Sexual Selection Increases Male Behavioral Consistency in Drosophila melanogaster.

AbstractSexual selection has been suggested to influence the expression of male behavioral consistency. However, despite predictions, direct experimental support for this hypothesis has been lacking. Here, we investigated whether sexual selection altered male behavioral consistency in Drosophila melanogaster-a species with both pre- and postcopulatory sexual selection. We took 1,144 measures of locomotor activity (a fitness-related trait in D. melanogaster) from 286 flies derived from replicated populations that have experimentally evolved under either high or low levels of sexual selection for >320 generations. We found that high sexual selection males were more consistent (decreased within-individual variance) in their locomotor activity than male conspecifics from low sexual selection populations. There were no differences in behavioral consistency between females from the high and low sexual selection populations. Furthermore, while females were more behaviorally consistent than males in the low sexual selection populations, there were no sex differences in behavioral consistency in high sexual selection populations. Our results demonstrate that behavioral plasticity is reduced in males from populations exposed to high levels of sexual selection. Disentangling whether these effects represent an evolved response to changes in the intensity of selection or are manifested through nongenetic parental effects represents a challenge for future research.

Information Gathering Is Associated with Increased Survival: A Field Experiment in Black-Capped Chickadees (Poecile atricapillus).

AbstractSampling, investing time or energy to learn about the environment, allows organisms to track changes in resource distribution and quality. The use of sampling is predicted to change as a function of energy expenditure, food availability, and starvation risk, all of which can vary both within and among individuals. We studied sampling behavior in a field study with black-capped chickadees (Poecile atricapillus) and show that individuals adjust their use of sampling as a function of ambient temperature (a proxy for energy expenditure), the presence of an alternative food source (yes or no, a proxy for risk of energy shortfall), and their interaction, as predicted by models of optimal sampling. We also observed repeatable differences in sampling. Some individuals consistently sampled more, and individuals that sampled more overall also had a higher annual survival. These results are consistent with among-individual differences in resource acquisition (e.g., food caches or dominance-related differences in priority access to feeders), shaping among-individual differences in both sampling and survival, with greater resource acquisition leading to both higher sampling and higher survival. Although this explanation requires explicit testing, it is in line with several recent studies suggesting that variation in resource acquisition is a key mechanism underlying animal personality.

Sea anemones (Actinia equina) show consistent individual differences in boldness and thoroughness but lack a behavioural syndrome.

Behavioural syndromes are suites of behaviours that corelate between-individuals but the same behaviours may also show within-individual correlations owing to state dependency or trade-offs. Therefore, overall phenotypic behavioural correlations must be separated into their between- and within-individual components. We investigate how startle response duration (an index of boldness) and time taken to reject an inert item (an index of investigation thoroughness) covary in beadlet sea anemones, Actinia equina. Anemones took longer to reject a more complex item compared to a simpler one, validating this measure of investigation thoroughness. We then quantified between- and within-individual correlations using a Bayesian analysis and an alternative frequentist analysis, which returned the same results. Startle responses decreased with anemone size while thoroughness decreased across repeated observations, indicative of simple learning. For each behaviour, repeatability was significant but relatively low and there was no behavioural syndrome. Rather, the two behaviours showed a negative within-individual correlation in most individuals. Thus, boldness and thoroughness are unlikely to be under correlative selection, and they may instead be expressed independently, in line with the general pattern that cross-contextual behavioural syndromes are comparatively rare. It now appears that this pattern may extend broadly across animal diversity.

Context-dependent effects of thermal acclimation on physiological correlates of animal personality in Asiatic toads.

Persistent individual variation in behaviour, or 'personality', is a widespread phenomenon in animals, and understanding the evolution of animal personality is a key task of current biology. Natural selection has been proposed to promote the integration of personality with animal 'intrinsic states', such as metabolic or endocrine traits, and this integration varies with ecological conditions. However, these external ecological modulatory effects have rarely been examined. Here, we investigate the effects of thermal acclimation on between-individual covariations between physiology and behaviour in Asiatic toads (Bufo gargarizans) along an altitudinal gradient. Our results reveal that the thermal modulatory effects on the covariations depend on the altitudinal population. Specifically, at low altitudes, between-individual covariations are highly plastic, with risk-taking behaviour covarying with baseline glucocorticoids (GCs) under warm acclimation, but risk-taking and exploration behaviour covarying with resting metabolic rate (RMR) under cold acclimation. In contrast, between-individual covariations are relatively fixed at high altitudes, with risk-taking behaviour consistently covarying with baseline GCs. Furthermore, at low altitudes, changes in covariations between RMR and personality are associated with adjustment of energy management models. Evidently, animal physiological states that determine or covary with personality can adapt according to the seasonal thermal environment and the thermal evolutionary background of populations. Our findings highlight the importance of a multi-system physiological approach to understand the evolution of animal personality.

