Bold Individuals Research Articles

Welcome to the Dark Side: Partial Nighttime Illumination Affects Night-and Daytime Foraging Behavior of a Small Mammal

Differences in natural light conditions caused by changes in moonlight are known to affect perceived predation risk in many nocturnal prey species. As artificial light at night (ALAN) is steadily increasing in space and intensity, it has the potential to change movement and foraging behavior of many species as it might increase perceived predation risk and mask natural light cycles. We investigated if partial nighttime illumination leads to changes in foraging behavior during the night and the subsequent day in a small mammal and whether these changes are related to animal personalities. We subjected bank voles to partial nighttime illumination in a foraging landscape under laboratory conditions and in large grassland enclosures under near natural conditions. We measured giving-up density of food in illuminated and dark artificial seed patches and video recorded the movement of animals. While animals reduced number of visits to illuminated seed patches at night, they increased visits to these patches at the following day compared to dark seed patches. Overall, bold individuals had lower giving-up densities than shy individuals but this difference increased at day in formerly illuminated seed patches. Small mammals thus showed carry-over effects on daytime foraging behavior due to ALAN, i.e., nocturnal illumination has the potential to affect intra- and interspecific interactions during both night and day with possible changes in personality structure within populations and altered predator-prey dynamics.

Capture vulnerability of sea turtles on recreational fishing piers.

Capture vulnerability of commercial and recreational fishes has been associated with behavioral, morphological, and life‐history traits; however, relationships with non‐target species, such as sea turtles, have not been adequately studied. We examined species composition, timing of captures, morphological variables including body size and head width, and body condition of sea turtles captured from a recreational fishing pier in the northern Gulf of Mexico and of sea turtles captured in the waters adjacent to the pier. From 2014 to 2019, 148 net captures and 112 pier captures of three sea turtle species were documented. Green turtles were captured most frequently in the net and on the pier. Turtles captured from the pier were larger than those captured in the net. There was no difference in head width between net‐caught and pier‐caught turtles; however, small sample sizes limited those comparisons. The body condition index was lower for pier‐caught than net‐caught Kemp’;s ridleys but did not differ with green turtles or loggerheads. Differences were also observed in the timing of capture on the pier as compared to in the net. Finally, the relationship between size, body condition, and pier‐capture vulnerability suggests these are complex interactions. Mortality of sea turtles captured from fishing piers could be selecting against bolder individuals, which may result in changes in sea turtle population demographics over a long time period.

Individuality in flounder ( Paralichthys olivaceus ): Differential responses of immune–endocrine during temperature stress in head kidney

Individual differences in behaviour and reactions to various environmental stress stimulus could reflect substantial differences in coping patterns among animals, including immune–endocrine responses. However, few studies have been conducted in this domain. In this study, two types of flounder (Paralichthys olivaceus) (bold individuals (BI) and shy individuals (SI)) were screened out and the expression of genes related to the immune–endocrine was in their head kidneys under temperature stress. BI and SI had the long-term and stable differential expression of IRAF6 (tumour necrosis factor receptor-associated factor 6), IL10 (Interleukin 10) and UII (urotensin Ⅱ) genes in the head kidney at optimum temperature (18℃). During acute hypothermal stress, the SI inflammatory gene TNFα (tumour necrosis factor-α) was significantly downregulated, and IL6 (interleukin 6) and IL10 (interleukin10) were significantly upregulated. In acute hyperthermal stress, the SI inflammatory genes TNFα and IL6 were significantly downregulated, while IL10 continued to be significantly upregulated. Immune genes in BI showed no significant changes under acute temperature stress. We found that endocrine genes CRH (corticotropin-releasing hormone), UI (Urotensin I) and UII showed opposite expression patterns in the head kidney of BI and SI after temperature stress. Meanwhile, gene expression of Hsp70 (heat shock protein 70) responded to hypothermal stress only in SI but not in BI, indicating that Hsp70 is involved in resistance to hypothermal stress only in SI. Through the correlation analysis of the genes discovered in this study, there is an opposite correlation between the part of endocrine–immune genes of BI and SI. It indicates differences in the regulatory mechanisms of the immune and endocrine systems in the head kidney of BI and SI under temperature stress.

