Abstract: This study explored if boldness could be used to predict social status. First, boldness was assessed by monitoring individual zebrafish behaviour in (1) an unfamiliar barren environment with no shelter (open field), (2) the same environment when a roof was introduced as a shelter, and (3) when the roof was removed and an unfamiliar object (Lego® brick) was introduced. Next, after a resting period of minimum one week, social status of the fish was determined in a dyadic contest and dominant/subordinate individuals were determined as the winner/loser of two consecutive contests. Multivariate data analyses showed that males were bolder than females and that the behaviours expressed by the fish during the boldness tests could be used to predict which fish would later become dominant and subordinate in the ensuing dyadic contest. We conclude that bold behaviour is positively correlated to dominance in zebrafish and that boldness is not solely a consequence of social dominance.

Abstract: There is now a broad consensus in the policy community that strengthening the macroprudential orientation of regulatory and supervisory frameworks is essential for the promotion of financial stability. The window of opportunity to put in place fully fledged macroprudential frameworks should not be missed. Meeting this challenge calls for a finely balanced blend of boldness and realism. Boldness is required to face the hard design questions head-on; realism to avoid overreach and to manage expectations. Policymakers should be as ambitious as possible, but no more. In all this, research has an important role to play in allowing the framework to grow at a pace commensurate with our knowledge. This speech considers how to strike the balance between boldness and realism in several aspects of the framework: in the criterion for judging its success; in how closely systemic risk should be tracked; in the mix between an aggregate and a sectoral approach; in that between rules and discretion; and in governance arrangements. It also highlights some key questions for research.

Abstract: Understanding/predicting ecological invasions is an important challenge in modern ecology because of their immense economical and ecological costs. Recent studies have revealed that within-species variation in behaviour (i.e. animal personality) can shed light on the invasion process. The general hypothesis is that individuals' personality type may affect their colonization success, suggesting that some individuals might be better invaders than others. We have recently shown that, in the invasive mosquitofish (Gambusia affinis), social personality trait was an important indicator of dispersal distance, with more asocial individuals dispersing further. Here, we tested how mean personality within a population, in addition to individual personality type, affect dispersal and settlement decisions in the mosquitofish. We found that individual dispersal tendencies were influenced by the population's mean boldness and sociability score. For example, individuals from populations with more asocial individuals or with more bold individuals are more likely to disperse regardless of their own personality type. We suggest that identifying behavioural traits facilitating invasions, even at the group level, can thus have direct applications in pest management.

Abstract: In many animals, individual differences in behavior show remarkable consistency across situations and contexts (i.e., animal personality and behavioral syndromes). Studies on the association between personality traits and fitness-related measures in nature are, however, important to clarify the causes and consequences of this phenomenon. Here, we tested for correlations between 3 behavioral axes in brown trout (Salmo trutta) parr: exploration tendency, behavioral flexibility, and aggressiveness. Next, we tested how these individual behaviors relate to social dominance and performance under natural conditions (growth, survival, and movement). We found support for behavioral syndromes in brown trout with less explorative individuals being less aggressive and showing more flexible behavior. In addition, these low-explorative personality types grew faster than bolder conspecifics in the wild. Standardized aggression in the laboratory was a poor indicator of social dominance, and neither of these 2 traits affected performance in the wild. These results challenge the view that personality traits can be predicted by constant associations with life-history trade-offs (e.g., boldness is linked with rapid growth). Moreover, our findings suggest that fitness predictions from laboratory measures of behavior should be made with caution and ideally tested in nature. Key words: aggressiveness and cryptic prey, animal personality, behavioral flexibility, behavioral syndrome, dominance, exploration tendency, life history, fitness. [Behav Ecol]

Abstract: Behavioral syndromes are suites of two or more behaviors that correlate across environmental contexts. The aggression-boldness syndrome links aggression, boldness, and exploratory activity in a novel environment. Although aggression-boldness has been described in many animals, the mechanism linking its behavioral components is not known. Here we show that mutation of the gene encoding fibroblast growth factor receptor 1a (fgfr1a) simultaneously increases aggression, boldness, and exploration in adult zebrafish. We demonstrate that altered Fgf signaling also results in reduced brain histamine levels in mutants. Pharmacological increase of histamine signaling is sufficient to rescue the behavioral phenotype of fgfr1a mutants. Together, we show that a single genetic locus can underlie the aggression-boldness behavioral syndrome. We also identify one of the neurotransmitter pathways that may mediate clustering of these behaviors.

