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1.
Many prey species have a genetic predisposition to recognise and respond to predators and can fine-tune their anti-predator behaviour following appropriate experience. Although the Trinidadian guppy ( Poecilia reticulata) has become a model species for the investigation of adaptive behaviour, the extent to which experience mediates predator recognition remains unclear. In this study, we examined the effects of relaxed predation pressure on patterns of anti-predator behaviour in populations differing in evolutionary history. The anti-predator behaviour of wild- and laboratory-born guppies from high- and low-predation localities in Trinidad were compared using three models resembling Crenicichla alta, a dangerous guppy predator, Aequidens pulcher, a less dangerous piscivore, and a snake. Snakes are not known to prey on guppies in Trinidad. Specifically, the following predictions were tested: (1) wild caught fish from the high-predation localities (where guppies co-occur with C. alta and A. pulcher) would respond to the three models according to their perceived level of threat, whereas guppies from the low-predation site would show a reduced response to all of the predator models; (2) high-predation laboratory-reared fish would display a reduced but qualitatively similar response to their wild counterparts; and (3) there would be no behavioural differences between wild- and laboratory-reared low-predation fish. In accordance with these predictions, the results revealed that wild fish originating from high-predation sites responded more strongly to the models than fish from low-predation sites. When reared in the laboratory, guppies from the high-predation population showed a reduced response compared to their wild-caught counterparts, but there was no difference in the behaviour of wild- and laboratory-reared low-predation fish. Model type affected predator inspection behaviour but not schooling tendency, and both wild- and laboratory-reared guppies were more wary of the fish models than the snake. These results suggest that early experience differentially mediates the anti-predator responses of fish from high-risk localities. 相似文献
2.
Emotions such as fear in vertebrates are often strongly lateralised, that is, a single cerebral hemisphere tends to be dominant when processing emotive stimuli. Boldness is a measure of an individual’s propensity to take risks and it has obvious connections with fear responses. Given the emotive nature of this well-studied personality trait, there is good reason to suspect that it is also likely to be expressed in a single hemisphere. Here, we examined the link between laterality and boldness in wild and captive-reared rainbowfish, Melanotaenia nigrans. We found that fish from the wild were bolder than those from captivity, which might be a reflection of the differences in the level of predation pressure experienced by the two populations. Secondly, we found that non-lateralised fish were bolder than strongly lateralised fish. In addition, differences in boldness scores between left- and right-biased fish were revealed. We suggest that variation in cerebral lateralisation contributes to the persistence of individual differences in boldness scores in animal populations. 相似文献
3.
Raine Kortet Anssi Vainikka Matti Janhunen Jorma Piironen Pekka Hyvärinen 《Behavioral ecology and sociobiology》2014,68(6):927-934
Animal personalities (sometimes referred also as coping styles) and their fitness consequences are currently among the most intensively explored subjects in behavioral ecology. To estimate the evolvability and adaptability of individually consistent behavioral variation, there is a crucial need to quantify the genetics underlying personality. Here, we experimentally studied the repeatability of various individual behaviors and then estimated heritability of formed boldness, exploration, and aggression components in juvenile brown trout Salmo trutta in standardized laboratory environment. Principal component analysis indicated that individually recorded behaviors were described by two personality axes: the first reflecting boldness, exploration, and aggression and the second tendency to freeze. These personality components, as well as the originally recorded behaviors, were statistically significantly repeatable over time. The latter PC, but not the first one, was statistically significantly heritable, though at low level (h 2?=?0.142?±?0.096). These results suggest that additive genetic variation underlies phenotypically consistent behavioral patterns, proposing that any selection acting on behavior, stress tolerance, or correlated traits has a potential to induce evolution in fish personality. 相似文献
4.
