scholarly journals Temporal autocorrelation: a neglected factor in the study of behavioral repeatability and plasticity

2019 ◽  
Author(s):  
David J Mitchell ◽  
Antoine M Dujon ◽  
Christa Beckmann ◽  
Peter A Biro
Keyword(s):  
Individual Differences ◽  
Individual Variation ◽  
Repeated Measures ◽  
Poecilia Reticulata ◽  
Energy Levels ◽  
Worked Examples ◽  
Reaction Norm ◽  
Physiological Data ◽  
Temporal Autocorrelation ◽  
Internal States

Abstract Quantifying individual variation in labile physiological or behavioral traits often involves repeated measures through time, so as to test for consistency of individual differences (often using repeatability, “R”) and/or individual differences in trendlines over time. Another form of temporal change in behavior is temporal autocorrelation, which predicts observations taken closely together in time to be correlated, leading to nonrandom residuals about individual temporal trendlines. Temporal autocorrelation may result from slowly changing internal states (e.g., hormone or energy levels), leading to slowly changing behavior. Autocorrelation is a well-known phenomenon, but has been largely neglected by those studying individual variation in behavior. Here, we provide two worked examples which show substantial temporal autocorrelation (r > 0.4) is present in spontaneous activity rates of guppies (Poecilia reticulata) and house mice (Mus domesticus) in stable laboratory conditions, even after accounting for temporal plasticity of individuals. Second, we show that ignoring autocorrelation does bias estimates of R and temporal reaction norm variances upwards, both in our worked examples and in separate simulations. This bias occurs due to the misestimation of individual-specific means and slopes. Given the increasing use of technologies that generate behavioral and physiological data at high sampling rates, we can now study among- and within-individual changes in behavior in more detailed ways, including autocorrelation, which we discuss from biological and methodological perspectives and provide recommendations and annotated R code to help researchers implement these models on their data.

scholarly journals Using a robotic fish to investigate individual differences in social responsiveness in the guppy

2018 ◽  
Vol 5 (8) ◽  
pp. 181026 ◽  
Author(s):  
David Bierbach ◽  
Tim Landgraf ◽  
Pawel Romanczuk ◽  
Juliane Lukas ◽  
Hai Nguyen ◽  
...  
Keyword(s):  
Individual Differences ◽  
Individual Variation ◽  
Poecilia Reticulata ◽  
Open Loop ◽  
Social Cues ◽  
Social Responsiveness ◽  
Small Fish ◽  
Repeated Testing ◽  
Test Environment ◽  
Biomimetic Robots

Responding towards the actions of others is one of the most important behavioural traits whenever animals of the same species interact. Mutual influences among interacting individuals may modulate the social responsiveness seen and thus make it often difficult to study the level and individual variation in responsiveness. Here, open-loop biomimetic robots that provide standardized, non-interactive social cues can be a useful tool. These robots are not affected by the live animal's actions but are assumed to still represent valuable and biologically relevant social cues. As this assumption is crucial for the use of biomimetic robots in behavioural studies, we hypothesized (i) that meaningful social interactions can be assumed if live animals maintain individual differences in responsiveness when interacting with both a biomimetic robot and a live partner. Furthermore, to study the level of individual variation in social responsiveness, we hypothesized (ii) that individual differences should be maintained over the course of multiple tests with the robot. We investigated the response of live guppies ( Poecilia reticulata ) when allowed to interact either with a biomimetic open-loop-controlled fish robot—‘Robofish’—or with a live companion. Furthermore, we investigated the responses of live guppies when tested three times with Robofish. We found that responses of live guppies towards Robofish were weaker compared with those of a live companion, most likely as a result of the non-interactive open-loop behaviour of Robofish. Guppies, however, were consistent in their individual responses between a live companion and Robofish, and similar individual differences in response towards Robofish were maintained over repeated testing even though habituation to the test environment was detectable. Biomimetic robots like Robofish are therefore a useful tool for the study of social responsiveness in guppies and possibly other small fish species.

scholarly journals Metabolism, personality and pace of life in the Trinidadian guppy, Poecilia reticulata

