggest that the inclusion of autotomy as a factor explaining observed digit ratio patterns and their variability between taxa has great potential. We used computerised measurements of photographed limbs to determine the length of digits. We found that the digit ratios for all four limbs were significantly lower in females than in males, excluding the 3D:4D ratio for the right hindlimbs. Therefore, the results confirmed the pattern already observed for most lizards. The novel element in our study is the detection of the relationship between a tendency towards caudal autotomy and digit ratio. Individuals with a tendency towards autotomy have a higher 2D:4D ratio in the right forelimbs and a lower 2D:3D ratio in the right hindlimbs. Obtained results suggest that these morphological characteristics are most likely related to intraspecific differences (between bold and shy individuals) which consequently may determine an individual's reaction or susceptibility to be a prey and escape behaviour. Thus, our results are probably the first attempt to link digit ratio to the susceptibility of lizards to tail autotomy.

Does consistent individual variability in pelagic fish larval behaviour affect recruitment in nursery habitats?

Individual animals across all taxa differ consistently in behaviour, i.e. they show personality traits. This inter-individual variability has significant ecological and evolutionary consequences, since it affects a range of population-level processes. Here, we focus on the selection and recruitment of nursery habitats in temperate fish larvae. The “Sense Acuity and Behavioural Hypothesis” has proposed that fish larvae could detect and follow environmental cues to actively choose suitable nursery habitats. We empirically tested this hypothesis questioning if this non-random active process occurs and if it could be linked to consistency in individual behaviours. Individual larvae of the white seabream Diplodus sargus (Linnaeus, 1758) were tested repeatedly at different ages in a two-channel choice-chamber apparatus exposing them to a flow with different stimuli, as nursery habitats (lagoon, coastal), different temperatures or salinities and recording exploratory activity and preference in the different conditions. Most larvae changed behaviour during ontogeny, but they were also significantly consistent in their behaviour, revealing strong individuality; yet, no significant preference for the presented stimuli emerged, nor it was related to individuality. Exploratory activity was higher when larvae showed unresponsive or inconclusive behaviours, meaning that the larvae tried to find a different stimulus from the one that we were offering or had random habitat selection. Individual behavioural consistency could influence the process of searching for suitable nursery habitats and, consequently, dispersion and connectivity of white seabream population. Characterizing the behaviour of temperate pelagic marine fish larvae may shed light on fish recruitment variability, help refining larval dispersion models and possibly help understanding effects of climate change on population distribution and connectivity. A Chinese idiom says that “It is easier to change mountains and rivers than to alter one’s character.” What about fish? Well, fish can exhibit individuality traits that control autoecological and demecological processes. For example, shy fish have lower fitness while the rate of invasion progress is faster in populations with bolder individuals. Individuality studies rarely focused on fish larvae, except for coral fish. So, we tested if temperate fish larvae display consistent behaviour throughout ontogeny. This goal delves into the Sense Acuity And Behavioural Hypothesis which incorporated behaviour into the hypotheses deeming to explain fish recruitment variability. We found that temperate fish larvae display consistent individual behavioural differences in exploratory activity since early in ontogeny. This confirms the deterministic role of pelagic fish larvae behaviour on population connectivity processes, namely to control their dispersion and choose a nursery habitat.

Evidence for the ‘behavioural character’ hypothesis: does boldness programme disparate antipredator strategies?

Risk-taking behaviours that are optimal in one context (predators absent) may be suboptimal in a different context (predators present), suggesting that individuals with ‘bold’ behaviours will experience increased predation risk. Yet, in some instances, bold individuals experience lower predation. Thus, there is not always a direct trade-off between boldness and predation risk. To better understand the relationship between boldness and predation risk, suboptimal behaviours must be viewed within the context of an organism's entire integrated antipredator strategy. Using freshwater snails exposed to a predator cue, we examined whether quickly re-emerging from the shell was a repeatable, carryover behaviour that was tied to behavioural and morphological antipredator traits. Slow-emerging snails invested in morphological shell defence and remained in the predator environment, whereas quick-emerging snails consistently avoided the predator environment and did not invest in shell defences. Therefore, slow-emerging snails used a sit-and-wait antipredator strategy by relying on their shells for protection and were less likely to avoid the predator environment; conversely, quick-emerging snails used an avoidance (or dispersal) strategy by consistently associating with the water's surface and investing less in shell defences. A path analysis of these antipredator traits indicates that the carryover effect of bold behaviour may be an important factor that mediates complementary behavioural and morphological traits that reduce predation risks. This study supports the ‘behavioural character’ hypothesis, which suggests that boldness is a latent variable upon which selection can act and thereby shape a variety of quasi-independent traits (e.g. antipredator traits). According to this perspective, selection is not acting on a single antipredator behavioural trait in isolation, but rather on an integrated antipredator strategy that is facilitated by individual differences in carryover risk-taking behaviour.