Gerbils from populations located in low vegetation habitats emerge later than those from more densely vegetated habitats

How personality changes across different populations is still a poorly studied topic. We compared Allenby’s gerbils (Gerbillus andersoni allenbyi) from three different populations in the Negev Desert regarding their latency to emerge from a shelter and explore new environments. These three localities represented a gradient of vegetation cover (Kmehin < Shivta Dunes < Shivta Flats) and thus of predation risk. Furthermore, two populations were in sand dunes (Kmehin and Shivta Dunes) and the other in sandy flats. We expected individuals from the same population to show the similar latency, and to differ from that of the other localities. We collected five individuals from Kmehin, 10 in Shivta Dunes, and 12 in Shivta Flats. We tested their latency 3 times in two different contexts (a lit chamber, and the same chamber darked). We found latency to be repeatable in both contexts. Using a generalized linear mixed model, we found support for an interaction between context and site and sex and site. Kmehin individuals had much longer latency in the light than all other combinations, and males had much longer latency in the first period. This supports the hypothesis that different locations can have consistent population phenotypes. We discuss how this effect may be caused by different quantities of predators or different numbers of bold individuals within each population.

Parental personality influence offspring performance traits in olive flounder (Paralichthys olivaceus)

In animals, personalities have demonstrated links to behavioral traits, health and disease susceptibility, and welfare. These performance differences are more obvious under environmental stress. Previous studies have shown that animal personality is heritable. However, it is still unclear whether there will be differences in the performance traits of the offspring of flounders with different personalities (OFDP). In this study, we measured the weight and length of OFDP at 25 days-post-hatch (DPH) and 50 DPH. The offspring of bold individuals (OB) were heavier than the offspring of shy individuals (OS). Temperature tolerance (4 °C, 18 °C and 28 °C) and disease resistance (bacteria half lethal concentration) of larvae at 25 DPH and 50 DPH of OB and OS were investigated, and OB had a higher survival rate than OS at both 4 °C, 18 °C and Vibrio anguillarum (Va) exposure. 20 microsatellite markers related to growth rate, temperature tolerance, and disease resistance traits were used to analyze the variability of microsatellites and the possible relationship with OFDP. 16 microsatellites were correlated with the personality of flounder, and they had significant differences between OB and OS. The polymorphic microsatellite loci with the most significant correlation with growth, heat tolerance, and disease resistance were selected and sequenced. The microsatellite sequence comparison indicated that the microsatellite molecular composition of the OB was related to some better performance traits. These results add to the knowledge base available to olive flounder aquaculture and suggest that OB presents advantages for production purposes and provides valuable insights for fish personality selective breeding.

The individuality affects the hormone secretion of the caudal neurosecretory system (CNSS) and correlation with respiratory metabolism, spontaneous activity and appetite in olive flounder (Paralichthys olivaceus)

In farmed animals, individuality have demonstrated links to performance traits, health and disease susceptibility, and animal welfare. This research aims at exploring whether there are differences in the secretion of hormones in the caudal neurosecretory system of different individuailty, and investigating whether it is related to physiological behaviors. In the experiment we selected through multiple behavioral tests two types of olive flounders, bold individuals (BI) and shy individuals (SI), and found that they differed in behavior and physiology. The standard metabolic rate, maximum metabolic rate, and absolute aerobic scope of BI were markedly higher than those of SI. Additionally, the swimming speed of BI was also higher than that of SI in the natural photoperiod. BI and SI showed distinct coping styles to deal with acute stress. Overall, the number of Dahlgren cells secreting UI, the relative UI and CRH mRNA expression in the caudal neurosecretory system (CNSS) of SI was relatively higher than that in BI. By contrast, the number of Dahlgren cells secreting UII and the mRNA expression of UII was lower than that of BI. Through the correlation analysis, it was found that there were some differences in hormone secretion among different individuality groups, which indicated individuality affected hormone production and the number of secretion cells and existed correlation with respiratory metabolism, spontaneous behavior, appetite. It means differences in the regulation mechanism of the flounders in BI and SI.

