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  • 1.
    Acerbi, Alberto
    et al.
    Stockholms universitet, Humanistiska fakulteten, Centrum för evolutionär kulturforskning.
    Ghirlanda, Stefano
    Stockholms universitet, Humanistiska fakulteten, Centrum för evolutionär kulturforskning.
    Enquist, Magnus
    Stockholms universitet, Humanistiska fakulteten, Centrum för evolutionär kulturforskning. Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen.
    The logic of fashion cycles2012Inngår i: PLoS ONE, ISSN 1932-6203, Vol. 7, nr 3, e32541- s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Many cultural traits exhibit volatile dynamics, commonly dubbed fashions or fads. Here we show that realistic fashion-like dynamics emerge spontaneously if individuals can copy others' preferences for cultural traits as well as traits themselves. We demonstrate this dynamics in simple mathematical models of the diffusion, and subsequent abandonment, of a single cultural trait which individuals may or may not prefer. We then simulate the coevolution between many cultural traits and the associated preferences, reproducing power-law frequency distributions of cultural traits (most traits are adopted by few individuals for a short time, and very few by many for a long time), as well as correlations between the rate of increase and the rate of decrease of traits (traits that increase rapidly in popularity are also abandoned quickly and vice versa). We also establish that alternative theories, that fashions result from individuals signaling their social status, or from individuals randomly copying each other, do not satisfactorily reproduce these empirical observations.

  • 2.
    Ahlen, Ingemar
    Utförare miljöövervakning, Universitet, Sveriges lantbruksuniversitet, SLU, Sveriges lantbruksuniversitet, skoglig resurshållning.
    Skydd av biotoper för bevarande av vitryggig hackspett i nedre Dalälven1976Rapport (Annet vitenskapelig)
    Abstract [sv]

    Den vitryggiga hackspetten Dendrocopos leucotos, som ursprungligen förekommit över nästan hela landet, har under de senaste hundra åren blivit allt sällsyntare och finns nu, förutom i några spridda förekomster av enstaka par eller ensamma fåglar, i landet endast kvar med en fast population i nedre Dalälvsområdet mellan Avesta och Älvkarleby.

    De hotade hackspettarterna har sedan 1974 varit föremål för ekologisk forskning och inventeringsarbete. I bilagda ”information om projekt hackspettars ekologi” 1976-01-18 redovisas projektets syfte och kortfattad redogörelse för arbetet under 1975 ges. Hänvisning kan också göras till tidskriften Vår Fågelvärlds första nummer 1976 där resultat av 1973 års riksinventering av gråspett och vitryggig hackspett redovisas.

  • 3.
    Ahlrot, Ulrica
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biologi.
    Welfare in zoo kept felids: A study of resource usage2016Independent thesis Advanced level (degree of Master (Two Years)), 40 poäng / 60 hpOppgave
    Abstract [en]

    Due to a large number of felid species being endangered they are subjects of conservation projects both in situ and ex situ. Keeping felids in zoos are problematic with stereotypic behaviours such as pacing and reproduction difficulties often occurring. The aim of this study was to review research and zoo husbandry knowledge about which resources are most important for the welfare of zoo kept felids, and in addition perform behavioural observations in seven felid species in four Swedish zoos to try to find an order of priority of resources. Observations were performed during opening hours in 36 sessions per species and zoo. The results showed that studies of felid resource usage are missing. Zoo husbandry practice is probably based mainly on traditions and anecdotal knowledge. The observations showed that except for minor differences felids behave similarly regardless of species but the use of resources varies. Small felid species seems to be hiding rather than pacing as a way of coping. Elevated resources and areas as well as numerous hiding places are important to felids but many factors might affect the choice of resting places. Therefore it is important to provide the felids with multiple choices. It is also important to evaluate both species and individuals when designing enclosures and providing resources. More multi-institutional studies with large number of individuals of all zoo kept felid species are needed to gather knowledge about felids needs and preferences of resources.

  • 4.
    Almberg, Johan
    Linköpings universitet, Institutionen för fysik, kemi och biologi. Linköpings universitet, Tekniska högskolan.
    Variation in proactive - reactive personality types in the red junglefowl2013Independent thesis Basic level (degree of Bachelor), 10,5 poäng / 16 hpOppgave
    Abstract [en]

    It has been shown in many species that individuals exhibit consistent differences in behaviour over time and/or across situations. These differences in behaviour are called personality. One way to categorise personality types typically used for rodents, is along a proactive-reactive gradient, which describes how individuals cope with stressful challenges. Proactive individuals pay less attention to their environment, form routines easily and take longer to adapt when routines are broken compared to reactive individuals. Avian species have to date rarely been described along this gradient, thus the generality of this description across species is unclear. The present study has investigated variation in proactivity-reactivity in red junglefowl chicks (Gallus gallus). To observe the chicks’ coping styles, a proactive-reactive test was conducted where the chicks were trained to form a routine, which was then broken. Their behavioural response to this was recorded and used as a measure for proactivity-reactivity. The behavioural response was then linked to individual behavioural variation in additional personality assays. Individuals that were more vigilant in the proactive-reactive test often uttered stress calls and took longer to complete the test. In contrast, individuals that walked more and did not utter stress calls had a shorter time to complete the test. These findings can be used to describe proactive red junglefowl chicks; those that are more stressed when routines are broken, compared to calmer reactive individuals. I found no difference in routine formation between proactive and reactive red junglefowl chicks, suggesting that what describes proactive and reactive individuals may vary across species.

  • 5.
    Almbro, Maria
    et al.
    Centre for Evolutionary Biology, University of Western Australia.
    Kullberg, Cecilia
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för etologi.
    Season, sex and flight muscle investment affect take-off performance in the hibernating small tortoiseshell butterfly Agalis urticae (Lepidoptera: Nymphalidae)2011Inngår i: The Journal of Research on the Lepidoptera, ISSN 0022-4324, Vol. 44, 77-84 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Flight ability is generally expected to increase with relative flight muscle mass. Changes in weight can therefore be expected to influence the capacity to rapidly take-off, which can determine mating success and predator avoidance. This study examined the influence of relative flight muscle mass, sex, and season on free take-off flight ability in a butterfly model (Aglais urticae) that undergoes adult winter hibernation. Mass change and take-off flight ability (velocity and take-off angle), was predicted to fluctuate with season (before, during and after hibernation) and sex (due to reproductive investment). Our results indeed showed changes in take-off ability in relation to both parameters. Females maintained velocity across seasons but reduced take-off angles during and after hibernation. Male flight speed increased during and after hibernation, whereas take-off angles were significantly reduced during hibernation. Finally, we showed that investment in relative flight muscle mass increased velocity in female, but not in male butterflies.

  • 6.
    Amundin, Mats
    et al.
    Kolmården Wildlife Park.
    Hållsten, Henrik
    Filosofiska institutionen, Stockholms universitet.
    Eklund, Robert
    Linköpings universitet, Institutionen för kultur och kommunikation, Avdelningen för språk och kultur. Linköpings universitet, Filosofiska fakulteten.
    Karlgren, Jussi
    Kungliga Tekniska Högskolan.
    Molinder, Lars
    Carnegie Investment Bank, Swedden.
    A proposal to use distributional models to analyse dolphin vocalisation2017Inngår i: Proceedings of the 1st International Workshop on Vocal Interactivity in-and-between Humans, Animals and Robots, VIHAR 2017 / [ed] Angela Dassow, Ricard Marxer & Roger K. Moore, 2017, 31-32 s.Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This paper gives a brief introduction to the starting points of an experimental project to study dolphin communicative behaviour using distributional semantics, with methods implemented for the large scale study of human language.

  • 7.
    Andersson, Elin
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biologi. Linköpings universitet, Tekniska högskolan. IFM.
    Dogs´understanding of human pointing gestures2014Independent thesis Basic level (degree of Bachelor), 10,5 poäng / 16 hpOppgave
    Abstract [en]

    To investigate the ability for animals to understand human communication signals and the communication between animals and humans, scientists often investigate the understanding of human gestural cues. Dogs (Canis lupus familiaris) which have a long history of co-evolution with humans have been shown to make good use of human gestural cues. In the present study I investigated whether dogs in general understand a human pointing gesture and if there are differences between sex, age or breeds. In total 46 dogs of different breeds participated in the study. The study was carried out in a dog center in Linköping, Hundens och djurens beteendecenter. To test if dogs understand human pointing gestures, a two-way object choice test were used, where an experimenter pointed at a baited bowl at a distance of three meter from the dog. The results showed that dogs in general can understand human pointing gestures. However, no significant differences were found for sex, age or breeds. As a conclusion, I found that dogs in general can understand human pointing gestures, but sex, age or breed did not affect the ability.

