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.

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.

Social dominance relationships are formed within numerous animal species and reduce costly fights over resources. Dominant individuals often enjoy greater access to important resources such as food and mating partners, and are generally more aggressive, bold, active and explorative compared to subdominant individuals. These behavioural traits can differ among individuals, but they can also be consistent within the individual, thereby describing the individual’s personality type. However, the causal direction of the observed correlation between dominance and personality is not well studied. One possibility is that some personality types have higher chances of obtaining a dominant social position. This would suggest that personality has consequences for fitness. Another possible explanation is that possessing different social positions gives rise to consistent behavioural differences among individuals on various timescales. If social status has a lasting effect on behaviour, social status would constitute a ‘stable state’ that explains some of the diversity of personality types that has been observed in a multitude of animal species. Dominance and personality may also share underlying proximate factors. In this thesis, I investigate the relationship between social dominance and personality using male domestic fowl, Gallus gallus domesticus. The species is group-living with pronounced dominance hierarchies, and dominance increases male access to mating partners. I show that some aspects of personality, exploration, vigilance and in particular aggressiveness, increased a male’s chances of obtaining dominance (paper III, IV, V), and that aggressiveness can be even more important than body weight and ornament size (comb size, paper V) or recent experience of winning or losing (paper IV). Winning a social interaction resulted in an increase in aggressiveness, while a decrease was seen in males that experienced a loss (paper IV). By observing behaviour before and after changes in male dominance relationships, I further show that a recent (2 days earlier) change in social status induced behavioural adjustments to the new social status in activity, exploration and vigilance (paper I). By extending the time of the new social relationship to 3 weeks, I show that such behavioural changes did not continue (paper II). Finally, I show that the social environment during juvenile development had little impact on adult male competitiveness (paper V). Social interactions appear to have several short-term effects on behaviour, but did not contribute significantly to variation and long-term consistency of personality in male fowl. Instead, a male's personality, and in particular his aggressiveness, affected the outcome of dominance interactions. Overall, my studies reveal important consequences of individual differences in behaviour, and contribute to the highly sought-after empirical testing of hypotheses explaining variation in animal personality. / <p>At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 2: Manuscript. Paper 5: Manuscript.</p>

Anxiety disorders share the feature of excessive fear, anxiety and related behavioural disturbances. Fear is defined as the emotional response to a real or a perceived imminent threat and anxiety is the anticipation of a future threat. The anxiety disorders covered in this thesis are panic disorder with or without agoraphobia, social phobia, post-traumatic stress disorder, generalized anxiety disorder and anxiety disorder not otherwise specified. Cognitive behavioural treatment protocols are typically designed to target one specific disorder and falls under the definition of disorder-specific cognitive behavioural therapy. It is however unclear if this is the most optimal approach in regards to the high comorbidity between anxiety disorders and depressive disorders. Internet-based cognitive behavioural therapy has in the past generally been disorder-specific and from above mentioned predicament two alternative treatment approaches emerged, the tailored and the transdiagnostic approach that aims to simultaneously treat both principal and comorbid disorders. Previous trials on internet-based cognitive behavioural therapy have targeted adults in general and relatively few target adolescents, young adults and older adults. The aims of this thesis were to further develop and test the effects of tailored internet-based cognitive behavioural therapy on the basis of age, for adolescents, young adults and older adults. Specifically by developing and testing the effects of individually tailored internet-based cognitive behavioural therapy for adolescents with anxiety and comorbid depressive symptoms and by adapting and testing the effects of individually tailored internet-based cognitive behavioural therapy for young adults and older adults with anxiety and comorbid depressive symptoms. These aims were tested in two pilot effectiveness studies (Paper I and III) and two efficacy randomised controlled trials (Paper II and IV). The results from these four trials showed significant results across all outcome measures with overall moderate to large effect sizes. The tentative conclusion based on these results is that tailoring internet-based cognitive behavioural therapy can be a feasible approach in the treatment of anxiety symptoms and comorbid depressive symptoms for adolescents, young adults and older adults. Despite the positive findings of the studies in this thesis, there is a need for more research examining the acceptability and effectiveness of internet-based cognitive behavioural therapy for adolescents, young adults and older adults with anxiety and depression before implementation on a larger scale.