David L. Sinn Natalie A. Moltschaniwskyj Erik Wapstra Sasha R. X. Dall 《Behavioral ecology and sociobiology》2010,64(4):693-702
Behavioral syndromes are correlated suites of behavior, analogous to human personality traits. Most work to date has been
taken from limited “snapshots” in space and time, with the implicit assumption that a behavioral syndrome is an invariant
property, fixed by evolutionary constraints or adaptations. However, directional selection on two mechanistically independent
traits (selective covariance) could also result in correlated behaviors. Previously, we have shown that shy/bold behavior
in Southern dumpling squid (Euprymna tasmanica) across predator encounter and feeding risk contexts is genetically and phenotypically uncoupled, and hence potentially free
to vary independently. Here, we collected data on shy/bold behaviors from two independent wild populations of squid in two
different years to test whether behavioral correlations across these same two functional contexts vary through time and space.
We detected significant influences of population, sex, and body size on the expression of boldness in squid within each functional
context, and this was coupled with significant differences in relative population density and adult sex ratio. Despite these
changes in behavior and demographic parameters, we found that correlations between boldness scores across the two functional
contexts were largely absent in both wild populations of squid in both years. Our work suggests that some animal groups may
be largely characterized by context-specific behavioral expression. A theoretical framework which conceptualizes behavioral
syndromes resulting from context-specific behavioral rules may be needed to fully understand why behaviors are sometimes correlated,
and why sometimes they are not. 相似文献
5.
Sophie L. Mowles Peter A. Cotton Mark Briffa 《Behavioral ecology and sociobiology》2012,66(7):1087-1094
Consistent individual variation in behaviour has been termed ‘animal personality’ and has been identified across a range of behavioural contexts including aggression, boldness in response to a threatening stimulus and exploration. When behaviours are correlated across multiple functional behavioural categories or ‘contexts’, ‘behavioural syndromes’ are said to be present. It is possible, however, that behavioural syndromes may also show consistencies. Here we investigated the presence of behavioural syndromes linking startle responses, exploration and aggression in hermit crabs and assessed their stability across two situations (low versus high predation risk). Correlation analyses detected behavioural syndromes between startle responses, a measure of ‘boldness’, and the latency to investigate a novel object, as well as the latency to attack an opponent in an aggressive context. The startle response–investigation and startle response–aggression syndromes were stable between situations, whilst there was a lack of relationship between investigation and aggression in each situation. Here we propose that these consistent individual differences in the expression of behavioural syndromes reveal the presence of animal personality, manifesting in not just one, but a suite of interacting traits. 相似文献
6.
Darren P. Croft Jens Krause Safi K. Darden Indar W. Ramnarine Jolyon J. Faria Richard James 《Behavioral ecology and sociobiology》2009,63(10):1495-1503
The social fine structure of a population plays a central role in ecological and evolutionary processes. Whilst many studies
have investigated how morphological traits such as size affect social structure of populations, comparatively little is known
about the influence of behaviours such as boldness and shyness. Using information on social interactions in a wild population
of Trinidadian guppies (Poecilia reticulata), we construct a social network. For each individual in the network, we quantify its behavioural phenotype using two measures
of boldness, predator inspection tendency, a repeatable and reliably measured behaviour well studied in the context of co-operation,
and shoaling tendency. We observe striking heterogeneity in contact patterns, with strong ties being positively assorted and
weak ties negatively assorted by our measured behavioural traits. Moreover, shy fish had more network connections than bold
fish and these were on average stronger. In other words, social fine structure is strongly influenced by behavioural trait.
We assert that such structure will have implications for the outcome of selection on behavioural traits and we speculate that
the observed positive assortment may act as an amplifier of selection contributing to the maintenance of co-operation during
predator inspection. 相似文献
7.