  • 8.
    Aplin, L. M.
    et al.
    Univ Oxford, Dept Zool, Edward Grey Inst Field Ornithol, Oxford OX1 3PS, England.;Univ Calif Davis, Dept Anthropol, Davis, CA 95616 USA..
    Firth, J. A.
    Univ Oxford, Dept Zool, Edward Grey Inst Field Ornithol, Oxford OX1 3PS, England..
    Farine, D. R.
    Univ Oxford, Dept Zool, Edward Grey Inst Field Ornithol, Oxford OX1 3PS, England.;Univ Calif Davis, Dept Anthropol, Davis, CA 95616 USA.;Smithsonian Trop Res Inst, Ancon, Italy..
    Voelkl, B.
    Univ Oxford, Dept Zool, Edward Grey Inst Field Ornithol, Oxford OX1 3PS, England..
    Crates, R. A.
    Univ Oxford, Dept Zool, Edward Grey Inst Field Ornithol, Oxford OX1 3PS, England..
    Culina, A.
    Univ Oxford, Dept Zool, Edward Grey Inst Field Ornithol, Oxford OX1 3PS, England..
    Garroway, C. J.
    Univ Oxford, Dept Zool, Edward Grey Inst Field Ornithol, Oxford OX1 3PS, England..
    Hinde, C. A.
    Wageningen Univ, Dept Anim Sci, Behav Ecol Grp, NL-6700 AP Wageningen, Netherlands..
    Kidd, L. R.
    Univ Oxford, Dept Zool, Edward Grey Inst Field Ornithol, Oxford OX1 3PS, England..
    Psorakis, I.
    Univ Oxford, Math Inst, Oxford, England..
    Milligan, N. D.
    Univ Oxford, Dept Zool, Edward Grey Inst Field Ornithol, Oxford OX1 3PS, England..
    Radersma, R.
    Univ Oxford, Dept Zool, Edward Grey Inst Field Ornithol, Oxford OX1 3PS, England.;Lund Univ, Dept Biol, Evolutionary Ecol Unit, Lund, Sweden..
    Verhelst, B. L.
    Univ Oxford, Dept Zool, Edward Grey Inst Field Ornithol, Oxford OX1 3PS, England..
    Sheldon, B. C.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik. Univ Oxford, Dept Zool, Edward Grey Inst Field Ornithol, Oxford OX1 3PS, England..
    Consistent individual differences in the social phenotypes of wild great tits, Parus major2015Inngår i: Animal Behaviour, ISSN 0003-3472, E-ISSN 1095-8282, Vol. 108, 117-127 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Despite growing interest in animal social networks, surprisingly little is known about whether individuals are consistent in their social network characteristics. Networks are rarely repeatedly sampled; yet an assumption of individual consistency in social behaviour is often made when drawing conclusions about the consequences of social processes and structure. A characterization of such social phenotypes is therefore vital to understanding the significance of social network structure for individual fitness outcomes, and for understanding the evolution and ecology of individual variation in social behaviour more broadly. Here, we measured foraging associations over three winters in a large PIT-tagged population of great tits, and used a range of social network metrics to quantify individual variation in social behaviour. We then examined repeatability in social behaviour over both short (week to week) and long (year to year) timescales, and investigated variation in repeatability across age and sex classes. Social behaviours were significantly repeatable across all timescales, with the highest repeatability observed in group size choice and unweighted degree, a measure of gregariousness. By conducting randomizations to control for the spatial and temporal distribution of individuals, we further show that differences in social phenotypes were not solely explained by within-population variation in local densities, but also reflected fine-scale variation in social decision making. Our results provide rare evidence of stable social phenotypes in a wild population of animals. Such stable social phenotypes can be targets of selection and may have important fitness consequences, both for individuals and for their social-foraging associates.

  • 9.
    Aronsson, Marianne
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen.
    Colour patterns in warning displays2012Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    In aposematism a prey species use bright colours, often combined with a black contrasting pattern, to signal unprofitability as prey to potential predators. Although there are several different hypotheses about the presence of these internally contrasting patterns, there is little experimental evidence of any beneficial effects. In this thesis I have used bird predators and artificial prey signals to investigate if the contrasting internal patterns in warning displays may have evolved to increase signal efficacy, especially regarding the speed of avoidance learning. In paper I the relative importance of colour and pattern in avoidance learning was studied. The conclusion was that birds primarily attend to colour, not pattern, when learning the discrimination, which was further supported by the results in paper II-IV, all suggesting a secondary role of patterns. In paper II I show that predators may to some degree use patterns for discrimination, if they convey important information about prey quality. The predators showed a hierarchical way of learning warning colour components, where colour is learned to a higher degree than pattern. In paper III I investigate if internal contrasting patterns promote avoidance learning by increasing conspicuousness as prey-to-background contrast does. The study did not support this idea, as the presence of internal black patterns did not improve avoidance learning on a colour matching background. In paper IV, however, I show that the presence of many internal colour boundaries resulted in faster avoidance learning on a multi-coloured background, and predator generalization favoured more internal boundaries, while there was no effect of pattern regularity. From these studies I conclude that internal pattern contrasts may function to increase the efficacy of the warning colour, its salience, and as a means for aposematic prey to be discriminated from harmful mimics. However, the major finding is the importance of colour over pattern.

  • 10.
    Aronsson, Marianne
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för etologi.
    Gamberale-Stille, Gabriella
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för etologi.
    Colour and pattern similarity in mimicry - evidence for a hierarchical discriminative learning of warning colour pattern components.Manuskript (preprint) (Annet vitenskapelig)
  • 11.
    Aronsson, Marianne
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen.
    Gamberale-Stille, Gabriella
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen.
    Evidence of signaling benefits to contrasting internal color boundaries in warning coloration2013Inngår i: Behavioral Ecology, ISSN 1045-2249, E-ISSN 1465-7279, Vol. 24, nr 2, 349-354 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    It has been suggested that the common existence of regular patterning in aposematic prey animals makes them stand out from the background, improving detection and recognition. Another suggestion is that internal patterns could have a similar positive effect on predator aversion learning as prey-to-background contrast. We used wild caught blue tits (Cyanistes caeruleus) and artificial prey signals to investigate if internal color boundaries, pattern regularity and pattern symmetry affect learning. Birds in different treatments were trained, on a complex background, to discriminate between artificial prey with different nonrewarding color stimuli with a black pattern and rewarding stimuli without a black pattern, followed by a generalization test. This study provides evidence of learning benefits to internally contrasting patterns as the striped prey stimuli were learned faster than the unstriped. Also, we found no beneficial effects of pattern regularity and symmetry. The birds generalized more between prey with different black patterns than to the profitable prey, suggesting that color is of foremost importance. The generalization test also showed a greater avoidance of striped than that of unstriped prey, suggesting some attention on patterns. Thus, internal patterning may affect signal salience and in some circumstances benefit prey due to both a faster avoidance learning and generalization behavior.

  • 12.
    Aronsson, Marianne
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för etologi.
    Gamberale-Stille, Gabriella
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för etologi.
    Why do aposematic prey often have contrasting internal patterns: Evidence of benefits through predator avoidance learning and generalization.Manuskript (preprint) (Annet vitenskapelig)
  • 13. Barber, I.
    et al.
    Svensson, P. A.
    Effects of experimental Schistocephalus solidus infections on growth, morphology and sexual development of female three-spined sticklebacks, Gasterosteus aculeatus2003Inngår i: Parasitology, ISSN 0031-1820, E-ISSN 1469-8161, Vol. 126, 359-367 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The use of naturally infected hosts in studies attempting to identify parasite-induced changes in host biology is problematical because it does not eliminate the possibility that infection may be a consequence, rather than a cause, of host trait variation. In addition, uncontrolled concomitant infections may confound results. In this study we experimentally infected individual laboratory-bred female three-spined sticklebacks Gasterosteus aculeatus L. with the pseudophyllidean cestode Schistocephalus solidus [Muller], and compared the morphology and growth patterns of infected females with sham-exposed controls over a 16-week period. Fish were fed a ration of 8% body weight per day. Non-invasive image analysis techniques allowed the growth of individual plerocercoids to be tracked in vivo throughout the course of infection, and patterns of host and parasite growth were determined. Females that developed infections diverged morphometrically from unexposed control females and exposed-uninfected females at 6 weeks post-infection, with the width of the body at the pectoral fins giving the earliest indication of infection success. When including the plerocercoid, infected females gained weight more quickly than controls, but when plerocercoid weight was removed this trend was reversed. There was no effect of infection on the increase in fish length. Plerocercoids grew at different rates in individual hosts, and exhibited measurable sustained weight increases of up to 10% per day. Final estimates of plerocercoid weight from morphometric analysis prior to autopsy were accurate to within +/-17% of actual plerocercoid weight. At autopsy, infected female sticklebacks had significantly lower perivisceral fat reserves but had developed significantly larger ovaries than controls. The results are discussed in relation to previous studies examining natural infections, and the value of utilizing experimental infections to examine ecological aspects of host-parasite interactions is discussed.

