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Results for “Animal Behavior and Cognition”

Search indexed bioRxiv preprints in genomics, neuroscience, cell biology and bioinformatics. Read source abstracts and check manuscript versions; preprints are not peer reviewed.

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bioRxiv2017

Payoff-biased social learning underlies the diffusion of novel extractive foraging traditions in a wild primate

AO_SCPLOWBSTRACTC_SCPLOWThe type and variety of learning strategies used by individuals to acquire behaviours in the wild are poorly understood, despite the presence of behavioural traditions in diverse taxa. Social learning strategies such as conformity can be broadly adaptive, but may also retard the spread of adaptive innovations. Strategies like payoff-biased learning, in contrast, are effective at diffusing new behaviour but may perform poorly when adaptive behaviour is common. We present a field experiment in a wild primate, Cebus capucinus, that introduced a novel food item and documented the innovation and diffusion of successful extraction techniques. We develop a multilevel, Bayesian statistical analysis that allows us to quantify individual-level evidence for different social and individual learning strategies. We find that payoff-biased social learning and age-biased social learning are primarily responsible for the diffusion of new techniques. We find no evidence of conformity; instead rare techniques receive slightly increased attention. We also find substantial and important variation in individual learning strategies that is patterned by age, with younger individuals being more influenced by both social information and their own individual experience. The aggregate cultural dynamics in turn depend upon the variation in learning strategies and the age structure of the wild population.

animal behavior and cognition↗

bioRxiv2017

Strategic exploration in human adaptive control

How do people explore in order to gain rewards in uncertain dynamical systems? Within a reinforcement learning paradigm, control normally involves trading off between exploration (i.e. trying out actions in order to gain more knowledge about the system) and exploitation (i.e. using current knowledge of the system to maximize reward). We study a novel control task in which participants must steer a boat on a grid, aiming to follow a path of high reward whilst learning how their actions affect the boats position. We find that participants explore strategically yet conservatively, exploring more when mistakes are less costly and practicing actions that will be required later on.

animal behavior and cognition↗

bioRxiv2017

GCalignR: An R package for aligning Gas-Chromatography data

Chemical cues are arguably the most fundamental means of animal communication and play an important role in mate choice and kin recognition. Consequently, gas chromatography (GC) in combination with either mass spectrometry (MS) or flame ionisation detection (FID) are commonly used to characterise complex chemical samples. Both GC-FID and GC-MS generate chromatograms comprising peaks that are separated according to their retention times and which represent different substances. Across chromatograms of different samples, homologous substances are expected to elute at similar retention times. However, random and often unavoidable experimental variation introduces noise, making the alignment of homologous peaks challenging, particularly with GC-FID data where mass spectral data are lacking. Here we present GCalignR, a user-friendly R package for aligning GC-FID data based on retention times. The package also implements dynamic visualisations to facilitate inspection and fine-tuning of the resulting alignments, and can be integrated within a broader workflow in R to facilitate downstream multivariate analyses. We demonstrate an example workflow using empirical data from Antarctic fur seals and explore the impact of user-defined parameter values by calculating alignment error rates for multiple datasets. The resulting alignments had low error rates for most of the explored parameter space and we could also show that GCalignR performed equally well or better than other available software. We hope that GCalignR will help to simplify the processing of chemical datasets and improve the standardization and reproducibility of chemical analyses in studies of animal chemical communication and related fields.