Alastair J Wilson Andrew Grimmer Gil G. Rosenthal 《Behavioral ecology and sociobiology》2013,67(7):1151-1161
Although our understanding of how animal personality affects fitness is incomplete, one general hypothesis is that personality traits (e.g. boldness and aggressiveness) contribute to competitive ability. If so, then under resource limitation, personality differences will generate variation in life history traits crucial to fitness, like growth. Here, we test this idea using data from same-sex dyadic interaction trials of sheepshead swordtails (Xiphophorus birchmanni). In males, there was evidence of repeatable variation across a suite of agonistic contest behaviours, while repeatable opponent effects on focal behaviour were also detected. A single vector explains 80 % of the among-individual variance in multivariate phenotype and can be viewed as aggressiveness. We also find that aggressiveness predicts dominance—the repeatable tendency to win food in competition—and dominant individuals show faster post-trial weight gain (independently of initial size). In females, a dominance hierarchy predictive of weight gain was also found, but there was no evidence of variation in aggressiveness. While size often predicts contest outcome, our results show that individuals may sometimes grow larger because they are behaviourally dominant rather than vice versa. When resources are limited, personality traits such as aggression can influence growth, life history, and fitness through impacts on resource acquisition. 相似文献
8.
Alecia J. Carter Harry H. Marshall Robert Heinsohn Guy Cowlishaw 《Behavioral ecology and sociobiology》2012,66(1):153-160
The animal personality literature uses three approaches to assess personality. However, two of these methods, personality
ratings and experimentation, have been little compared in captivity and never compared in the wild. We assessed the boldness
of wild chacma baboons Papio ursinus using both ratings and experimental methods. Boldness was experimentally assessed when individuals were presented with a
novel food item during natural foraging. The boldness of the same individuals was rated on a five-point scale by experienced
observers. The ratings and experimental assessments of boldness were found to correlate positively and in a linear fashion.
When considered categorically the two approaches showed variable agreement depending on the number of categories assigned
and the cut-off criteria adopted. We suggest that the variation between approaches arises because each method captures different
aspects of personality; ratings consider personality in absolute terms (using predefined criteria) and multiple contexts,
while experimental assessments consider personality in relative terms (using experimental scores relative to the population
average) and in limited contexts. We encourage animal personality researchers to consider adopting both methodologies in future
studies. We also propose that future studies restrict their analyses to continuous data, since the greatest comparability
between methods was found with these data. However, if individuals must be categorised, we suggest that researchers either
(a) analyse only those individuals categorised as bold or shy by both ratings and experimental approaches or, if these methods
cannot be employed simultaneously, (b) do not use approach-specific criteria but choose a cut-off that can be compared by
both approaches. 相似文献
9.
Condition indices (CI), hepatosomatic indices (HSI) and proximate, lipid and fatty acid composition of wild and laboratory-reared yellowtail flounder (Limanda ferruginea) (Storer, 1839) were compared from data taken throughout spring and summer 1996–1998. Cluster analysis was performed on the fatty acid signatures of these two groups along with a commercial diet and several invertebrate species to determine possible feeding patterns in Conception Bay, Newfoundland. HSI and levels of storage fat were significantly higher in the muscle and liver of laboratory-reared yellowtail flounder, indicating an efficient absorption of dietary lipid and an increase in fat deposition. Fatty acid analysis of the liver showed that wild fish contained significantly higher proportions of the essential fatty acids 20:46, 20:53 and 22:63; whereas proportions of 18:1 and 18:26 were significantly higher in all fractions of lipid examined from laboratory-reared fish than they were from wild fish. Polar fractions of lipid were more similar than the neutral fraction of lipid when comparing wild and laboratory-reared fish. Taken together, the differences in CI, HSI, proximate and fatty acid composition suggest that feeding commercial diets to L. ferruginea can cause changes in patterns of lipid deposition and metabolism. Cluster analysis of marine plankton, sedimenting particulate matter, wild invertebrates, the commercial diet and fish tissues showed that the fatty acid signatures of both wild and laboratory-reared yellowtail flounder closely resembled their respective food items. Fatty acid signatures from wild fish were more closely related to plankton and settling particulate matter, suggesting relatively few steps in the food web leading to yellowtail flounder. In addition to the resemblance between fatty acids in the commercial diet and the tissues of laboratory-reared yellowtail flounder, these fish had similar fatty acid signatures to those of wild invertebrates.Communicated by J.P. Grassle, New Brunswick 相似文献
10.