Feeding strategy changes boldness and agonistic behaviour in the swimming crab ( Portunus trituberculatus )

Agonistic behaviours and cannibalism are key factors that restrict increases in the production of crab aquaculture. To explore the effects of feeding strategies on the boldness, agonistic behaviour and physiological response of swimming crab (Portunus trituberculatus), three treatment groups were established (feeding once a day:S0, every 3 days: S3 and every 6 days:S6). The intensity and duration of fighting, and agonistic behaviours were compared. The hepatosomatic index and the concentration of glycogen, glucose and lactate were also measured. The main results were as follows: (1) With an increase in time between feeding, boldness, duration and intensity of fighting increased first, then decreased, reaching a maximum in the S3 group, and this was significantly higher than in the S6 group. (2) Agonistic behaviour increased first and then decreased. The ‘move to’, ‘cheliped display’ and ‘contact behaviours’ of crabs in the S3 group were significantly higher than the S6 group; (3) Before fighting, with the increase in feeding time, the hepatosomatic index, glycogen and glucose concentration of crabs decreased, and these indicators were significantly higher in the S0 group than in the S6 group. (4) After fighting, the glucose and lactate concentrations were significantly greater than those before fighting. These results suggest that both boldness and feeding strategy can affect the agonistic behaviour of crab. Short-term reductions in food resources promoted inter-individual fighting, and bold individuals were more likely to win battles. However, a long-term decrease in food resources reduced fighting among individuals.

Animal personality drives individual dietary specialisation across multiple dimensions in a mammalian herbivore

Abstract Animal personality influences how individuals perceive and react to different stimuli, such as food quality and predation risk, thereby shaping foraging behaviour. As a consequence, animal personality is predicted to influence the diet and dietary specialisation of individuals within a population, but animal personality and dietary specialisation have yet to be linked. Here, we tested whether individual diet and dietary specialisation are a function of animal personality, using an arboreal herbivore, the common brushtail possum, as a model species. We hypothesised that proactive individuals have more diverse foraging opportunities than reactive individuals. We therefore predicted that proactive animals (more exploratory, bold and more active) would be less specialised, with a broader and higher quality diet than their reactive counterparts. We quantified the personality traits and dietary niche using proportional similarity index and specialisation categories of possums (n = 30) in a population flanking native eucalypt woodland and residential gardens in suburban Sydney, Australia. We found that personality traits were related to the breadth and quality of the realised diets of individual possums. As predicted, proactive individuals had a broad, high‐quality diet with less individual dietary specialisation than reactive individuals. Highly exploratory individuals had a more diverse diet than less exploratory individuals, and bold individuals were more likely than shy individuals to consume plants on the ground. Our study demonstrates an important link between animal personality and individual dietary specialisation. The finding that the personality of individuals is associated with different diet choices within the same landscape is fundamentally significant. First, personality as a driver of niche partitioning likely reduces within‐species competition and hence could contribute to adaptive capacity. Second, the strength of ecological processes arising from interactions (e.g. predator–prey and plant–herbivore interactions) could differ among individuals according to their personality traits. Our findings are also relevant for effectively managing both threatened native and invasive species. Management strategies will be improved by incorporating knowledge of individual traits and their ecological consequences, plus the ecological context of food‐ and fear‐scapes. A free Plain Language Summary can be found within the Supporting Information of this article.

Linking personality and health to use of space in the gray partridge: perspectives for management

Behavioral adjustments are of critical importance for the survival of animals when exposed to risk and resource variations in their environment. Moving to safer habitats allows prey to reduce the risk of mortality triggered by predation. This response has been well studied at the population level to assist in identifying key habitat components for wildlife conservation. However, while individuals may differ in their response to risk and thus in their survival expectancy, the determinants of individual adjustments in space and habitat use are largely unknown in management and conservation studies. Using GPS monitoring, we investigated the relationship between individual traits (morphometry, personality, health status) and adjustments in the use of space relative to risky features (hedgerows, roads/tracks, woodlands, built-up areas) with regard to predation risk. We used the gray partridge (Perdix perdix) as a study model (captive-reared birds released into the farmlands). During the diel cycle, predation risk mainly occurs by carnivores at night, whereas human hunting pressure occurs during the day. We found that personality and health status had an effect on adjustments in the use of space as response to risky features. At night, when carnivore activity is expected to be high, bolder individuals were farther from hedgerows relative to the day. Similarly, individuals in good health were located farther from hedgerows, roads/tracks, and woodland at night relative to the day. We discuss the need for better consideration of individual traits in management and conservation programs, with a particular focus on recovery programs that rely on translocation of captive-reared individuals.