animal behavior and cognition↗

bioRxiv2017

Dissociable effects of surprising rewards on learning and memory

The extent to which rewards deviate from learned expectations is tracked by a signal known as a \"reward prediction error\", but it is unclear how this signal interacts with episodic memory. Here, we investigated whether learning in a high-risk environment, with frequent large prediction errors, gives rise to higher fidelity memory traces than learning in a low-risk environment. In Experiment 1, we showed that higher magnitude prediction errors, positive or negative, improved recognition memory for trial-unique items. Participants also increased their learning rate after large prediction errors. In addition, there was an overall higher learning rate in the low-risk environment. Although unsigned prediction errors enhanced memory and increased learning rate, we did not find a relationship between learning rate and memory, suggesting that these two effects were due to separate underlying mechanisms. In Experiment 2, we replicated these results with a longer task that posed stronger memory demands and allowed for more learning. We also showed improved source and sequence memory for high-risk items. In Experiment 3, we controlled for the difficulty of learning in the two risk environments, again replicating the previous results. Moreover, equating the range of prediction errors in the two risk environments revealed that learning in a high-risk context enhanced episodic memory above and beyond the effect of prediction errors to individual items. In summary, our results across three studies showed that (absolute) prediction error magnitude boosted both episodic memory and incremental learning, but the two effects were not correlated, suggesting distinct underlying systems.

animal behavior and cognition↗

bioRxiv2017

A practical guide for inferring reliable dominance hierarchies and estimating their uncertainty

Many animal social structures are organized hierarchically, with dominant individuals monopolizing resources. Dominance hierarchies have received great attention from behavioural and evolutionary ecologists. As a result, there are many methods for inferring hierarchies from social interactions. Yet, there are no clear guidelines about how many observed dominance interactions (i.e. sampling effort) are necessary for inferring reliable dominance hierarchies, nor are there any established tools for quantifying their uncertainty. In this study, we simulated interactions (winners and losers) in scenarios of varying steepness (the probability that a dominant defeats a subordinate based on their difference in rank). Using these data, we (1) quantify how the number of interactions recorded and hierarchy steepness affect the performance of three methods, (2) propose an amendment that improves the performance of a popular method, and (3) suggest two easy procedures to measure uncertainty in the inferred hierarchy. First, we found that the ratio of interactions to individuals required to infer reliable hierarchies is surprisingly low, but depends on the hierarchy steepness and method used. We then show that Davids score and our novel randomized Elo-rating are the two best methods, whereas the original Elo-rating and the recently described ADAGIO perform less well. Finally, we propose two simple methods to estimate uncertainty at the individual and group level. These uncertainty measures further allow to differentiate non-existent, very flat and highly uncertain hierarchies from intermediate, steep and certain hierarchies. Overall, we find that the methods for inferring dominance hierarchies are relatively robust, even when the ratio of observed interactions to individuals is as low as 10 to 20. However, we suggest that implementing simple procedures for estimating uncertainty will benefit researchers, and quantifying the shape of the dominance hierarchies will provide new insights into the study organisms.\n\nHighlightsO_LIDavids score and the randomized Elo-rating perform best.\nC_LIO_LIMethod performance depends on hierarchy steepness and sampling effort.\nC_LIO_LIGenerally, inferring dominance hierarchies requires relatively few observations.\nC_LIO_LIThe R package \"aniDom\" allows easy estimation of hierarchy uncertainty.\nC_LIO_LIHierarchy uncertainty provides insights into the shape of the dominance hierarchy.\nC_LI

animal behavior and cognition↗

bioRxiv2017

Good tutors are not Dear Enemies in Song Sparrows

Bird song is the most widely studied example of vocal learning outside human language and shares important parallels with it, including the importance of social factors during development. Our understanding of how social factors affect song learning however remains surprisingly incomplete. Here we examine the possible role of aggressive interactions in determining song \"tutor\" choice in song sparrows (Melospiza melodia), a songbird in which individuals display song learning strategies ranging from learning primarily from one tutor, to learning a few songs each from a number of tutors. We test two hypotheses: The Competition hypothesis suggests that young birds learn more from tutors with whom they compete especially intensely and predicts that tutees will respond with high aggression to tutor songs. In contrast the Cooperation hypothesis suggests that song learning reflects a cooperative relationship between the tutor and the tutee and predicts that tutees will respond with low aggression to tutor songs. In a playback experiment we found that birds respond more aggressively to songs of their tutors than they do to songs of strangers and that the strength of aggressive response correlated positively with how much they had learned from that tutor. These results provide the first field evidence for the hypothesis that young males preferentially learn their songs from adult males with whom they compete most intensely during the song-learning phase, and perhaps afterwards.