  • 14. Barber, I.
    et al.
    Svensson, P. Andreas
    Synchrony between parasite development and host behaviour change2003Inngår i: Journal of Fish Biology, ISSN 0022-1112, E-ISSN 1095-8649, Vol. 63 Supp A, 246- s.Artikkel i tidsskrift (Fagfellevurdert)
  • 15. Barber, I.
    et al.
    Walker, P.
    Svensson, P. A.
    Behavioural responses to simulated avian predation in female three spined sticklebacks the effect of experimental Schistocephalus solidus infections2004Inngår i: Behaviour, ISSN 0005-7959, E-ISSN 1568-539X, Vol. 141, 1425-1440 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Plerocercoid larvae of Schistocephalus solidus are common parasites of three-spined sticklebacks that require the ingestion of stickleback hosts by birds to complete their life cycle. Amongst wild-caught sticklebacks, infection is associated with a reduction in antipredator behaviour; however, to date no study has examined the escape responses of experimentally infected sticklebacks, and thus assigning causality remains difficult. Here, we compare aspects of the antipredator behaviour of five experimentally infected female sticklebacks with shamexposed controls over a 16 post-exposure week period. During weeks 1-7 post-exposure, the escape responses of infected fish did not differ significantly from those of sham-exposed fish. However, over weeks 9-15, when infected fish had developed plerocercoids of >50 mg—the size at which they become infective to birds —a lower proportion of infected fish performed directional responses and reached cover within 2 s of the strike. Infected fish also performed a lower frequency of ‘staggered dashes’, and a higher frequency of ‘slow swims’, than shamexposed fish over weeks 9-15. Amongst sham-exposed fish, re-emergence from cover was uncommon throughout the study, but infected fish regularly left cover during weeks 9-15. Our results support those of previous studies examining behavioural change in naturally infected fish and, although other explanations remain possible, our finding that behaviour change in experimentally-infected fish is limited to hosts harbouring single infective parasites provides further evidence that the behaviour changes may be parasite adaptations.

  • 16.
    Beltéky, Johan
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biologi. Linköpings universitet, Tekniska fakulteten.
    Eklund, Beatrix
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biologi. Linköpings universitet, Tekniska fakulteten.
    Jensen, Per
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biologi. Linköpings universitet, Tekniska fakulteten.
    Gene expression of behaviorally relevant genes in the cerebral hemisphere changes after selection for tameness in Red Junglefowl.2017Inngår i: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 12, nr 5, e0177004Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The process of domestication in animals has led to alterations in behavior, physiology and phenotypic traits, changes that may be driven by correlations with reduced fear of humans. We used Red Junglefowl, ancestors of all domesticated chickens selected for either high or low fear of humans for five generations to study the effects of selection on gene transcription in the cerebral hemisphere, which is heavily involved in behaviour control. A total of 24 individuals from the parental generation as well as from the fifth selected generation were used. Twenty-two genes were significantly differentially expressed at p < 0.05 after false discovery rate (FDR) correction. Those genes that were upregulated in the low fearful animals were found to be involved in neural functions. Gene ontology and pathway analysis revealed enrichment for terms associated with behavioural processes. We conclude that five generations of divergent selection for high or low tameness has significantly changed gene expression patterns in the cerebral hemisphere in the Red Junglefowl population used here, which could underlie a range of changes in the domestic phenotype.

  • 17.
    Bergvall, Caroline
    Linköpings universitet, Institutionen för fysik, kemi och biologi. Linköpings universitet, Tekniska högskolan.
    The domestication effects on social support in chickens (Gallus gallus)2012Independent thesis Basic level (degree of Bachelor), 10,5 poäng / 16 hpOppgave
    Abstract [en]

    When animals are stressed they use a trait called social support to alleviate their stress responses. With domestication many traits from the ancestor red junglefowl have changed in the domesticated breed white leghorn. White leghorns are bred to be able to live in large groups where it becomes hard to recognize every chicken. They are therefore not as dependent of familiar stimuli birds for social support as red junglefowl. Our hypotheses were that red jungle males would be more interested in unfamiliar stimuli birds than white leghorn male before stress due to their territoriality. We tested total 56 chickens in an open field test. The test arena was divided in three zones and the time the focal birds spent in each zone was recorded. The focal bird was recorded in 300 seconds before being stressed by being suspended in a net and then recorded again in 300 seconds. The results showed that social support and social behaviour differs between females and males for both breeds. No significant differences were found between the breeds. There was a tendency for significant of breed (P=0.08) effects in the central zone unstressed. The two interactions before stressed between breed and sex, central zone (P<0.01) and unfamiliar zone (P<0.01) had significant effects. We observed fights between white leghorn males and familiar stimuli. Waltzing did also occur in red jungle males in front of unfamiliar. In conclusion, numeric differences can be seen but not large enough to be significant and our hypotheses are not confirmed.

  • 18.
    Bergvall, Ulrika Alm
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen.
    Leimar, Olof
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen.
    Plant secondary compounds and the frequency of food types affect food choice by mammalian herbivores2005Inngår i: Ecology, ISSN 0012-9658, E-ISSN 1939-9170, Vol. 86, nr 9, 2450-2460 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We have investigated food choice in individual fallow deer (Dama dama) encountering different relative frequencies of food types in the form of bowls containing pellets with either high or low concentrations of hydrolyzable tannin. We performed two similar experiments, one with large and one with small differences in tannic acid concentration. With small differences in tannic acid concentration, the ratio of the consumption per low- and high-tannin bowl was independent of frequency of occurrence, but with large differences in tannic acid concentration, we found frequency-dependent food choice. The deer ate proportionally less from high-tannin bowls if these occurred at low relative frequency. Variation between frequency treatments in the average order of encounter of bowl types might have produced this effect, because we found that the deer left a high-tannin bowl more quickly if they had switched to it from a low-tannin bowl. We argue that the perceived contrast between the tastes of different food types can play a role for food choice by mammalian herbivores.

  • 19.
    Bjällerhag, Nathalie
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biologi. Linköpings universitet, Tekniska fakulteten.
    Behaviours and experiences as indicators for the result in a behavioural test for dogs2013Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    In 2005 Swedish Armed Forces (SAF) started a breeding program of military working dogs. The dogs leave SAF’s kennel at an age of 8 weeks and live with puppy raisers. To evaluate the suitability of dogs for military work the dogs conduct a behavioural test at an age of 15-18 months. An “Index value” is extracted from this behavioural test. The puppy raisers answered a modified version of Canine Behavioral Assessment and Research Questionnaire (C-BARQ) when the dogs were approximately 12 months old. Answered questionnaires and results from the behavioural test were obtained for 59 dogs. Dogs that had passed the behavioural test had tendency for higher scores for “Trainability” (p = 0.078) and “If lived with other animals” (p = 0.066). Failing dogs had significantly higher score for “Stranger Directed Fear” (p = 0.006), ”Non-Social Fear” (p = 0.005), “Dog Directed Fear” (p = 0.021), “Hours of daily activation” (p = 0.001), “Mounting objects” (p = 0.012), and a tendency for higher risk of “Urinating when home alone” (p = 0.058). In a regressions between the “Index value” and the values of the questions from C-BARQ, the “Index value” was negatively correlated to “Stranger Directed Fear” (p = 0.002), “Non-social Fear” (p = 0.003), and “Dog Directed Fear” (p = 0.006). The “Index value” was positively correlated to “Trainability” (p = 0.013), “Hours left home alone” (p=0.043), “Hyperactive” (p = 0.018), “Chases shadows/light spots” (p = 0.043), and a positive tendency for “Chewing on inappropriate objects” (p = 0.075). From a PCA at the categories in C-BARQ, 3 components were extracted. All three components had a correlation to the “Index value”. The results show that the use of C-BARQ can indicate whether the dog will pass the behavioural test or not.

