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bioRxiv2018

Tibetan antelope rests like a Puppet

AbstractRest contributes to a large part of animals daily life, and animals usually rest in two ways, standing or in recumbence. For small or medium sized ungulates, they bed to rest in most cases, and standing rest is very rare and hardly seen. Here we described a standing rest behaviour of medium sized Tibetan antelopes (Pantholops hodgsonii) living on the roof of the world, Tibet Plateau, which has not been reported before. We named the standing rest behaviour here as Puppet behaviour, since the antelope can stand still for a certain time just like a Puppet. Of the total 304 focal individuals, 48.3% (98/203) of adult and sub-adult males expressed the Puppet behaviour, whereas only 6.3% (6/96) of females did, indicating an obvious sexual difference. Puppet behaviour occurred more frequently at noon and in the afternoon on sunny and cloudy days, meaning that day time and weather were both influential factors. Puppet behaviour was usually accompanied with rumination and sometimes ended with leg-shaking. Our results suggest that Puppet behaviour is probably an adaptive form of rest, which serves a thermoregulatory and anti-predation function, and is much simpler and safer than recumbent rest.

animal behavior and cognition↗

bioRxiv2018

Repeated assessment of anxiety-like behavior in mice: a new tool with increased reliability and consistency.

Stress-related illnesses such as major depressive and anxiety disorders are characterized by maladaptive responses to stressful life events. Chronic stress-based animal models have provided critical insight into the understanding of these responses. Currently available assays measuring chronic stress-induced behavioral states in mice are limited in their design (short, not repeatable, sensitive to experimenter-bias) and often inconsistent. Using the Noldus PhenoTyper apparatus, we identified a new readout that repeatedly assesses behavioral changes induced by chronic stress in two mouse models i.e. chronic restraint stress (CRS) and chronic unpredictable mild stress (UCMS). The PhenoTyper test consists of overnight monitoring of animals behavior in home-cage setting before, during and after a 1hr light challenge applied over a designated food zone. We tested the reproducibility and reliability of the PhenoTyper test in assessing the effects of chronic stress exposure, and compared outcomes with commonly-used tests. While chronic stress induced heterogeneous profiles in classical tests, CRS- and UCMS-exposed mice showed a very consistent response in the PhenoTyper test. Indeed, CRS and UCMS mice continue avoiding the lit zone in favor of the shelter zone. This \"residual avoidance\" after the light challenge, lasted for hours beyond termination of the challenge, was not observed after acute stress and was consistently found throughout stress exposure in both models. Chronic stress-induced residual avoidance was alleviated by chronic imipramine treatment but not acute diazepam administration. This behavioral index should be instrumental for studies aiming to better understand the trajectory of chronic stress-induced deficits and potentially screen novel anxiolytics and antidepressants.

animal behavior and cognition↗

bioRxiv2018

Hormonal regulation of social ascent and temporal patterns of behavior in an African cichlid

For many species, social rank determines which individuals perform certain social behaviors and when. Higher ranking or dominant (DOM) individuals maintain status through aggressive interactions and perform courtship behaviors while non-dominant (ND) individuals do not. In some species ND individuals ascend (ASC) in social rank when the opportunity arises. Many important questions related to the mechanistic basis of social ascent remain to be answered. We probed whether androgen signaling regulates social ascent in male Astatotilapia burtoni, an African cichlid whose social hierarchy can be readily controlled in the laboratory. As expected, androgen receptor (AR) antagonism abolished reproductive behavior during social ascent. However, we discovered multiple AR-dependent--and AR-independent--temporal behavioral patterns that typify social ascent and dominance. AR antagonism in ASC males reduced the speed of behavioral performance compared to DOM males. Socially ascending males, independent of AR activation, were more likely than DOM males to follow aggressive displays with another aggressive display. Further analyses revealed differences in the sequencing of aggressive and courtship behaviors, wherein DOM males were more likely than ASC males to follow male-directed aggression with courtship displays. Strikingly, this difference was driven mostly by ASC males taking longer to transition from aggression to courtship, suggesting ASC males can perform certain DOM-typical temporal behavioral patterns. Our results indicate androgen signaling drives social ascent, but hormonal signaling and social experience shape the full suite of DOM-typical behavioral patterns.

animal behavior and cognition↗

bioRxiv2018

Olfactory object recognition based on fine-scale stimulus timing in Drosophila

Odorants of behaviorally relevant objects (e.g., food sources) intermingle with those from other sources. Therefore, to sniff out whether an odor source is good or bad - without actually visiting it - animals first need to segregate the odorants from different sources. To do so, animals could use temporal cues, since odorants from one source exhibit correlated fluctuations, while odorants from different sources are less correlated. However, it remains unclear whether animals can rely solely on temporal cues for odor source segregation. Here we show that 1) flies can use a few milliseconds differences in odorant arrival to segregate a target odorant from a binary mixture, 2) segregation does not improve when the target odorant arrives first, and 3) segregation works for odorants with innate, as well as learned valences. These properties of odor segregation parallel those of concurrent sound segregation and figure-ground segregation by onset asynchrony in humans.

animal behavior and cognition↗

bioRxiv2018

How do owners perceive dominance in dogs?