animal behavior and cognition↗

bioRxiv2017

Ethoscopes: An Open Platform For High-Throughput Ethomics

We present ethoscopes, machines for high-throughput analysis of behaviour in Drosophila and other animals. Ethoscopes provide a software and hardware solution that is reproducible and easily scalable; they perform, in real-time, tracking and profiling of behaviour using a supervised machine learning algorithm; they can deliver behaviourally-triggered stimuli to flies in a feedback-loop mode; and they are highly customisable and open source. Ethoscopes can be built easily using 3D printing technology and rely on Raspberry Pi microcomputers and Arduino boards to provide affordable and flexible hardware. All software and construction specifications are available at http://lab.gilest.ro/ethoscope.

animal behavior and cognition↗

bioRxiv2017

CaMK (CMK-1) and O-GlcNAc transferase (OGT-1) modulate mechanosensory responding and habituation in an interstimulus interval-dependent manner in Caenorhabditis elegans

The ability to learn is an evolutionarily conserved adaptation that remains incompletely understood. Genetically tractable model organisms facilitate mechanistic explanations of learning that span genetic, neural circuit, and behavioural levels. Many aspects of neural physiology, including processes that underlie learning (e.g. neurotransmitter release and long-lasting changes in synaptic strength), are regulated by brief and local changes in [m] levels of free intracellular Ca2+. On this scale, changes in [Ca2+] activate many Ca2+-sensors, including the Ca2+/calmodulin-dependent kinases (CaMKs). Here we reveal that the Caenorhabditis elegans ortholog of CaMK1/4, CMK-1, functions in primary sensory neurons to regulate responses to mechanical stimuli and behavioral plasticity, specifically habituation, a conserved form of non-associative learning. The habituation phenotypes of cmk-1 mutants were dependent on interstimulus interval (ISI), such that CMK-1 slows habituation at short ISIs, but promotes it at long ISIs. We predicted potential CaMK phosphorylation targets from catalytic site analysis of the human and C. elegans CaMKs and mutant analysis of these candidates implicated O-linked N-acetylglucosamine (O-GlcNAc) transferase, OGT-1, in mechanosensitivity and learning. Cell specific rescue and knockdown experiments showed that both CMK-1 and OGT-1 function cell autonomously in mechanosensory neurons to modulate learning. Interestingly, despite their similar mutant phenotypes, detailed behavioral analysis of double mutants demonstrated that CMK-1 and OGT-1 act in parallel genetic pathways. Our research identifies CMK-1 and OGT-1 as co-expressed yet independent regulators of mechanosensitivity and learning.

animal behavior and cognition↗

bioRxiv2017

Optimal construction of army ant living bridges

Integrating the costs and benefits of collective behaviors is a fundamental challenge to understanding the evolution of group living. These costs and benefits can rarely be quantified simultaneously due to the complexity of the interactions within the group, or even compared to each other because of the absence of common metrics between them. The construction of living bridges by New World army ants - which they use to shorten their foraging trails - is a unique example of a collective behavior where costs and benefits have been experimentally measured and related to each other. As a result, it is possible to make quantitative predictions about when and how the behavior will be observed. In this paper, we extend a previous mathematical model of these costs and benefits into a general framework for analyzing the optimal formation, and final configuration, of army ant living bridges. We provide experimentally testable predictions of the final bridge position, as well as the optimal formation process for certain cases, for a wide range of scenarios, which more closely resemble common terrain obstacles that ants encounter in nature. As such, our framework offers a rare benchmark for determining the evolutionary pressures governing the evolution of a naturally occurring collective animal behavior.

animal behavior and cognition↗

bioRxiv2017

Temporary mate removal during incubation leads to variable compensation in a biparental shorebir