  • 20.
    Björklund Aksoy, Simon
    Linköpings universitet, Institutionen för fysik, kemi och biologi. 2015.
    Effects of serotonin on personality in field crickets (Gryllus bimaculatus)2017Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    Animal personality can be defined as a set of physiological and behavioral characteristics that differ between individuals, but are consistent over time and across situations. The evolution of individual differences in behavior that are consistent over time and situations is still not clear. Our understanding of why animals have personality can be improved by investigating the underlying physiological mechanisms of animal behavior. Serotonin is a key monoamine that serves as a physiological modulator of animal behavior. Selective serotonin reuptake inhibitors are a group of chemicals that increase levels of serotonin in the brain. Fluoxetine is one such chemical and is used to treat depression in humans. In the field cricket (Gryllus bimaculatus), increased levels of serotonin have been linked to higher activity and boldness, which are both personality traits. In the current study, the effects of induced serotonin on activity, exploration, boldness and aggression was investigated. My results show that injecting fluoxetine causes substantial changes in behavioral traits used to describe personality in field crickets. This result is opposite to previous studies, as serotonin induced individuals were less active, less explorative, and won less fights, compared to control individuals. This could be due to serotonin existing naturally within the circulatory system of the field cricket, whereas fluoxetine is a manufactured chemical intended for human receptors, or that fluoxetine has a similar effect in modulating personality in field crickets as in humans. Since fluoxetine acts similarly in field crickets as in humans, an increased understanding of the effects of induced serotonin on different behaviors in field crickets could be beneficial for treating psychological illnesses.

  • 21.
    Blixt, Torbjörn
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biologi. Linköpings universitet, Tekniska högskolan.
    The behavioural response of mice to predator odours2012Independent thesis Basic level (degree of Bachelor), 10,5 poäng / 16 hpOppgave
    Abstract [en]

    The ability to detect and react to a predator odour is crucial for prey species. In the present study 10 mice (Mus musculus) were used to test the behavioural response of mice towards two predator odours (3-methyl-1-butanethiol and 3-mercapto-3-methyl-butan-1-ol) and one fruity odour (n-pentyl acetate). All three odours were tested against a near odourless blank stimulus (diethyl phthalate). The animals were individually placed in a test chamber of two equally sized compartments divided by a vertical Plexiglas wall with a semicircular opening. Their proximity to the odours, placed beneath the floor in petri dishes in each compartment, was measured continuously with stop watches. The mice spent less time in proximity to 3-methyl-1-butanethiol and n-pentyl acetate compared to diethyl phthalate (P<0,05). The mice did not prefer any specific compartment in the test with 3-mercapto-3-methyl-butan-1-ol compared to diethyl phthalate (P>0,05). The avoidance of 3-methyl-1-butanethiol and n-pentyl acetate can be explained either by neophobia, or in the case of 3-methyl-1-butanethiol that it contains sulphur. The lack of behavioural response towards 3-mercapto-3-methyl-butan-1-ol may be due to its loss of intensity over time. From this study it is not certain if mice have an innate fear of predator odours.

  • 22.
    Brodd, Louise
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biologi.
    Behavioural differences between and within retriever breeds2016Independent thesis Advanced level (degree of Master (Two Years)), 40 poäng / 60 hpOppgave
    Abstract [en]

    The retriever breeds have the same origin and have long been used as a gundog for hunting of game, mostly birds. However, recently the retriever breeds have become a popular pet and show dog. This have affected the breeding of the dogs as the same traits are not bred for a gundog and a pet or show dog. Breeds as the Labrador retriever consists of a field- and common-type. The aim of this study is to investigate any differences between and within five of the retriever breeds in behaviours as retrieving, search and game reaction. 64 dogs undergoing the field trial Description of Function- Retriever was video recorded and scores from 430 dogs that have undergone field trials was obtained. Both differences between and within breeds were found when analysing both the videos and scores. In the video analysis, the Flatcoated retriever showed the most retrieving behaviours and was the most passive. The Nova scotia duck tolling retriever was in both the video and score analyses the most active breed. The Labrador retriever scored high in game reaction. The field- and mixed-types had almost always higher scores in behaviours linked to hunting, compared to the common-type. This supports findings that recent selection in breeding have a larger effect on behaviour than the origin uses of the dogs.

  • 23.
    Brodd, Louise
    Linköpings universitet, Institutionen för fysik, kemi och biologi. Linköpings universitet, Tekniska högskolan.
    The help-seeking behaviour of dogs (Canis familiaris)2014Independent thesis Basic level (degree of Bachelor), 10,5 poäng / 16 hpOppgave
    Abstract [en]

    During domestication, the dog( Canis familiaris), have become skilful in understanding human communication and also in communicating with humans. The wolf ( Canis lupus), is not as skilled with this interspecific communication. When dogs are faced with an unsolvable problem, they seek help from human by e.g. gazing at them. This behaviour has been studied and both age and breed group differences have been showed. In this study, we presented dogs with a task that consisted of a solvable and unsolvable problem in order to see if they gazed at their owner and/or an unfamiliar person for help. Although we did not find any difference in breed groups regarding gazing at humans, we did find that adult dogs (dogs older than 2 years) gazed more frequently at their owner and for a longer duration than adolescent dogs (6 months to 2 years). This may be because the adult dogs have more experience of this communication with humans, as they have lived longer with them. These findings empathize the bond between a dog and its owner that seems to grow stronger during the dogs’ life.

  • 24. Bäckman, Lars
    et al.
    Lindenberger, Ulman
    Li, Shu-Chen
    Nyberg, Lars
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Fysiologi. Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper.
    Linking cognitive aging to alterations in dopamine neurotransmitter functioning: Recent data and future avenues2010Inngår i: Neuroscience and Biobehavioral Reviews, ISSN 0149-7634, E-ISSN 1873-7528, Vol. 34, nr 5, 670-677 s.Artikkel, forskningsoversikt (Fagfellevurdert)
    Abstract [en]

    Molecular-imaging studies of dopaminergic neurotransmission measure biomarkers of dopamine (DA), such as the DA transporter and D(1) and D(2) receptor densities in the living brain. These studies indicate that individual differences in DA functions are linked to cognitive performance irrespective of age, and serve as powerful mediators of age-related decline in executive functioning, episodic memory, and perceptual speed. This focused review targets several recent findings pertaining to these relationships. Specifically, we discuss novel evidence concerning (a) the role of DA in within-person cognitive variability; (b) age-related differences in DA release during cognitive processing; (c) DA release following cognitive training in younger and older adults; and (d) the relationship between DA and task-induced functional brain activity. Based on these lines of empirical inquiry, we outline a series of avenues for future research on aging, DA, and cognition.

  • 25.
    Calais, Andreas
    Linköpings universitet, Institutionen för fysik, kemi och biologi. Linköpings universitet, Tekniska högskolan.
    Is personality dependent of growth rate in red junglefowl (Gallus gallus)?2013Independent thesis Basic level (degree of Bachelor), 10,5 poäng / 16 hpOppgave
    Abstract [en]

    Personality has been reported in a large variety of animal species, but it is not obvious why animals have personality. Variation in physiological traits, such as growth rate, should theoretically affect variation in behaviours and thus can explain why we observe variation in personalities. Growth rate is, theoretically, positively correlated with active personality types. Empirical studies have reported this pattern in different fish species, but there are not yet many studies on endothermic animals. I have therefore scored behaviours of 100 red junglefowl (Gallus gallus) chicks in four personality assays; novel arena, novel object, tonic immobility, and a proactive-reactive test, together with recording variation in growth rate of these individuals. The chicks individual growth rate (% day-1) were calculated and the relationship between personality and growth rate investigated. There was significant difference in growth rate between the sexes, where males grew faster than females, detected already at one week of age. However, no significant correlations between behavioural traits and growth rate were observed, indicating that personality seem to be independent of growth rate. Further studies should therefore investigate the generality of this finding, and alternative underlying mechanisms for variation in personality should be explored.

