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The subthalamic nucleus (STN) is a major neuromodulation target for the alleviation of neurological and neuropsychiatric symptoms using deep brain stimulation (DBS). STN-DBS is today applied as treatment in Parkinson ' s disease, dystonia, essential tremor, and obsessive-compulsive disorder (OCD). STN-DBS also shows promise as a treatment for refractory Tourette syndrome. However, the internal organization of the STN has remained elusive and challenges researchers and clinicians: How can this small brain structure engage in the multitude of functions that renders it a key hub for therapeutic intervention of a variety of brain disorders ranging from motor to affective to cognitive? Based on recent gene expression studies of the STN, a comprehensive view of the anatomical and cellular organization, including revelations of spatio-molecular heterogeneity, is now possible to outline. In this review, we focus attention to the neurobiological architecture of the STN with specific emphasis on molecular patterns discovered within this complex brain area. Studies from human, non-human primate, and rodent brains now reveal anatomically defined distribution of specific molecular markers. Together their spatial patterns indicate a heterogeneous molecular architecture within the STN. Considering the translational capacity of targeting the STN in severe brain disorders, the addition of molecular profiling of the STN will allow for advancement in precision of clinical STN-based interventions. The subthalamic nucleus is a highly evolutionary conserved brain region. Emerging studies reveal spatio-molecular heterogeneity leading to improved understanding of the organization of the STN and targeting for specific neurological disorders.

The organization and coordination of fish schools provide a valuable model to investigate the genetic architecture of affiliative behaviours and dissect the mechanisms underlying social behaviours and personalities. Here we used replicate guppy selection lines that vary in schooling propensity and combine quantitative genetics with genomic and transcriptomic analyses to investigate the genetic basis of sociability phenotypes. We show that consistent with findings in collective motion patterns, experimental evolution of schooling propensity increased the sociability of female, but not male, guppies when swimming with unfamiliar conspecifics. This finding highlights a relevant link between coordinated motion and sociability for species forming fission–fusion societies in which both group size and the type of social interactions are dynamic across space and time. We further show that alignment and attraction, the two major traits forming the sociability personality axis in this species, showed heritability estimates at the upper end of the range previously described for social behaviours, with important variation across sexes. The results from both Pool-seq and RNA-seq data indicated that genes involved in neuron migration and synaptic function were instrumental in the evolution of sociability, highlighting a crucial role of glutamatergic synaptic function and calcium-dependent signalling processes in the evolution of schooling.

Social learning is a mechanism used by many species to efficiently gain information about their environment. Although many animals live in an environment where members of other species are present, little is known about interspecific social learning. Domesticated and urbanized species provide the opportunity to investigate whether nonhuman animals can learn from heterospecifics such as humans, who are integral parts of their social landscape. Although domestic dogs Canis familiaris have been intensively researched for their ability to learn from humans, most studies have focused on dogs living as pets. However, free-ranging dogs represent the majority of the world’s dog population, they live alongside humans, scavenge on human refuse, and are subject to natural and sexual selection. Thus, free-ranging dogs with extensive exposure to humans and their artifacts provide the opportunity to investigate interspecific social learning in a naturalistic setting, where learning from humans might be a benefit for them. Here we tested individual free-ranging dogs in a between-subject design: Dogs in the control group could spontaneously choose between two novel and differently patterned food-delivering boxes. In the experimental group, instead, dogs could first observe an unfamiliar human approaching and eating from 1 of the 2 boxes. We provide the first evidence that free-ranging dogs match the choice of an unfamiliar human. These results show that at least simple forms of interspecific social learning might be involved in dogs’ success in living alongside humans in a complex urbanized environment.

Melanin-based color polymorphism is predicted to evolve and maintain through differential fitness of morphs in different environments, and several empirical studies indicate that life history strategies, physiology, and behavior vary among color morphs. Sex allocation theory predicts that parents should adjust their sex allocation based on differential costs of raising sons and daughters, and therefore, color morphs are expected to modify their brood sex ratio decisions. In color polymorphic tawny owls (Strix aluco), the pheomelanistic brown morph is associated with higher energy requirements, faster growth, and higher parental effort than the gray morph. As hypothesized, we find that brown tawny owl mothers produced more daughters in early broods and more males in late broods, whereas gray mothers did the opposite. At fledging, daughters of early broods and of brown mothers were heavier than those of late broods or gray mothers. Hence, larger and more costly daughters appeared to benefit more than males from being born to brown mothers early in the season. Brown mothers breeding later in the season produced more cheap sons, while gray mothers face fewer challenges under limited resources and favor daughters. These findings suggest that environmental conditions influence brood sex allocation strategies of genetically determined color morphs differently. Which sex to produce might make a difference. In color polymorphic tawny owls brown mothers overproduce daughters early in the season, whereas gray mothers don't. The benefit for brown mothers of overproducing daughters early is that the daughters grow substantially bigger then. For gray mothers, and among sons of gray or brown mothers, it makes less difference. Hence, brown mothers choose differently and overproduce daughters early in the season to improve their offspring quality.

Although problem-solving tasks are frequently used to assess innovative ability, the extent to which problem-solving performance reflects variation in cognitive skills has been rarely formally investigated. Using wild breeding great tits facing a new non-food motivated problem-solving task, we investigated the role of associative learning in finding the solution, compared to multiple other non-cognitive factors. We first examined the role of accuracy (the proportion of contacts made with the opening part of a string-pulling task), neophobia, exploration, activity, age, sex, body condition and participation time on the ability to solve the task. To highlight the effect of associative learning, we then compared accuracy between solvers and non-solvers, before and after the first cue to the solution (i.e., the first time they pulled the string opening the door). We finally compared accuracy over consecutive entrances for solvers. Using 884 observations from 788 great tits tested from 2010 to 2015, we showed that, prior to initial successful entrance, solvers were more accurate and more explorative than non-solvers, and that females were more likely to solve the task than males. The accuracy of solvers, but not of non-solvers, increased significantly after they had the opportunity to associate string pulling with the movement of the door, giving them a first cue to the task solution. The accuracy of solvers also increased over successive entrances. Our results demonstrate that variations in problem-solving performance primarily reflect inherent individual differences in associative learning, and are also to a lesser extent shaped by sex and exploratory behaviour.

Human (Homo sapiens sapiens) language (hereafter mostly referred to as just “language”) is often claimed to differ completely from nonhuman communication regarding both use and acquisition. Since language is by many considered essential for other said human unique skills it constitutes a useful case to explore whether human behaviours can be explained by the same principles as cognitive performances in other animals. Language is therein examined in the current thesis, by review of interdisciplinary literature including ethological, psychological, behaviour analytical and philosophical. Once learned, language may play an important role in guiding further reasoning, signifying its role in many cognitive phenomena. However, word learning can be explained by associative means, and I suggest the same mechanism underlies further language connected capacities. This is supported by the recent proposition that human cognition differs quantitatively from other species because of increased information capacity. Nevertheless, thorough calculations and experiments would bring further insight if associative principles can be applied as I theoretically propose. Critical welfare implications follow if experiences we “know” exist in humans could be equally true in nonhuman animals partaking in similar activities, which is the case if “simpler” explanations apply even to humans with these capabilities. Herein, seemingly simple mechanisms do not rule out complex results. Contradicting arguments may be explained by biases and cognition based validation. The latter is elaborated on in order to highlight ethical risks by comparative research regardless of motives.