Aggressive encounters lead to negative affective state in fish

Animals show various behavioural, neural and physiological changes in response to losing aggressive encounters. Here, we investigated affective state, which are emotion-like processes influenced by positive or negative experiences, in a territorial fish following aggressive encounters and explore links to bold/shy behavioural traits. Eighteen 15-month old Murray cod (Maccullochella peelii) received three tests in order to determine bold/shy behavioural traits then underwent a typical go/no-go judgement bias (JB) test. The JB apparatus had five adjacent chambers with access provided by a sliding door and fish underwent a training procedure to enter a chamber at one end of the apparatus to receive a food reward but were chased using a net if they entered the chamber at the opposite end. Only one third (N = 6) of fish successfully completed the training procedure (trained fish), and the remaining 12 fish failed to reach the learning criterion (untrained fish). Trained fish housed with a larger aggressive Murray cod for 24 h were significantly less likely to enter intermediate chambers during probe tests compared to control fish, demonstrating a pessimistic response. Trained fish showed “bolder” responses in emergence and conspecific inspection tests than untrained fish, suggesting that shyer individuals were less able to apply a learned behaviour in a novel environment. Our limited sample was biased towards bold individuals but supports the hypothesis that losing an aggressive encounter leads to pessimistic decision-making.

Integration of physiology, behaviour and life history traits: personality and pace of life in a marine gastropod

Attempts to unravel the proximate and ultimate causes of individual behavioural and life history variation have often pointed to predicted correlations between behavioural, physiological and life history traits, forming pace-of-life syndromes (POLS). The POLS hypothesis predicts that high levels of production (growth, fecundity) require high levels of foraging effort and risk taking, supported by high metabolism. Despite tremendous interest in this topic, the POLS hypothesis still has limited empirical support, which has led to calls for more stringent empirical tests of the hypothesis and its assumptions. To that end, we examined the associations between risk-taking behaviour (boldness), resting metabolic rate (RMR) and somatic growth rate in a marine gastropod, Littoraria irrorata, under controlled laboratory conditions using a longitudinal repeated measures design. After accounting for the effects of sex, size and time (trial number), a multivariate mixed model revealed that bolder individuals had higher RMR, and grew faster, whereas RMR and growth were not strongly correlated. Further, if individuals were bolder than their average on a given day, then their RMR was also higher. Our study represents rare and compelling support for the POLS hypothesis, simultaneously studying its three key components (behaviour, energetics and life history), the success of which we attribute to careful control, concurrent sampling of each trait, and rigorous analysis of the among- and within-individual patterns of variation and covariance.

Zebrafish Danio rerio shows behavioural cross-context consistency at larval and juvenile stages but no consistency between stages.

Coping style is defined as a set of individual physiological and behavioural characteristics that are consistent across time and context. In the zebrafish Danio rerio, as well as in many other animals, several covariations have been established among behavioural, physiological and molecular responses. Nonetheless, not many studies have addressed the consistency in behavioural responses over time starting at the larval stage. Therefore, this study aimed to improve the understanding of behavioural consistency across contexts and over time in zebrafish from the larval to juvenile stages. Two distinct experiments were conducted: a larval stage experiment (from 8 to 21 days post fertilization, dpf) and a juvenile stage experiment (from 21 to 60 dpf). On one hand, the larval experiment allows to focus on the transition between 8 and 21 dpf, marked by significant morphological changes related to the end of larval stage and initiation of metamorphosis. On the other hand, the juvenile experiment allows to properly cover the period extending from the end of larval stage to the juvenile stage (60 dpf), including metamorphosis which is itself completed around 45 dpf. Within each experiment, boldness was determined using a group risk-taking test to identify bold and shy individuals. A novel environment test was then performed at the same age to evaluate consistency across contexts. Groups of fish (either bold or shy) were bathed in an alizarin red S solution for later identification of their initially determined coping style to evaluate behavioural consistency over time. Fish were then reared under common garden conditions and challenged again with the same behavioural tests at a later age (21 and 60 dpf in the larval and juvenile experiments, respectively). Behavioural consistency was observed across contexts, with bold fish being more active and expressing higher thigmotaxis regardless of age. There was, however, little behavioural consistency over age, suggesting behavioural plasticity during development. Moreover, the use of alizarin red S to conduct this experiment provides new perspectives for the further study of the longitudinal evolution of various traits, including behaviour, over life stages in fish.