Kay Boulton Andrew J. Grimmer Gil G. Rosenthal Craig A. Walling Alastair J. Wilson 《Behavioral ecology and sociobiology》2014,68(5):791-803
Many studies have revealed repeatable (among-individual) variance in behavioural traits consistent with variation in animal personality; however, these studies are often conducted using data collected over single sampling periods, most commonly with short time intervals between observations. Consequently, it is not clear whether population-level patterns of behavioural variation are stable across longer timescales and/or multiple sampling periods or whether individuals maintain consistent ranking of behaviours (and/or personality) over their lifetimes. Here, we address these questions in a captive-bred population of a tropical freshwater poeciliid fish, Xiphophorus birchmanni. Using a multivariate approach, we estimate the among-individual variance-covariance matrix (I), for a set of behavioural traits repeatedly assayed in two different experimental contexts (open-field trials, emergence and exploration trials) over long-term (56 days between observations) and short-term (4-day observation interval) time periods. In both long- and short-term data sets, we find that traits are repeatable and the correlation structure of I is consistent with a latent axis of variation in boldness. While there are some qualitative differences in the way individual traits contribute to boldness and a tendency towards higher repeatabilities in the short-term study, overall, we find that population-level patterns of among-individual behavioural (co)variance to be broadly similar over both time frames. At the individual level, we find evidence that short-term studies can be informative for an individual’s behavioural phenotype over longer (e.g. lifetime) periods. However, statistical support is somewhat mixed and, at least for some observed behaviours, relative rankings of individual performance change significantly between data sets. 相似文献
11.
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. 相似文献
12.
In young-of-the-year perch (Perca fluviatilis), individuals within groups differed in the degree of boldness, estimated by habitat utilisation and feeding activity in visual contact with a potential predator. We looked at changes in individual behaviour in connection with change of group composition. During the first period, perch were randomly assigned to groups, and time spent in open habitat versus in vegetation and number of prey attacks were registered. The perch were then categorised into personality types (shy, bold, intermediate) according to their behaviour. During the second period, fish were observed when sorted into new groups, each containing only one personality type. Shy individuals showed the largest changes in behaviour, and increased both the time spent in the open and the number of prey attacks when placed into the new groups. Feeding activity in shy fish during the second period was affected by group composition during the first period. After regrouping, bold individuals decreased their time in the open, whereas intermediate individuals did not change behaviour. Time in the open habitat was, to some extent, influenced by the behaviour of the other members of the group, but number of prey attacks was not. The behaviour of fish of the different personality types we have defined in this study seemed to be based on innate traits, but also modified by the influence of other group members and by habituation to the environment.Communicated by J.Krause 相似文献
13.
Johanneke E. Oosten Carin Magnhagen Charlotte K. Hemelrijk 《Behavioral ecology and sociobiology》2010,64(5):793-802
Most studies of animal personality attribute personality to genetic traits. But a recent study by Magnhagen and Staffan (Behav
Ecol Sociobiol 57:295–303, 2005) on young perch in small groups showed that boldness, a central personality trait, is also shaped by social interactions
and by previous experience. The authors measured boldness by recording the duration that an individual spent near a predator
and the speed with which it fed there. They found that duration near the predator increased over time and was higher the higher
the average boldness of other group members. In addition, the feeding rate of shy individuals was reduced if other members
of the same group were bold. The authors supposed that these behavioral dynamics were caused by genetic differences, social
interactions, and habituation to the predator. However, they did not quantify exactly how this could happen. In the present
study, we therefore use an agent-based model to investigate whether these three factors may explain the empirical findings.
We choose an agent-based model because this type of model is especially suited to study the relation between behavior at an
individual level and behavioral dynamics at a group level. In our model, individuals were either hiding in vegetation or feeding
near a predator, whereby their behavior was affected by habituation and by two social mechanisms: social facilitation to approach
the predator and competition over food. We show that even if we start the model with identical individuals, these three mechanisms
were sufficient to reproduce the behavioral dynamics of the empirical study, including the consistent differences among individuals.