  • 26.
    Cederlund, Joakim
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biologi.
    Eye preference in humans and its correlation with eye dominance, visual acuity and handedness2016Independent thesis Basic level (degree of Bachelor), 10,5 poäng / 16 hpOppgave
    Abstract [en]

    Handedness is the most obvious expression of lateralized behaviour in humans. However, there is only limited knowledge about other forms of lateralized behaviour, e.g. preferential use of an eye and whether these may correlate with handedness. Thus to investigate this, 100 subjects (50 males and 50 females) between 11 and 80 years of age were assessed for their eye preference, eye dominance, visual acuity, and handedness. Eye preference was assessed by performing four different monocular tasks, eye dominance by performing the binocular Dolman test, visual acuity was assessed with a Snellen chart and handedness was surveyed using the Edinburgh Handedness Inventory. Regarding eye preference, the right eye was preferred by 69% of the subjects. 90 % of the subjects were consistent for their preferred eye across all four tasks. 66% of the subjects had a dominant right eye, 33% had left eye dominance and 1% could not be assessed using the Dolman test. 56% of the subjects differed in their visual acuity between both eyes, while 43% had the same visual acuity in both of their eyes. 86% of the subjects were right-handed while 4% were left handed and 10% were ambidextrous. Significant correlations were found between visual acuity and eye preference and between visual acuity and eye dominance. The study also found a positive correlation between handedness and eye preference. These results support the notion that there is a weak correlation between the different aspects of lateralized behaviour in humans. 

  • 27. Chiarle, Alberto
    et al.
    Kronestedt, Torbjörn
    Naturhistoriska riksmuseet, Enheten för zoologi.
    Isaia, Marco
    Courtship behavior in European species of the genus Pardosa (Araneae, Lycosidae)2013Inngår i: Journal of Arachnology, ISSN 0161-8202, Vol. 41, nr 2, 108-125 s.Artikkel i tidsskrift (Fagfellevurdert)
  • 28. Collis, Ken
    et al.
    Roby, Daniel D.
    Larson, Keith W.
    Department of Fisheries and Wildlife, 104 Nash Hall, Oregon State University, Corvallis, OR, 97331, USA; Evolutionary Ecology, Lund University, Sølvegatan 37, 223 62 Lund, Sweden.
    Adrean, Lindsay J.
    Nelson, S. Kim
    Evans, Allen F.
    Hostetter, Nathan
    Battaglia, Dan
    Lyons, Donald E.
    Marcella, Tim
    Patterson, Allison
    Trends in Caspian Tern Nesting and Diet in San Francisco Bay: Conservation Implications for Terns and Salmonids2012Inngår i: Waterbirds (De Leon Springs, Fla.), ISSN 1524-4695, E-ISSN 1938-5390, Vol. 35, nr 1, 25-34 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Colony size, nesting ecology and diet of Caspian Terns (Hydroprogne caspia) were investigated in the San Francisco Bay area (SFBA) during 2003-2009 to assess the potential for conservation of the tern breeding population and possible negative effects of predation on survival of juvenile salmonids (Oncorhyn-chusspp.). Numbers of breeding Caspian Terns declined 36% from 2003 to 2009, mostly due to abandonment of the Knight Island colony and decline of the Brooks Island colony, the two largest colonies in the SFBA. Concurrently, nesting success declined 69% associated with colony site characteristics such as (a) quality and quantity of nesting substrate, (b) vulnerability to nest predators, (c) displacement by other colonial waterbirds and (d) human disturbance. Marine fishes were the predominant prey in tern diets from the SFBA; however, diet composition varied among colonies. Juvenile salmonids comprised 22.9% of the diet of terns nesting in the North Bay, 5.3% of diet of terns nesting in the Central Bay, and 0.1% in the South Bay. Construction or restoration of nesting islands in the South Bay may help maintain and restore breeding Caspian Terns without enhancing mortality of salmonid stocks of conservation concern.

  • 29.
    Crespo Mingueza, Laia
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biologi.
    Assessment of lateralized behaviour in free-ranging Mexican mantled howler monkeys (Alouatta palliata mexicana)2015Independent thesis Advanced level (degree of Master (Two Years)), 40 poäng / 60 hpOppgave
    Abstract [en]

    The evolutionary origins of human handedness are still unknown. The study of lateralized behaviour in our closest relatives, the nonhuman primates, is useful to clarify how this trait appeared and evolved in our species. In the present study, lateralized behaviour was assessed in a population of 32 free-ranging Mexican mantled howler monkeys (Alouatta palliata mexicana) for thirteen spontaneous motor patterns, at individual and group levels, as well as the effect that age, sex and posture have on its strength and direction. The studied population of howler monkeys displayed only few significant lateral biases at the individual level with single motor patterns (Binomial tests, p≤0.05). No biases towards the use of a particular limb or side of the body were found at a population level. Therefore, even though some individuals showed significant limb/side preference with single motor patterns, no signs of task specialization, side specialization, or true handedness were found. Similarly, no effects of sex, age or posture were found on the direction or strength of lateralized behaviour. The general absence of limb/side preferences found in this population may be due to the constraints imposed by the arboreal life and/or the type of diet. Possible causal agents of the few significant individual biases found here may be the presence of handicaps and/or experience. Further research is needed in order to assess whether the lack of human-like handedness reported in this study is only specific to the studied population, a general phenomenon of the genus Alouatta or perhaps of all the Platyrrhini.

  • 30. Cunha, Mário
    et al.
    Berglund, Anders
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Zooekologi.
    Alves, T
    Monteiro, Nuno
    Reduced cannibalism during male pregnancy2016Inngår i: Behaviour, ISSN 0005-7959, E-ISSN 1568-539X, Vol. 153, nr 1, 91-106 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Cannibalism provides energetic benefits but is also potentially costly, especially when directed towards kin. Since fitness costs increase with time and energy invested in offspring, cannibalism should be infrequent when parental investment is high. Thus, filial cannibalism in male syngnathids, a group known for the occurrence of male pregnancy, should be rare. Using the pipefish (Syngnathus abaster) we aimed to investigate whether cannibalism does occur in both sexes and how it is affected by reproductive and nutritional states. Although rare, we witnessed cannibalism both in the wild and in the laboratory. Unlike non-pregnant males and females, pregnant and postpartum males largely refrained from cannibalising juveniles. Reproducing males decreased their feeding activity, thus rendering cannibalism, towards kin or non-kin, less likely to occur. However, if not continuously fed, all pipefish adopted a cannibal strategy, revealing that sex and life history stages influenced the ratio between the benefits and costs of cannibalism.

  • 31. Debeffe, L.
    et al.
    Lemaitre, J. F.
    Bergvall, Ulrika A.
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen. Swedish University of Agricultural Science, Sweden.
    Hewison, A. J. M.
    Gaillard, J. M.
    Morellet, N.
    Goulard, M.
    Monestier, C.
    David, M.
    Verheyden-Tixier, H.
    Jäderberg, L.
    Vanpe, C.
    Kjellander, P.
    Short- and long-term repeatability of docility in the roe deer: sex and age matter2015Inngår i: Animal Behaviour, ISSN 0003-3472, E-ISSN 1095-8282, Vol. 109, 53-63 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Behavioural consistency is a key assumption when evaluating how between-individual differences in behaviour influence life history tactics. Hence, understanding how and why variation in behavioural repeatability occurs is crucial. While analyses of behavioural repeatability are common, few studies of wild populations have investigated variation in repeatability in relation to individual status (e.g. sex, age, condition) and over different timescales. Here, we aimed to fill this gap by assessing within-population variation in the repeatability of docility, as assessed by the individual’s response to human handling, in a free-ranging population of European roe deer, Capreolus capreolus. Docility was an equally repeatable behaviour at both short- and long-term timescales, suggesting that this behavioural trait is stable across time. Repeatability did not differ markedly between age and sex categories but tended to be higher in juvenile males than in juvenile females. Finally, contrary to expectation, individual variation in the repeatability of docility was not correlated with individual body mass. Further studies are required to assess the life history consequences of the individual variation in docility we report here.

  • 32.
    Domeij Hilliges, Isak
    et al.
    Högskolan i Halmstad, Sektionen för ekonomi och teknik (SET).
    Stendahl, Cecilia
    Högskolan i Halmstad, Sektionen för ekonomi och teknik (SET).
    Ocean acidification effects on marine organisms: a study of Littorina littorea and Balanus improvisus 2011Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    The world’s oceans are becoming more acid in a process called ocean acidification. The pH of the ocean have already decreased by 0.1 units from pre-industrial time until today. Scientists predict that by the year of 2100 the pH will decrease by as much as 0.4 units. This is a big potential problem to many marine species, because they have developed in such a stable environment that has not changed for millions of years. It is difficult to predict how they might be affected by such a decrease in pH during a relatively short time period. Several studies have been made on marine species exposed to decreased pH-levels, the results showed changes in their physiology but it is hard to predict how these changes will affect the organism in a long-term scale and if this might change ecosystem dynamics. Our study measured the activity of Littorina littorea and Balanus improvisus when exposed to lower pH, the results of our study showed an increase in activity for the lower pH (pH 6.0-7.5) when compared to the control (~pH8). The area of ocean acidification is a field that requires further studies to fully understand its effects on the marine ecosystems and the species within it.