Differential gene expression associated with behavioral variation in ecotypes of Lake Superior brook trout (Salvelinus fontinalis)

Associations between behaviors and the development of different life history tactics have been documented in several species of salmon, trout, and charr. While it is well known that such behaviors are heritable the genes and molecular pathways connected to these behaviors remain unknown. We used an RNA-seq approach to identify genes and molecular pathways differentially regulated in brain tissue between “shy” and “bold” brook trout (Salvelinus fontinalis). A small number of genes were differentially expressed between the behavioral types at several months after hatching and two years of age. Pathway analysis revealed that EIF2 signaling differed consistently between shy and bold individuals suggesting large-scale differences in protein synthesis between behavioral types in the brain. Additionally, the RNA-seq data were used to find polymorphisms within the brook trout genome and a GWAS approach was used to test for statistical associations between genetic variants and behavior type. One allele located in a transcription factor (TSHZ3) contained a protein-coding non-synonymous SNP suggesting that functional variation within TSHZ3 is connected to the development of different behaviors. These results suggest that the molecular basis of behavioral development is complex and due to the differential expression of many genes involved in a wide-range of different molecular pathways.

Reproductive aging and pace-of-life syndromes: more active females age faster

Abstract A common pattern of reproductive aging is that reproductive performance increases during early life and reaches a peak, followed by a decline with age. Such quadratic reproductive aging patterns can differ among individuals. Moreover, if individual differences in reproductive aging patterns reflect individual-specific life-history trade-off strategies, they are also predicted to be associated with behavior according to the pace-of-life syndrome. For example, more active, aggressive, or bolder individuals may invest more in early reproduction, resulting in more rapid reproductive aging. In this study, we estimated individual differences in quadratic reproductive aging patterns and the relationship between reproductive aging and the activity of the virgin female bean bug (Riptortus pedestris) in the absence of mating costs. We found that the egg production of virgin females followed a parabolic trajectory with age and that individuals varied significantly in their quadratic reproductive aging patterns. In addition, we found that females that were relatively more active during early life invested in egg production more heavily at a young age and suffered from a sharper decline in egg production later in life. Thus, our results indicate that individual reproductive aging patterns may be a key component in the study of pace-of-life syndromes. We suggest that within-individual plastic characteristics of life-history traits such as reproductive aging patterns may explain the mixed results from multiple studies on pace-of-life syndromes.

Transcriptomics reveals that the caudal neurosecretory system in the olive flounder (Paralichthys olivaceus) is more responsive in bold individuals and to chronic temperature change

In farmed animals, personalities have demonstrated links to performance traits, health and welfare, disease susceptibility, and to coping with environmental stress. The teleost caudal neurosecretory system (CNSS) of the posterior spinal cord is involved in the regulation of the osmoregulatory and stress responses and can directly sense a hypothermal challenge via a transient receptor potential ion channel. Here we investigated the global transcriptomic response of the CNSS of shy and bold individuals of the olive flounder (Paralichthys olivaceus) acclimated to 18 °C and transferred to 12 °C (low temperature treatment, LT) or 24 °C (high temperature treatment, HT) for 2 h (acute) or 8 days (chronic) in relation to fish maintained at 18 °C (control). Overall, differential transcriptomic responses were stronger in bold individuals and induced by acute HT and chronic LT treatments. Acute HT induced innate immunity, circadian rhythm, and cellular stress response pathways and, specifically in bold individuals, a heightened response of molecular chaperones of cellular response to heat which may be related to the mechanisms of rescue of downregulated RNA splicing processes. Chronic LT also caused downregulation of innate immunity pathways as well as pathways related to cell division. In addition, the CNSS of bold individuals was enriched in pathways related to regulation of cell cycle, adaptive immune response, and apoptosis, while cellular metabolism pathways were downregulated in shy individuals. The putative temperature sensor genes Trpv1 and Trpa1 were upregulated, respectively, after acute HT and chronic LT treatments, but there was no indication of a specific neurosecretory response of the CNSS. While several of the observed transcriptomic responses to temperature appear to be shared by other tissues and species, it is also clear that bold and shy behavioural personalities show marked different responses, with bold individuals the most responsive. These results add to the knowledge base available on olive flounder aquaculture, indicating a differential role of the CNSS in the response to temperature change according to behavioural personalities.