Dominance is well defined in ethology, debated in psychology, and is often unclear among the dog owning public and in the press. However, to date, no study has examined how owners perceive dominance in dogs, and what different behaviours and personality types are used to describe dominant and subordinate individuals. A questionnaire study was launched to investigate the external validity of owner-derived estimates of dominance in dog dyads sharing the same household (N = 1151). According to the owners, dogs rated as dominant (87%) have priority access to resources (resting place, food, and rewards), undertake certain tasks (defend and lead the group, bark more), display dominance (win fights, lick the others mouth less, and mark over the others urine), share certain personality traits (smarter, more aggressive and impulsive), and are older than their partner dog (all p < 0.0001). An age-related hypothesis has been suggested to explain dominance in dogs, but we found that dog age did not explain the occurrence of dominance-related behaviours over the owners estimate of dominance status. Results suggest that owner-derived reports of dominance ranks of dogs living in multi-dog households correspond to ethologically valid behavioural markers of dominance. Size and physical condition were unrelated to the perceived dominance. Surprisingly, in mixed-sex dyads, females were more frequently rated as dominant than males, which might correspond to a higher proportion of neutered females in this subgroup. For future studies that wish to allocate dominance status using owner report, we offer a novel survey.

animal behavior and cognition↗

bioRxiv2018

Predation at a snails pace. What is needed for a successful hunt?

Daily observations of wild Paryphanta busbyi (New Zealand Kauri snail) along the edge of a driveway were carried out for just over one year. Documented behaviours include the snails speed of movement, thrusting their heads down into leaf litter to wait in ambush for prey, the daily retreat into lairs, burrowing, and the grooming of the snails shell. The most significant environmental factors affecting the presence of the snails were humidity and wind direction. There was a migration of snails into and out of the observable study area at different times of year. Due to the snails pace of 1.9 to 3 m/hr relative to its prey at 5-10m/hr the snails would need to migrate to and inhabit areas where there is likely to be trackable prey. Overall the observations indicate the hunting strategy of a periodically active ambush predator sometimes based in a lair and migrating to suitably humid and windless areas as needed to allow tracking of their prey.

animal behavior and cognition↗

bioRxiv2018

Dissociating addiction-related endophenotypes: Incentive salience attribution, sensation-seeking and novelty-seeking are independent traits in male and female heterogeneous stock rats

There are a number of traits that are thought to increase susceptibility to addiction, and some of these are modeled in preclinical studies. For example, \"sensation-seeking\" is predictive of the initial propensity to take drugs; whereas \"novelty-seeking\" predicts compulsive drug-seeking behavior. In addition, the propensity to attribute incentive salience to reward cues can predict the propensity to approach drug cues, and reinstatement or relapse, even after relatively brief periods of drug exposure. The question addressed here is the extent to which these three vulnerability factors are related; that is, predictive of one another. Some relationships have been reported in small samples, but here a large sample of 1,598 outbred male and female heterogeneous stock rats were screened for Pavlovian conditioned approach behavior (to obtain an index of incentive salience attribution; sign-tracking), and subsequently tested for sensation-seeking and novelty-seeking. Despite the large N there were no significant correlations between these traits, in either males or females. There were, however, novel relationships between multiple measures of incentive salience attribution and, based on these findings, we generated a new metric that captures \"incentive value\". Furthermore, there were sex differences on measures of incentive salience attribution and sensation-seeking behavior that were not previously apparent.

animal behavior and cognition↗

bioRxiv2018

Male Anolis lizards prefer virgin females

Males can gain fitness benefits by preferentially courting and mating with virgin females if they represent a lower risk of sperm competition. When females mate multiply, but do not remate frequently, males can experience a lower level of sperm competition when mating with virgins. Male preference for virgins has been demonstrated many times in invertebrates but rarely in vertebrates. In this study, I tested if Anolis apletophallus males preferentially courted virgin females more than non-virgin females, in two-choice trails where the virgin was smaller than the non-virgin, and trails where the females were size-matched. In both trails males preferentially courted the virgin females more than non-virgin females. This suggests males can discriminate between females based on their reproductive history and that they do not use body size as a cue. Males most likely used visual signals from the female, although these signals could not be identified in this study. This is only the second study to show male preference for virgins in vertebrates. Although it is possible that male preference for virgins is relatively rare in vertebrates, I argue that certain life history traits, namely, where large females do not have reproductive benefits, and or when sperm is stored between subsequent reproductive events this preference function can evolve. Future studies focusing on such systems are likely to be fruitful with respect to this male mating preference and may help us to better understand the evolution of male mating preferences and female traits.