When personality matters: personality and social structure in wild bottlenose dolphins, Tursiops truncatus

There is increasing evidence that animal personality can affect many aspects of an individual's behaviour, life history and fitness. However, there have been few studies about the link between personality and social organization in the context of wild mammals in their own natural environments. This article reports on ecologically relevant data, linking experimental data from the wild to long-term social association data in a socially and cognitively complex mammal species (bottlenose dolphin, Tursiops truncatus). Here, I used behavioural data to describe personality differences between bottlenose dolphins and social network analysis to assess the relationship between personality and social structure. First, I measured the reaction of photo-identified individuals over time and across contexts as a trade-off between a novelty-seeking behaviour (boldness) and a novelty-averse behaviour (shyness). Second, I applied social network analysis to understand the link between the observed shy–bold continuum and social organization, while controlling for other factors that could contribute to affiliation. This study presents for the first time consistent individual differences in behavioural response to novelty, as a proxy for the shy–bold continuum, in wild bottlenose dolphins. Bold individuals had a central role in the social network with stronger associations than shy individuals, suggesting that bold individuals may play an important role in group cohesion, group stability and the spread of information through the network. Together, these findings provide insights into how a social network is structured by personality in wild bottlenose dolphins, with potential fitness consequences. Furthermore, this study provides additional evidence of the existence of social personalities in nonhuman animals and contributes to the understanding of the role of personality in determining the extent to which mammals associate with others.

Are bolder individuals more likely to choose heterospecific mates? A test in cyprinid fishes

Mating between different species is ubiquitous in nature. While environmental conditions and population density have been shown to affect the occurrence of heterospecific matings, much less is known about the potential role of individual characteristics. Here, we examined the association between boldness and mate choice to con- and heterospecifics in a cyprinid fish (Pseudaspius sachalinensis) which naturally hybridizes with congeneric species. We found a positive correlation between risk-taking tendency in an emergence test and a preference for heterospecific females. This finding suggests that bolder males may prefer novel phenotypes or are likely to make a wrong choice for their mating partners.

Sex, personality and conspecific density influence natal dispersal with lifetime fitness consequences in urban and rural burrowing owls.

There is a growing need to understand how species respond to habitat changes and the potential key role played by natal dispersal in population dynamics, structure and gene flow. However, few studies have explored differences in this process between conspecifics living in natural habitats and those inhabiting landscapes highly transformed by humans, such as cities. Here, we investigate how individual traits and social characteristics can influence the natal dispersal decisions of burrowing owls (Athene cunicularia) living in urban and rural areas, as well as the consequences in terms of reproductive success and apparent survival. We found short dispersal movements among individuals, with differences between urban and rural birds (i.e., the former covering shorter distances than the latter), maybe because of the higher conspecific density of urban compared to rural areas. Moreover, we found that urban and rural females as well as bold individuals (i.e., individuals with shorter flight initiation distance) exhibited longer dispersal distances than their counterparts. These dispersal decisions have effects on individual fitness. Individuals traveling longer distances increased their reproductive prospects (productivity during the first breeding attempt, and long term productivity). However, the apparent survival of females decreased when they dispersed farther from their natal territory. Although further research is needed to properly understand the ecological and evolutionary consequences of dispersal patterns in transformed habitats, our results provide information about the drivers and the consequences of the restricted natal movements of this species, which may explain its population structuring through restricted gene flow between and within urban and rural areas.

Effects of personality and rearing-history on the welfare of captive Asiatic lions (Panthera leo persica).

