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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, E-ISSN 1932-6203, Vol. 7, nr 3, s. e32541-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.

    Fulltekst (pdf)
    fulltext
  • 2.
    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, s. 77-84Artikkel 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.

  • 3.
    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.

    Fulltekst (pdf)
    Fulltext
  • 4.
    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)
  • 5.
    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, s. 349-354Artikkel 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.

  • 6.
    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)
  • 7.
    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, s. 2450-2460Artikkel 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.

  • 8.
    Berio, Fidji
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen.
    Morerod, Camille
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen.
    Qi, Xuewei
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen.
    Di Santo, Valentina
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen.
    Ontogenetic Plasticity in Shoaling Behavior in a Forage Fish under Warming2023Inngår i: Integrative and Comparative Biology, ISSN 1540-7063, E-ISSN 1557-7023, Vol. 63, nr 3, s. 730-741Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Shoaling behavior is known to increase survival rates during attacks from predators, minimize foraging time, favor mating, and potentially increase locomotor efficiency. The onset of shoaling typically occurs during the larval phase, but it is unclear how it may improve across ontogenetic stages in forage fishes. Warming is known to increase metabolic rates during locomotion in solitary fish, and shoaling species may adjust their collective behavior to offset the elevated costs of swimming at higher temperatures. In this study, we quantified the effects of warming on shoaling performance across the ontogeny of a small forage fish, zebrafish (Danio rerio) at different speeds. Shoals of larval, juvenile, and adult zebrafish were acclimated at two temperatures (28°C and 32°C), and metabolic rates were quantified prior to and following nonexhaustive exercise at high speed. Shoals of five individuals were filmed in a flow tank to analyze the kinematics of collective movement. We found that zebrafish improve shoaling swimming performance from larvae to juveniles to adults. In particular, shoals become more cohesive, and both tail beat frequency (TBF) and head-to-tail amplitude decrease with ontogeny. Early life stages have higher thermal sensitivity in metabolic rates and TBF especially at high speeds, when compared to adults. Our study shows that shoaling behavior and thermal sensitivity improve as zebrafish shift from larval to juvenile to adult stages. 

  • 9. Brand, Jack A.
    et al.
    Yee, Winston K. W.
    Aitkenhead, Ian J.
    Martin, Jake M.
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen. Monash University, Australia; Swedish University of Agricultural Sciences, Sweden.
    Polverino, Giovanni
    Chown, Steven L.
    Wong, Bob B. M.
    Dowling, Damian K.
    Temperature change exerts sex-specific effects on behavioural variation2023Inngår i: Proceedings of the Royal Society of London. Biological Sciences, ISSN 0962-8452, E-ISSN 1471-2954, Vol. 290, nr 2002, artikkel-id 20230110Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

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

  • 10. Cimarelli, Giulia
    et al.
    Juskaite, Magdelena
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för biologisk grundutbildning (BIG). University of Veterinary Medicine Vienna, Austria.
    Range, Friederike
    Marshall-Pescini, Sarah
    Free-ranging dogs match a human's preference in a foraging task2023Inngår i: Current Zoology, ISSN 1674-5507Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

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

  • 11.
    Corral-Lopez, Alberto
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för etologi. University of British Columbia, Canada; University College London, UK; Uppsala University, Sweden.
    Kotrschal, Alexander
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för etologi. Wageningen University & Research, Netherlands.
    Szorkovszky, Alexander
    Garate-Olaizola, Maddi
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för etologi. Uppsala University, Sweden.
    Herbert-Read, James
    van der Bijl, Wouter
    Romenskyy, Maksym
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för etologi. Imperial College London, UK.
    Zeng, Hong-Li
    Buechel, Severine Denise
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för etologi. Wageningen University & Research, Netherlands.
    Fontrodona Eslava, Ada
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för etologi. University of St Andrews, UK.
    Pelckmans, Kristiaan
    Mank, Judith E.
    Kolm, Niclas
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för etologi.
    Evolution of schooling drives changes in neuroanatomy and motion characteristics across predation contexts in guppies2023Inngår i: Nature Communications, E-ISSN 2041-1723, Vol. 14, artikkel-id 6027Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