Biparental care for offspring requires cooperation, but it is also a potential source of conflict, since one parent may care less at the expense of the other. How, then, do parents respond to the reduction of their partners care? Theoretical models predict that parents that feed offspring should partially compensate for the reduced care of their partner. However, for incubating birds partial compensation is unlikely the optimal strategy, because the entire brood can fail with reduced care. Although biparental incubation dominates in non-passerine birds, short-term manipulations of parental care and evaluations of individual differences in the response, both crucial to our understanding of parental cooperation, are scarce. Here, we describe the response of semipalmated sandpiper (Calidris pusilla) parents to a 24-hour removal of their partner during the incubation period, explore factors that can explain individual variation in the response, and describe how incubation rhythms changed after the removed parent returned. On average, the parents compensated partially for the absence of their partners care (59%; 95%CI: 49-70%, N = 25 individuals). The level of compensation did not differ between the sexes. However, individual responses varied from no to full compensation (2-101%). In seven nests where the removed parent never returned, the widowed parent attended the nest for 0-10 days (median: 4 days). In contrast to patterns observed in undisturbed nests or in uniparental species, nest attendance during compensation tended to be higher during the warmer part of the day. Although the level of compensation was not related to the before-experimental share of incubation, more responsive parents (that left the nest earlier upon human approach) compensated more. The quality of incubation in the after-experimental period was lower than usual, but improved quickly over time. Our findings suggest that full compensation might be limited by energetic constraints or by variation in responsiveness to the absence of the partner. Nevertheless, semipalmated sandpiper parents are able to adjust their subsequent incubation behaviour to take full responsibility for the nest when widowed. Because (nearly) full compensation was the most common response, we speculate that all individuals attempt full compensation, but that some fail because their energy stores get depleted, or because they are less responsive to the absence of their partner.

animal behavior and cognition↗

bioRxiv2017

Association Indices For Quantifying Social Relationships: How To Deal With Missing Observations Of Individuals Or Groups

Social network analysis has provided important insight into many population processes in wild animals. Constructing social networks requires quantifying the relationship between each pair of individuals in the population. Researchers often use association indices to convert observations into a measure of propensity for individuals to be seen together. At its simplest, this measure is just the probability of observing both individuals together given that one has been seen (the simple ratio index). However, this probability becomes more challenging to calculate if the detection rate for individuals is imperfect. We first evaluate the performance of existing association indices at estimating true association rates under scenarios where (i) only a proportion of all groups are observed (group location errors), (ii) not all individuals are observed despite being present (individual location errors), and (iii) a combination of the two. Commonly-used methods aimed at dealing with incomplete observations perform poorly because they are based on arbitrary observation probabilities. We then derive complete indices that can be calibrated for the different types of observation probabilities to generate accurate estimates of association rates. These are provided in an R package that readily interfaces with existing routines. We conclude that using calibration data is an important step when constructing animal social networks, and that in their absence, researchers should use a simple estimator and explicitly consider the impact of this on their findings.

animal behavior and cognition↗

bioRxiv2017

Aggressiveness As A Latent Personality Trait Of Domestic Dogs: Testing Local Independence And Measurement Invariance

Studies of animal personality attempt to uncover underlying or latent personality traits that explain broad patterns of behaviour, often by applying latent variable statistical models (e.g. factor analysis) to multivariate data sets. Two integral, but infrequently confirmed, assumptions of latent variable models in animal personality are: i) behavioural variables are independent (i.e. uncorrelated) conditional on the latent personality traits they reflect (local independence), and ii) personality traits are associated with behavioural variables in the same way across individuals or groups of individuals (measurement invariance). We tested these assumptions using observations of aggression in four age classes (4 - 10 months, 10 months - 3 years, 3 - 6 years, over 6 years) of male and female shelter dogs (N = 4,743) in 11 different contexts. A structural equation model supported the hypothesis of two positively correlated personality traits underlying aggression across contexts: aggressiveness towards people and aggressiveness towards dogs (comparative fit index: 0.96; Tucker-Lewis index: 0.95; root mean square error of approximation: 0.03). Aggression across contexts was moderately repeatable (towards people: intraclass correlation coefficient (ICC) = 0.479; towards dogs: ICC = 0.303).\n\nHowever, certain contexts related to aggressiveness towards people (but not dogs) shared significant residual relationships unaccounted for by latent levels of aggressiveness.\n\nFurthermore, aggressiveness towards people and dogs in different contexts interacted with sex and age. Thus, sex and age differences in displays of aggression were not simple functions of underlying aggressiveness. Our results illustrate that the robustness of traits in latent variable models must be critically assessed before making conclusions about the effects of, or factors influencing, animal personality. Our findings are of concern because inaccurate aggressive personality trait attributions can be costly to dogs, recipients of aggression and society in general.