Non-Synonymous Substitutions in Cadherin 13, Solute Carrier Family 6 Member 4, and Monoamine Oxidase A Genes are Associated with Personality Traits in Thoroughbred Horses.

Retraining retired racehorses for various purposes can help correct behavioral issues. However, ensuring efficiency and preventing accidents present global challenges. Based on the hypothesis that a simple personality assessment could help address these challenges, the present study aimed to identify genetic markers associated with personality. Eight genes were selected from 18 personality-related candidate genes that are orthologs of human personality genes, and their association with personality was verified based on actual behavior. A total of 169 Thoroughbred horses were assessed for their tractability (questionnaire concerning tractability in 14 types of situations and 3 types of impressions) during the training process. Personality factors were extracted from the data using principal component analysis and analyzed for their association with single nucleotide variants as non-synonymous substitutions in the target genes. Three genes, CDH13, SLC6A4, and MAOA, demonstrated significant associations based on simple linear regression, marking the identification of these genes for the first time as contributors to temperament in Thoroughbred horses. All these genes, as well as the previously identified HTR1A, are involved in the serotonin neurotransmitter system, suggesting that the tractability of horses may be correlated with their social personality. Assessing the genotypes of these genes before retraining is expected to prevent problems in the development of a racehorse's second career and shorten the training period through individual customization of training methods, thereby improving racehorse welfare.

Key Grazing Behaviours of Beef Cattle Identify Specific Genotypes of the Glutamate Metabotropic Receptor 5 Gene (GRM5).

Genotype-phenotype associations between the bovine genome and grazing behaviours measured over time and across contexts have been reported in the past decade, with these suggesting the potential for genetic control over grazing personalities in beef cattle. From the large array of metrics used to describe grazing personality behaviours (GP-behaviours), it is still unclear which ones are linked to specific genes. Our prior observational study has reported associations and trends towards associations between genotypes of the glutamate metabotropic receptor 5 gene (GRM5) and four GP-behaviours, yet the unbalanced representation of GRM5 genotypes occurring in observational studies may have limited the ability to detect associations. Here, we applied a subsampling technique to create a genotypically-balanced dataset in a quasi-manipulative experiment with free ranging cows grazing in steep and rugged terrain of New Zealand's South Island. Using quadratic discriminant analysis, two combinations of eleven GP-behaviours (and a total of fifteen behaviours) were selected to build an exploration model and an elevation model, respectively. Both models achieved ∼ 86% accuracy in correctly discriminating cows' GRM5 genotypes with the training dataset, and the exploration model achieved 85% correct genotype prediction of cows from a testing dataset. Our study suggests a potential pleiotropic effect, with GRM5 controlling multiple grazing behaviours, and with implications for the grazing of steep and rugged grasslands. The study highlights the importance of grazing behavioural genetics in cattle and the potential use of GRM5 markers to select individuals with desired grazing personalities and built herds that collectively utilize steep and rugged rangelands sustainably.

Energy allocation is revealed while behavioural performance persists after fire disturbance.

Metabolic physiology and animal behaviour are often considered to be linked, positively or negatively, according to either the performance or allocation models. Performance seems to predominate over allocation in natural systems, but the constraining environmental context may reveal allocation limitations to energetically expensive behaviours. Habitat disturbance, such as the large-scale fire that burnt wetlands of Biebrza National Park (NE Poland), degrades natural ecosystems. It arguably reduces food and shelter availability, modifies predator-prey interactions, and poses a direct threat for animal survival, such as that of the wetland specialist root vole Microtus oeconomus. We hypothesized that fire disturbance induces physiology-behaviour co-expression, as a consequence of changed environmental context. We repeatedly measured maintenance and exercise metabolism, and behavioural responses to the open field, in a root voles from post-fire and unburnt locations. Highly repeatable maintenance metabolism and distance moved during behavioural tests correlated positively, but relatively labile exercise metabolism did not covary with behaviour. At the same time, voles from a post-fire habitat had higher maintenance metabolism and moved shorter distances than voles from unburnt areas. We conclude there is a prevalence of the performance mechanism, but simultaneous manifestation of context-dependent allocation constraints of the physiology-behaviour covariation after disturbance. The last occurs at the within-individual level, indicating the significance of behavioural plasticity in the context of environmental disturbance.