Social boldness correlates with brain gene expression in male green anoles

Within populations, some individuals tend to exhibit a bold or shy social behavior phenotype relative to the mean. The neural underpinnings of these differing phenotypes – also described as syndromes, personalities, and coping styles – is an area of ongoing investigation. Although a social decision-making network has been described across vertebrate taxa, most studies examining activity within this network do so in relation to exhibited differences in behavioral expression. Our study instead focuses on constitutive gene expression in bold and shy individuals by isolating baseline gene expression profiles that influence social boldness predisposition, rather than those reflecting the results of social interaction and behavioral execution. We performed this study on male green anole lizards (Anolis carolinensis), an established model organism for behavioral research, which provides a crucial comparison group to investigations of birds and mammals. After identifying subjects as bold or shy through repeated reproductive and agonistic behavior testing, we used RNA sequencing to compare gene expression profiles between these groups within various forebrain, midbrain, and hindbrain regions. The ventromedial hypothalamus had the largest group differences in gene expression, with bold males having increased expression of neuroendocrine and neurotransmitter receptor and calcium channel genes compared to shy males. Conversely, shy males express more integrin alpha-10 in the majority of examined regions. There were no significant group differences in physiology or hormone levels. Our results highlight the ventromedial hypothalamus as an important center of behavioral differences across individuals and provide novel candidates for investigations into the regulation of individual variation in social behavior phenotype.

Flexible behaviour in a mesopelagic fish (Maurolicus muelleri)

Abstract Variability of mesopelagic scattering layers is often attributed to environmental conditions or multi-species layer composition. Yet, little is known about variation in behaviour among the individuals forming scattering layers. Based on a 10 months high-resolution dataset from stationary echosounders in a Norwegian fjord, we here assess short-term and long-term behaviour of a single mesopelagic fish species, the pearlside Maurolicus muelleri. The daytime vertical extension of the monospecific pearlside scattering layers spanned four orders of magnitude ambient light in the autumn and winter and less than one order of magnitude in summer. While the main layers tracked relatively stable light levels over daytime, some individuals actively crossed light gradients of up to 1.5 orders of magnitude. This included individuals that moved between scattering layers, and apparently bold individuals that made regular upward excursions beyond the main population distribution. During the daytime, M. muelleri mitigated the risk of predation by forming tight groups in the upper scattering layer and, at light levels &amp;gt;10−6 µmol m−2 s−1, by instantly diving into deeper waters upon encounters with predators. Our observations suggest that individual, and probably state-dependent, decisions may extend the pearlsides’ vertical distribution, with implications for predator–prey interactions.

Towards understanding bold behaviour of large carnivores: the case of brown bears in human‐modified landscapes

AbstractHuman–wildlife conflicts sometimes involve bold animals that do not fear humans and their activities. Such behaviour is detrimental to both wildlife and people and may lead to conflicts, which can be especially serious for large carnivores. Like most wildlife, these species have adapted to live in highly humanized landscapes by adopting human avoidance behaviours. However, bold individuals exist, which represent a main cause of conflicts, public fear and negative attitudes, that greatly influence management and conservation actions. Although costly decisions are constantly made to deal with such individuals, evidence‐based knowledge of their behaviour, that is how and when they move, especially in relation to human activities, is lacking. We analysed telemetry data of brown bears (Ursus arctos) that were GPS‐collared across Slovenia and Trentino (Italy) to explore spatial behaviour and rhythms of activity of bears that were identified as bold by managers and to assess if and how their behaviour differs from that of their ‘non‐bold’ conspecifics (hereafter, control individuals). Because other factors such as sex and age of the bear, season, daytime and region may affect behaviour, we also included these variables in our analyses. On one hand, bold bears were more active at the daytime and used open areas considerably more often than control bears. On the other hand, although differences in distance to settlements and roads, movement rates and daily home ranges were also found, they were not as pronounced as expected. Instead, other factors were found to affect bear behaviour and, most importantly, we found strong inter‐individual differences in all behaviours. Such results suggest that, although bold bears have some behavioural attributes in common that distinguish them from control bears, each individual differs from one another. Our study represents a first step towards understanding bold bears’ behaviour and provide novel evidence‐based knowledge that can help to better know and manage these individuals.