  • 33.
    Dussutour, Audrey
    et al.
    Centre National de la Recherche Scientifique, Université Toulouse III.
    Ma, Qi
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Matematiska institutionen, Analys och tillämpad matematik.
    Vogel, David
    Department of Chemistry and of Animal Biology, Université libre de Bruxelles.
    Sumpter, David
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Matematiska institutionen, Analys och tillämpad matematik.
    Speed-accuracy tradeoffs and the construction of transport netowrksManuskript (preprint) (Annet vitenskapelig)
    Abstract [en]

    One of the key challenges in the study of networks is linking structure to function. For example, how do design requirements about the speed and accuracy with which information is transferred through a network determine its form?  We show that different strains of the slime mould Physarum polycephalum form different network structures, ranging from a diffuse network of thin links to a tree-like branching structure.  Using a current-reinforced random walk model, we explain these different structures in terms of two model parameters: the strength and the degree of non-linearity in the reinforcement. These parameters are further shown to tune the speed and accuracy with which the network can detect resource gradients. We use a battery of experimental tests to show that Physarum strains with diffuse networks make more accurate but slower decisions and those with thick, trunk branches make faster less accurate decisions. Intermediate structures can also be found which are relatively fast and accurate. The current reinforced random walk employed by the slime mould provides a tunable algorithm for decision-making, which may also apply in other systems where transport networks are constructed.

  • 34.
    Elebring, Viktoria
    Linköpings universitet, Institutionen för fysik, kemi och biologi.
    Vad skiljer domesticerade värphöns från de röda djungelhönsen (Gallus gallus) i återhämtningsprocessen efter en standardiserad stressupplevelse?: En studie med ett didaktiskt perspektiv2011Independent thesis Advanced level (professional degree), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Tidigare studier har visat att domesticerade höns påvisar en lägre nivå av rädsla jämfört med förfadern, de röda djungelhönsen. I denna studie testades 18 domesticerade White Leghorn (WL) och 18 röda djungelhöns (RJF). Målet med studien var att studera återhämtningen för de båda raserna vid en standardiserad stressupplevelse. Försöket gick ut på att hönsen vistades i enskilda burar och blev efter ett dygn utsatta av en akut stress. Därefter startades observationerna omedelbart för att se när hönsen återhämtade sig och återigen började visa naturliga beteenden. Utifrån alla hönsens resultat beräknades medelvärde och standardfel för varje ras och kön, som sedan jämfördes med variansanalys (repeated measures ANOVA). Beteenden som visade signifikanta resultat över tiden analyseras och visade i några fall tyda på en återhämtningsprocess. Överlag visade White Leghorn på en snabbare och effektivare återhämtning jämfört med de röda djungelhönsen. Resultatet tyder även på att honor har en snabbare återhämtning jämfört med hanar. Studien innehåller även ett didaktiskt moment då etologi studerades utifrån skolverkets föreskrifter om vad biologiundervisning ska innehålla för grundskolans senare år. Läroplanen och kursplaner studerades därefter och jämfördes med läroböcker.

  • 35.
    Elmberg, Johan
    et al.
    Högskolan Kristianstad, Sektionen för lärande och miljö, Avdelningen för Naturvetenskap. Högskolan Kristianstad, Forskningsmiljön Man & Biosphere Health (MABH).
    Dessborn, Lisa
    Högskolan Kristianstad, Sektionen för lärande och miljö, Avdelningen för Naturvetenskap.
    Arzel, Céline
    Andungar har bra koll när faran hotar2014Inngår i: Vår fågelvärld, ISSN 0042-2649, Vol. 73, nr 3, 34-35 s.Artikkel i tidsskrift (Annet (populærvitenskap, debatt, mm))
  • 36.
    Elmberg, Johan
    et al.
    Högskolan Kristianstad, Sektionen för lärande och miljö, Avdelningen för Naturvetenskap. Högskolan Kristianstad, Forskningsmiljön Man & Biosphere Health (MABH).
    Dessborn, Lisa
    Högskolan Kristianstad, Sektionen för lärande och miljö, Avdelningen för Naturvetenskap.
    Arzel, Céline
    Så undviker andungarna rovdjuren2015Inngår i: Svensk jakt, ISSN 0039-6583, Vol. 153, nr 6, 38-40 s.Artikkel i tidsskrift (Annet (populærvitenskap, debatt, mm))
  • 37. Engkvist, R.
    et al.
    Malm, T.
    Svensson, A.
    Asplund, L.
    Isaeus, M.
    Kautsky, L.
    Greger, M.
    Lanberg, T.
    Makroalgsblomningar längs Ölands kuster, effekter på det lokala näringslivet och det marina ekosystemet. (English title: Macro algal blooms in the central Baltic proper, effects on the economy and the marine ecosystem.)2001Rapport (Fagfellevurdert)
  • 38.
    Enquist, Magnus
    et al.
    Stockholms universitet, Humanistiska fakulteten, Institutionen för arkeologi och antikens kultur, Centrum för evolutionär kulturforskning. Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen.
    Lind, Johan
    Stockholms universitet, Humanistiska fakulteten, Institutionen för arkeologi och antikens kultur, Centrum för evolutionär kulturforskning.
    Ghirlanda, Stefano
    Stockholms universitet, Humanistiska fakulteten, Institutionen för arkeologi och antikens kultur, Centrum för evolutionär kulturforskning. Brooklyn College, USA; Graduate Center of the City University of New York, USA.
    The power of associative learning and the ontogeny of optimal behaviour2016Inngår i: Royal Society Open Science, E-ISSN 2054-5703, Vol. 3, nr 11, 160734Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Behaving efficiently (optimally or near-optimally) is central to animals' adaptation to their environment. Much evolutionary biology assumes, implicitly or explicitly, that optimal behavioural strategies are genetically inherited, yet the behaviour of many animals depends crucially on learning. The question of how learning contributes to optimal behaviour is largely open. Here we propose an associative learning model that can learn optimal behaviour in a wide variety of ecologically relevant circumstances. The model learns through chaining, a term introduced by Skinner to indicate learning of behaviour sequences by linking together shorter sequences or single behaviours. Our model formalizes the concept of conditioned reinforcement (the learning process that underlies chaining) and is closely related to optimization algorithms from machine learning. Our analysis dispels the common belief that associative learning is too limited to produce ‘intelligent’ behaviour such as tool use, social learning, self-control or expectations of the future. Furthermore, the model readily accounts for both instinctual and learned aspects of behaviour, clarifying how genetic evolution and individual learning complement each other, and bridging a long-standing divide between ethology and psychology. We conclude that associative learning, supported by genetic predispositions and including the oft-neglected phenomenon of conditioned reinforcement, may suffice to explain the ontogeny of optimal behaviour in most, if not all, non-human animals. Our results establish associative learning as a more powerful optimizing mechanism than acknowledged by current opinion.

  • 39.
    Ericsson, Maria
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biologi. Linköpings universitet, Tekniska fakulteten.
    Stress in chickens: Effects of domestication and early experience on behaviour and welfare2016Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [sv]

    The domestication is the process where animals have adapted to human conditions. A prerequisite for domestication is tame behaviour towards humans and subsequently, selection for other desirable traits took place which led to changes in several behavioural and physiological parameters. The domestication of chickens (Gallus gallus) was initiated around 8000 years ago, and today we see clear phenotypic and genotypic alterations when comparing domestic breeds with the wild ancestor. Our modern domestic production breeds have been selected for, and still undergo heavy selection for high meat and egg yields. Beside obvious morphological changes, studies investigating behavioural differences between the ancestral Red Junglefowl and domestic breeds show, for example, differences in fearfulness, foraging strategies, exploratory behaviour and sociality. The modern production environments are intense and already from hatch chicks are exposed to harsh conditions. From an animal welfare perspective, the production environment contain many stressful aspects. The shift in stressor types between wild and captive conditions have likely contributed to alterations in stress tolerance when comparing domestic breeds to the wild ancestors. Previous research on mammalian models have underlined that early-life stressor exposure can induce negative consequences both immediately and in adulthood, but can also affect the offspring in a transgenerational fashion. The effects observed are for example disturbance of normal brain development, a hyper-reactive hypothalamic-pituitary-adrenal (HPA) -axis, decreased immune function and increased risk of developing cognitive dysfunction and abnormal behaviour. In chickens, the long-term effects of stress during the chick phase and during puberty are not well-investigated, and further, conflicting data has been presented on the hatchling HPA-axis reactivity.