Aposematic species have evolved conspicuous warning signals, such as bright colors and striking patterns, to deter predators. Some edible and harmless species take advantage of this deterrent effect by mimicking their appearance. Mimicry is a great example of how natural selection produces remarkable adaptations. However, while some species evolve a very close similarity to their models to effectively avoid attacks, others are successful in doing so despite an incomplete similarity, i.e. imperfect mimicry. In some cases, it is surprising how such a crude disguise can fool predators. Why and how imperfect mimicry can persist has been much discussed and considered as a problem for the theory of natural selection. It is therefore of great interest to understand what makes it possible. Predator psychology is an important factor in the evolution of aposematism and mimicry. In the past decades it has been suggested that certain components of prey appearance are more important to predators than others during prey assessment. We developed this idea by incorporating concepts from associative learning, and presented a new approach to explain imperfect mimicry. Our general hypothesis is that prey traits have different salience to predators. Certain traits are perceived as highly salient and are thus used primarily in the discrimination and generalization of prey, while traits with low salience are overshadowed and not used in the assessment. The salience of a trait can depend on how conspicuous or discriminable it is in the particular context, and can vary due to for example previous predator experience. We tested our ideas with wild blue tits and domestic chickens as predators, and artificial and semi-natural prey stimuli. In paper I we found that the trait that was perceived as most salient (color) was the one used to discriminate and generalize between prey. Mimics of that specific trait were highly avoided, despite differences in the other traits. We also found that salience is relative and context dependent (paper II). In a context where two traits were perceived as similarly salient, mimicry of a single trait offered intermediate protection, while mimicry of both offered high protection. In another context, the traits were perceived differently salient, and mimicry of one trait was enough for high protection. In paper III we tested a proposed scenario for the initiation of mimicry evolution in the edible butterfly mimic Papilio polyxenes asterius to its noxious model Battus philenor. The results showed that a partial similarity with the model in the salient black wing color offered intermediate protection from attacks, despite a general dissimilarity. This thesis investigates the major questions of imperfect mimicry: the initial step of mimicry evolution, the persistence of imperfect mimicry, and variation in mimic-model similarity. We conclude that mimicry evolution can begin in a non-mimetic species that acquires similarity to a model species in a high-salience trait. When multiple traits have similar salience, multi-trait mimicry is needed for higher protection. Mimicry can remain imperfect if the differences are in traits with low salience, and therefore under low or no selection pressure to change. To complete the picture, we showed that predators can have a biased generalization toward a more pronounced version of a salient trait (paper IV). The evolution of aposematism could therefore be explained by gradual enhancement of salient traits. / <p>At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 3: Accepted. Paper 4: Manuscript.</p>

One out of several distinguishing features of multiple sclerosis (MS) is the epidemiological variation of geographic distribution. Population-based studies on the prevalence and incidence of MS in Sweden have previously been performed only in Göteborg. Another feature of MS is the clinical variation between individuals. To a large extent data on the clinical characteristics of MS come from studies on cases frequenting MS clinics and therefore, may be biased. Also rare are population-based studies of the consequences of MS-related incapacity on socio­economic factors. As for MS aetiology, both environment and genes are involved. Human herpesviruses are often the main suspected environmental aetiological agents. Our aim was to estimate the prevalence of MS in Västerbotten County for 1 January 1990, the incidence during a 10-year period 1988-97, and the prevalence 31 December 1997; and also to present detailed clinical data including onset symptoms and the disability distribution for the latter two MS populations. Furthermore, we wanted to estimate the prevalence of sick leave, professional assistance, and housing; and also, to study the risk factors for sick leave. In order to investigate the association between MS and human herpesviruses, samples were identified in two regional population-based serumbank registers. This linkage identified samples collected from before MS-onset in 73 MS cases and after MS onset in 161 cases The prevalence and incidence populations were identified through multiple sources. Diagnostic ascertainment, the reliability of clinical data, and additional information were assured from a questionnaire with follow-up interview and neurological examination. The onset adjusted crude prevalence of MS was 125/100,000 (95% CI: 112-140) in January 1990, and 154/100,000 (95% Cl: 139-170) in December 1997. The increase was mainly attributable to a higher incidence than mortality. The crude incidence rate 1988-97 was 5.2/100,000 (95% CI: 4.4-6.2). The disability distribution in the 1997 prevalence population in Västerbotten was compared to the disability distribution in a Canadian MS population, which has been used for publications on the natural history of MS. One difference from the Canadian studies appears to be the better recognition of cases with more benign disease. Nevertheless almost half of prevalent MS cases aged 18-64 years were fully sick-listed, and one-fourth of all prevalent cases received professional assistance. High disability level was the strongest predictor for sick leave. All MS cases showed signs of past Epstein-Barr virus (EBV) infection. High activity to EBV (EBNA-1 but not VCA) and human herpesvirus 6 (HHV-6) significantly (borderline significance for HHV-6) increased the risk to develop MS. These estimates show that Västerbotten County is a high risk area for MS. Both incidence and prevalence were significantly higher when compared to estimates from Göteborg. The comparison with the Canadian MS population shows that MS might be a slightly more benign disease than previously recognized. Still, the consequences of MS regarding socio-economic aspects are considerable. We suggest that EBV is a prerequisite for the development of MS. Individuals that will develop MS exhibit an altered immune response against the EBV virus characterised by high activities to EBNA-1 in the absence of high VCA activities, this being most pronounced in the five-year period preceding MS onset. A pathogenetic role is suggested for EBV and remains possible also for HHV-6. / digitalisering@umu