Collective motion is common across all animal taxa, from swarming insects to schools of fish. The collective motion requires intricate behavioral integration among individuals, yet little is known about how evolutionary changes in brain morphology influence the ability for individuals to coordinate behavior in groups. In this study, we utilized guppies that were selectively bred for relative telencephalon size, an aspect of brain morphology that is normally associated with advanced cognitive functions, to examine its role in collective motion using an open-field assay. We analyzed high-resolution tracking data of same-sex shoals consisting of 8 individuals to assess different aspects of collective motion, such as alignment, attraction to nearby shoal members, and swimming speed. Our findings indicate that variation in collective motion in guppy shoals might not be strongly affected by variation in relative telencephalon size. Our study suggests that group dynamics in collectively moving animals are likely not driven by advanced cognitive functions but rather by fundamental cognitive processes stemming from relatively simple rules among neighboring individuals.

The amino acid tryptophan (Trp) is a precursor of the neurotransmitter serotonin. Trp supplementation or other forms of serotonergic enhancement generally promote pro-social behavior, decreasing aggression, and also feeding in different animals. However, past research has been conducted in confined spaces, and there is little work in naturalistic conditions where animals move and associate more freely. We gave a Trp-enriched diet to a free-flying flock of common waxbills (Estrilda astrild) in semi-natural conditions and monitored group foraging, aggressions during feeding, and the social network. Contrary to expectations, aggressiveness and feeding increased during Trp supplementation. Consistent with the prediction of increased social associations, foraging groups became larger, and individuals joined more foraging groups, but these changes appear driven by increased appetite during Trp treatment. Also, the mean strength of associations in the social network did not change. Overall, Trp supplementation affected group behavior in this free-flying flock, but mostly in directions unanticipated based on research conducted in small spaces. To harmonize our results with those found in small confined spaces, we hypothesize that free-flying birds have energetic requirements not experienced in lab-housed individuals, which may impact social behavior and responses to Trp.

The Spotted hyena (Crocuta crocuta) is a gregarious carnivore known for its strictly structured hierarchical rank relationships. At the zoo of Borås a clan, consisting out of two Spotted hyenas, are participating in an ex-situ program. In order to successfully enact conservational work, within zoos, sustainable management of zoo populations is of importance, and the behavioral aspect is vital in enabling welfare. In this study, I observed social interactions and activity in the Spotted hyenas at the zoo of Borås, for ten continuous days. The study aimed to investigate the dominance relationship and daily activity of the individuals. Furthermore, if this correlates with concentrations of testosterone. I performed two different observational studies, one focusing on social and agonistic behaviors, and the other on general behaviors. A third method, blood sampling, was intended to be performed but due to non-optimal conditions it was not executed. The results implied that the two individuals were highly nocturnal, with activity peaks to be observed during the first half of the night and at dawn. The individuals spent the majority of the time, 60.6%, resting which signifies that they are active during shorter periods. They were highly social with each other, but force measurements and aggressive displays did occur, mainly during the night. Sansa was the one taking initiative in conflicts, which suggests attempts in dominating Arya. Further, this indicates that the activity and dynamic of the individuals resembles that of a wild population, along with corresponding with previously performed studies and behavioral descriptions.

In commercial hatcheries, laying hen chicks are exposed to a range of stressors that have previously been shown to induce long-term negative effects on their welfare. It has been suggested that stimulation of play behaviour, a self-rewarding activity associated with positive emotions, may be a way to improve animal welfare. We have previously found that chicks play extensively during their first weeks of life if offered the possibility. Our hypothesis was therefore that stimulating play in chicks could buffer the long-term consequences of stress from commercial hatchery routines. Sixty female Lohmann LSL chicks were hatched at a commercial hatchery and transported for four hours before being randomly allocated to two different treatments. Play-stimulated chicks (PC) were taken out of the home pens and introduced in groups of five into a spacious, object-enriched play arena 3x30 min per week for five weeks starting from 9 days of age. Control chicks (CC) were taken out of the home pens at the same time as PC and placed in cardboard boxes for the same amount of time as PC were allowed to play. Between 46 and 57 days of age,behavioural and corticosterone reactivity tests were conducted. There were no differences between the treatment groups in open field activity, but in a novel object test PC were more active and interacted more with the novel object, indicating reduced fear. There were no differences between the treatment groups in duration of tonic immobility or in corticosterone reaction to a brief restraint. Contrary to our predictions, PC showed a more negative bias compared to CC in a cognitive judgement bias test. In conclusion, play stimulation may reduce fearfulness in early-stressed chickens, but the reason for the opposite reaction in the cognitive judgement bias needs further investigation., Funding Agencies|Swedish Research Agency Formas [2019-02084]

Dogs have previously been shown to synchronise their behaviour with their owner and the aim of this study was to test the effect of immediate interactions, breed, and the effects of domestication. The behavioural synchronisation test was conducted in outdoor enclosures and consisted of 30 s where the owner/handler was walking and 30 s of standing still. Three studies were conducted to explore the effect of immediate interaction (study A), the effect of breed group (study B), and the effect of domestication (study C). In study A, a group of twenty companion dogs of various breeds were tested after three different human interaction treatments: Ignore, Pet, and Play. The results showed that dogs adjusted their movement pattern to align with their owner's actions regardless of treatment. Furthermore, exploration, eye contact, and movement were all influenced by the owners moving pattern, and exploration also decreased after the Play treatment. In study B, the synchronisation test was performed after the Ignore treatment on three groups: 24 dogs of ancient dog breeds, 17 solitary hunting dogs, and 20 companion dogs (data from study A). Irrespective of the group, all dogs synchronised their moving behaviour with their owner. In addition, human walking positively influenced eye contact behaviour while simultaneously decreasing exploration behaviour. In study C, a group of six socialised pack-living wolves and six similarly socialised pack-living dogs were tested after the Ignore treatment. Interestingly, these animals did not alter their moving behaviour in response to their handler. In conclusion, dogs living together with humans synchronise with their owner's moving behaviour, while wolves and dogs living in packs do not. Hence, the degree of interspecies behavioural synchronisation may be influenced by the extent to which the dogs are immersed in everyday life with humans., Funding Agencies|Svelands Foundation

The application of supervised machine learning methods to identify behavioural modes from inertial measurements of bio-loggers has become a standard tool in behavioural ecology. Several design choices can affect the accuracy of identifying the behavioural modes. One such choice is the inclusion or exclusion of segments consisting of more than a single behaviour (mixed segments) in the machine learning model training data. Currently, the common practice is to ignore such segments during model training. In this paper we tested the hypothesis that including mixed segments in model training will improve accuracy, as the model would perform better in identifying them in the test data. We test this hypothesis using a series of data simulations on four datasets of accelerometer data coupled with behaviour observations, obtained from four study species (Damaraland mole-rats, meerkats, olive baboons, polar bears). Results show that when a substantial proportion of the test data are mixed behaviour segments (above similar to 10%), including mixed segments in machine learning model training improves the accuracy of classification. These results were consistent across the four study species, and robust to changes in segment length, sample size, and degree of mixture within the mixed segments. However, we also find that in some cases (particularly in baboons) models trained with mixed segments show reduced accuracy in classifying test data containing only single behaviour (pure) segments, compared to models trained without mixed segments. Based on these results, we recommend that when the classification model is expected to deal with a substantial proportion of mixed behaviour segments (> 10%), it is beneficial to include them in model training, otherwise, it is unnecessary but also not harmful. The exception is when there is a basis to assume that the training data contains a higher rate of mixed segments than the actual (unobserved) data to be classified-such a situation ma

Variations in stress responses between individuals are linked to factors ranging from stress coping styles to the sensitivity of neurotransmitter systems. Many anxiolytic compounds can increase stressor engagement through the modulation of neurotransmitter systems and are used to investigate stress response mechanisms. The effect of such modulation may vary in time depending on concentration or environment, but those effects are hard to dissect because of the slow transition. We investigated the temporal effect of ethanol and found that ethanol-treated individual zebrafish larvae showed altered behavior that is different between drug concentrations and decreases with time. We used an artificial neural network approach with a time-dependent method for analyzing long (90 min) experiments on zebrafish larvae and found that individuals from the 0.5% group begin to show locomotor activity corresponding to the control group starting from the 60th minute. The locomotor activity of individuals from the 2% group after the 80th minute is classified as the activity of individuals from the 1.5% group. Our method shows three clusters of different concentrations in comparison with two clusters, which were obtained with the usage of a statistical approach for analyzing just the speed of fish movements. In addition, we show that such changes are not explained by basic behavior statistics such as speed and are caused by shifts in locomotion patterns.