    In this thesis, results from four projects are presented, which all concern stress and welfare at different ages in chickens. The development of the HPA-axis and how chicks respond to early stress both on the short- and long term was investigated. Furthermore, an experiment on the effects of stress exposure a different ages during puberty was conducted, in search of particularly stress-sensitive periods. Two papers address domestication effects on the stress response.

    In paper I, the results show that the HPA-axis is fully functioning at hatch, resulting in elevated corticosterone levels at exposure to stressful conditions. Breed differences indicate domestication effects on the reactivity and development of the HPA-axis; the Red Junglefowl displayed a lower corticosterone baseline and a lower stress response on day one, compared to a domestic breed, whereas the results were the opposite on day 23. Similar results were seen in paper IV, conducted on adult birds, where the Red Junglefowl had a more pronounced reaction to acute stress but a faster recovery period, both with respect to behaviour and physiology. In commercial hatcheries, chick are exposed to multiple potential stressors on their first day of life. In paper II, chicks who had experienced the potentially stressful environment in a commercial hatchery was compared to a quietly treated control group. The hatchery managed birds displayed a reduced growth pattern and tendencies towards altered vigilance and reduced locomotion was seen as an effect of stress in adulthood.

    In paper III, it was demonstrated that one week of stress exposure at different ages during the chick phase and puberty affect long-term behaviour and physiology, however depending on age of stress exposure, different parameters were affected. The early stress also induced transgenerational effects, most clearly on HPA-axis reactivity, and showed some overlapping differentially expressed genes.

    In summary, domestication has altered the acute stress coping behaviours as well as the development and reactivity of the HPA-axis both in young and adult birds. Furthermore, puberty can be regarded as an equally stress sensitive period as the chick stage and affect various behaviours, stress physiology and gene expression. The outcome can vary depending on timing and nature of stressor.

  • 40.
    Favati, Anna
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen.
    Social dominance and personality in male fowl (Gallus gallus domesticus)2013Licentiatavhandling, monografi (Annet vitenskapelig)
    Abstract [en]

    Individuals in social species commonly form dominance relationships among each other, and

    are often observed to differ in behaviour depending on their social status. However, whether

    such behavioural differences are a consequence of dominance position, or also a cause to it,

    remains unclear. In this thesis I therefore investigated two perspectives of the relationship

    between social dominance and personality in the domestic fowl (Gallus gallus domesticus), a

    social species that forms relatively stable dominance hierarchies. In paper I I investigated the

    influence of social status on the expression and consistency of behaviours by experimentally

    changing status between repeated personality assays. The level of vigilance, activity and

    exploration changed with social status, while boldness and territorial crows appeared as

    stable individual properties, independent of status. These results showed that social status

    contribute to both variation and consistency in behavioural responses. Social status should

    therefore be taken into account when investigating and interpreting variation in personality.

    In paper II I showed that behaviour in a novel arena test and during encounter with an

    opponent can predict social status, more specifically that fast exploration and aggressiveness

    predicted a dominant social position. Together, these results highlight the dynamics of the

    two-way relationship between social position and individual behaviour and indicate that

    individual behaviour can both be a cause and a consequence of social status.

  • 41.
    Favati, Anna
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen.
    The relationship between personality and social dominance in the domestic fowl – a critical perspective2017Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    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.

  • 42.
    Favati, Anna
    et al.
    Stockholm University, Sweden.
    Leimar, Olof
    Stockholm University, Sweden.
    Radesäter, Tommy
    Stockholm University, Sweden.
    Løvlie, Hanne
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biologi. Linköpings universitet, Tekniska högskolan. Stockholm University, Sweden.
    Social status and personality: stability in social state can promote consistency of behavioural responses2014Inngår i: Proceedings of the Royal Society of London. Biological Sciences, ISSN 0962-8452, E-ISSN 1471-2954, Vol. 281, nr 1774, 20132531- s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Stability of ‘state’ has been suggested as an underlying factor explainingbehavioural stability and animal personality (i.e. variation among, andconsistency within individuals in behavioural responses), but the possibilitythat stable social relationships represent such states remains unexplored.Here, we investigated the influence of social status on the expression andconsistency of behaviours by experimentally changing social status betweenrepeated personality assays. We used male domestic fowl (Gallus gallusdomesticus), a social species that forms relatively stable dominance hierarchies,and showed that behavioural responses were strongly affected bysocial status, but also by individual characteristics. The level of vigilance,activity and exploration changed with social status, whereas boldnessappeared as a stable individual property, independent of status. Furthermore,variation in vocalization predicted future social status, indicatingthat individual behaviours can both be a predictor and a consequence ofsocial status, depending on the aspect in focus. Our results illustrate thatsocial states contribute to both variation and stability in behaviouralresponses, and should therefore be taken into account when investigatingand interpreting variation in personality.

  • 43.
    Favati, Anna
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen.
    Løvlie, Hanne
    Leimar, Olof
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen.
    Effects of social experience during development on competitive ability and personality traits in male domestic fowlManuskript (preprint) (Annet vitenskapelig)
    Abstract [en]

    The ability to dominate conspecifics and thereby gain access to important resources depends on a number of traits and skills that may be both heritable and influenced by the environment. Experience of dominance relationships during development is a potential source of learning such skills. We here study the relative importance of social experience, personality, and morphological traits on competitive ability in male domestic fowl (Gallus gallus domesticus). By letting males grow up as either a single (dominant) male, as the dominant male of a pair, or as an intermediate ranked male in a group of males, we investigate if competitiveness in social interactions (winning duels) is mainly due to individual qualities or also influenced by social experience. We found that males were consistent over time in their competitive ability. Single raised males were inferior to pair dominant males and group-raised males in competitive ability, while pair dominant and group males did not differ significantly. This indicates that social training is important for future fighting success, but that the social position during development does not have a decisive influence on male fighting success in adulthood. Aggression and comb size, the latter possibly being a proxy for testosterone levels, had a marked effect on competitive ability. Together, our results indicate that certain behavioural and morphological traits are more important than experience of a social position in shaping competitive ability. These findings elucidate the relationship between social dominance and personality.

  • 44.
    Favati, Anna
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen.
    Løvlie, Hanne
    Leimar, Olof
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen.
    Individual aggression, but not winner–loser effects, predicts social rank in male domestic fowl2017Inngår i: Behavioral Ecology, ISSN 1045-2249, E-ISSN 1465-7279, Vol. 28, nr 3, 874-882 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Many factors can affect the probability for an individual to obtain a high social rank, including size, weaponry, and behavioral attributes such as aggression. Recent experiences of winning or losing can also affect the chances of winning future contests, commonly referred to as “winner–loser effects”. Individuals often differ in behavior in a consistent way, including in aggression, thereby showing differences in personality. However, the relative importance of recent experience and aspects of personality in determining rank, as well as the extent to which winning or losing affects aggression, has rarely been studied. Here, we investigate these questions using male domestic fowl. We matched males for body size, comb size, and aggression in pair-wise duels to: 1) study the effect of contest outcome on aggression and 2) compare the effect of individual aggression and contest experience on future social status in small groups. We found that aggression was a highly repeatable personality trait and that aggression increased after winning and decreased after losing. Nevertheless, such winner–loser effects were not enough to increase the odds of becoming dominant in a small group. Instead, aggressiveness measured prior to a contest experience best predicted future rank. Boldness and exploration did not predict rank and of the 2, only boldness was positively correlated with aggressiveness. We conclude that for male domestic fowl in contests among phenotypically matched contestants, aggressiveness is more important for obtaining high rank than winner–loser effects, or other aspects of personality.