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

  • 12.
    Corral-López, Alberto
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för etologi. University of British Columbia, Canada; Uppsala University, Sweden.
    Bloch, Natasha I.
    van der Bijl, Wouter
    Cortazar-Chinarro, Maria
    Szorkovszky, Alexander
    Kotrschal, Alexander
    Darolti, Iulia
    Buechel, Severine D.
    Romenskyy, Maksym
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för etologi.
    Kolm, Niclas
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för etologi.
    Mank, Judith E.
    Functional convergence of genomic and transcriptomic architecture underlies schooling behaviour in a live-bearing fish2024Inngår i: Nature Ecology & Evolution, E-ISSN 2397-334X, Vol. 8, nr 1, s. 98-110Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

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

  • 13. 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, s. 53-63Artikkel 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.

  • 14.
    Eckerström-Liedholm, Simon
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen.
    Behavioural, physiological and morphological correlates of life-history in killifishes − a macroevolutionary approach2019Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Life-histories commonly evolve along a continuum from short-lived and fecund, to long-lived and less fecund. Because life-history traits are mostly components of reproduction and survival, understanding the causes and consequences of life-history variation is at the core of evolutionary biology. This thesis aims to identify what other key traits (e.g. behavioural, physiological and morphological traits) covary with life-history, and why. Numerous hypotheses describe how life-history might be associated with other traits, with life-history trade-offs often considered to be a primary driver of any such relationships. For example, since resources are limited, increased investment in one trait must lead to decreased investment in one or several other traits, all else equal. Hypotheses on the relationship between life-history and other traits have been tested in many studies, but empirical studies in controlled experimental settings are rare. In this thesis I explore how behaviour, physiology and morphology relate to variation along the life-history continuum from fast to slow, in a system with substantial variation in life-history traits - the killifishes.

    I began by exploring the patterns of egg to body size allometry in killifishes (Paper I), where species with faster life-histories showed indications of constraints on the independent evolution of egg size and body size. Furthermore, I found evidence of differences in variance and in the rates of evolution of egg size and body size across species, potentially caused by the colonisation of ephemeral habitats, which could have selected for adaptations that lead to differences in size.

    I then performed a comparative common garden study (Paper II) of the pace-of-life syndrome hypothesis, which predicts that species with fast life-histories should take larger risks in order to maintain their increased reproductive rate. I obtained data on risk taking behaviours, including movement, tendency to enter an open environment, and aggressiveness, in addition to metabolic rate, for 20 species of killifish, with multiple replicates per species. The results indicated trait dependent associations with life-history, where aggression seemed to correlate positively with speed of life-history, in congruence with our prediction.

    Next, my colleagues and I assessed the association between life-history and sexual selection (Paper III), in order to determine if investment in secondary sexual traits might be traded off against survival in killifish. Fin size was found to be negatively associated with escape performance in a simulated predator attack, suggesting survival costs for individuals with large fins. Importantly, fin size was also positively associated with the speed of life-history, supporting the hypothesis that costs to survival probability is lower in fast-living species.

    Lastly, I tested the hypothesized negative covariation between relative brain size and speed of life-history, by collecting and analysing brain size measurements for 21 species of killifish (Paper IV). Surprisingly, a positive relationship between speed of life-history and relative brain size was found for adults, although juveniles did not differ in relative brain size. This implies at least one of two things: either there is no need to trade off brain size with life-history since resource acquisition is higher, or brain size and life-history are traded-off with other traits.

    In conclusion, I show that previously found trade-offs between life-history and investment in other costly traits are only sometimes present, when tested in a system with substantial divergences in the speed of life-history. I also provide evidence for a trait dependent association between life-history and among species differences in risk-taking and metabolic rate.

    Fulltekst (pdf)
    Behavioural, physiological and morphological correlates of life-history in killifishes
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  • 15.
    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, artikkel-id 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.

  • 16.
    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.

    Fulltekst (pdf)
    Fulltext
  • 17.
    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.