animal behavior and cognition↗

bioRxiv2018

Proximity sensors reveal social information transfer in maternity colonies of Greater noctule bats

O_LIBats are a highly gregarious taxon suggesting that social information should be readily available for making decision. Social information transfer in maternity colonies might be a particularly efficient mechanism for naive pups to acquire information on resources from informed adults. However, such behaviour is difficult to study in the wild, in particular in elusive and small-bodied animals such as bats.\nC_LIO_LIThe goal of this study was to investigate the role of social information in acquiring access to two types of resources, which are crucial in the life of a juvenile bat: suitable roosting sites and fruitful feeding grounds. We hypothesized that fledging offspring will make use of social information by following informed members of the social groups to unknown roosts or foraging sites.\nC_LIO_LIIn the present study we applied for the first time the newly developed miniaturized proximity sensor system BATS, a fully automated system for documenting associations among individual bats both while roosting and while on the wing. We quantified associations among juveniles and other group member while switching roosts and during foraging.\nC_LIO_LIWe found clear evidence for information transfer while switching roosts, mainly among juveniles and their genetically identified mothers. Anecdotal observations suggest intentional guidance behaviour by mothers, indicated by repeated commuting flights among the pup and the target roost. Infrequent, short meetings with colony members other than the mother indicate local enhancement at foraging sites, but no intentional information transfer.\nC_LIO_LIOur study illustrates how advances in technology enable researchers to solve long-standing puzzles. Miniaturized proximity sensors facilitate the automated collection of continuous data sets and represent an ideal tool to gain novel insights into the sociobiology of elusive and small-bodied species.\nC_LI

animal behavior and cognition↗

bioRxiv2018

Facial masculinity is only weakly correlated with handgrip strength in young adult women

ObjectivesAncestrally, strength is likely to have played a critical role in determining the ability to obtain and retain resources and the allocation of social status among humans. Responses to facial cues of strength are therefore thought to play an important role in human social interaction. Although many researchers have proposed that sexually dimorphic facial morphology is reliably correlated with physical strength, evidence for this hypothesis is somewhat mixed. Moreover, to date, only one study has investigated the putative relationship between facial masculinity and physical strength in women. Consequently, we tested for correlations between handgrip strength and objective measures of face-shape masculinity.\n\nMethods531 women took part in the study. We measured each participants handgrip strength (dominant hand). Sexual dimorphism of face shape was objectively measured from each face photograph using two methods: discriminant analysis and vector analysis. These methods use shape components derived from principal component analyses of facial landmarks to measure the probability of the face being classified as male (discriminant analysis method) or to locate the face on a female-male continuum (vector analysis method).\n\nResultsOur analyses revealed that handgrip strength is, at best, only weakly correlated with facial masculinity in women. There was a weak significant association between handgrip strength and one measure of womens facial masculinity. The relationship between handgrip strength and our other measure of womens facial masculinity was not significant.\n\nDiscussionTogether, these results do not support the hypothesis that face-shape masculinity is an important cue of physical strength, at least in women.

animal behavior and cognition↗

bioRxiv2018

Continuous and discrete quantity discrimination in tortoises

The ability to estimate quantity, which is crucially important in several aspects of animal behaviour (e.g., foraging), has been extensively investigated in most taxa, with the exception of reptiles. The few studies available, in lizards, report lack of spontaneous discrimination of quantity, which may suggest that reptiles could represent an exception in numerical abilities among vertebrates. We investigated the spontaneous ability of Hermanns tortoises (Testudo hermanni) to select the larger quantity of food items. Tortoises showed able to choose the larger food item when exposed with two options differing in size (0.25, 0.50, 0.67 and 0.75 ratio) and when presented with two groups differing in numerousness (1 versus 4, 2 versus 4, 2 versus 3 and 3 versus 4 items). The tortoises succeeded in both size and numerousness discrimination, and their performance appeared to depend on the ratio of items to be discriminated (thus following Webers Law). These findings in chelonians provide evidence of an ancient system for the extrapolation of numerical magnitudes from given sets of elements, shared among vertebrates.