The subthalamic nucleus (STN) is critical for behavioral control; its dysregulation consequently correlated with neurological and neuropsychiatric disorders, including Parkinson's disease. Deep brain stimulation (DBS) targeting the STN successfully alleviates parkinsonian motor symptoms. However, low mood and depression are affective side effects. STN is adjoined with para-STN, associated with appetitive and aversive behavior. DBS aimed at STN might unintentionally modulate para-STN, causing aversion. Alternatively, the STN mediates aversion. To investigate causality between STN and aversion, affective behavior is addressed using optogenetics in mice. Selective promoters allow dissociation of STN (e.g., Pitx2) vs. para-STN (Tac1). Acute photostimulation results in aversion via both STN and para-STN. However, only STN stimulation-paired cues cause conditioned avoidance and only STN stimulation interrupts on-going sugar self-administration. Electrophysiological recordings identify post-synaptic responses in pallidal neurons, and selective photostimulation of STN terminals in the ventral pallidum replicates STN-induced aversion. Identifying STN as a source of aversive learning contributes neurobiological underpinnings to emotional affect.

Domesticated species differ from their wild ancestors in a mosaic of traits. Classical domestication theories agree that reactivity to fear and stress is one of the main traits affected. Domesticated species are expected to be less fear and stress prone to than their wild counterparts. To test this hypothesis, we compared the behavioural responses of White Leghorn (WL) chicks to their wild counterparts, Red Junglefowl (RJF) chicks in risk-taking situations. In order to obtain food, the chicks faced an unknown and potentially harmful object at the presence or absence of a social partner. We found that according to our predictions, RJF were more stressed and fearful of the object than the WL. Still, RJF were more explorative than WL. Additionally, the presence of a social partner reduced the fear response in both, but had a stronger effect on RJF. Finally, WL were more food orientated than the RJF. Our results confirmed classical domestication hypotheses of downregulation of the stress system and importance of the social partner in domesticated farm chicken., Funding Agencies|Austrian Science Fund (FWF) [W1262-B29]; Swedish Research Council [2019-04869]

The ability to visualize small moving objects is vital for the survival of many animals, as these could represent predators or prey. For example, predatory insects, including dragonflies, robber flies and killer flies, perform elegant, high-speed pursuits of both biological and artificial targets. Many non-predatory insects, including male hoverflies and blowflies, also pursue targets during territorial or courtship interactions. To date, most hoverfly pursuits have been studied outdoors. To investigate hoverfly (Eristalis tenax) pursuits under more controlled settings, we constructed an indoor arena that was large enough to encourage naturalistic behavior. We presented artificial beads of different sizes, moving at different speeds, and filmed pursuits with two cameras, allowing subsequent 3D reconstruction of the hoverfly and bead position as a function of time. We show that male E. tenax hoverflies are unlikely to use strict heuristic rules based on angular size or speed to determine when to start pursuit, at least in our indoor setting. We found that hoverflies pursued faster beads when the trajectory involved flying downwards towards the bead. Furthermore, we show that target pursuit behavior can be broken down into two stages. In the first stage, the hoverfly attempts to rapidly decreases the distance to the target by intercepting it at high speed. During the second stage, the hoverfly's forward speed is correlated with the speed of the bead, so that the hoverfly remains close, but without catching it. This may be similar to dragonfly shadowing behavior, previously coined ‘motion camouflage’.

Free-range systems provide an outdoor range for broilers to give them the possibility to express a higher frequency and a wider range of behaviours, such as exploration, compared with those raised indoors. Greater variability in outdoor range use between individuals of the same flock is often reported. Individual variation in range use may result from differences in early-life behaviour or genetic background. Understanding how earlylife behaviour influences range use may provide opportunities to enhance and predict range use. Previous studies have shown that range use could be influenced by the animals personality traits such as social motivation, boldness and foraging motivation. Therefore, this study investigated personality traits in several broiler strains, namely Hubbard JA757, Hubbard S757N, White Bresse and a dual-purpose strain; we examined the latter as it represents a potential solution to the ban of 1-day-old chick culling. The present study also investigated early-life behaviours, before range access, of range use to identify and assess the stability of these early-life indicators among the four broiler strains. For that purpose, we recorded the behaviour and range use of 100 male chickens per strain, both in the barn and during individual tests, before and after range access. We examined which behaviours were time consistent, whether early-life behaviours were influenced by genetic variation and whether early-life behavioural indicators predicted range use regardless of genetic variation. There was a significant (p < 0.001) difference between strains in several early-life behaviours, including the time spent resting or standing. Range use was time consistent regardless of the strain as our range use indicator followed a high-quality linear regression model (R-2 > 0.7) for 82-99% of the individuals depending on their strain. Besides, time consistency of social motivation and boldness seemed to depend on the strain. Even though foraging show, Funding Agencies|PPILOW project; French National Research Institute for Agriculture, Food, and Environment (INRAE); European Union [816172]

Anthropogenic sources of environmental pollution are ever-increasing as urban areas expand and more chemical compounds are used in daily life. The stimulant caffeine is one of the most consumed chemical compounds worldwide, and as a result, has been detected as an environmental contaminant in all types of major water sources on all continents. Exposure of wildlife to environmental pollutants can disrupt the energy balance of these organisms, as restoration of homeostasis is prioritised. In turn, energy allocated to other key biological processes such as growth or reproduction may be affected, consequently reducing the overall fitness of an individual. Therefore, we aimed to investigate if long-term exposure to environmentally relevant concentrations of caffeine had any energetic consequences on wildlife. Specifically, we exposed wild eastern mosquitofish (Gambusia holbrooki) to one of three nominal concentrations of caffeine (0, 100 and 10,000 ng/L) and assayed individuals for metabolic rate, general activity, antipredator and foraging behaviour and body size as measures of energy expenditure or energy intake. We found no differences in any measured traits between any of the given exposure treatments, indicating that exposure to caffeine at current environmental levels may not adversely affect the energy balance and fitness of vulnerable freshwater fish.

One of the most spectacular displays of social behavior is the synchronized movements that many animal groups perform to travel, forage and escape from predators. However, elucidating the neural mechanisms underlying the evolution of collective behaviors, as well as their fitness effects, remains challenging. Here, we study collective motion patterns with and without predation threat and predator inspection behavior in guppies experimentally selected for divergence in polarization, an important ecological driver of coordinated movement in fish. We find that groups from artificially selected lines remain more polarized than control groups in the presence of a threat. Neuroanatomical measurements of polarization-selected individuals indicate changes in brain regions previously suggested to be important regulators of perception, fear and attention, and motor response. Additional visual acuity and temporal resolution tests performed in polarization-selected and control individuals indicate that observed differences in predator inspection and schooling behavior should not be attributable to changes in visual perception, but rather are more likely the result of the more efficient relay of sensory input in the brain of polarization-selected fish. Our findings highlight that brain morphology may play a fundamental role in the evolution of coordinated movement and anti-predator behavior.