Behaviour ◽  
2016 ◽  
Vol 153 (13-14) ◽  
pp. 1517-1543 ◽  
Author(s):  
S.J. White ◽  
T.J. Kells ◽  
A.J. Wilson
Keyword(s):  
Individual Variation ◽  
Repeated Measures ◽  
Life Histories ◽  
Poecilia Reticulata ◽  
High Growth ◽  
Early Maturation ◽  
Metabolic Traits ◽  
Personality Differences ◽  
Pace Of Life ◽  
Trinidadian Guppy

While among-individual variation in behaviour, or personality, is common across taxa, its mechanistic underpinnings are poorly understood. The Pace of Life syndrome (POLS) provides one possible explanation for maintenance of personality differences. POLS predicts that metabolic differences will covary with behavioural variation, with high metabolism associated with risk prone behaviour and ‘faster’ life histories (e.g., high growth, early maturation). We used a repeated measures approach, assaying metabolic traits (rate and scope), behaviour and growth to test these predictions in the Trinidadian guppy, Poecilia reticulata. We found that while individuals varied significantly in their behaviour and growth rate, more risk prone individuals did not grow significantly faster. Furthermore, after accounting for body size there was no support for among-individual variation in metabolic traits. Thus, while personality differences are clearly present in this population, they do not covary with metabolism and the POLS framework is not supported.

scholarly journals Psychoactive pollution suppresses individual differences in fish behaviour

2021 ◽  
Vol 288 (1944) ◽  
pp. 20202294
Author(s):  
Giovanni Polverino ◽  
Jake M. Martin ◽  
Michael G. Bertram ◽  
Vrishin R. Soman ◽  
Hung Tan ◽  
...  
Keyword(s):  
Individual Differences ◽  
Risk Taking ◽  
Strong Evidence ◽  
Environmental Contamination ◽  
Individual Variation ◽  
Poecilia Reticulata ◽  
Fish Behaviour ◽  
Adaptive Potential ◽  
Relative Contribution ◽  
Low Concentrations

Environmental contamination by pharmaceuticals is global, substantially altering crucial behaviours in animals and impacting on their reproduction and survival. A key question is whether the consequences of these pollutants extend beyond mean behavioural changes, restraining differences in behaviour between individuals. In a controlled, two-year, multigenerational experiment with independent mesocosm populations, we exposed guppies ( Poecilia reticulata ) to environmentally realistic levels of the ubiquitous pollutant fluoxetine (Prozac). Fish (unexposed: n = 59, low fluoxetine: n = 57, high fluoxetine: n = 58) were repeatedly assayed on four separate occasions for activity and risk-taking behaviour. Fluoxetine homogenized individuals' activity, with individual variation in populations exposed to even low concentrations falling to less than half that in unexposed populations. To understand the proximate mechanism underlying these changes, we tested the relative contribution of variation within and between individuals to the overall decline in individual variation. We found strong evidence that fluoxetine erodes variation in activity between but not within individuals, revealing the hidden consequences of a ubiquitous contaminant on phenotypic variation in fish—likely to impair adaptive potential to environmental change.

scholarly journals Male aggressiveness and risk-taking during reproduction are repeatable but not correlated in a wild bird population

2021 ◽  
Vol 75 (7) ◽  
Author(s):  
Stephen M. Salazar ◽  
Julia I. Camacho García ◽  
Miriam Kuspiel ◽  
Rienk W. Fokkema ◽  
Jan Komdeur ◽  
...  
Keyword(s):  
Individual Differences ◽  
Risk Taking ◽  
Individual Variation ◽  
Repeated Measures ◽  
Human Observer ◽  
Recent Theory ◽  
Blue Tit ◽  
Animal Kingdom ◽  
Cyanistes Caeruleus ◽  
Pace Of Life