animal behavior and cognition↗

bioRxiv2017

Bridging Computational Neuroscience and Machine Learning on Non-Stationary Multi-Armed Bandits

Fast adaptation to changes in the environment requires both natural and artificial agents to be able to dynamically tune an exploration-exploitation trade-off during learning. This trade-off usually determines a fixed proportion of exploitative choices (i.e. choice of the action that subjectively appears as best at a given moment) relative to exploratory choices (i.e. testing other actions that now appear worst but may turn out promising later). The problem of finding an efficient exploration-exploitation trade-off has been well studied both in the Machine Learning and Computational Neuroscience fields. Rather than using a fixed proportion, non-stationary multi-armed bandit methods in the former have proven that principles such as exploring actions that have not been tested for a long time can lead to performance closer to optimal - bounded regret. In parallel, researches in the latter have investigated solutions such as progressively increasing exploitation in response to improvements of performance, transiently increasing exploration in response to drops in average performance, or attributing exploration bonuses specifically to actions associated with high uncertainty in order to gain information when performing these actions. In this work, we first try to bridge some of these different methods from the two research fields by rewriting their decision process with a common formalism. We then show numerical simulations of a hybrid algorithm combining bio-inspired meta-learning, kalman filter and exploration bonuses compared to several state-of-the-art alternatives on a set of non-stationary stochastic multi-armed bandit tasks. While we find that different methods are appropriate in different scenarios, the hybrid algorithm displays a good combination of advantages from different methods and outperforms these methods in the studied scenarios.

animal behavior and cognition↗

bioRxiv2017

Insect behavioral evidence of spatial memories during environmental reconfiguration

Insects are great explorers, able to navigate through long-distance trajectories and successfully find their way back. Their navigational routes cross dynamic environments suggesting adaptation to novel configurations. Arthropods and vertebrates share neural organizational principles and it has been shown that rodents modulate their neural spatial representation accordingly with environmental changes. However, it is unclear whether insects reflexively adapt to environmental changes or retain memory traces of previously explored situations. We sought to disambiguate between insect behavior at environmental novel situations and reconfiguration conditions. An immersive mixed-reality multi-sensory setup was built to replicate multi-sensory cues. We have designed an experimental setup where female crickets Gryllus Bimaculatus were trained to move towards paired auditory and visual cues during primarily phonotactic driven behavior. We hypothesized that insects were capable of identifying sensory modifications in known environments. Our results show that, regardless of the animals history, novel situation conditions did not compromise the animals performance and navigational directionality towards a novel target location. However, in trials where visual and auditory stimuli were spatially decoupled, the animals heading variability towards a previously known location significantly increased. Our findings showed that crickets are able to behaviorally manifest environmental reconfiguration, suggesting the encoding for spatial representation.

animal behavior and cognition↗

bioRxiv2017

Sex-specific inhibition and stimulation of worker-reproductive transition in a termite

In social insects, the postembryonic development of individuals exhibits strong phenotypic plasticity in response to environment, thus generating the caste system. Different from eusocial Hymenoptera, in which queens dominate reproduction and inhibit worker fertility, the primary reproductive caste in termites (kings and queens) can be replaced by neotenic reproductives derived from functionally sterile individuals. Feedback regulation of nestmate differentiation into reproductives has been suggested, but the sex-specificity remains inconclusive. In the eastern subterranean termite, Reticulitermes flavipes, we tested the hypothesis that neotenic reproductives regulate worker-reproductive transition in a sex-specific manner. With this R. flavipes system, we demonstrate a sex-specific regulatory mechanism with both inhibitory and stimulatory functions. Neotenics inhibit workers of the same sex from differentiating into additional reproductives, but stimulate workers of the opposite sex to undergo this transition. Furthermore, this process is not affected by the presence of soldiers. Our results highlight the extraordinary reproductive plasticity of termites in response to social cues, and provide insights into the regulation of reproductive division of labour in a hemimetabolous social insect.