In a recent study, Wasserman, Kain, and O'Donoghue (Current Biology, 33(6), 1112–1116, 2023) set out to resolve the associative learning paradox by showing that pigeons can solve a complex category learning task through associative learning. The present Outlook paper presents their findings, expands on this paradox, and discusses implications of their results.

Vector-borne diseases account for over 17 percent of all infectious diseases and lead to more than 700,000 mortalities annually. Importantly, there is a complex interaction between infectious organisms and their host. Vectors spread pathogens, which have a significant negative health effect on humans and animals and therefore detrimental economic and environmental impacts. Only 2% of the more than 3,600 mosquito species are blood feeders, primarily; the Anopheles, Culex, and Aedes which spread the Malaria parasite, Zika, Chikungunya, West Nile, and Dengue viruses. Therefore, understanding the complex chemical signaling and the molecular mechanisms that mediate pathogen and vector interaction, and allow the pathogen to survive and spread, are the subjects of this thesis. In project I, we determined the production and release of Anopheles male aggregation Volatile Organic Compounds (VOCs) that initiate swarming, and enhance mating success. In addition, we compared the RNA-sequencing libraries of swarming to flag for chemosensory and circadian genes. The goal was to identify the molecular mechanisms of swarming and metabolite roles in mating success. In project II, we evaluated the phagostimulant effects of (E)-4-Hydroxy-3-methyl-but-2-enyl pyrophosphate (HMBPP) on an artificial feeding system for some important vectors (Anopheles coluzzii, An. arabiensis, An. gambiae s.s., Culex pipiens/Culex torrentium, and Aedes aegypti). We showed that our toxic plant-based solution can kill the five lethal vectors. In project III, we studied the alteration of An. gambiae behavior by the Plasmodium falciparum at infected (oocyst-carrying, 7 days post-infection) and infective (sporozoite-carrying, 14 days post-infection) stages. To discover whether antennal chemosensory genes expression changes at different stages of infection, we performed RNA-seq and examined the candidate olfactory genes’ abundance to provide a possible molecular mechanism for manipulating the parasite-carrying m

Striking variation is observed in sexually selected traits. These traits influence the outcome of competition and choice before and after mating. Before mating, animals compete for the access to mating partners and choose who to mate with between several potential mates. After mating, sperm from several males can compete for the fertilization of the same eggs, and there can be cryptic choice, since the female may be able to influence which sperm gets to fertilize her eggs. Animals are expected to invest in traits that increase their success in competition and choice. However, external and internal factors shape which sexually selected traits are most beneficial and can cause animals to trade investment in some traits over others. Environmental conditions and availability of resources can influence how animals balance their time and energy to different traits, and males and females can respond to these factors in different ways. However, understanding these complex selective pressures remain challenging. In this thesis, I combine field and experimental studies to examine how environmental conditions and resource availability influence how males and females invest in sexually selected traits. The thesis uses the pygmy halfbeak (Dermogenys collettei) as a study system, a small livebearing fish which exhibit a range of sexually selected traits in both males and females. Using observations of natural populations of halfbeaks in Singapore, I found that male and female halfbeaks show considerable behavioral variation in varying degree of canopy cover and water flow (Paper I). Next, I experimentally manipulated resource quantity in a series of laboratory studies to examine resource-dependence in sexual traits in male and female halfbeaks. In males, the expression of some, but not all, pre- and postcopulatory sexually selected traits were reduced following resource restriction. These patterns were surprisingly consistent between when the resource restriction was applied on

Restaurering av Juktån är ett samverkansprojekt som har drivits på frivillig basis av den ideella föreningen Samverkan Umeälven (www.umealven.se) tillsammans med Umeälvensvattenregleringsföretag, Vattenfall och Umeå Universitet. Juktån är en 60 kilometer lång torrfåra med minimitappning om 12% av det oreglerade flödet (MQ) vid reglerings. I produktionssystemet har den en funktion som spillfåra. Projektets ambition och mål var att Juktån skulle återfå ekologisk funktion med fungerande reproduktion av öring och harr, mer naturlig och bredare strandvegetation och svämskogar, mer naturlig artsammansättning av makrofyter samt en sedimentationsprocess med mindre deponering av silt och finsediment. Juktånprojektet har kartlagt och genomfört biotopåtgärder samt restaurerat huvudfåran sträckan nedströms Tjangarn och sidofåran Lickotgrenen under 2019 och 2020. Totalt har dryga 35 kilometer torrfåra restaurerats, hundratals trösklar och flottledsobjekt har rivits ut. Juktåprojektet ansökte hos Mark och Miljö Domstolen (MMD) om att ändra den relativt statiska minimitappningen till en säsongsanpassad minimitappning, vilket beviljades i augusti 2020 och infördes våren 2021. Metoderna för att genomföra restaureringen bygger på restaureringsekologi och sambandet till naturlig flödesregim. Juktåns restaurering har inneburit en komplex restaurering från utrivning av grunddammar och trösklar, restaurering av den fysiska miljön för att gynna öring, harr, makrofyter, strandvegetation och processer. Vi har utgått från ekologi i oreglerade vattendrag och utvecklat metoder speciellt anpassat för torrfåror med minimitappning. Preliminära resultat visar på en ökad reproduktion av öring, mer naturliga processer kopplat till flöde, sedimentation, vattenhastighet och som har påverkat både makrofyter samt strandvegetation.

Ras signaling pathways are involved in numerous cellular functions and, for this reason, are highly regulated. In addition to alterations in the Ras proteins themselves, defects in Ras regulatory proteins, such as GTPase-activating proteins (GAPs) and guanine nucleotide exchange factors (GEFs), may be relevant to disease development. DrosophilaRasGAP1 is a protein with important physiological implications in flies due to its participation in the signaling of different pathways. In this work, the changes that occur in Drosophila behavior by reducing the pan-neuronal expression of RasGAP1 were investigated. Thus, RasGAP1 knockdown was found to cause a significant increase in total activity (p ≤ 0.001) and activity at 30 min (p ≤ 0.001). In contrast, total sleep duration (p ≤ 0.001), sleep within 30 min (p ≤ 0.001), and mean duration of sleep episodes (p ≤ 0.0001) were all reduced. Furthermore, circulating levels of glucose (p ≤ 0.05) and triacylglycerol (p ≤ 0.05) were found to be elevated. No significant changes were found in feeding behavior, food source selection, trehalose, or glycogen levels. All these results show new functions of RasGAP1 in Drosophila physiology and may also serve to explain some functions of human orthologs (RasGAP2/3 [RASA2/3]).

Deaths from malaria remain staggering despite global support that drives research into new territories. One major gap is our understanding of the sexual biological aspects of the male mosquito, which maintain the vector population solidity. Although Anopheles funestus s.s. is an extremely efficient African vector, little is known about the network between its sexual physiology and gene expression. The Culicidae male’s sexual maturity involves a suite of physiological changes, such as genitalia rotation that is necessary for successful mating to occur. We show that mating success is guided by genes and physiological plasticity. Transcriptome analysis between newly emerged males (immature) versus males with rotating genitalia (maturing) provides insight into possible molecular mechanisms regulating male sexual behaviour. Putative transcripts that were associated with male sexual maturation were identified and validated. The discovery of the functions of these transcripts could lead to identifying potential targets for innovative vector control interventions, and mosquito population suppression.