Abstract The existence of among-individual variation in behaviour within populations is poorly understood. Recent theory suggests that fine-scale individual differences in investment into current versus future reproduction may lead to a ‘slow-fast’-pace-of-life continuum, also referred to as the ‘pace-of-life-syndrome’ (POLS) hypothesis. According to this idea, individuals are predicted to differ in their level of risk-taking, which may drive among-individual variation and covariation of behaviours. Consistent individual differences in aggression, an ecologically relevant and potentially risky behaviour, have been reported across the animal kingdom. Here we test whether such individual differences in aggression are a manifestation of underlying differences in risk-taking. In a wild blue tit (Cyanistes caeruleus) population, we used standard behavioural tests to investigate if male territorial aggressiveness and risk-taking during breeding are positively related. At the start of breeding, we simulated conspecific territorial intrusions to obtain repeated measures of male aggressiveness. Subsequently, we measured male risk-taking as their latency to resume brood provisioning after presenting two different predators at their nest: human and sparrowhawk, a common predator of adult songbirds. First, we found substantial repeatability for male aggressiveness (R = 0.56 ± 0.08 SE). Second, while males took longer to resume provisioning after presentation of a sparrowhawk mount as compared to a human observer, risk-taking was repeatable across these two predator contexts (R = 0.51 ± 0.13 SE). Finally, we found no evidence for a correlation between male aggressiveness and risk-taking, thereby providing little support to a main prediction of the POLS hypothesis. Significance statement Consistent, and often correlated, individual differences in basal behaviours, such as aggression, exploration and sociability, are found across the animal kingdom. Why individuals consistently differ in their behaviour is poorly understood, as behavioural traits would seem inherently flexible. The ‘pace-of-life syndrome’ (POLS) hypothesis proposes observed behavioural variation to reflect differences in risk-taking associated with individual reproductive strategies. We tested this idea in a wild blue tit population by investigating whether individual males that were more aggressive toward territorial intruders also took more risk when provisioning their nestlings under a threat of predation. While we found consistent individual differences in both aggressiveness and risk-taking, these behaviours were not significantly correlated. Therefore, our study demonstrates among-individual variation in ecologically relevant behaviours in wild blue tits but provides little support for the POLS hypothesis.

scholarly journals Habituation and individual variation in the endocrine stress response in the Trinidadian guppy (Poecilia reticulata)

2018 ◽  
Author(s):  
T.M. Houslay ◽  
R.L. Earley ◽  
A.J. Young ◽  
A.J. Wilson
Keyword(s):  
Individual Differences ◽  
Stress Response ◽  
Chronic Stress ◽  
Individual Variation ◽  
Poecilia Reticulata ◽  
General Pattern ◽  
Small Fish ◽  
Habituation Rate ◽  
Endocrine Stress Response ◽  
Cortisol Release

AbstractThe vertebrate stress response enables individuals to react to and cope with environmental challenges. A crucial aspect of the stress response is the elevation of circulating glucocorticoids. However, continued activation of the stress response under repeated (or chronic) stress can be damaging to fitness. Under certain circumstances it may therefore be adaptive to habituate to repeated exposures to a particular stressor by reducing the magnitude of any associated release of glucocorticoids. Here, we investigate whether Trinidadian guppies (Poecilia reticulata) habituate to repeated exposure to a mild stressor, using a waterborne hormone sampling approach that has previously been shown to elicit a stress response in small fish. We also test for individual variation in the extent of habituation to this stressor. Concentrating on freely circulating cortisol, we found that the first exposure to the assay induced high cortisol release rates but that guppies tended to habituate quickly to subsequent exposures. There were consistent differences among individuals in their average cortisol release rate (after accounting for effects of variables such as body size) over repeated exposures. Our analyses did not find evidence of individual differences in habituation rate, although limitations in statistical power could account for this finding. We also present data on free 11-ketotestosterone, in addition to conjugated forms of both hormones. We discuss consistent individual differences around the general pattern of habituation in the flexible stress response, and highlight the potential for individual variation in habituation to facilitate selection against the deleterious effects of chronic stress.Summary statementTrinidadian guppies habituate quickly to repeated stress exposure, and exhibit consistent differences in their endocrine stress response. We provide a framework for analysing individual variation in habituation rate.

The challenge of accounting for individual differences in folk-economic beliefs

2018 ◽  
Vol 41 ◽  
Author(s):  
Benjamin C. Ruisch ◽  
Rajen A. Anderson ◽  
David A. Pizarro
Keyword(s):  
Individual Differences ◽  
Individual Variation ◽  
Political Ideologies ◽  
Economic Beliefs ◽  
Existing Data

AbstractWe argue that existing data on folk-economic beliefs (FEBs) present challenges to Boyer & Petersen's model. Specifically, the widespread individual variation in endorsement of FEBs casts doubt on the claim that humans are evolutionarily predisposed towards particular economic beliefs. Additionally, the authors' model cannot account for the systematic covariance between certain FEBs, such as those observed in distinct political ideologies.