Abstract: Size-selective harvesting associated with commercial and recreational fishing practices has been shown to alter life history traits through a phenomenon known as fishing-induced evolution. This phenomenon may be a result of selection pathways targeting life-history traits directly or indirectly through correlations with behavioral traits. Here, we report on the relationship between individual differences in behavior and capture technique (beach seining versus angling) in wild-caught juvenile bluegill sunfish (Lepomis macrochirus). Both fish caught by using a seine net (seined) and fish caught by using a lure (angled) were individually tested under standardized laboratory conditions for their boldness, water-column use, and general activity. Observed inter-individual differences in boldness were strongly correlated with method of capture in the wild. Fish caught by angling were more timid and had fewer ectoparasites than fish caught using a seine net. However, this relationship did not carry over to an experiment in a large outdoor pool with seine-caught, individually tagged wild fish, where bolder individuals were more likely to be angled in open water away from refuges than more timid individuals, based on their previously assessed boldness scores. Our study is both novel and important, as it describes the relationship between capture technique and boldness in a natural population and underscores the potential risk of sampling biases associated with method of animal capture for behavioral, population, and conservation biologists.

Abstract: Consistent individual differences in behavioural responses to perceived predation risk may have extensive ecological and evolutionary implications. We studied the repeatability of boldness across time and its relation to resource holding potential in the noble crayfish, Astacus astacus L., using predator-naive immature individuals. We followed individual’s shelter use both with and without exposure to the chemical and physical cues of predators, and with and without the presence of a conspecific. In addition, we examined if armament, i.e. relative chelae size, would be correlated with individual differences in behaviour. Individuals showed repeatable behaviours across time and context. Individuals that occupied the shelter in competitive dyadic tests also spent more time in the shelter during individual control observations, suggesting that boldness is a personality trait that does not necessarily relate positively to high resource holding potential in the noble crayfish. The relative size of chelae did not correlate with any of the measured behavioural variables. Our results suggest that boldness can be considered as individually consistent and ecologically important personality trait in the noble crayfish.

Abstract: In group-living species, decisions made by individuals may result in collective behaviours. A central question in understanding collective behaviours is how individual variation in phenotype affects collective behaviours. However, how the personality of individuals affects collective decisions in groups remains poorly understood. Here, we investigated the role of boldness on the decision-making process in different-sized groups of barnacle geese. Naive barnacle geese, differing in boldness score, were introduced in a labyrinth in groups with either one or three informed demonstrators. The demonstrators possessed information about the route through the labyrinth. In pairs, the probability of choosing a route prior to the informed demonstrator increased with increasing boldness score: bolder individuals decided more often for themselves where to go compared with shyer individuals, whereas shyer individuals waited more often for the demonstrators to decide and followed this information. In groups of four individuals, however, there was no effect of boldness on decision-making, suggesting that individual differences were less important with increasing group size. Our experimental results show that personality is important in collective decisions in pairs of barnacle geese, and suggest that bolder individuals have a greater influence over the outcome of decisions in groups.

Abstract: In group-living species, decisions made by individuals may result in collective behaviours. A central question in understanding collective behaviours is how individual variation in phenotype affects collective behaviours. However, how the personality of individuals affects collective decisions in groups remains poorly understood. Here, we investigated the role of boldness on the decision-making process in different-sized groups of barnacle geese. Naive barnacle geese, differing in boldness score, were introduced in a labyrinth in groups with either one or three informed demonstrators. The demonstrators possessed information about the route through the labyrinth. In pairs, the probability of choosing a route prior to the informed demonstrator increased with increasing boldness score: bolder individuals decided more often for themselves where to go compared with shyer individuals, whereas shyer individuals waited more often for the demonstrators to decide and followed this information. In groups of four individuals, however, there was no effect of boldness on decision-making, suggesting that individual differences were less important with increasing group size. Our experimental results show that personality is important in collective decisions in pairs of barnacle geese, and suggest that bolder individuals have a greater influence over the outcome of decisions in groups.