Pilfering personalities: Effects of small mammal personality on cache pilferage.

Small mammals such as mice and voles play a fundamental role in the ecosystem service of seed dispersal by caching seeds in small hoards that germinate under beneficial conditions. Pilferage is a critical step in this process in which animals steal seeds from other individuals' caches. Pilferers often recache stolen seeds, which are often pilfered by new individuals, who may recache again, and so on, potentially leading to compounded increased dispersal distance. However, little research has investigated intraspecific differences in pilfering frequency, despite its importance in better understanding the role of behavioural diversity in the valuable ecosystem service of seed dispersal. We conducted a field experiment in Maine (USA) investigating how intraspecific variation, including personality, influences pilferage effectiveness. Within the context of a long-term capture-mark-recapture study, we measured the unique personality of 3311 individual small mammals of 10 species over a 7-year period. For this experiment, we created artificial caches using eastern white pine (Pinus strobus) seeds monitored with trail cameras and buried antennas for individual identification. Of the 436 caches created, 83.5% were pilfered by 10 species, including deer mice ((Peromyscus maniculatus) and southern red-backed voles (Myodes gapperi). We show how individuals differ in their ability to pilfer seeds and that these differences are driven by personality, body condition and sex. More exploratory deer mice and those with lower body condition were more likely to locate a cache, and female southern red-backed voles were more likely than males to locate caches. Also, caches were more likely to be pilfered in areas of higher small mammal abundance. Because the risk of pilferage drives decisions concerning where an animal chooses to store seeds, pilferage pressure is thought to drive the evolution of food-hoarding behaviour. Our study shows that pilferage ability varies between individuals, meaning that some individuals have a disproportionately strong influence on others' caching decisions and disproportionately contribute to compounded longer-distance seed dispersal facilitated by pilferage. Our results add to a growing body of knowledge showing that the unique personalities of individual small mammals play a critical role in forest regeneration by impacting seed dispersal.

Resource manipulation reveals interactive phenotype-dependent foraging in free-ranging lizards.

Recent evidence suggests that individuals differ in foraging tactics and this variation is often linked to an individual's behavioural type (BT). Yet, while foraging typically comprises a series of search and handling steps, empirical investigations have rarely considered BT-dependent effects across multiple stages of the foraging process, particularly in natural settings. In our long-term sleepy lizard (Tiliqua rugosa) study system, individuals exhibit behavioural consistency in boldness (measured as an individual's willingness to approach a novel food item in the presence of a threat) and aggressiveness (measured as an individual's response to an 'attack' by a conspecific dummy). These BTs are only weakly correlated and have previously been shown to have interactive effects on lizard space use and movement, suggesting that they could also affect lizard foraging performance, particularly in their search behaviour for food. To investigate how lizards' BTs affect their foraging process in the wild, we supplemented food in 123 patches across a 120-ha study site with three food abundance treatments (high, low and no-food controls). Patches were replenished twice a week over the species' entire spring activity season and feeding behaviours were quantified with camera traps at these patches. We tracked lizards using GPS to determine their home range (HR) size and repeatedly assayed their aggressiveness and boldness in designated assays. We hypothesised that bolder lizards would be more efficient foragers while aggressive ones would be less attentive to the quality of foraging patches. We found an interactive BT effect on overall foraging performance. Individuals that were both bold and aggressive ate the highest number of food items from the foraging array. Further dissection of the foraging process showed that aggressive lizards in general ate the fewest food items in part because they visited foraging patches less regularly, and because they discriminated less between high and low-quality patches when revisiting them. Bolder lizards, in contrast, ate more tomatoes because they visited foraging patches more regularly, and ate a higher proportion of the available tomatoes at patches during visits. Our study demonstrates that BTs can interact to affect different search and handling components of the foraging process, leading to within-population variation in foraging success. Given that individual differences in foraging and movement will influence social and ecological interactions, our results highlight the potential role of BT's in shaping individual fitness strategies and population dynamics.

Group phenotypic composition drives task performances in ants.