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    The relationship between personality and social dominance in the domestic fowl – a critical perspective
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  • 18.
    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.

  • 19.
    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, s. 874-882Artikkel 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.

  • 20.
    Fernlund Isaksson, Erika
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen.
    Resources, the environment, and sex: Examining variation in sexually selected traits in a livebearing fish2023Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Striking variation is observed in sexually selected traits. These traits influence the outcome of competition and choice before and after mating. Before mating, animals compete for the access to mating partners and choose who to mate with between several potential mates. After mating, sperm from several males can compete for the fertilization of the same eggs, and there can be cryptic choice, since the female may be able to influence which sperm gets to fertilize her eggs. Animals are expected to invest in traits that increase their success in competition and choice. However, external and internal factors shape which sexually selected traits are most beneficial and can cause animals to trade investment in some traits over others. Environmental conditions and availability of resources can influence how animals balance their time and energy to different traits, and males and females can respond to these factors in different ways. However, understanding these complex selective pressures remain challenging. 

    In this thesis, I combine field and experimental studies to examine how environmental conditions and resource availability influence how males and females invest in sexually selected traits. The thesis uses the pygmy halfbeak (Dermogenys collettei) as a study system, a small livebearing fish which exhibit a range of sexually selected traits in both males and females. Using observations of natural populations of halfbeaks in Singapore, I found that male and female halfbeaks show considerable behavioral variation in varying degree of canopy cover and water flow (Paper I). Next, I experimentally manipulated resource quantity in a series of laboratory studies to examine resource-dependence in sexual traits in male and female halfbeaks. In males, the expression of some, but not all, pre- and postcopulatory sexually selected traits were reduced following resource restriction. These patterns were surprisingly consistent between when the resource restriction was applied on adults and throughout development (Paper II). In females, the size and color reflectance of an ornamental trait (orange belly spot) was resource dependent, and males preferred females with larger belly spots (Paper III).  Lastly, I examined if female reproductive fluids are resource-dependent in their effect on sperm, as female reproductive fluids may be a key mechanism for cryptic female choice. While female reproductive fluid increased sperm swimming speed and viability, there was no evidence that female reproductive fluid effects on sperm are resource-dependent (Paper IV). The results of this thesis highlight how environmental conditions and variation in resources can influence how males and females invest in different traits and emphasize the need to study both males and females in a sexual selection framework. 

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    Resources, the environment, and sex
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  • 21.
    Fernlund Isaksson, Erika
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen.
    Social learning and brain size in the guppy (Poecilia reticulata)2018Independent thesis Advanced level (degree of Master (One Year)), 40 poäng / 60 hpOppgave
    Fulltekst (pdf)
    Fernlund Isaksson 2018
  • 22.
    Fernlund Isaksson, Erika
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen. Stockholm University, Zoology department.
    Social learning and brain size in the guppy (Poecilia reticulata)2018Independent thesis Advanced level (degree of Master (One Year)), 40 poäng / 60 hpOppgave
    Fulltekst (pdf)
    Fernlund 2018 Master Thesis
  • 23. 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.

  • 24.
    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, s. 423-432Artikkel 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

  • 25.
    Ghirlanda, Stefano
    et al.
    Stockholms universitet, Humanistiska fakulteten, Centrum för evolutionär kulturforskning. Brooklyn College, USA; CUNY Graduate Center, USA.
    Lind, Johan
    Stockholms universitet, Humanistiska fakulteten, Centrum för evolutionär kulturforskning.
    ‘Aesop's fable’ experiments demonstrate trial-and-error learning in birds, but no causal understanding2017Inngår i: Animal Behaviour, ISSN 0003-3472, E-ISSN 1095-8282, Vol. 123, s. 239-247Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Experiments inspired by Aesop's fable The crow and the pitcher have been suggested to show that some birds (rooks, Corvus frugilegus, New Caledonian crows, Corvus moneduloides, and Eurasian jays, Garrulus glandarius) understand cause–effect relationships pertaining to water displacement. For example, the birds may prefer to drop stones in water rather than in sand in order to retrieve a floating food morsel, suggesting that they understand that only the level of water can be so raised. Here we re-evaluate the evidence for causal understanding in all published experiments (23 928 choices by 36 individuals). We first show that commonly employed statistical methods cannot disentangle the birds' initial performance on a task (which is taken as an indicator of causal understanding) from trial-and-error learning that may occur during the course of the experiment. We overcome this shortcoming with a new statistical analysis that quantifies initial performance and learning effects separately. We present robust evidence of trial-and-error learning in many tasks, and of an initial preference in a few. We also show that both seeming demonstrations of causal understanding and of lack of it can be understood based on established properties of instrumental learning. We conclude that Aesop's fable experiments have not yet produced evidence of causal understanding, and we suggest how the experimental designs can be modified to yield better tests of causal cognition.