Abstract: To examine if a behavioural syndrome is present in juvenile three-spined stickleback Gasterosteus aculeatus from anadromous populations, individuals were repeatedly exposed to a variety of conditions to assess behavioural consistency and determine if a shyness-boldness syndrome occurred. The degree of exploration in a novel environment was positively correlated with boldness in all other test conditions. Activity level in all contexts, foraging, predator inspection and shoaling were found to be repeatable while other behaviours such as latency to respond appeared more plastic. Both similarities and differences were found for behavioural correlations within and across contexts when compared to prior studies on freshwater populations of G. aculeatus. This suggests that selection pressures may vary across ontogeny and environments.

Abstract: We assessed developmental stability and context generalizability of temperament in pigtailed macaques (Macaca nemestrina) from the University of Washington Infant Primate Research Lab. A principal components analysis condensed 6 behavioral measures into 2 components, interpreted as reactivity and boldness. Changes in these measures over the 1st 10 months of development showed a trend toward calmer and bolder behavior with age, with significant individual variation in the pattern of change. Boldness showed a quadratic pattern of change, whereas reactivity decreased linearly. We also studied the relationship between temperament and response to a novelty probe. The magnitude of the response to the novelty probe decreased slightly over time, and boldness and reactivity in a familiar setting did not predict these changes in response to novelty. In a 2nd principal components analysis, reactivity to novelty represented a distinct aspect of temperament. Our results demonstrate developmental changes and context dependency in macaque behavior.

Abstract: Predation is often thought of as an unforgiving and strong selective force, quickly selecting against maladaptive behaviour in the prey. It is argued that experience is likely to have low influence on the phenotypic response to predation, as failing to react correctly to a predator may mean death to the prey and no second chance to learn and correct the behaviour. Individuals from different populations of Eurasian perch are known to differ in risk-taking behaviour. Variation in predation pressure has been suggested as a key factor causing these differences, but little is known about the underlying mechanism by which predation generates risk-taking phenotypes in perch. We compared the degree of boldness between two natural populations of Eurasian perch, living under different predation regimes, and the same populations hatched and reared under identical conditions, free from predation. By this common-garden approach, we sought to investigate patterns in the influence of inheritance and experience on boldness phenotype. The wild fish differed in risk taking, with fish from the low predation-risk population acting bolder than fish from the high-risk environment. In the reared fish, both populations behaved equally bold. Only the fish originating from the high predation population showed different behaviour when comparing wild and reared ecotypes. Our results suggest that experience has an important impact on the response to predators and that geographic variation in risk taking between populations of Eurasian perch to a high degree is shaped by adjustments to the current environment. Habituation had an effect of risk-taking behaviour over the experimental period, but consistent differences between individuals were also found. Furthermore, we also show, by the estimation of variance components, that the behaviour we observe is affected by a range of random effects, such as aquaria and group membership, that in concert shapes the behaviour of an individual perch.

Abstract: Individuals tend to judge personality traits on the basis of physical characteristics, particularly facial traits, although this phenomenon has been mostly studied in relation to the halo effect of attractiveness. However, there are other facial traits which may also have an impact on personality attributions; here, we focused on masculinity. We carried out principal component analysis (PCA) of 15 anthropometric measurements from 71 male faces, resulting in three components: Face Height (C1), Inner Face Breadth (C2), and Cheekbones–Jaw Prominence (C3). The targets’ photographs were rated by 210 women and 177 men on scales for masculinity, attractiveness, and nine psychological characteristics (selected Cattell’s factors): Warmth, Reasoning, Emotional Stability, Dominance, Liveliness, Rule-Consciousness, Social Boldness, Abstractedness, and Privateness. We found that masculinity correlated positively with ratings of Dominance and Social Boldness and that masculinity rated by men correlated positively with ratings of Emotional Stability and Privateness. We found no relationship between masculinity rated by women and the PCA components, while masculinity rated by men correlated negatively with C2 (possibly related to babyface features) and positively with C3 (which included features developed under the control of testosterone, such as jaw prominence). Our results imply sex differences in masculinity ratings. In particular, men used Cheekbones–Jaw Prominence and Inner Face Breadth as cues for masculinity judgments; on the other hand, women apparently perceive masculinity in a more holistic way.