Differences in individual behaviour within a group can give rise to functional dissimilarities between groups, particularly in social animals. However, how individual behavioural phenotypes translate into the group phenotype remains unclear. Here, we investigate whether individual behavioural type affects group performance in a eusocial species, the ant Aphaenogaster senilis. We measured individual behavioural traits and created groups of workers with similar behavioural type, either high-exploratory or low-exploratory workers. We tested these groups in four different, ecologically relevant, tasks: reaction to an intruder, prey retrieval from a maze, nest relocation and tool use. We show that, compared to groups of low-exploratory workers, groups of high-exploratory workers were more aggressive towards intruders, more efficient in collecting prey, faster in nest relocation and more likely to perform tool use. Our results demonstrate a strong link between individual and collective behaviour in ants. This supports the 'behavioural type hypothesis' for group dynamics, which suggests that an individual's behaviour in a social environment reflects its own behavioural type. The average behavioural phenotype of a group can therefore be predicted from the behavioural types of individual group members.

Slow-exploring captive red knots were quicker to find food in a social setting than fast explorers.

Individuals foraging in groups face increased competition but can benefit from social information on foraging opportunities that can ultimately increase survival. Personality traits can be associated with food-finding strategies, such as shyer individuals scrounging on the food discoveries of others. How personality and foraging strategy interact in a social foraging context with different group compositions received less attention. Here, we conducted experiments to investigate the relationship between exploratory personality, group size (1-4 birds) and foraging success (i.e. speed of finding a food patch) in wild-caught red knots. We found that faster explorers, when foraging alone, discover food patches quicker than slower explorers. In groups, however, slower-exploring birds became quicker at finding food than fast explorers. This shows that slower-exploring individuals benefit from group foraging. They seem to be more perceptive to social cues, and in contrast to faster explorers, they become quicker at finding food when they are in a group than when foraging alone. We discuss how individuals with different personalities and foraging strategies can coexist in a social foraging context with different costs and benefits associated with their strategies.

Intraspecific variation in crayfish behavioral traits affects leaf litter breakdown in streams.

Although intraspecific trait variation is increasingly recognized as affecting ecosystem processes, few studies have examined the ecological significance of among-population variation in behavioral traits in natural ecosystems. In freshwater habitats, crayfish are consumers that can influence ecosystem structure (e.g., macroinvertebrate communities) and function (e.g., leaf litter breakdown). To test whether crayfish behavioral traits (activity, boldness, and foraging voracity) are major contributors of leaf litter breakdown rates in the field, we collected rusty crayfish (Faxonius rusticus) from eight streams across the midwestern USA and measured behaviors using laboratory assays. At the same streams, we measured breakdown rates of leaf packs that were accessible or inaccessible to crayfish. Our results provide evidence that among-population variation in crayfish boldness and foraging voracity was a strong predictor of leaf litter breakdown rates, even after accounting for commonly appreciated environmental drivers (water temperature and human land use). Our results suggest that less bold rusty populations (i.e., emerged from shelter more slowly) had greater direct impacts on leaf litter breakdown than bold populations (P = 0.001, r2 = 0.85), potentially because leaf packs can be both a shelter and food resource to crayfish. Additionally, we found that foraging voracity was negatively related to breakdown rates in leaf packs that were inaccessible to crayfish (P = 0.025, r2 = 0.60), potentially due to a trophic cascade from crayfish preying on other invertebrates that consume leaf litter. Overall, our results add to the growing evidence that trait variation in animals may be important for understanding freshwater ecosystem functioning.

Water-borne testosterone levels predict exploratory tendency in male poison frogs.

Hormones play a fundamental role in mediating social behaviors of animals. However, it is less well understood to what extent behavioral variation between individuals can be attributed to variation in underlying hormonal profiles. The goal of the present study was to infer if individual androgen levels, and/or the modulation thereof, can explain among-individual variation in aggressiveness, boldness and exploration. We used as a model the dart-poison frog Allobates femoralis and took repeated non-invasive water-borne hormonal samples of individual males before (baseline) and after (experimental) a series of behavioral tests for assessing aggression, boldness, and exploratory tendency. Our results show that androgen levels in A. femoralis are quite stable across the reproductive season. Repeatability in wbT baseline levels was high, while time of day, age of the frog, and trial order did not show any significant impact on measured wbT levels. In general, experimental wbT levels after behavioral tests were lower compared to the respective baseline levels. However, we identified two different patterns with regard to androgen modulation in response to behavioral testing: individuals with low baseline wbT tended to have increased wbT levels after the behavioral testing, while individuals with comparatively high baseline wbT levels rather showed a decrease in hormonal levels after testing. Our results also suggest that baseline wbT levels are linked to the personality trait exploration, and that androgen modulation is linked to boldness in A. femoralis males. These results show that differences in hormonal profiles and/or hormonal modulation in response to social challenges can indeed explain among-individual differences in behavioral traits.