  • 26.
    Gérard, Maxence
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för funktionell zoomorfologi.
    Cariou, Bérénice
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för funktionell zoomorfologi. Sorbonne Université, France.
    Henrion, Maxime
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för funktionell zoomorfologi. Ecole Normale Supérieure de Lyon, France.
    Descamps, Charlotte
    Baird, Emily
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för funktionell zoomorfologi.
    Exposure to elevated temperature during development affects bumblebee foraging behavior2022Inngår i: Behavioral Ecology, ISSN 1045-2249, E-ISSN 1465-7279, Vol. 33, nr 4, s. 816-824Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

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

  • 27.
    Hagman, Mattias
    et al.
    University of New South Wales, Australia.
    Löwenborg, Kristin
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen.
    Shine, Richard
    University of Sydney, Australia.
    Determinants of anti-predator tactics in hatchling grass snakes (Natrix natrix)2015Inngår i: Behavioural Processes, ISSN 0376-6357, E-ISSN 1872-8308, Vol. 113, s. 60-65Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Many organisms exhibit diverse anti-predator tactics, influenced by genetics and prior experience. In ectothermic taxa, offspring phenotypes are often sensitive to developmental temperatures. If the effectiveness of alternative anti-predator responses depends on thermally sensitive traits, then the temperatures experienced during embryonic life should also affect how offspring respond to an approaching predator. We incubated 16 clutches of Swedish grass snakes (Natrix natrix) at a range of developmental temperatures, and scored body size, colour pattern, locomotor performance and anti-predator responses of 213 hatchlings from those clutches. A hatchling snake’s size and locomotor abilities were affected by its clutch of origin, its developmental temperature, and by an interaction between these two factors. Anti-predator tactics were strongly linked to locomotor ability, such that slower snakes tended to rely upon aggressive displays rather than flight. Incubation temperatures that generated slow (and thus aggressive) snakes also modified the colour of the snake’s nuchal spot. Temperatures in the low to medium range generated mostly cream, white and orange spots, whereas medium to high temperatures generated more yellow spots. Incubation effects, and gene X environment interactions, thus may generate complex correlations between morphology, locomotor ability, and anti-predator tactics.

  • 28.
    Hagman, Mattias
    et al.
    Univ Sydney, Sch Biol Sci A08, Sydney, NSW 2006, Australia.
    Shine, Rick
    Univ Sydney, Sch Biol Sci A08, Sydney, NSW 2006, Australia.
    Australian tadpoles do not avoid chemical cues from invasive cane toads (Bufo marinus)2008Inngår i: Wildlife research (East Melbourne), ISSN 1035-3712, E-ISSN 1448-5494, Vol. 35, nr 4, s. 59-64Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In previous work, we have shown that tadpoles of invasive cane toads (Bufo marinus) strongly avoid scent cues from crushed conspecific tadpoles. Thus, identifying the identity of the chemical involved may provide novel approaches to toad control, by manipulating the behaviour of toad tadpoles. A first step in the search for that chemical is to see whether toad tadpoles are similarly repelled by chemical cues from crushed tadpoles of other species. Our experimental trials with four native Australian frogs (three hylids, one myobatrachid) show that toads do not respond to chemical cues from these taxa. Hence, the specific chemicals that induce avoidance cannot be generic ones (e.g. body fluids, tissue fragments) but instead, must reflect some underlying chemical divergence in body composition between the tadpoles of cane toads versus the other anurans that we have tested.