Inter-individual variation shapes the human microbiome

2019 ◽  
Vol 42 ◽  
Author(s):  
Emily F. Wissel ◽  
Leigh K. Smith
Keyword(s):  
Individual Differences ◽  
Individual Variation ◽  
Human Microbiome ◽  
Individual Variability ◽  
Microbiota Composition ◽  
Target Article ◽  
Microbiome Research

Abstract The target article suggests inter-individual variability is a weakness of microbiota-gut-brain (MGB) research, but we discuss why it is actually a strength. We comment on how accounting for individual differences can help researchers systematically understand the observed variance in microbiota composition, interpret null findings, and potentially improve the efficacy of therapeutic treatments in future clinical microbiome research.

scholarly journals Imminent risk of predation reduces the relative strength of postcopulatory sexual selection in the guppy

2020 ◽  
Vol 375 (1813) ◽  
pp. 20200076
Author(s):  
Alexandra Glavaschi ◽  
Silvia Cattelan ◽  
Alessandro Grapputo ◽  
Andrea Pilastro
Keyword(s):  
Sexual Selection ◽  
Sperm Competition ◽  
Repeated Measures ◽  
Poecilia Reticulata ◽  
Male Reproductive Success ◽  
Sperm Production ◽  
Postcopulatory Sexual Selection ◽  
Repeated Measures Design ◽  
Risk Of Predation ◽  
Livebearing Fish

Fifty years of research on sperm competition has led to a very good understanding of the interspecific variation in sperm production traits. The reasons why this variation is often very large within populations have been less investigated. We suggest that the interaction between fluctuating environmental conditions and polyandry is a key phenomenon explaining such variation. We focus here on imminent predation risk (IPR). IPR impacts significantly several aspects of prey behaviour and reproduction, and it is expected to influence the operation of sexual selection before and after mating. We estimated the effect of IPR on the male opportunity for pre- and postcopulatory sexual selection in guppies ( Poecilia reticulata ), a livebearing fish where females prefer colourful males and mate multiply. We used a repeated-measures design, in which males were allowed to mate with different females either under IPR or in a predator-free condition. We found that IPR increased the total opportunity for sexual selection and reduced the relative contribution of postcopulatory sexual selection to male reproductive success. IPR is inherently variable and our results suggest that interspecific reproductive interference by predators may contribute towards maintaining the variation in sperm production within populations. This article is part of the theme issue ‘Fifty years of sperm competition'.

scholarly journals Individual variation and the biomechanics of maneuvering flight in hummingbirds

2020 ◽  
Vol 223 (20) ◽  
pp. jeb161828
Author(s):  
R. Dakin ◽  
P. S. Segre ◽  
D. L. Altshuler
Keyword(s):  
Individual Differences ◽  
Best Practices ◽  
High Throughput ◽  
Individual Variation ◽  
Simulated Data ◽  
Maneuvering Flight ◽  
Sample Average ◽  
Voluntary Behavior ◽  
Sample Maximum ◽  
Tracking Technology

ABSTRACTAn animal's maneuverability will determine the outcome of many of its most important interactions. A common approach to studying maneuverability is to force the animal to perform a specific maneuver or to try to elicit maximal performance. Recently, the availability of wider-field tracking technology has allowed for high-throughput measurements of voluntary behavior, an approach that produces large volumes of data. Here, we show how these data allow for measures of inter-individual variation that are necessary to evaluate how performance depends on other traits, both within and among species. We use simulated data to illustrate best practices when sampling a large number of voluntary maneuvers. Our results show how the sample average can be the best measure of inter-individual variation, whereas the sample maximum is neither repeatable nor a useful metric of the true variation among individuals. Our studies with flying hummingbirds reveal that their maneuvers fall into three major categories: simple translations, simple rotations and complex turns. Simple maneuvers are largely governed by distinct morphological and/or physiological traits. Complex turns involve both translations and rotations, and are more subject to inter-individual differences that are not explained by morphology. This three-part framework suggests that different wingbeat kinematics can be used to maximize specific aspects of maneuverability. Thus, a broad explanatory framework has emerged for interpreting hummingbird maneuverability. This framework is general enough to be applied to other types of locomotion, and informative enough to explain mechanisms of maneuverability that could be applied to both animals and bio-inspired robots.

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