animal behavior and cognition↗

bioRxiv2018

The dorsolateral striatum regulates habits by way of performance vigor when actions are initiated

Despite clear evidence linking basal ganglia control to habits, it remains unclear through what mechanisms this control occurs. Here, we demonstrate that a key function of the dorsolateral striatum (DLS) is to regulate the vigor of a learned behavior at the moment of initiation in a habit-promoting manner. Shifts in vigor by phasic DLS perturbations coincide closely with how outcome-insensitive (i.e., habitual) the behaviors are in both response-based and cue-based task situations. Surprisingly, the control over habit strength by way of changes in vigor occurs without consistent changes in accuracy, suggesting that mechanisms controlling habit and vigor are dissociable from performance governed task rules. Finally, we show that increased DLS activity improves vigor preferentially when learned outcome values are stable, while reduced DLS activity dampens vigor preferentially when outcome values change. These data indicate that improving action vigor could be a principle route by which the basal ganglia facilitate habits.

animal behavior and cognition↗

bioRxiv2018

pavo 2.0: new tools for the spectral and spatial analysis of colour in R

O_LIBiological colouration presents a canvas for the study of ecological and evolutionary processes. Enduring interest in colour-based phenotypes has driven, and been driven by, improved techniques for quantifying colour patterns in ever-more relevant ways, yet the need for flexible, open frameworks for data processing and analysis persists.\nC_LIO_LIHere we introduce pavo 2, the latest iteration of the R package pavo. This release represents the extensive refinement and expansion of existing methods, as well as a suite of new tools for the cohesive analysis of the spectral and (now) spatial structure of colour patterns and perception. At its core, the package retains a broad focus on (a) the organisation and processing of spectral and spatial data, and tools for the alternating (b) visualisation, and (c) analysis of data. Significantly, pavo 2 introduces image-analysis capabilities, providing a cohesive workflow for the comprehensive analysis of colour patterns.\nC_LIO_LIWe demonstrate the utility of pavo with a brief example centred on mimicry in Heliconius butterflies. Drawing on visual modelling, adjacency, and boundary strength analyses, we show that the combined spectral (colour and luminance) and spatial (pattern element distribution and boundary salience) features of putative models and mimics are closely aligned.\nC_LIO_LIpavo 2 offers a flexible and reproducible environment for the analysis of colour, with renewed potential to assist researchers in answering fundamental questions in sensory ecology and evolution.\nC_LI

animal behavior and cognition↗

bioRxiv2018

Food collection behavior of Apis mellifera and Tetragonisca angustula bees in Brassica napus L. in response to different environmental covariates.

The objective was to evaluate the behavior of Apis mellifera and Tetragonisca angustula bees in pollination tests in Brassica napus at different times of the day, temperature and relative humidity. The experimental design was completely with eight treatments and two pollination tests, repeated in five randomized blocks during seven days of observations for two years, totaling 560 records. During the visits, the following parameters were recorded: collected resources, nectar collection site, time spent on flower, number of flowers visited in one minute, pollen load in the pollen basket and bee contact with anthers and stigma. Data were analyzed using generalized linear models. The number of Africanized and T. angustula bees collecting nectar increased with the passage of time throughout the day and with the decrease of relative humidity. The same was observed for nectar collection in both nectaries. The proportion of bees collecting pollen was higher in the morning hours, as well as when there was an increase in temperature for the two species of bees. Foraging behavior of A. mellifera in B. napus crop favored its pollination, indifferent of which collected floral resource as they came into contact with anthers and stigma. T. angustula bees performed pollination only during pollen collection. Pollination of B. napus was more effective in the warmer hours of the morning, when more of both species of bees carried out pollen collection. Due to its foraging behavior, A. mellifera had greater efficiency for pollination of B. napus; however, the association with T. angustula may potentiate the benefits generated for the crop by cross-pollination.

animal behavior and cognition↗

bioRxiv2018

Optimising colour for camouflage and visibility: the effects of the environment and the observers visual system