Suppression of personality variation in boldness during foraging in three-spined sticklebacks

Consistent inter-individual variation in behaviour within a population, widely referred to as personality variation, can be affected by environmental context. Feedbacks between an individual’s behaviour and state can strengthen (positive feedback) or weaken (negative feedback) individual differences when experiences such as predator encounters or winning contests are dependent on behavioural type. We examined the influence of foraging on individual-level consistency in refuge use (a measure of risk-taking, i.e. boldness) in three-spined sticklebacks, Gasterosteus aculeatus, and particularly whether changes in refuge use depended on boldness measured under control conditions. In the control treatment trials with no food, individuals were repeatable in refuge use across repeated trials, and this behavioural consistency did not differ between the start and end of these trials. In contrast, when food was available, individuals showed a higher degree of consistency in refuge use at the start of the trials versus controls but this consistency significantly reduced by the end of the trials. The effect of the opportunity to forage was dependent on behavioural type, with bolder fish varying more in their refuge use between the start and the end of the feeding trials than shyer fish, and boldness positively predicted the likelihood of feeding at the start but not at the end of the trials. This suggests a state-behaviour feedback, but there was no overall trend in how bolder individuals changed their behaviour. Our study shows that personality variation can be suppressed in foraging contexts and a potential but unpredictable role of feedbacks between state and behaviour.Significance statementIn this experimental study, we examined how foraging influences consistency in risk-taking in individual three-spined sticklebacks. We show that bolder individuals become less consistent in their risk-taking behaviour than shyer individuals during foraging. Some bolder individuals reinforce their risk-taking behaviour, suggesting a positive feedback between state and behaviour, while others converge on the behaviour of shyer individuals, suggesting a negative feedback. In support of a role of satiation in driving negative feedback effects, we found that bolder individuals were more likely to feed at the start but not at the end of the trials. Overall, our findings suggest that foraging can influence personality variation in risk-taking behaviour; however, the role of feedbacks may be unpredictable.

Heritability of animal individuality in fish: Distribution, behavior, metabolism and stress response

Animal individuality is proposed to describe individual differences in behavior. Individuals may exhibit consistent differences in behavioral traits within a population, and these traits are heritable. It has also been known that animal individuality can be attributed to both genetic and environmental effects. We previously observed the presence of bold individuals (BI) and shy individuals (SI) in olive flounder (Paralichthys olivaceus). However, the individuality distribution and the behavioral phenotype of offspring with different individualities remain unclear. In this study, the temperature and acidity challenges of larvae at 25 days-post-hatch (DPH) and juvenile (50 DPH) of bold and shy flounder offspring were investigated at pH = 7.3, 7.7, 8.1 and temperature at 4, 18, 28 °C. On 25 DPH, bold offspring (BO) showed higher survival rates with acidity at pH = 7.3 and 4 °C challenge. Three behavioral phenotypes (bold, middle and shy individuals, BI, MI and SI) were observed in both juvenile (8 MPH) bold and shy flounder offspring. The percentage of SI offspring from the shy maternal line (SS) was higher than BI offspring from the bold maternal line (BB) (0.75 vs. 0.58). BI from both BO (BB) and SO (SB) were more motivated to feed and active during net confinement than SI (BS and SS). Furthermore, BB and SB exhibited higher metabolic rates and actively responded to predator stressor, while BS and SS showed a divergent tendency. However, the metabolism of the offspring seemed to be partially affected by their maternal line. Taken together, our study indicates that screening of animal individuality in population would improve animal welfare and increase the output efficiency of flounder in aquaculture.