Moreover, if we start the model with individuals that already differ in boldness, the behavioral dynamics produced remained
the same. Our results indicate the importance of previous experience and social interactions when studying animal personality
empirically. 相似文献
14.
Rüdiger Riesch Virginia Duwe Nina Herrmann Lisa Padur Annemarie Ramm Kristin Scharnweber Matthias Schulte Tanja Schulz-Mirbach Madlen Ziege Martin Plath 《Behavioral ecology and sociobiology》2009,63(10):1515-1526
One potential trade-off that bold individuals face is between increased predation risks and gains in resources. Individuals
experiencing high predation and hungry individuals (or individuals with low body condition) are predicted to show increased
boldness. We examined one behavioral trait previously reported to be associated with boldness (the time individual fish needed
to emerge from shelter) in various populations of mollies (Poecilia spp.). Our study system included several southern Mexican surface streams with high piscine predation and high food availability,
sulfidic surface streams with high avian predation, in which the inhabiting fish show reduced body condition, and a sulfidic
cave, where predation and body condition are low. Our comparison revealed very short times to emerge from the start box in
populations from non-sulfidic streams. In sulfidic habitats (whether surface or cave), it took individual Poecilia mexicana considerably longer to emerge from the start box, and the same difference was also found in an independent comparison between
P. mexicana and the closely related, highly sulfide-adapted Poecilia sulphuraria. Fish reared under common garden conditions (in the absence of predators and hydrogen sulfide) showed intermediate boldness
scores to the extremes observed in the field. Our data thus indicate that (a) boldness is shaped by environmental conditions/experiential
effects, but is not heritable, (b) predation affects boldness in the predicted direction, but (c) low body condition leads
to reduced boldness. Extremophile Poecilia spp. spend most of their time surfacing to survive under sulfidic and hypoxic conditions, which exposes them to increased
levels of predations, but the fish forage on the bottom. Hence, in this system, increased boldness does not increase foraging
success. We argue that energy limitation favors reducing energetically costly behaviors, and exploring novel environments
may be just one of them. 相似文献
15.
Johan Höjesjö Bart Adriaenssens Torgny Bohlin Christopher Jönsson Illka Hellström Jörgen I. Johnsson 《Behavioral ecology and sociobiology》2011,65(9):1801-1810
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. 相似文献
16.
Alexander D. M. Wilson Emily M. Whattam Rachel Bennett Laksanavadee Visanuvimol Chris Lauzon Susan M. Bertram 《Behavioral ecology and sociobiology》2010,64(5):703-715
Recently, there has been increasing interest in behavioral syndrome research across a range of taxa. Behavioral syndromes
are suites of correlated behaviors that are expressed either within a given behavioral context (e.g., mating) or between different
contexts (e.g., foraging and mating). Syndrome research holds profound implications for animal behavior as it promotes a holistic
view in which seemingly autonomous behaviors may not evolve independently, but as a “suite” or “package.” We tested whether
laboratory-reared male and female European house crickets, Acheta domesticus, exhibited behavioral syndromes by quantifying individual differences in activity, exploration, mate attraction, aggressiveness,
and antipredator behavior. To our knowledge, our study is the first to consider such a breadth of behavioral traits in one
organism using the syndrome framework. We found positive correlations across mating, exploratory, and antipredatory contexts,
but not aggression and general activity. These behavioral differences were not correlated with body size or condition, although
age explained some of the variation in motivation to mate. We suggest that these across-context correlations represent a boldness
syndrome as individual risk-taking and exploration was central to across-context mating and antipredation correlations in
both sexes. 相似文献
17.
The results reported here demonstrate the existence of cannibalistic behaviour in laboratory-reared Tigriopus fulvus (Fischer, 1860) females towards first-stage non-related nauplii; mothers, sparing their own offspring, do not share this behaviour. The phenomenon is related to the probability of nauplius/female encounters. It is suggested that mother/offspring recognition is mediated by a chemical compound. 相似文献
18.