  • 29.
    Hagman, Mattias
    et al.
    Univ Sydney, Sch Biol Sci, Sydney, NSW 2006, Australia.
    Shine, Rick
    Univ Sydney, Sch Biol Sci, Sydney, NSW 2006, Australia.
    Deceptive digits: the functional significance of toe waving by cannibalistic cane toads (Bufo marinus)2008Inngår i: Animal Behaviour, ISSN 0003-3472, E-ISSN 1095-8282, Vol. 75, s. 123-131Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Many ambush foraging predators possess specialized structures and behaviours that plausibly function to attract prey, but this hypothesis has rarely been subject to direct empirical tests. If luring evolved to attract specific prey types then we predict that it will be manifested only if that prey type is present, and only by predators of the size class that feed on that prey type. Also, luring should induce closer approach by prey; and aspects of the behaviour (e. g. frequency of movement of the lure) should have been. ne tuned by selection to induce maximal response from prey. We describe a novel luring system: small- and medium-sized ( but not metamorph and large) cane toads, Chaunus marinus, wave the long middle toe of the hind-foot up and down in an obvious display. In keeping with the functional hypothesis, toe waving is elicited by moving edible-sized objects such as crickets or metamorphic toads. Metamorphic toads are attracted to this stimulus, and trials with a mechanical model show that both the colour and the vibrational frequency of the toe correspond closely with those most effective at attracting smaller conspecifics towards the lure. The independent evolution of visual luring systems in many animal lineages provides a powerful opportunity for robust empirical tests of adaptive hypotheses about signal design.

  • 30.
    Hajkazemian, Melika
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för molekylär biovetenskap, Wenner-Grens institut.
    Decoding the language of transmission among vector-pathogen-host2023Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Vector-borne diseases account for over 17 percent of all infectious diseases and lead to more than 700,000 mortalities annually. Importantly, there is a complex interaction between infectious organisms and their host. Vectors spread pathogens, which have a significant negative health effect on humans and animals and therefore detrimental economic and environmental impacts. Only 2% of the more than 3,600 mosquito species are blood feeders, primarily; the Anopheles, Culex, and Aedes which spread the Malaria parasite, Zika, Chikungunya, West Nile, and Dengue viruses. Therefore, understanding the complex chemical signaling and the molecular mechanisms that mediate pathogen and vector interaction, and allow the pathogen to survive and spread, are the subjects of this thesis.

    In project I, we determined the production and release of Anopheles male aggregation Volatile Organic Compounds (VOCs) that initiate swarming, and enhance mating success. In addition, we compared the RNA-sequencing libraries of swarming to flag for chemosensory and circadian genes. The goal was to identify the molecular mechanisms of swarming and metabolite roles in mating success.

    In project II, we evaluated the phagostimulant effects of (E)-4-Hydroxy-3-methyl-but-2-enyl pyrophosphate (HMBPP) on an artificial feeding system for some important vectors (Anopheles coluzzii, An. arabiensis, An. gambiae s.s., Culex pipiens/Culex torrentium, and Aedes aegypti). We showed that our toxic plant-based solution can kill the five lethal vectors.

    In project III, we studied the alteration of An. gambiae behavior by the Plasmodium falciparum at infected (oocyst-carrying, 7 days post-infection) and infective (sporozoite-carrying, 14 days post-infection) stages. To discover whether antennal chemosensory genes expression changes at different stages of infection, we performed RNA-seq and examined the candidate olfactory genes’ abundance to provide a possible molecular mechanism for manipulating the parasite-carrying mosquitoes' behavior.

    Finally, in project IV, we presented the results of RNA-seq analysis that revealed the network connection between developmental genes and the physiological plasticity in male mosquitoes of An. funestus. We identified the transcripts that associated with the male An. funestus sexual maturation and mating success.

    In summary, this thesis focuses on understanding how vector-pathogen interaction manipulates the vector’s transcriptome, physiology, and behavior to enhance transmission success and thereby identify novel targets for vector-borne disease control. 