  • 45.
    Favati, Anna
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen.
    Udén, Eva
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen.
    Leimar, Olof
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen.
    Løvlie, Hanne
    Personality remains: no effect of three-week social status experience on personality in male fowlManuskript (preprint) (Annet vitenskapelig)
    Abstract [en]

    Individuals often differ in behavior in a consistent way, i.e. show variation in personality. Understanding the processes explaining the emergence and maintenance of this variation is a major topic in the field of animal behavioral research. Recent theoretical models predict that differences in various 'states' can generate individual variation in behavior. Previous studies have mainly focused on endogenous states like metabolic rate or energy reserves, but theory also suggests that more complex states based on social interactions could play important roles in shaping personality. We have earlier demonstrated short-term status-dependent variation in behavior in the domestic fowl (Gallus gallus domesticus), but whether such behavioral variation remains also after a longer period of time, is unknown. Therefore, we examine the influence of social status on variation in behavior, using experimental manipulation of social status in pairs of male domestic fowl. We scored males in three personality assays (aggression test, novel arena test, novel object test) before and after three weeks in pairs as either dominant or subdominant. We found no support for social status acting as a state that generates variation in personality over this time interval: social status had no significant effect on behavioral responses in personality tests. Instead, we observed individual consistency of behavior despite alteration of social status. Our results suggest that the effect of social environment on behavior is dependent on context and time, and that personality is more important than current social situation for describing individual behavior in stable groups.

  • 46. Fleischer, Siegfried
    et al.
    Bauhn, Lovisa
    Fors, Patrik
    En kolsänka med syrebildning på köpet2014Inngår i: Kemivärlden Biotech med Kemisk Tidskrift, ISSN 1650-0725, nr 4, 24-24 s.Artikkel i tidsskrift (Annet vitenskapelig)
  • 47.
    Foyer, Pernilla
    et al.
    Försvarshögskolan, Militärvetenskapliga institutionen (MVI). Linköpings universitet, Biologi.
    Svedberg, Anna-Maria
    Linköpings universitet, Biologi.
    Nilsson, Emma
    Linköpings universitet, Biologi.
    Wilsson, Erik
    Swedish Armed Forces Dog Training Unit, Märsta, Sweden.
    Olsen Faresjö, Åshild
    Linköpings universitet, Avdelningen för samhällsmedicin.
    Jensen, Per
    Linköpings universitet, Biologi.
    Behavior and cortisol responses of dogs evaluated in a standardized temperament test for military working dogs2016Inngår i: Journal of Veterinary Behavior: Clinical Applications and Research, ISSN 1558-7878, E-ISSN 1878-7517, Vol. 11, 7-12 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Military and police working dogs are often exposed to stressful or threatening events, and an improper response, e.g., fear, may implicate both reduced working efficiency and welfare. Therefore, identifying individuals that display a favorable response to potentially threatening situations is of great interest. In the present study, we investigated behavior responses of 85 prospective military working dogs in 4 subtests in a standardized temperament test used to select working dogs for the Swedish Armed Forces. Our goal was to evaluate behavioral responses in specific subtests and cortisol responses of candidate dogs. After dogs were rated as approved or nonapproved based on the test leader’s assessment of the full test result, we independently analyzed video recordings of 4 subtests. In addition, for 37 dogs, we analyzed pretest and posttest salivary cortisol levels. Dogs which were approved by the test leader for further training scored higher in the video recordings on emotionality and, in particular, fear-related behavior during a subset of the test and had higher levels of cortisol both before and after the test, than nonapproved dogs. Although this may actually reflect the desired traits, it could also indicate a bias in the selection procedure, which may pose limitations on the attempts to recruit the most suitable working dogs.

  • 48.
    Foyer, Pernilla
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biologi. Linköpings universitet, Tekniska fakulteten. Department of Military Studies, Military-Technology Division, Swedish Defence University, Stockholm, Sweden.
    Svedberg, Anna-Maria
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biologi. Linköpings universitet, Tekniska fakulteten.
    Nilsson, Emma
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biologi. Linköpings universitet, Tekniska fakulteten.
    Wilsson, Erik
    Swedish Armed Forces Dog Training Unit, Märsta, Sweden.
    Olsen Faresjö, Åshild
    Linköpings universitet, Institutionen för medicin och hälsa, Avdelningen för samhällsmedicin. Linköpings universitet, Medicinska fakulteten.
    Jensen, Per
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biologi. Linköpings universitet, Tekniska fakulteten.
    Behavior and cortisol responses of dogs evaluated in a standardized temperament test for military working dogs2016Inngår i: Journal of Veterinary Behavior: Clinical Applications and Research, ISSN 1558-7878, E-ISSN 1878-7517, Vol. 11, 7-12 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Military and police working dogs are often exposed to stressful or threatening events, and an improper response, e.g., fear, may implicate both reduced working efficiency and welfare. Therefore, identifying individuals that display a favorable response to potentially threatening situations is of great interest. In the present study, we investigated behavior responses of 85 prospective military working dogs in 4 subtests in a standardized temperament test used to select working dogs for the Swedish Armed Forces. Our goal was to evaluate behavioral responses in specific subtests and cortisol responses of candidate dogs. After dogs were rated as approved or nonapproved based on the test leader’s assessment of the full test result, we independently analyzed video recordings of 4 subtests. In addition, for 37 dogs, we analyzed pretest and posttest salivary cortisol levels. Dogs which were approved by the test leader for further training scored higher in the video recordings on emotionality and, in particular, fear-related behavior during a subset of the test and had higher levels of cortisol both before and after the test, than nonapproved dogs. Although this may actually reflect the desired traits, it could also indicate a bias in the selection procedure, which may pose limitations on the attempts to recruit the most suitable working dogs.

  • 49. Fransson, Thord
    et al.
    Kullberg, Cecilia
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för etologi.
    Stach, Robert
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för etologi.
    Barboutis, Christos
    Extensive fuelling in great reed warblers following the trans-Sahara crossing in springManuskript (preprint) (Annet vitenskapelig)
    Abstract [en]

    Migratory birds wintering in Africa face the challenge of passing the Sahara desert with little opportunities to forage. During spring migration birds thus arrive in the Mediterranean area after crossing the desert with very low energy reserves. Since early arrival to the breeding grounds often is of importance to maximize reproductive success, finding stopover sites with good refuelling possibilities after the Saharan passage is of utmost importance. Here we report on extensive fuelling in the great reed warbler, Acrocephalus arundinaceus, on the south coast of Crete in spring, the first land that they encounter after crossing the Sahara desert and the Mediterranean Sea in this area. Birds were trapped with mist nets at a river mouth, individually ringed and information about body mass, wing length, muscle score and fat score were recorded. Due to an exceptional high recapture rate at the trapping site (45%), we were able to calculate minimum stopover time and fuel deposition rates in 25 individual great reed warblers during one spring season. The large proportion of trapped great reed warbler compared to other species and the large number of recaptures suggests that great reed warbler actively choose this area for stopover. The relatively long stopover period at the site, the high fuel deposition rate (1 g day-1) and the large body mass increase show that great reed warblers at this site regularly deposit a much larger fuel load than needed for one continued flight stage to the north. It was also shown that birds with lower body mass at first capture had a higher fuel deposition rate than birds with higher body mass. This indicates that individuals are able to adjust their food intake in relation to energy reserves.

  • 50.
    Gamberale-Stille, Gabriella
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen.
    Johansen, Aleksandra I.
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen.
    Tullberg, Birgitta S.
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen.
    Change in protective coloration in the striated shieldbug Graphosoma lineatum (Heteroptera: Pentatomidae): predator avoidance and generalization among different  life stages2010Inngår i: Evolutionary Ecology, ISSN 0269-7653, E-ISSN 1573-8477, Vol. 24, nr 2, 423-432 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    There are two major forms of protective coloration, camouflage and warning coloration, which often entail different colour pattern characteristics. Some species change strategy between or within life stages and one such example is the striated shieldbug, Graphosoma lineatum. The larvae and the pale brownish-and-black striated pre-diapause adults are more cryptic in the late summer environment than is the red-and black striation that the adults change to after diapause in spring. Here we investigate if the more cryptic pre-diapause adult and larval coloration may affect the aposematic function of the coloration as compared to the red adult form. In a series of trials we presented fifth instar larvae, pale or red adults to shieldbug-naïve domestic chicks, Gallus gallus domesticus, to investigate the birds’ initial wariness, avoidance learning, and generalization between the three prey types. The naïve chicks found the red adults most aversive followed by pale adults, and they found the larvae the least aversive. The birds did not find the larvae unpalatable and did not learn to avoid them, while they learned to avoid the two adult forms and then to a similar degree. Birds generalized asymmetrically between life stages, positively from larvae to adults and negatively from adults to larvae. We conclude that the lower conspicuousness in the pale forms of G. lineatum may entail a reduced aposematic function, namely a reduced initial wariness in inexperienced birds. The maintenance of the colour polymorphism is discussed

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