Although animal personality research may have applied uses, this suggestion has yet to be evaluated by assessing empirical studies examining animal personality and conservation. To address this knowledge gap, we performed a systematic review of the peer-reviewed literature relating to conservation science and animal personality. Criteria for inclusion in our review included access to full text, primary research articles, and relevant animal conservation or personality focus (i.e., not human personality studies). Ninety-two articles met these criteria. We summarized the conservation contexts, testing procedures (including species and sample size), analytical approach, claimed personality traits (activity, aggression, boldness, exploration, and sociability), and each report's key findings and conservation-focused suggestions. Although providing evidence for repeatability in behavior is crucial for personality studies, repeatability quantification was implemented in only half of the reports. Nonetheless, each of the 5 personality traits were investigated to some extent in a range of conservations contexts. The most robust studies in the field showed variance in how personality relates to other ecologically important variables across species and contexts. Moreover, many studies were first attempts at using personality for conservation purposes in a given study system. Overall, it appears personality is not yet a fully realized tool for conservation. To apply personality research to conservation problems, we suggest researchers think about where individual differences in behavior may affect conservation outcomes in their system, assess where there are opportunities for repeated measures, and follow the most current methodological guides on quantifying personality. 相似文献
19.
Grant E. Brown Camille J. Macnaughton Chris K. Elvidge Indar Ramnarine Jean-Guy J. Godin 《Behavioral ecology and sociobiology》2009,63(5):699-706
The antipredator behaviour of prey organisms is shaped by a series of threat-sensitive trade-offs between the benefits associated
with successful predator avoidance and a suite of other fitness-related behaviours such as foraging, mating and territorial
defence. Recent research has shown that the overall intensity of antipredator response and the pattern of threat-sensitive
trade-offs are influenced by current conditions, including variability in predation risk over a period of days to weeks. In
this study, we tested the hypothesis that long-term predation pressure will likewise have shaped the nature of the threat-sensitive
antipredator behaviour of wild-caught Trinidadian guppies (Poecilia reticulata). Female guppies were collected from two populations that have evolved under high- and low-predation pressure, respectively,
in the Aripo River, Northern Mountain Range, Trinidad. Under laboratory conditions, we exposed shoals of three guppies to
varying concentrations of conspecific damage-released chemical alarm cues. Lower Aripo (high-predation) guppies exhibited
the strongest antipredator response when exposed to the highest alarm cue concentration and a graded decline in response intensity
with decreasing concentrations of alarm cue. Upper Aripo (low-predation) guppies, however, exhibited a nongraded (hypersensitive)
response pattern. Our results suggest that long-term predation pressure shapes not only the overall intensity of antipredator
responses of Trinidadian guppies but also their threat-sensitive behavioural response patterns. 相似文献
20.
Jukka Kekäläinen Yi-Te Lai Anssi Vainikka Ilkka Sirkka Raine Kortet 《Behavioral ecology and sociobiology》2014,68(2):197-204
Despite that the existence of animal personalities is widely recognized, no consensus has been reached on the relative importance of different ecological factors behind their expression. Recently, it has been suggested that parasites may have a crucial role in shaping animal personalities, but only a very few studies have experimentally tested the idea. We infected Eurasian minnows (Phoxinus phoxinus) with the brain-encysted trematode parasite, Diplostomum phoxini, and studied whether infection could modify the personality of their hosts. Our results show that D. phoxini infection did not affect the mean levels of boldness, activity or exploration, but infected minnows showed higher repeatability in boldness and activity, and reduced repeatability in exploration. We also found that D. phoxini may be able to break the associations (behavioral syndromes) between behavioral traits, but that this effect may be dependent on parasite intensity. Furthermore, the effect of D. phoxini infection on personality of the hosts was found to be nonlinearly dependent on infection intensity. Taken together, our results suggest that D. phoxini parasites may shape the personality of their hosts, but that behavioral consequences of ecologically relevant infection levels may be rather subtle and easily remain undetected if only the mean trait expressions are compared. 相似文献