animal behavior and cognition↗

bioRxiv2017

Limitation Of Dogwhelk Consumption Of Mussels By Crab Cues Depends On Dogwhelk Density And Cue Type

Predator nonconsumptive effects (NCEs) on prey activity are common in nature. Upon sensing predator cues, a common prey response is to reduce feeding to avoid being detected by predators. Using an aquatic system, this study investigated how prey density and predator cue type affect predator NCEs on prey feeding. Prey density was investigated because, as it increases, the individual risk of being preyed upon decreases, which may reduce NCEs if prey can detect conspecifics. Predator cue type was investigated because waterborne cues would trigger weaker NCEs than waterborne and tactile cues combined, as predation risk may be perceived by prey to be stronger in the second case. Specifically, a factorial experiment tested the hypotheses that (i) increasing dogwhelk (prey) density reduces the limitation that crab (predator) chemical cues can have on dogwhelk consumption of mussels and that (ii) chemical and tactile crab cues combined limit dogwhelk feeding more strongly than chemical crab cues alone. The results broadly supported these hypotheses. On the one hand, crab chemical cues limited the per-capita consumption of mussels by dogwhelks at a low dogwhelk density, but such NCEs disappeared at intermediate and high dogwhelk densities. On the other hand, the combination of chemical and tactile cues from crabs caused stronger NCEs, as dogwhelk consumption of mussels was negatively affected at all three dogwhelk densities. The structurally complex mussel beds may provide not only food for dogwhelks but a refuge from crab predation that allows dogwhelk density to limit crab NCEs when mediated by waterborne cues. Overall, this study suggests that prey evaluate conspecific density when assessing predation risk and that the type of cues prey are exposed to can affect their interpretation of risk.

animal behavior and cognition↗

bioRxiv2017

Evolution Of Coprophagy And Nutrient Absorption In A Cave Salamander

The transition from carnivory to omnivory is poorly understood. The ability to feed at more than one trophic level theoretically increases an animals fitness in a novel environment. Because of the absence of light and photosynthesis, most subterranean ecosystems are characterized by very few trophic levels, such that food scarcity is a challenge in many subterranean habitats. One strategy against starvation is to expand diet breadth. Grotto salamanders (Eurycea spelaea) are known to ingest bat guano deliberately, challenging the general understanding that salamanders are strictly carnivorous. Here we tested the hypothesis that grotto salamanders have broadened their diet related to cave adaptation and found that, although coprophagous behavior is present, salamanders are unable to acquire sufficient nutrition from bat guano alone. Our results suggest that the coprophagic behavior has emerged prior to physiological or gut biome adaptations.

animal behavior and cognition↗

bioRxiv2017

Wall following in Xenopus laevis is passive

The tendency of animals to follow boundaries within their environment can serve as a strategy for spatial learning or defence. We examined whether animals of Xenopus laevis employ such a strategy by characterizing their swimming behaviour. We also investigated potential developmental changes, the influence of tentacles, which some of the developmental stages possess, and whether wall-following is active (animals seek out wall contact) or passive. Animals swimming movements were recorded with a camera from above in a square tank with shallow water and their trajectories were analysed especially for proximity to the nearest wall. With the exception of young larvae, in which wall following was less strong, the vast majority of animals - tadpoles and froglets - spent more time near the wall than what would be expected from the proportion of the area near the wall. The total distance covered was not a confounding factor. Wall following was also not influenced by whether the surrounding of the tank was black or white, illuminated by infrared light, or by the presence or absence of tentacles. Animals were stronger wall followers in smaller tanks. When given a choice in a convex tank to swim straight and leave the wall or turn to follow the wall, the animals consistently left the wall, indicating that wall following in Xenopus laevis is passive. This implies that wall following behaviour in Xenopus derives from constraints imposed by the environment (or the experimenter) and is unlikely a strategy for spatial learning or safety-seeking.\n\nSummary statementXenopus laevis tadpoles and froglets tend to swim along the walls of a square tank; but this wall following is passive - in a convex tank, they leave the wall.

animal behavior and cognition↗