Abstract: Considering the high costs of sexual reproduction (e.g., the production of males), its maintenance and predominance throughout the Animal Kingdom remain elusive. Especially the mechanisms allowing for a stable coexistence of closely related sexual and asexual species are still subject to a lively debate. Asexuals should rapidly outnumber sexuals due to higher population growth rates, unless they face some disadvantages. Here, we investigate potential differences in feeding behavior in a system of sexual (sailfin mollies, Poecilia latipinna) and coexisting gynogenetic fishes (Amazon mollies, Poecilia formosa). In two different experiments, we tested for differences in behavioral traits associated with boldness. Bold individuals take higher risks for gains in resources, so shyer individuals should be less competitive. Our study was motivated by the recent finding that P. formosa are less likely to be preyed upon by piscine predators than P. latipinna. We asked whether this result is indicative of low boldness in P. formosa. However, no differences between the two species were detectible in our behavioral experiments measuring (a) time to emerge from shelter to explore a novel environment, (b) latency time until feeding in a novel environment, and (c) recovery time until feeding restarted after a simulated predator attack. Furthermore, different boldness measures were not correlated with each other within individuals.

Abstract: Behavior can explain population-level processes such as dispersal, yet connecting a specific behavioral phenomenon with a larger ecological pattern is often speculative rather than supported by experimental studies. We investigate how exploratory behavior may develop in the killifish, Rivulus hartii through association with another taxon, the guppy, Poecilia reticulata. We hypothesize that exploratory behavior is enhanced by nearby guppies, which embolden Rivulus to move along the river edge, through zones of high predation risk. We tested individual boldness in the presence of both guppies and conspecifics. We also tested for the effect of prior experience with guppies, comparing boldness in Rivulus from locations in which it was either allopatric to or sympatric with guppies. Guppies increased boldness in Rivulus, equivalent to the effect of conspecifics, and prior experience with guppies also increased boldness over that of inexperienced Rivulus. Sympatric Rivulus were shy compared with the allopatric ones when each was tested alone, but this relationship reversed when guppies were present, showing that boldness is a plastic trait that can be influenced by the population of origin. An experimental field-stream test showed that guppies increased movement of Rivulus under predation threat, supporting links in a conceptual framework that connects a behavioral phenomenon, exploratory boldness, with a larger ecological pattern, selection of favorable habitats that, in turn, can lead to increased reproduction and fitness relative to non-dispersers.

Abstract: Animals colonizing urban habitats are often noticeably bold in the presence of humans, and such boldness is typically thought to arise as urban individuals habituate to the repeated presence of humans. However, recent studies in animal behavior suggest that: 1) boldness may be an inherent trait as opposed to a learned behavior and 2) some individuals exhibit behavioral syndromes that restrict behavioral plasticity, and may limit an individual’s ability to adapt to environmental change. In a recent study, we examined differences in urban and rural populations of song sparrows and confirmed that urban birds were bolder toward humans, but also, this boldness was correlated with higher levels of territorial aggression. This study also examined the correlation between testosterone, a hormone associated with aggression in birds, and variation in aggression and boldness in urban and rural song sparrows (Melospiza melodia). Despite significant differences in aggression and boldness between urban and rural populations, this study found no evidence of differences in testosterone between the two populations. It is possible that other mechanisms (e.g. sensitivity to circulating testosterone) may be involved, and further examination into these possibilities will provide better understanding of these behavioral differences.