Heterogeneous selection on exploration behavior within and among West European populations of a passerine bird.

Heterogeneous selection is often proposed as a key mechanism maintaining repeatable behavioral variation ("animal personality") in wild populations. Previous studies largely focused on temporal variation in selection within single populations. The relative importance of spatial versus temporal variation remains unexplored, despite these processes having distinct effects on local adaptation. Using data from >3,500 great tits (Parus major) and 35 nest box plots situated within five West-European populations monitored over 4 to 18 y, we show that selection on exploration behavior varies primarily spatially, across populations, and study plots within populations. Exploration was, simultaneously, selectively neutral in the average population and year. These findings imply that spatial variation in selection may represent a primary mechanism maintaining animal personalities, likely promoting the evolution of local adaptation, phenotype-dependent dispersal, and nonrandom settlement. Selection also varied within populations among years, which may counteract local adaptation. Our study underlines the importance of combining multiple spatiotemporal scales in the study of behavioral adaptation.

Artificial selection for reversal learning reveals limited repeatability and no heritability of cognitive flexibility in great tits (Parus major).

Cognitive flexibility controls how animals respond to changing environmental conditions. Individuals within species vary considerably in cognitive flexibility but the micro-evolutionary potential in animal populations remains enigmatic. One prerequisite for cognitive flexibility to be able to evolve is consistent and heritable among-individual variation. Here we determine the repeatability and heritability of cognitive flexibility among great tits (Parus major) by performing an artificial selection experiment on reversal learning performance using a spatial learning paradigm over three generations. We found low, yet significant, repeatability (R = 0.15) of reversal learning performance. Our artificial selection experiment showed no evidence for narrow-sense heritability of associative or reversal learning, while we confirmed the heritability of exploratory behaviour. We observed a phenotypic, but no genetic, correlation between associative and reversal learning, showing the importance of prior information on reversal learning. We found no correlation between cognitive and personality traits. Our findings emphasize that cognitive flexibility is a multi-faceted trait that is affected by memory and prior experience, making it challenging to retrieve reliable values of temporal consistency and assess the contribution of additive genetic variation. Future studies need to identify what cognitive components underlie variation in reversal learning and study their between-individual and additive genetic components.

The timid invasion: behavioural adjustments and range expansion in a non-native rodent.

Animal behaviour can moderate biological invasion processes, and the native fauna's ability to adapt. The importance and nature of behavioural traits favouring colonization success remain debated. We investigated behavioural responses associated with risk-taking and exploration, both in non-native bank voles (Myodes glareolus, N = 225) accidentally introduced to Ireland a century ago, and in native wood mice (Apodemus sylvaticus, N = 189), that decline in numbers with vole expansion. We repeatedly sampled behavioural responses in three colonization zones: established bank vole populations for greater than 80 years (2 sites), expansion edge vole populations present for 1-4 years (4) and pre-arrival (2). All zones were occupied by wood mice. Individuals of both species varied consistently in risk-taking and exploration. Mice had not adjusted their behaviour to the presence of non-native voles, as it did not differ between the zones. Male voles at the expansion edge were initially more risk-averse but habituated faster to repeated testing, compared to voles in the established population. Results thus indicate spatial sorting for risk-taking propensity along the expansion edge in the dispersing sex. In non-native prey species the ability to develop risk-averse phenotypes may thus represent a fundamental component for range expansions.

Temperature change exerts sex-specific effects on behavioural variation.

Temperature is a key factor mediating organismal fitness and has important consequences for species' ecology. While the mean effects of temperature on behaviour have been well-documented in ectotherms, how temperature alters behavioural variation among and within individuals, and whether this differs between the sexes, remains unclear. Such effects likely have ecological and evolutionary consequences, given that selection acts at the individual level. We investigated the effect of temperature on individual-level behavioural variation and metabolism in adult male and female Drosophila melanogaster (n = 129), by taking repeated measures of locomotor activity and metabolic rate at both a standard temperature (25°C) and a high temperature (28°C). Males were moderately more responsive in their mean activity levels to temperature change when compared to females. However, this was not true for either standard or active metabolic rate, where no sex differences in thermal metabolic plasticity were found. Furthermore, higher temperatures increased both among- and within-individual variation in male, but not female, locomotor activity. Given that behavioural variation can be critical to population persistence, we suggest that future studies test whether sex differences in the amount of behavioural variation expressed in response to temperature change may result in sex-specific vulnerabilities to a warming climate.