Filial imprinting is a type of early developmental learning in which certain species buildstrong and mostly irreversible connections to objects or individuals. These connections couldbe shaped by the contribution of several stimuli including the fragments of auditory and visual components. This study aims to describe the duration of the imprinting process as well asestimate long-term behavioural changes in chicks. In this experiment, a total of 78 chicks were used out of which 39 were exposed to imprinting stimuli and the rest served as control.We applied three different tests and replicated them after the imprinting procedure. These tests are Imprinting Preference Test, Social Preference Test and Social isolation Test. Imprinted chicks had a constantly shorter latency to approach the imprinting stimuli for boththose two experiments with or without novel objects, whereas no preferences spent time inimprinting stimuli. However, introducing a novel object affected imprinting preferences more in terms of spending a longer time around the hen zone. During social isolation, the control group showed a relatively higher rate of distress calls even though our results don’t bear on the significant effect of filial imprinting on changes in distress calling. Overall, this study suggests the presence of long-lasting filial imprinting that is more triggered by external situations.

Bird song can teach us much about animal behaviour and evolution. This study presents a type of song variation that has yet to be extensively studied. The Monotonous Lark Mirafra passerina is a nomadic lark with an iconic, simple and repetitive song. It has been noted to have a large song variation between irruptions, but limited variation in the same irruption, a behaviour previously, to my knowledge, unknown in the avian world. This study aims to describe the song and analyse the variation within and between irruptions, and try to explain the underlying mechanisms behind the variation. This article studies the song by analysing song material spanning 30 years with 140 samples, most from South Africa. The whole song and the syllables were measured. A custom edit distance and Euclidean distance were used to quantify song differences. Principal component analysis was performed on both syllable measurements and the whole song. The results showed a larger song variation between irruptions compared to within irruptions. It also showed that the song varies greatly between irruptions; however, a general pattern of how the song is structured was found. In addition, some indications of song retention between years were noticed. This study describes a unique example of avian behaviour that can broaden our knowledge of animal communication and its evolution and development.

Many dogs suffer from separation anxiety and become excessively stressed when their owner is absent. Since many dogs are left home alone daily, their welfare is at stake. Attention bias tests (ABTs) have previously been used as a way to measure welfare in other non-human animals. The aim of this study was to investigate attention bias in dogs with separation anxiety and dogs without separation anxiety in situations of different short-term emotional states. Three ABTs were performed to assess this, the first one was baseline and included no treatment (neutral) prior to the ABT. The second one was play which had a play treatment (positive) before the ABT, where the dog played with their owner for 2.5 min. The third one was isolation which had an isolation treatment (negative) prior to the ABT, where the dog was alone for 2.5 min. The owner was only present during the ABT in baseline and play. The results showed that separation anxiety only had an effect on barking during isolation, where dogs with separation anxiety barked more. Dogs performed more behaviours related to the owner being absent during isolation: more vocalisation, more looking at the door, being closer to the door (zone five), and being less in the area where the owner stood during baseline and play (zone six), compared to both baseline and play. To my knowledge, the usage of ABTs to measure welfare in dogs are few, and this study revealed that separation anxiety does not affect attention bias.

In studies of migration and life-history of many large whales, photo-identification has proven a very powerful tool. Unfortunately, photo-identification is not as established and common when it comes to the second largest animal on earth, the fin whale (Balaenoptera physalus).Despite the massive size of the creatures many things remain unknown about them, such asmigration patterns, the geographical and temporal locations of wintering and individual seasonal range. This study aimed to investigate when fin whales normally visit Skjálfandi Bay, Iceland, and if they migrate between Skjálfandi Bay and Ireland, using photo-identification. The results showed somewhat that the fin whale visits in Skjálfandi Bay were most common in March and April which could be connected to arrival of schooling fish such as capelin (Mallotus villosus) early spring, and that visits have not changed noticeably over the years, suggesting that the fin whales will keep coming to Skjálfandi Bay. One possible fin whale match was found between Skjálfandi Bay and Ireland, suggesting but not confirming migration between the two locations. Further investigation is needed to understand fin whale migration patterns. Because of typical fin whale behavior, similar dorsal fins and unreliable weather, the photo-identification system was discussed, and improvements suggested. A more established photo-identification system could include fin whale photo-ID catalogues with pictures from dorsal view and from the left and right side. However, the photo-identification methods need further investigating to improve even more and to find the best possible way to identify and photograph fin whales., Foto-identifiering har visat sig vara ett användbart verktyg för att studera migration men även livshistoria hos många stora valar. Tyvärr är fotoidentifiering inte lika etablerat och vanligt när det gäller det näst största djuret vår jord, sillvalen (Balaenoptera physalus). Trots valens massiva storlek finns det en stor kunskapsbrist kring dess migrationsmönster, de geografiska och tidsmässiga platserna för övervintring och individuellt säsongsutbrednings-område bland annat. Denna studie syftade till att undersöka när sillvalarna normalt kommer till Skjálfandi Bay, Island, och om de migrerar mellan Skjálfandi Bay och Irland, med hjälp av foto-identifiering. Resultaten visade delvis att sillvalarna oftast besöker Skjálfandi Bay i mars och april, vilket kan vara kopplat till att stimfiskar såsom lodda (Mallotus villosus) kommer dit tidig vår, och att besökssiffrorna inte har ändrats mycket över åren vilket tyder på att sillvalarna kommer fortsätta komma till Skjálfandi Bay. En möjlig matching hittades mellan en identifierad sillval i Skjálfandi Bay och en identifierad sillval i irländska vatten, vilket tyder på men inte bekräftar migration mellan de två platserna. På grund av det typiska sillvalbeteendet och derasliknande ryggfenor samt det opålitliga vädret som en faktor, diskuterades fotoidentifieringssystemet och förbättringar föreslogs. Ett mer etablerat fotoidentifieringssystem hade kunnat inkludera fotoidentifieringskataloger med bilder på sillvalar från ovan sida och från båda sidor. Däremot behöver fotoidentifieringsmetoderna vidare undersökning för ytterligare förbättringar och för att hitta det bästa sättet att identifiera och fotografera sillvalar.

In layer hen commercial production systems, chicks are not raised by hens and do therefore not receive any maternal care. In the wild, after hatching, chicks undergo filial imprinting where they create a social bond with a stimulus in their surrounding environment, usually the mother hen. Filial imprinting behaviors remain in chicks until adulthood. This bond and maternal care influence the emotional development of chicks. Here, I aimed to investigate short- and long-term effects of filial imprinting on a model hen, on the emotional state of White Leghorn chicks, hatched at Linköping University. To measure optimism, pessimism, and fear, a judgment bias test (JBT), an open field test (OFT), and a novel object test (NOT), was performed and replicated. Before the tests, half of the chicks were imprinted on a model hen, while the other half was not given such a model to imprint on. All chicks were weighed during the entire project. The hypotheses were that the imprinted chicks would be more optimistic in the JBT, show less fearful behavior in the OFT and NOT, and weigh more compared to the non-imprinted chicks. If these results would be found, imprinting could potentially be used to reduce stress in commercially hatched chicks, and thus improve their welfare. The results were inconsistent with all three hypotheses. This indicates that imprinting on a model hen, did not have a positive impact on the chicks’ emotional state. Further studies need to be performed to find methods to improve commercially hatched chicks’ emotional welfare.