Abstract: BEHAVIORAL SYNDROMES IN JUVENILE DASCYLLUS TRIMACULATUS (THREE-SPOT DASCYLLUS) IN MO’OREA, FRENCH POLYNESIA: INDIVIDUAL VARIATION IN SHYNESS/ BOLDNESS T ESS A. P ARKHOUSE Integrative Biology, University of California, Berkeley, California 94720 USA Abstract. Behavioral syndromes can provide an evolutionary advantage because they allow a population to quickly adapt to dynamic selective pressures. This study used field manipulations to determine whether a behavioral syndrome is present in juvenile Dascyllus trimaculatus. Within- and between- individual consistency was found in individuals' responses to a predator model, a non-predator model, and a novel object. These tests were completed in the wild in Mo’orea, French Polynesia and filmed for further analysis. Behavioral syndromes are shaped by a wide array of factors, so studies in this topic contribute both to a better understanding of a species’ behavior, as well as the selective pressures it faces. Key words: animal behavior; Dascyllus trimaculatus; behavioral syndromes; individual variations; bold/shy continuum; Mo’orea, French Polynesia I NTRODUCTION Behavioral responses differ between individuals in a species or population, which can provide crucial understanding about the selective pressures that shape behavior (Dzieweczynski et al. 2011). Individuals in a given population must trade off potential risks (e.g., exploring a novel object, defending territory from a threat) for possible gains in resources (Scharnweber et al. 2011). Research in various animal taxa, including mammals, birds, reptiles, amphibians, fish, arachnids, crustaceans, insects, and cephalopods, has shown that there are consistent differences in behavioral patterns between individuals (Smith 2008). Dynamic selective pressures maintain individual variation, allowing species or populations to better adapt to their environment and reduce the risk of extinction (Smith 2008). Therefore, the study of individual variations in behavior, called behavioral syndromes, is a key aspect of both behavioral and conservation biology. Previous studies have shown that individuals may vary in the level of risk they will take along a bold/shy continuum (Scharnweber et al. 2011). This trait, like many others, is represented as a continuum with two extremes represented as tendencies. Boldness represents the way an individual reacts to a risky situation. In this trait, “bold” and “shy” are two extremes rather than different traits (Reale et al. 2007). These variations in boldness may be a result of a wide array of abiotic or biotic factors, including limited habitable space, increased predator density, amount of food available, etc. When there are correlations between an individual’s behavior across multiple contexts or situations, a behavioral syndrome is thought to exist (Sih et al. 2004b). The presence of a behavioral syndrome is significant because it indicates limited plasticity that carries over to multiple contexts, and shows the significance of behavioral variation for the survival of a population (Sih et al. 2004a).

Abstract: Animals need to make constant decisions throughout their lives and to make optimal decisions individuals rely on information. Information can be obtained in two distinct ways: personal or social information. The current paradigm in the information theory use in animal ecology assumes that the decision between using either personal or social information is entirely flexible and context dependent. However, the potential link between variation in personality and information use has received little attention. In this thesis I studied the effect of personality on the use of personal and social information in barnacle geese. I show that individual barnacle geese differ consistently in boldness and that boldness affects the type of information individuals use in various different contexts: In a maze solving task, a producer scrounger game and a public information experiment I found that bold individuals use less social information compared to shy individuals, providing strong evidence that the type of information individuals prefer to use depends on their boldness level. To study the ultimate causes of variation in boldness and the relationship between boldness and social information use I used an experimental and theoretical approach. In a producer scrounger experiment I tested whether the rare personality type outperformed the common personality type which could lead by means of negative frequency dependent selection to the maintenance of variation in boldness. Parallel to that I used a genetic algorithms approach to study the co-evolution of boldness and foraging tactic use in a producer scrounger game. The experimental results as well as the genetic algorithms provided no evidence for a role of negative frequency dependent selection for the maintenance of variation in boldness. Rather, our simulations suggest that differences in selection pressures in space or time (i.e., fluctuating environments) in a social foraging game may cause variation in boldness levels between populations. In our simulations bold individuals evolved to play both producer and scrounger, whereas shy individuals remained confined to scrounging, suggesting that shy individuals have difficulties when they have to collect personal information and that this might be the explanation for the increased tendency of shy individuals to use social information. I experimentally confirmed these model predictions in an experiment in which I forced individuals in either a producer or a scrounger role. Therefore, I argue that the value of social information is higher for shy individuals as compared to bold individuals since it is more costly for shy individuals to collect personal information. This thesis challenges the current paradigm that the decision between using either personal or social information is entirely context dependent. Rather, I provide evidence that personality affects the trade off between using personal and social information.