Conditional on the social environment? Roots of repeatability in hormone concentrations of male guinea pigs.

Individual differences in behavioral and physiological traits among members of the same species are increasingly being recognized as important in animal research. On the group level, shaping of behavioral and hormonal phenotypes by environmental factors has been reported in different taxa. The extent to which the environment impacts behavior and hormones on the individual level, however, is rather unexplored. Hormonal phenotypes of guinea pigs can be shaped by the social environment on the group level: pair-housed and colony-housed males differ systematically in average testosterone and stressor-induced cortisol levels (i.e. cortisol responsiveness). The aim of the present study was to evaluate whether repeatability and individual variance components (i.e. between- and within-individual variation) of hormonal phenotypes also differ in different social environments. To test this, we determined baseline testosterone, baseline cortisol, and cortisol responsiveness after challenge in same-aged pair-housed and colony-housed guinea pig males over a period of four months. We found comparable repeatability for baseline cortisol and cortisol responsiveness in males from both social conditions. In contrast, baseline testosterone was repeatable only in males from colonies. Interestingly, this result was brought about by significantly larger between-individual variation of testosterone, that was not explained by differences in dominance rank. Individualized social niches differentiated under complex colony, but not pair housing, could be an explanation for this finding.

Food patch use of Japanese quail (Coturnix japonica) varies with personality traits.

BACKGROUND: The classic optimal foraging theory (OFT) predicts animals' food patch use assuming that individuals in a population use the same strategy while foraging. However, due to the existence of animal personality, i.e. repeatable inter-individual differences and intra-individual consistency in behaviours over time and/or across contexts, individuals often exhibit different behavioural strategies, challenging the basic assumptions of the OFT. Here, we tested whether personality traits (boldness and exploration in open arena) of Japanese quail (Coturnix japonica, 38 females and 34 males) influenced their patch use in two foraging experiments with different inter-patch distances (i.e. 2 m in Experiment 1 and 3 m in Experiment 2). RESULTS: The total feeding time and food intake of individuals did not differ between Experiment 1 and 2, but in both experiments, proactive (i.e. bolder and more explorative) individuals had longer feeding time and higher food intake than reactive individuals. In Experiment 1, proactive quails changed patches more frequently and had shorter mean patch residence time than reactive individuals, while the effects were not significant in Experiment 2. The quails reduced patch residence time along with feeding, and this trend was weakened in Experiment 2 which had longer inter-patch distance. CONCLUSIONS: The above results suggest that personality traits affect animals' patch use, while the effects might be weakened with longer inter-patch distance. Our study highlights that animal personality should be considered when investigating animals' foraging behaviours because individuals may not adopt the same strategy as previously assumed. Furthermore, the interaction between personality traits and inter-patch distances, which is related to movement cost and capacity of information gathering, should also be considered.

Stressfulness of the design influences consistency of cognitive measures and their correlation with animal personality traits in wild mice (Mus musculus).

Individual variation in cognition is being increasingly recognized as an important evolutionary force but contradictory results so far hamper a general understanding of consistency and association with other behaviors. Partly, this might be caused by external factors imposed by the design. Stress, for example, is known to influence cognition, with mild stress improving learning abilities, while strong or chronic stress impairs them. Also, there might be intraspecific variation in how stressful a given situation is perceived. We investigated two personality traits (stress coping and voluntary exploration), spatial learning with two mazes, and problem-solving in low- and high-stress tests with a group of 30 female wild mice (Mus musculus domesticus). For each test, perceived stress was assessed by measuring body temperature change with infrared thermography, a new non-invasive method that measures skin temperature as a proxy of changes in the sympathetic system activity. While spatial learning and problem-solving were found to be repeatable traits in mice in earlier studies, none of the learning measures were significantly repeatable between the two stress conditions in our study, indicating that the stress level impacts learning. We found correlations between learning and personality traits; however, they differed between the two stress conditions and between the cognitive tasks, suggesting that different mechanisms underlie these processes. These findings could explain some of the contradictory findings in the literature and argue for very careful design of cognitive test setups to draw evolutionary implications.