An appreciation of the role of mutualism is essential when studying ecology and evolution in most ecosystems. Information covering aspects of mutualistic interactions can serve as a complement to the somewhat one-sided perspective from the 1950’s and 60’s that is used when teaching biology. In this thesis I applied an in-depth approach in which variation in the interspecific interaction between Aphis fabae aphids and Lasius niger ants was studied both in the field and in the laboratory. An emphasis was put on studies spanning several consecutive aphid generations. This approach revealed important differences between ant tended aphids and those without ants. In the lab, I found an initial decrease in aphid adult size and reproductive investment in the first generations after the start of ant tending, which was followed by a recovery to the pre-tending situation after about four generations. Another laboratory experiment showed an increase in alate (winged aphid) production from exposure to aphid alarm pheromones, and an even stronger decrease in alate production from ant attendance, suggesting that ants have gained the upper hand in an evolutionary conflict over aphid dispersal. Results from a field experiment further emphasized the possibility of negative effects of ants on aphids, showing that ant-tended aphid colonies experienced a higher rate of parasitoid attacks, produced fewer alates and embryos in adult aphids. The thesis highlights the scope for variation in the net effect of the interaction for aphids, and argues that, depending on the environmental circumstances, the interaction may sometimes and perhaps even often not really be a case of mutualism. / <p>At the time of the doctoral defense, the following paper was unpublished and had a status as follows: Paper 4: Manuscript.</p>

Egg-laying hens coming from commercial hatchery go through hatchery procedures considered as stressful and engaging prolonged stress response in adult chickens. The aim of our study was to evaluate the impact of commercial hatching procedure on the affective state of chicks, on their short- and long-term memory and on their need for social reinstatement. To assess the affective state of the chicks we used a cognitive bias protocol integrating the ecological response of a chick to the picture of another chick, to an owl and to an ambiguous cue mixing features of both the chickand the owl pictures. Short-term memory was evaluated by using a delayed matching-to-sample experiment (with 10, 30,60 and 120 s delays), with conspecifics as sample stimuli. We assessed long-term memory with an arena containing multiple doors leading to conspecifics, in which a chick had to remember which door was open after a delay of one hour or three hours. Finally, we observed the need for social reinstatement through a sociality test arena allowing a chick to be more or less close to conspecifics. We found that chicks coming from commercial hatchery were in a depressive affective state compare to control group. Those chicks also showed higher need for social reinstatement and loss weight. No differences were found regarding short- and long-time working memory between the two groups, but the methods used during these experiments will be discussed. Studying how commercial procedures impact the cognition and more specifically the emotions and state of mind of chickens, is a necessary step forward into the understanding of farm animals’ welfare.

Food waste is a major issue from various perspectives. During the process from harvest to the end consumer, almost one-third of food produced is wasted. It is not just the wasted food during the process that is concerning, there are issues in sustainability related to food waste that need to be considered. Moreover, there has been little attention to the issue of food waste in the downstream part of the supply chain and how specific behaviours affect the issue of wasting food.This thesis explores the food waste of fresh fruits and vegetables from a consumer´s perspective. To specify, the purpose of the study is to investigate the drivers of the disposal pattern of fresh fruit and vegetables, with an emphasis on the behaviour of "Generation Y" (born 1980 – 1995). Therefore, a revised model of the Theory of Planned Behaviour is applied. Also, to understand the behaviour of "Generation Y" regarding disposal, it is expected to identify impacts on the supply chain.A deductive approach is applied to this thesis. The qualitative study was conducted with open-ended survey questions to supplement the results with the answers of the respondents. The empirical data is collected from consumers within the “Generation Y” who usually purchase their fresh fruits and vegetables for their respective households. The data was analysed using the coding analysis which involves summarization and categorization of data.The results of the research reveal that external attitudinal factors such as price and marketing perception, storage habits, and quality consciousness and internal attitudinal factors such as sustainable environmental awareness, health consciousness, and subjective norms influence the respondents’ disposal behaviour. Moreover, the sustainable attitude of “Generation Y’’ leads to most of the consumers’ waste reduction, and highly influences the supply chain.

Horses are herbivores and can graze for up to 20 hours per day. It is well known that animals are motivated to perform natural behaviours and horses have, except from a physiological need to graze, a strong motivation to perform their natural feeding behaviour. This review aimed to give insight into how horses are kept, how the way they are kept affects their behaviour and welfare, if there are reasons why some horses cannot be kept on pasture, and if alternative feeding strategies can improve horse welfare by allowing horsesto perform their natural feeding behaviour. Most horses are kept in stables and are put on feeding regimes that do not resemble their natural feeding behaviour. This can lead to development of stereotypies, and when prevented from carrying out their feeding behaviour, oral stereotypies such as crib-biting can result. Horses kept free range display very few, if any, stereotypies and is therefore the best way to keep horses from a welfare approach. However, obesity and grass-related illnesses can restrict horses from being kept on pasture, thus, alternative feeding methods for stabled horses is imperative. Use of edible bedding, presenting several types of forage, providing ad libitumforage, or using slow feeders are alternative methods that could be implemented by horseowners and caretakers to improve horse welfare. Horses can however respond differently to these methods and a method that suits one horse might not be appropriate for another.