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

Introduction; Despite its popularity in research, there is very little scientifically validated knowledge about the best practices on zebrafish (Danio rerio) husbandry, which has led to several facilities having their own husbandry protocols. This study was performed to expand knowledge on the effects of enrichment and fish density on the welfare of zebrafish, with hopes of providing a scientific basis for future recommendations and legislations. Methods: Zebrafish were reared at three different stocking densities, (1, 3 or 6 fish/L), in tanks with or without environmental enrichment. Agonistic behavior was observed twice a week for 9 weeks directly in the housing tanks. Aspects of welfare is known to be reflected in neuroendocrine stress responses. Thus, cortisol secretion in response to lowering the water level was analyzed for each group. In addition, we assessed cortisol secretion in response to confinement and risk-taking behavior (boldness) using the novel tank diving test for individual fish. At termination of the experiment fish were subjected to stress by transfer to a novel environment and brain tissue was sampled for analysis of brain monoaminergic activity. Results: Fish kept at the lowest density (1 fish/L) showed a significantly higher level of aggression than fish kept at 3 or 6 fish/L. Moreover, fish kept at this low density showed significantly higher cortisol secretion on a group level than fish kept at the higher stocking densities, when subjected to lowering of the water level. Keeping fish at 1 fish/L also had effects on brain monoamines, these fish showing higher brain dopamine concentrations but lower dopamine turnover than fish kept at higher densities. Neither stocking density or enrichment had any clear effects on the behavior of individual fish in the novel tank diving test. However, fish kept at high densities showed lower and more variable growth rates than fish kept at 1 fish/L. Discussion: Taken together these results suggest that zebr

The effects of domestication on animals’ behaviors and morphology are well known and documented. Changes due to domestication include higher sociability, decreased fearfulness, and increased boldness. These changes have been documented in the chicken breed known as White Leghorn (Gallus gallus domesticus), which is a domesticated relative to the Red Junglefowl (Gallus gallus). Though domestication have altered the chicken’s behavior, its effect on the cognitive learning capabilities of the chicken is still unclear, which is the focus of the study. Two tests were conducted in this study: associative learning and spatial learning. The fowls natural desire to remain close to other fowl was used as the main motivation for completing the tests. The associative learning test was performed by testing the two breeds of associating an item with finding their way to their flock. The spatial learning test was performed by measuring the time needed for an individual to return to their flock from behind an obstacle. For the associative learning test, a significant difference between the cognitive learning capability of the two breeds could be found for part 2 (tests 11-20), as well between part 1 and part 2 within the breed White Leghorn. Between the sexes no significant difference could be seen, but within the females, a significant difference was detected between part 1 and part 2. For the spatial learning test, no significant difference could be found between the two breeds nor the sexes. No correlation could be found between associative- and spatial learning test on an individual level. Due to few significant results, further studies should be conducted to confirm the effects of domestication on learning.

Differences in taste perception between species are thought to reflect evolutionaryadaptations to dietary specializations such as seed predation. By employing a two-bottlepreference test, the purpose of the current study was to evaluate the taste responsiveness forfive food-associated carbohydrates and two steviol glycosides in four adult white-faced sakis(Pithecia pithecia). The taste preference thresholds were found to be 10 mM for sucrose, 10-40 mM for fructose, 20-30 mM for glucose and maltose, and 30-40 mM for lactose. The sakisalso showed a clear preference for rebaudioside A and stevioside over tap water atconcentrations as low as 0.04 and 0.2-0.5 mM, respectively. When given the choice betweenall binary combinations of the five carbohydrates at equimolar concentrations of 100, 200,and 300 mM, respectively, the sakis displayed the following preference pattern: sucrose >fructose > glucose ≥ maltose = lactose. The obtained taste preference thresholds for foodassociated carbohydrates fall into the lower range of values among primates, suggesting acomparatively high sweet-taste sensitivity in the sakis. The pattern of relative preferenceswas consistent with that reported in most tested primates. Altogether, the responsivenesstowards the sweet-tasting substances obtained in this seed predator resembles the resultsobtained in primates which act as seed dispersers. However, these results might reflect anevolutionary adaptation of white-faced sakis to exploit resources containing low sugarconcentrations such as unripe fruits and seeds.

A recent theory within behavioural ecology suggests that some animal behaviour traits are consistent over time and over different contexts as part of an animals’ “personality”. Animal personality has generally been accepted within vertebrates, but the idea of invertebrates expressing personality has long been meet with scepticism. In this study, I investigate if red wood ants (Formica rufa) show exploratory and bold behaviours that fulfil the personality criteria. Moreover, I test if this species prefers dark surfaces instead of white surfaces (scototaxis). My experiment included tests of 30 ants and two different behaviour trials targeting exploration and boldness that repeated over three different time periods. My results shows that the exploratory behaviours were correlated between trials conducted at different times and therefore, that this behaviour was repeatable. It was also clear that the red wood ant consistently showed large between individuals, indicating difference in personality. However, the studied ants did not show preferences for dark surfaces and the performance in the scototaxis trial did not correlate with any other measurable behaviour. The result of this study suggests that Formica rufa show behaviours that match the animal personality criteria for exploratory behaviour, but my result could not validate that bold behaviours were repeatable across time and context.

Prosocial behaviour is pronounced in humans and prevalent in some non-human animals, however, the occurrence of the trait in chickens has not yet been investigated. Here, we studied the occurrence of prosociality in four different lines of adult female chickens. To explore the effects of domestication, chickens of the domesticated layer White Leghorn (WL) and the ancestral Red Junglefowl (RJF) were compared. Additionally, to explore the role of tameness, Red Junglefowl selected for high (RJF HF), or low (RJF LF) fear of humans were also studied. The hens were all tested in a prosocial choice task adapted from a previous study conducted on rats. Each individual was first trained to differentiate between a compartment where itself and a companion received food treats simultaneously (representing a prosocial choice), and one where only itself received the treat. Following training, each bird was tested in a free-choice set-up. No occurrence of prosociality was found at group level in any of the lines, however, our results suggest that the trait may occur in some individuals, and that domestication and increased tameness may have increased its prevalence, although alternative explanations such as side bias and social competition cannot be ruled out. Since this study is the first of its kind, further research is required to make any definite conclusions., Funding Agencies|Carl Tryggers Stiftelse [CTS 21:1533]; Swedish Research Council [2019-04869]

Horses (Equus ferus caballus) engage their sense of smell in numerous behaviors. However, only few studies so far evaluated responses of horses to olfactory stimuli presumed to be either attractive or aversive and rather focused on presenting horses with only one type of odor. Therefore, we assessed behavioral responses of horses towards seven natural odors that are either potentially threatening, or socially attractive, or socially aversive. To this end, we presented a total of 10 horses with the following odors: same-sex and opposite-sex horse feces; same-sex and opposite-sex horse urine; tiger (Panthera tigris) feces and urine; and horse blood attached to one of two simul-taneously presented food buckets and recorded their behavior. We found that the horses displayed clear behavioral reactions towards potentially threatening odors (tiger feces and urine; horse blood) compared to socially attractive (opposite-sex feces and urine) and, in some cases, socially aversive (same-sex feces and urine) odors. More precisely, the horses put their ears back significantly more frequently and tended to do it for longer in the potentially threatening odor condition compared to the socially attractive one. In the potentially threat-ening odor condition, the horses ate from the control bucket significantly more frequently compared to the other two conditions. Detailed analyses showed that the horses behavioral responses were particularly pronounced following exposure to tiger feces and urine. Furthermore, we found that, in some situations, socially aversive odor stimuli caused higher vigilance and more cautious approach, as reflected in increased time of sniffing the odor-bearing bucket and decreased frequency of eating from it in the socially aversive compared to the poten-tially threatening odor condition. These findings suggest that horses, which are known as prey and social ani-mals, are sensitive to social odors and even more so to odors from predators.