BackgroundThe long-term success of ex-situ conservation programmes depends on species-appropriate husbandry and enrichment practices complemented by an accurate welfare assessment protocol. Zoos and conservation breeding programmes should employ a bottom-up approach to account for intraspecific variations in measures of animal welfare. We studied 35 (14:21) captive Asiatic lions in Sakkarbaug Zoological Garden, Junagadh, India to understand the implications of individual variations on welfare measures. We categorized the subjects based on personality traits (bold or shy), rearing history (wild-rescued or captive-raised), sex, and social-grouping. We explored the association of these categorical variables on welfare indices such as behavioural diversity, latency to approach novel objects, enclosure usage and aberrant repetitive behaviours. Further, we assessed the inter-relationships between different behavioural measures of welfare.ResultsOur results show that intraspecific variations based on rearing-history and personality traits are significantly associated with the welfare states of captive Asiatic lions. Asiatic lions with bold personality traits (M = 0.50, SD = 0.12, N = 21) and those raised in captivity (M = 0.47, SD = 0.12, N = 16) used enclosure space more homogenously compared to shy (M = 0.71, SD = 0.15, N = 14) and wild-rescued (M = 0.67, SD = 0.15, N = 19) animals. Behaviour diversity was significantly higher in captive-raised (M = 1.26, SD = 0.3, N = 16) and bold (M = 1.23, SD = 0.26, N = 21) subjects compared to wild-rescued (M = 0.83, SD = 0.35, N = 19) and shy (M = 0.73, SD = 0.34, N = 14) individuals. Aberrant repetitive behaviours (stereotypy) were significantly lower in bold (M = 7.01, SD = 4, N = 21) and captive-raised (M = 7.74, SD = 5.3) individuals compared to wild-rescued (M = 13.12, SD = 6.25, N = 19) and shy (M = 16.13, SD = 5.4, N = 16) lions. Sex and social-grouping of subjects did not show significant associations with behavioural welfare indices. Interestingly, behaviour diversity was reliably predicted by the enclosure usage patterns and aberrant repetitive behaviours displayed by subjects.DiscussionOur findings underline the importance of individual-centric, behaviour-based, and multi-dimensional welfare assessment approaches in ex-situ conservation programmes. The results suggest that behavioural welfare indices complemented with individual variations can explain inter-individual differences in behavioural welfare measure outcomes of Asiatic lions. These findings also provide zoo managers with a non-invasive tool to reliably assess and improve husbandry practices for Asiatic lions. Understanding the unique welfare requirement of individuals in captivity will be crucial for the survival of the species.

Esther Webman, 1947–2020

Esther Webman, 1947–2020 Dina Porat (bio) Dr. Esther Webman, a dear friend for decades and an outstanding scholar (who was on the advisory board of this journal, among others) passed away suddenly on June 16, 2020. We find ourselves in deep mourning, and with the certainty that Esti—as she was fondly called by her many friends and colleagues—has left behind a void that cannot be filled. Esti's research was well-known internationally and highly acclaimed. She stood at the forefront of scholarship on antisemitism and perceptions of the Holocaust in the Arab and Muslim worlds. Her leadership in this field was evident in her many publications and numerous conference papers and lectures. She distinguished herself by her original thinking, sharp and critical eye, and deep understanding of the political and social realities in the Arab world at large, whether today, or in the recent past. Esti's writing was always lucid and well balanced, and she shied away from any sort of exaggeration or extremism. Born in Cairo, Esti grew up speaking Arabic and French as a child. She had a gift for languages and later in life wrote impeccable English. After being driven out of Egypt, her family immigrated to Israel. She grew up in Migdal Ha'Emek, a small town in the Galilee, and was educated in an excellent boarding school, always standing at the top of her class. She served as a lieutenant in an elite IDF intelligence unit that later became known as 8200. [End Page 388] Upon completing her army service shortly after the Six Day War, Esti embarked on a brilliant academic career at Tel Aviv University, winning the highest praise of her professors. Click for larger view View full resolution Figure 1. Photo of Esther Webman. Reprinted with permission of Esther's family. Esti served as a senior researcher and editor-in-chief of publications at the Dayan Center for Middle Eastern and African Studies. She was a staff member at the Stephen Roth Institute for the Study of Antisemitism and Racism, and at the Kantor Center for the Study of Contemporary European Jewry, all housed at Tel Aviv University. Among her many publications are From Empathy to Denial: Arab Responses to the Holocaust, co-authored with Meir Litvak. This book won the gold prize of the Washington Institute for Middle Eastern Policy in 2010. She authored the sections on the Arab world for the reports on antisemitism that were published annually by the Stephen Roth Institute, and then by the Kantor Center beginning [End Page 389] in 1994. Those texts were exemplary in their accuracy, depth of analysis, use of a multitude of sources, and were characterized by their courageous assessments. Esti will be best remembered because of the steadfastness she displayed in defending the findings she reached after delving into a variety of primary sources. She insisted that in recent years, if one listened carefully, one could hear new voices in the Arab and Muslim worlds that deviate from the well-known antipathy toward Jews and the Jewish State, especially among intellectuals and political analysts. These bold individuals highlight the damage caused to the reputations of Arabs and Muslims in the West when The Protocols of the Elders of Zion or the idea that Jews use blood for ritual purposes are hailed as absolute truth along with other ludicrous notions about Jews. Esti had high hopes that these moderate voices would pave the way to at least a modest reconciliation between Israel and its neighbors. Those hopes matched her political and social convictions, which always led her to champion the rights of others, minorities, and the weak and disadvantaged. She leaves behind a son Oded, a daughter Adi, and a grandson Adam who was the apple of her eye. Her memory will definitely be a blessing. [End Page 390] Dina Porat Dina Porat is head of the Kantor Center for the Study of Contemporary European Jewry and incumbent of the Alfred P. Slaner Chair in Antisemitism and Racism at Tel Aviv University. She is also chief historian of Yad Vashem. Her most recent book is Vengeance and Recompence are Mine: The Yishuv, the Holocaust and...