Avoiding detection can provide significant survival advantages for prey, predators, or the military; conversely, maximising visibility would be useful for signalling. One simple determinant of detectability is an animals colour relative to its environment. But identifying the optimal colour to minimise (or maximise) detectability in a given natural environment is complex, partly because of the nature of the perceptual space. Here for the first time, using image processing techniques to embed targets into realistic environments, psychophysics to estimate detectability, and deep neural networks to interpolate between sampled colours, we propose a method to identify the optimal colour that either minimises or maximises visibility. We apply our approach in two natural environments (temperate deciduous forest and Mediterranean scrub) and show how a comparatively small number of samples can be used to predict robustly the most and least effective colours for camouflage. To illustrate how our approach can be generalised to other non-human visual systems, we also identify the optimum colours for concealment and visibility when viewed by red-green colour-blind dichromats, typical for non-human mammals. Contrasting the results from these visual systems sheds light on why some predators (e.g. tigers) seem, at least to humans, to have colouring that would appear detrimental to ambush hunting. We found that for simulated dichromatic observers, colour strongly affected detection time for both environments. In contrast, trichromatic observers were far more effective at breaking camouflage and detecting targets and while there were effects of colour, they were comparatively small.\n\nAuthor SummaryBeing the right colour is important in a natural and built environment, both for hiding (and staying alive) or being seen (and keeping safe). However, empirically establishing what these colours might be for a given environment is non-trivial, depending on factors such as size, viewing distance, lighting and occlusion. Indeed, even with a small number of factors, such as colour and occlusion, this is impractical. Using artificial intelligence techniques, we propose a method that uses a modest number of samples to predict robustly the most and least effective colours for camouflage. Our method generalises for classes of observer other than humans with normal (trichromatic) vision, which we show by identifying the optimum colours for red-green colour-blind observers, typical for non-human mammals, as well as for different environments, using temperate woodland and Mediterranean scrub. Our results reveal that colour strongly affects detection time for red-green colour-blind observers in both environments, but normal trichromatic observers were far more effective at breaking camouflage and detecting targets, with effects of colour being much smaller. Our method will be an invaluable tool, particularly for biologists, for rapidly developing and testing optimal colours for concealment or conspicuity, in multiple environments, for multiple classes of observer.

animal behavior and cognition↗

bioRxiv2018

Determination of sex of sacrum in adult Macaca mulatta

[Abstract]O_ST_ABSBackgroundC_ST_ABSSacrum being a part of pelvis is an important bone for identification of sex in both living primates and fossil ones.\n\nAimAim of this work was to examine the sex differences of sacral parameters in rhesus macaques and to compare with those of the other primates.\n\nMaterials and MethodsFifty-six adult scara of macaques (17 males and 39 females) have been investigated. Measurement of various parameters was done using sliding vernier calliper; and statistical analysis was done using SPSS 23.0 package.\n\nResultsThe present study showed that the cranial breadth of the sacrum, the sacral length, transverse diameter and sagittal diameter of the cranial articular surface, and two indices of relative sacral breadth were highly significant for sex determination in Macaca mulatta. Comparison of the present data with other studies suggest that sex determination of sacrum can be very different in various types of primates.\n\nConclusionThe results suggest that these measures may be functionally integrated in response to locomotion, obstetric adequacy and cephalopelvic proportions in primates. Sacral index is more reliable and should be applied for sex determination of sacrum in various anatomical and anthropological investigations.

animal behavior and cognition↗

bioRxiv2018

Evolving optimum camouflage with Generative Adversarial Networks

We describe a novel method to exploit Generative Adversarial Networks to simulate an evolutionary arms race between the camouflage of a synthetic prey and its predator. Patterns evolved using our methods are shown to provide progressively more effective concealment and outperform two recognised camouflage techniques. The method will be invaluable, particularly for biologists, for rapidly developing and testing optimal camouflage or signalling patterns in multiple environments.

animal behavior and cognition↗

bioRxiv2018

Copy parents or follow friends? Juvenile foraging behaviour changes with social environment

The first few months of juvenile independence is a critical period for survival as young must learn new behaviours to forage efficiently. Social learning by observing parents (vertical transmission) or others (horizontal/oblique transmission) may be important to overcome naivety, but these tutors are likely to differ in their reliability due to variation in their own experience. How young animals use different social information sources, however, has received little attention. Here we tested if wild juvenile hihi (Notiomystis cincta, a New Zealand passerine) retained foraging behaviours learned from parents, or if behaviour changed after independence in response to peers. We first trained parents with feeders during chick rearing: one-third could access food from any direction, one-third could access food from one side only, and the remaining third had no feeder. During post-fledge parental care, juveniles chose the same side as their parents. Once independent, juveniles formed mixed-treatment groups naturally so we then presented feeders with two equally profitable sides. Juveniles with natal feeder experience were quicker to use these feeders initially, but side choice was now random. Over time, however, juveniles converged on using one side of the feeder (which differed between groups). This apparent conformity was because juvenile hihi paid attention to the behaviour of their group and were more likely to choose the locally-favoured side as the number of visits to that side increased. They did not copy the choice of specific individuals, even when they were more social or more familiar with the preceding bird. Our study shows that early social experiences with parents affect foraging decisions, but later social environments lead juveniles to modify their behaviour.

animal behavior and cognition↗