Katter anses av många som mer självständiga, lättare att sköta och mindre tidskrävande jämfört med till exempel hundar. Detta har troligen bidragit till deras ökande popularitet och att de idag är ett av de vanligaste husdjuren i världen. Trots detta saknas adekvat kunskap kring kattens specifika behov och naturliga beteenden hos såväl djurägare som djurhälsopersonal. Otillräcklig kunskap kan leda till bristande djurhållning och att katter inte får utlopp för sina naturliga behov, vilket ofta orsakar oönskade beteenden. Trots den stora utbredningen av oönskade beteenden söker djurägare sällan hjälp för denna typ av problematik. En del väljer istället att omplacera eller avliva sina katter. Om djurägare istället får rådgivning och hjälp med att komma till rätta med oönskade problem skulle katternas välfärd ökas. Syftet med denna litteraturstudie var att beskriva de vanligaste oönskade beteenden hos tamkatter, samt kartlägga bakomliggande orsaker till dessa. En litteratursökning gjordes efter specifika sökord i databasen Primo. Detta arbete fann att de vanligaste oönskade beteendena hos tamkatter var urinmarkering, urinering och klösning på oönskade platser samt aggression. De främsta bakomliggande orsakerna är otillräcklig kunskap hos djurägarna vilket resulterar i bristande social och fysisk miljö för katterna. Det kan exempelvis handla om att katter inte får utlopp för jakt- och lekbeteende, att djurägare inte erbjuder klösplatser, har för litet antal kattlådor eller att det finns sociala spänningar i hushåll med flera katter. Även stress och oro kan ta sig uttryck i form av problembeteenden. Djurägare tenderar att söka hjälp främst för oönskade beteenden som drabbar djurägarna själva. Stress, oro och rädsla anses inte vara lika viktiga skäl för att söka rådgivning. När djurägare söker hjälp för oönskade beteenden är det viktigt att först utesluta medicinska orsaker, för att sedan kartlägga dess hemmiljö och sociala situation. Förhoppningsvis kan detta arbete leda, Cats are often considered to be more independent, easier to care for and less time consuming as pets compared to dogs. These are probably some of the reasons why cats have become one of the most common pets in the world. Despite their popularity, both cat owners and animal health personnel often lack adequate knowledge regarding the natural behaviour and needs of cats. Insufficient knowledge can cause unsatisfactory welfare and an environment where cats are unable to fulfil their natural needs, which can result in unwanted behaviour. Although unwanted behaviour is very common, cat owners rarely seek professional help for these types of issues, leading to abandonment to shelters or euthanization. Providing cat owners with advice and solutions to these problems from competent animal health personnel could significantly improve the welfare of cats. The aim of this literary study is to describe the most common unwanted behaviours in pet cats and the reasons behind their development. A literary search in the research database Primo was conducted using keywords. This study found that the most common unwanted behaviours in pet cats were scratching and urinating in unwanted places, urine marking, and aggression. The main underlying reasons for these behaviours were insufficient knowledge from the cat owners, resulting in inadequate social and physical environments for the cats. For example, not allowing cats to perform natural hunt and play behaviour, not offering designated scratch posts or enough litter boxes. Another common issue is that cats are experiencing social discomfort within the home. It has also been shown that stress and anxiety can manifest through the aforementioned unwanted behaviours. Cat owners tend to seek help for problems that are directly affecting themselves, while stress and anxiety of the cats was generally not considered to be a cause to seek professional help. When examining cats with unwanted behaviour, it is vital to first rule out any medical

Obesity is caused by a prolonged positive energy balance(1,2). Whether reduced energy expenditure stemming from reduced activity levels contributes is debated(3,4). Here we show that in both sexes, total energy expenditure (TEE) adjusted for body composition and age declined since the late 1980s, while adjusted activity energy expenditure increased over time. We use the International Atomic Energy Agency Doubly Labelled Water database on energy expenditure of adults in the United States and Europe (n = 4,799) to explore patterns in total (TEE: n = 4,799), basal (BEE: n = 1,432) and physical activity energy expenditure (n = 1,432) over time. In males, adjusted BEE decreased significantly, but in females this did not reach significance. A larger dataset of basal metabolic rate (equivalent to BEE) measurements of 9,912 adults across 163 studies spanning 100 years replicates the decline in BEE in both sexes. We conclude that increasing obesity in the United States/Europe has probably not been fuelled by reduced physical activity leading to lowered TEE. We identify here a decline in adjusted BEE as a previously unrecognized factor., Funding Agencies|Chinese Academy of Sciences [CAS 153E11KYSB20190045]; National Science Foundation of the United States [BCS-1824466]; Swedish Research Council International Postdoctoral Fellowship [VR 2018-06735]; National Institutes of Health; DBT-Wellcome Trust India Alliance; IAEA; Taiyo Nippon Sanso; SERCON; [K01DK109079]; [R03DK122189]; [R01DK090489]; [R01DK126447]; [IA/CRC/19/1/610006]

Har du undrat varför hundar gärna äter märkliga saker, som gräs eller bajs? Eller varför de rullar sig i stinkande högar och lägger så mycket tid på att leka och sova? På ett lättläst och pedagogiskt sätt tar Per Jensen upp dessa och en rad andra hittills obesvarade gåtor och presenterar, med humor och en stor kärlek till hundar, hur vetenskapen försökt lösa dem.[Bokinfo]

Members of social groups may negotiate among each other about the exchange of goods and services. If this involves asymmetries between interacting partners, for instance in condition, power, or expected payoffs, coercion may be involved in the bargain. Cooperative breeders are excellent models to study such interactions, because asymmetries are inherent in the relationship between dominant breeders and subordinate helpers. Currently it is unclear whether punishment is used to enforce costly cooperation in such systems. Here we investigated experimentally in the cooperatively breeding cichlid Neolamprologus pulcher whether alloparental brood care provided by subordinates is contingent on enforcement by dominant breeders. We manipulated first the brood care behavior of a subordinate group member and then the possibility of the dominant breeders to punish idle helpers. When subordinates were prevented from providing brood care, breeders increased their attacks on them, which triggered increased alloparental brood care by helpers as soon as this was again possible. In contrast, when the possibility to punish helpers was prevented, energetically costly alloparental brood care did not increase. Our results confirm predictions of the pay-to-stay mechanism causing alloparental care in this species and they suggest more generally that coercion can play an important role in the control of cooperation. When members of social groups negotiate about the exchange of goods and services, they may use coercion to increase the chances of a favorable outcome. However, it is still unclear whether animals use punishment to enforce cooperative behavior from others. In cooperatively breeding cichlids, we show that received aggression triggers increased alloparental brood care in subordinates. This suggests that fish punish idle helpers, such that these helpers then show increased helping effort.

Zoos have an important role when it comes to the conservation of endangered species. Animals kept in captivity have the same behavioral needs as animals in the wild and it is important that zoos provide them with a stimulating environment. If the environment in the enclosure is not optimal, abnormal behaviors such as stereotypies can develop. Tigers often express abnormal behavior in the form of pacing and there are many factors that can influence the degree to which the behavior is carried out. The purpose of this study was therefore to map the pacing of a male tiger on Nordens Ark. The mapping included how much pacing the male tiger performed, during which times it occurred and where in the enclosure the behavior was performed. Data collection was done by continuous recording and lasted for a total of 50 hours. The behaviors that the tiger spent the most time performing were pacing, locomotion and resting. The result showed that pacing often had a peak between 09:00-10:00 for both frequency and duration. However, the behavior occurred at all timings the tiger was observed. When the tiger was in the small middle cage between the enclosures, he spent more than half of the time performing pacing. When it came to placement for the behavior, it mainly occurred along the fence or next to the small middle enclosure in all of the tiger enclosures. It is difficult to determine why the behavior occured to the extent that it did because there are several factors that can influence it, but the results of the study could be strengthened with already existing research. No general conclusions for tigers in captivity can be drawn from the study but it can be used as a pilot study for future research. The study can also be used to try to improve the enclosure for the male tiger at Nordens Ark.