Influences of Personality on Ungulate Migration and Management

Loss of migratory behaviour in ungulates often occurs with habituation to people to cause several challenges for wildlife managers, particularly in protected and urban areas. Aversive conditioning to increase ungulate wariness towards people could be an important tool for managing this problem, but it is frequently thwarted by variation in responsiveness among individuals, an aspect of personality that is currently little understood by managers. In this paper, we describe the potential role of personality in the ecological progression associated with habituation, loss of migration, and human-wildlife conflict in ungulates. We do so by (a) synthesizing our prior work on two populations of wild elk (Cervus canadensis) living in national parks in the Canadian Rocky Mountains, (b) using it to articulate a conceptual model to explain how anthropogenic changes in landscapes favour bolder individuals, and (c) showing how targeted use of aversive conditioning could limit the advantages to bold individuals that promote residency. Our review showed how bolder elk, defined by a combination of seven separate personality metrics on a bold-shy continuum, are three times more likely to forego migration, but are also quicker to learn by association, whether via the provision or cessation of aversive conditioning. These differences may relate to cognitive flexibility, which we measured with limb use preferences, to imbue bolder elk with more rapid responses to changing environments. In our conceptual model, we show how four ecological drivers comprised by interactions with humans, predators and conspecifics, in addition to changes in forage, favour bolder elk that are more likely to adopt a resident migratory tactic. We also explain how bold personalities could result from behavioral flexibility, genetic differences, or gene-environment interactions, each of which could be moderated by frequency-dependent payoffs to individuals. We suggest that managers could limit the prevalence of bold, resident ungulates by targeting bolder individuals with active and specific aversive conditioning, while minimizing anthropogenic food sources in predator refugia. A better understanding of personality in wildlife could support more proactive strategies to limit habituation and encourage migration and other keystone behaviours in changing landscapes.

Are personalities genetically determined? Inferences from subsocial spiders

BackgroundRecent research has revealed that polymorphic behavioral strategies shape intra-and interspecific interactions and contribute to fitness in many animal species. A better understanding of the proximate mechanisms underlying these behavioral syndromes will enhance our grasp this phenomenon. Spiders in the genus Anelosimus exhibit inter-individual behavioral variation on several axes: individuals have consistent responses to stimuli (e.g. bold vs. shy individuals) and they are subsocial (exhibiting extended maternal care and sibling cooperation) across most of their range, but they sometimes form permanent social groups in northern temperate regions. Here, we seek genetic variants associated with boldness and with social structure in a socially polymorphic population of the spider Anelosimus studiosus. We also develop preliminary genomic resources, including a genome assembly and linkage map, that support this and future genomic research on this group.ResultsRemarkably, we identify a small genomic scaffold (~ 1200 bp) that harbors seven single nucleotide polymorphisms (SNPs) associated with boldness. Moreover, heterozygotes are less common than expected based on Hardy-Weinberg equilibrium, suggesting that either assortative mating or selection against heterozygotes may be occurring in this system. We find no loci significantly associated with social organization. Our draft genome assembly allows us to localize SNPs of interest in this study and to carry out genetic comparisons with other published genomes, although it remains highly fragmented.ConclusionsBy identifying a locus associated with a well-studied animal personality trait, this study opens up avenues for future research to link behavioral studies of animal personality with genotype and fitness.