Abstract: Animals in urban habitats face a number of unique stresses, including the necessity of dealing with high levels of human activity. Growing research suggests that: (1) inherent traits, as opposed to learned behavior, influence which species invade urban habitats, and (2) individuals exhibit behavioral syndromes that limit behavioral flexibility. As a result, perhaps only animals with inherently bold personalities successfully settle in areas of high human activity, and such animals may also exhibit correlated variation in other behavioral traits, such as territorial aggression. In this study, we examine boldness and aggression in several urban and rural populations of song sparrows (Melospiza melodia). We found that urban birds were both bolder toward humans and also showed higher levels of aggression. We found a correlation between boldness and aggression in all populations combined, but no correlation within urban populations. Our results agree with other recent studies of song sparrow behavior, suggesting that greater boldness and aggression are general features of urban song sparrow populations, and a lack of a correlation between boldness and aggression in urban habitats is a general phenomenon as well. Urban habitats may select for bold and aggressive birds, and yet the traits can vary independently. These results add to a small number of studies which find that behavioral syndromes break down in potentially high quality habitats.

Abstract: The main aims of this study were to investigate (1) the occurrence and strength of the shyness–boldness behavioural syndrome in brown trout fry, (2) whether this syndrome is associated with paternal migratory life history, (3) whether fry survival and growth in the wild is associated with paternal life history and/or boldness and (4) whether offspring performance showed maternal effects. Nine female migratory trout were each crossed with one migratory and one resident male and the offspring were raised in hatchery tanks until first feeding. The behavioural studies showed that fry that responded bold towards a novel object also accepted a novel food item earlier and responded more aggressively towards their own mirror image. Principal component analysis showed that this shyness–boldness syndrome (PC1) explained 34% of the behavioural variation. Offspring boldness was not affected by paternal migratory life history, but significant effects of the female parent suggested maternal and/or genetic effects. Deviations from this pattern (PC2), where some individuals behaved less aggressively and performed more approaches to food, explained an additional 17% of the variation in behaviour, and was significantly influenced by length and paternal migratory life history. Fry growth and survival in nature was not associated with boldness (PC1) or PC2, suggesting that alternative behavioural strategies can be successful in nature. However, female parent effects on variation in fry size persisted over the first growth period in the wild, suggesting that these effects may influence offspring fitness during early life when major selection occurs.

Abstract: Little is known about the factors causing variation in behavioural plasticity and the interplay between personality and plasticity. Habituation to predators is a special case of behavioural plasticity. We investigated the direct and indirect effects of boldness, exploration and sociability traits on the habituation ability of Iberian wall lizards, considering exposure and sex effects. Individual boldness was consistent across several non-habituation contexts, but it did not significantly affect habituation. Exploration had a strong direct effect on habituation, with more exploratory individuals being able to habituate faster than less exploratory ones, probably because of their ability to assess risk better. Individual variation in habituation was also affected by sociability, but this was an indirect effect mediated by exposure to the predator. Less social individuals avoided refuges with conspecific cues, increasing exposure to the predator and eventually habituation. Finally, the direct effects of sex (females habituated faster than males) were opposite to its indirect effects through exposure. We conclude that risk assessment, instead of the proactivity–reactivity gradient usually considered in the literature, can affect behavioural plasticity through complex interactions between direct and indirect effects, including exploratory behaviour, degree of exposure to the predator and sex, which represent novel mechanisms generating inter-individual variation in plasticity.