Temperament and sexual behaviour in the Furrowed Wood Turtle Rhinoclemmys areolata.

The variation in temperament among animals has consequences for evolution and ecology. One of the primary effects of consistent behavioral differences is on reproduction. In chelonians some authors have focused on the study of temperament using different methods. In our research our first aim was i) establish a methodology to determine the degree of boldness among individuals Rhinoclemmys areolata. Our second aim was to ii) determine the role boldness plays during reproduction, with emphasis on courtship and copulation, considering a) the interactions between males and females, and b) competition between males. We used 16 sexually mature individuals of each sex. Males were observed in four different situations and 17 behavioral traits were recorded. We selected 12 traits that allowed us distinguish between the bolder and the shier individuals and found that five behavioral traits were specific for bolder individuals and five others for shier individuals. In a second step, we observed a male in presence of a female and recorded courtship behaviors and breeding attempts. Bolder individuals did not display courtship behaviors and just attempted to copulate. Shier individuals displayed courtship behaviors and copulation attempts were rarely observed. Finally, in the simulations that compared two males in the presence of a female we noticed that bolder individuals displayed courtship behaviors while the shier ones simply ignored the female. Our results first allowed us to determine which methodology is the best to determine temperament in turtles. Secondly, temperament seems to be an important factor in modulating interaction between males and females. Bolder individuals have an advantage during competition and display courtship behaviours only if other males are present. Shier males displayed courtship behaviors and only try to copulate when no competitors were present. These two different temperament-dependant strategies are discussed in terms of ecology, evolution and management.

Personality-specific carry-over effects on breeding.

Carry-over effects describe the phenomenon whereby an animal's previous conditions influence its subsequent performance. Carry-over effects are unlikely to affect individuals uniformly, but the factors modulating their strength are poorly known. Variation in the strength of carry-over effects may reflect individual differences in pace-of-life: slow-paced, shyly behaved individuals are thought to favour an allocation to self-maintenance over current reproduction, compared to their fast-paced, boldly behaved conspecifics (the pace-of-life syndrome hypothesis). Therefore, detectable carry-over effects on breeding should be weaker in bolder individuals, as they should maintain an allocation to reproduction irrespective of previous conditions, while shy individuals should experience stronger carry-over effects. We tested this prediction in black-legged kittiwakes breeding in Svalbard. Using miniature biologging devices, we measured non-breeding activity of kittiwakes and monitored their subsequent breeding performance. We report a number of negative carry-over effects of non-breeding activity on breeding, which were generally stronger in shyer individuals: more active winters were followed by later breeding phenology and poorer breeding performance in shy birds, but these effects were weaker or undetected in bolder individuals. Our study quantifies individual variability in the strength of carry-over effects on breeding and provides a mechanism explaining widespread differences in individual reproductive success.

Geographical personality gradient in herbivorous animals: Implications for selective culling to reduce crop damage

AbstractTraditional lethal techniques used to mitigate wildlife damage have targeted entire populations through the use of random harvesting. However, recent literature has suggested that controlling population size by random harvesting is not the only mean to mitigate human‐wildlife conflicts. Controlling problem individuals may also be important because individuals with behavioral characteristics such as greater boldness and low neophobia are predicted to cause more damage to crops. Reducing the number of bold individuals may therefore mitigate crop damage, but a method to selectively cull bold individuals has not been determined. Hence, this study aimed to demonstrate their distribution in native habitats because if bold and shy individuals prefer different habitats, selective culling could target areas preferred by bold individuals. To detect differences in neophobia (i.e., shyness/boldness), 17 visible flash and invisible infrared flash sensor cameras were randomly placed in forest areas based on the assumption that neophobic (shy) sika deer (Cervus nippon) would be deterred by visible flash cameras (a novel stimulus). The relationship between camera flash type and the probability of detection (i.e., of being photographed by a camera) was used as an index of shyness/boldness. Geographical information system and regression analyses showed that bold individuals preferred forested areas near farmland. These results indicate that selective lethal control could be conducted in forest areas near farmlands to mitigate crop damage.