Vinciane Desprets på én gang analytiske og legende blik på kontroverserne i etologi og evolutionsbiologi gør bogen til en herlig hybrid af genrer – den er en videnskabsteoretisk afhandling med klassiker-potentiale, en populær introduktion til evolutionær adfærdsbiologi (som i kraft af sit noteapparat også gør den brugbar på kurser i biologi og antropologi), et casestudie om en videnskabelig kontrovers, en filosofisk-nyfeministisk refleksion over former for vidensproduktion, en antropologisk komedie, hvor forfatteren selv er en lattermild deltager i en virkelighed der selv tænkes at besidde humor, og en introduktion til en hypersocial og gavegivende fugl, den arabiske larmdrossel, der som en anden antropologisk trickster undslipper ethvert forsøg på kategorisering.

Bycatch in fishing gear is a global issue that affects numerous species worldwide, including the critically endangered Baltic Sea population of harbour porpoises. Acoustic deterrent devices or pingers have been shown to be very effective at reducing bycatch of harbour porpoises, and are currently widely used, but may have a serious negative side effect in aggravating seal depredation caused by the so-called “dinner bell” effect. This project consisted of two parts, the first one looked at the possible presence of a “dinner bell” effect in seals in three different pingers (Banana pinger from Fishtek, Netguard dolphin pinger from Future Oceans and a custom-configured PAL pinger from F3 Maritime Technology) all claimed to be seal-safe. This was tested by deploying baited stations, with and without pingers, at random locations near a seal haul-out site in the Blekinge County archipelago, Sweden. No evidence of a “dinner bell” effect was found, but the low seal engagement rate did not allow for high certainty in these results. The second part of this project looked at the effectiveness of these pingers (except the custom-configured PAL) at reducing porpoise bycatch in small-scale commercial fisheries on the Swedish West coast. For this, volunteer fishermen set their gillnets both with and without pingers and entered bycatch information in logbooks. An onboard, semi-autonomous two-camera monitoring system was also installed on their boats. The film and logbook data were compared, and the possible effect of the pingers on bycatch was investigated. The FO pinger was found to be effective at reducing porpoise bycatch, while the banana pingers in one area reduced bycatch, but in another had more bycatch than the control nets without pingers.

Choice and competition are essential parts of evolutionary biology. In an effort to pass their genes from one generation to the next, animals may carefully choose their mating partners, and/or compete for access to mates. Such choice and competition can occur both before mating through interactions between sexually mature adults (precopulatory sexual selection), and after mating (postcopulatory sexual selection), via competition among and choice of sperm (sperm competition and cryptic female choice, respectively). Choice and competition within and between the sexes have the potential to constrain or reinforce one another. How are mechanisms and episodes of sexual selection linked? Which environmental factors - external, internal, and/or social - act on specific sexually selected traits? When should an animal invest more into postcopulatory, rather than precopulatory traits? In the last decades, a number of sources of variation in sexual selection have been discovered. Yet, the sheer complexity of animal investment into traits, and the selective pressures acting onto them, prove challenging to unravel. In this thesis, I investigated how mechanisms of sexual selection interact and how selective pressures may change in various environments and under differing conditions. I used a multitude of approaches, conducting experimental studies on Dermogenys collettei, the pygmy halfbeak, a small livebearing freshwater fish, and employing comparative tools on even-toed ungulates, a diverse group of mammals that famously invest in horns and antlers used to compete for reproductive opportunities. Using dichotomous choice assays, I identified traits relevant to mate choice in the pygmy halfbeak Dermogenys collettei, and that female mating status may influence the perceived attractiveness of these male traits (Paper I). I found no influence of male social status on female choice, with females eavesdropping on male-male competition showing no preference for either subordinate or dom

Bee foraging behavior provides a pollination service that has both ecological and economic benefits. However, bee population decline could directly affect the efficiency of this interaction. Among the drivers of this decline, global warming has been implicated as an emerging threat but exactly how increasing temperatures affect bee foraging behavior remains unexplored. Here, we assessed how exposure to elevated temperatures during development affects the foraging behavior and morphology of workers from commercial and wild Bombus terrestris colonies. Workers reared at 33 °C had a higher visiting rate and shorter visiting time than those reared at 27°C. In addition, far fewer workers reared at 33 °C engaged in foraging activities and this is potentially related to the drastic reduction in the number of individuals produced in colonies exposed to 33 °C. The impact of elevated developmental temperature on wild colonies was even stronger as none of the workers from these colonies performed any foraging trips. We also found that rearing temperature affected wing size and shape. Our results provide the first evidence that colony temperature can have striking effects on bumblebee foraging behavior. Of particular importance is the drastic reduction in the number of workers performing foraging trips, and the total number of foraging trips made by workers reared in high temperatures. Further studies should explore if, ultimately, these observed effects of exposure to elevated temperature during development lead to a reduction in pollination efficiency.

Throughout the animal kingdom, animals vary in cognition (i.e., how they acquire, process, store, and act on environmental information). Yet, the causes and consequences of this variation are currently unclear. Inhibitory control is one such aspect of cognition that typically varies between individuals within all species investigated. Variation in inhibitory control underlies variation in impulsivity (i.e., the tendency to act without planning or considering the consequences). The causes and consequences of variation in impulsivity are, themselves, rarely explored, despite that these may have important ecological and evolutionary implications. My thesis (spanning 5 papers), therefore, aimed to fill some of these gaps by taking a holistic approach and investigating causes and consequences of variation in impulsivity (specifically, impulsive action and persistence measured in a detour task) in red junglefowl (Gallus gallus) males and females, chicks and adults. The red junglefowl was an ideal species for this investigation. Firstly, they show individual variation in impulsivity throughout their lives. They are also typically food motivated, and easily habituated to handling and new situations, which means they commonly willingly participate in behavioural and cognitive tests. Furthermore, they are precocial, which means that they can be hatched and raised without mothers, thus reducing parental effects. Finally, the large, accumulated knowledge of red junglefowl behaviour and cognition aids interpretations regarding this. As differences in experience early in life have been found to affect impulsivity, papers I and II empirically explored whether variation in two previously uninvestigated experiences in early life (exposure to enrichment, and social group size, respectively) influenced impulsivity. The dopaminergic and serotonergic systems are important signalling systems in the brain, which have been found to link to impulsivity in other species. Therefore, in paper

Video recording is a common method to study animal behaviour. In honey bee studies, short video-recordings are often used to learn more about a behaviour, but rarely used for their quantification. Standard methods for observing bee behaviour involve behavioural assays or direct observation of a limited subset of marked bees within an observation hive. This means that behaviour at the hive entrance may be overlooked. Here we describe a 4-camera set up for the study of behaviour at hive entrances. With minimal disturbance, we were able to record and quantify all previously described behaviours (9 in total - including self-grooming in drones) on and around the hive entrance. We briefly discuss the general feasibility of video footage and the relative frequency of each observed behaviour. Our conclusion is that video footage is a useful and perhaps overlooked method for unbiased quantification and comparisons of bee behaviour at the hive entrance. With this paper we are publishing some example short video-recordings as online supplementary material for educational purposes., CC BY-NC-ND 4.0Published online: 23 Aug 2022Copyright © 2022 Informa UK LimitedEmail: mats.niklasson@nordensark.seMilkywire and Trädgårdsresan provided financial support for technical equipment and salary to EC. MN, SL and NN were funded by INTERREG Project number 2020-1923 'BIstånd till Nordiska bin'.