     

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    Decoding the language of transmission among vector-pathogen-host
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  • 31.
    Johansen, Aleksandra I.
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen.
    Seasonal change in defensive coloration in a shieldbug2011Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Protective coloration such as aposematism and crypsis occurs in many insects but only a few species alter their defensive strategy during the same instar. We hypothesize the adult shield bug Graphosoma lineatum with an alternating black and non-melanised longitudinal striation exhibit such a change in defensive coloration. In Sweden, the non-melanised stripes of the pre-hibernation G. lineatum are pale brown and cryptic but they change during hibernation to red and aposematic. We have tested the adaptive functions of coloration of the two G. lineatum forms against bird predators. In Paper I we used great tits as predators and measured detection time of the two forms against a background of dry grass and plants, simulating late-summer conditions. We found that the birds took longer time to find the pale than the red form. Thus, the pale form of G. lineatum is more cryptic in a dry environment than the red form. In Paper II and III we used naïve predators and measured attack rate/latency on red and pale adults and fifth-instar larvae (black and brown) to investigate avoidance and generalisation between the stages. In Paper II domestic chicks initially found the red form most intimidating, but both adult forms are more intimidating than the larva. Moreover, there was a broad generalisation among forms. In Paper III naïve great tits did not find the red form significantly more aversive than the pale adult. Neither the chicks nor the tits showed any difference in the speed of avoidance learning between the two adult colour forms. In Paper IV the shieldbugs themselves were the main focus as we compared activity levels in the different colour forms and found that G. lineatum alters behaviour in accordance to their protective strategy. Thus they were significantly less active during the cryptic phase. Taken together, these experiments suggest that the pale brown adult invests in a cryptic strategy at the cost of reduced protection from aposematism, whereas the red adult benefits from aposematism at the cost of reduced camouflage.

    Fulltekst (pdf)
    fulltext
  • 32.
    Johansen, Aleksandra I.
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen.
    Exnerová, Alice
    Hotová Svádová, Katerina
    Stys, Pavel
    Gamberale-Stille, Gabriella
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen.
    Tullberg, Birgitta S.
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen.
    Adaptive change in protective coloration in adultstriated shieldbugs Graphosoma lineatum (Heteroptera:Pentatomidae): test of detectability of two colour formsby avian predators2010Inngår i: Ecological Entomology, ISSN 0307-6946, E-ISSN 1365-2311, Vol. 35, nr 5, s. 602-610Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    1. Protective coloration in insects may be aposematic or cryptic, and some species change defensive strategy between instars. In Sweden, the adult striated shieldbugs Graphosoma lineatum (Heteroptera: Pentatomidae) undergo a seasonal colour change from pale brown and black striation in the pre-hibernating adults, to red and black striation in the same post-hibernating individuals. To the human eye the pre-hibernating adults appear cryptic against the withered late summer vegetation, whereas the red and black post-hibernating adults appear aposematic. This suggests a possibility of a functional colour change. However, what is cryptic to the human eye is not necessarily cryptic to a potential predator.

    2. Therefore we tested the effect of coloration in adult G. lineatum on their detectability for avian predators. Great tits (Parus major) were trained to eat sunflower seeds hidden inside the emptied exoskeletons of pale or red G. lineatum. Then the detection time for both colour forms was measured in a dry vegetation environment.

    3. The birds required a longer time to find the pale form of G. lineatum than the red one. The pale form appears more cryptic on withered late summer vegetation than the red form, not only to the human eye but also to avian predators. The result supports the idea that the adult individuals of G. lineatum undergo a functional change from a cryptic protective coloration to an aposematic one.

  • 33.
    Johansen, Aleksandra I.
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen.
    Exnerová, Alice
    Svádová, Katerina Hotová
    Pavel, Stys
    Tullberg, Birgitta S.
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen.
    Gamberale-Stille, Gabriella
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen.
    Anti-Predatory defences in the shieldbug Graphosoma lineatum (Heteroptera: Pentatomidae) differ between life stages and colour forms: an experiment with hand reared great tits (Parus major) as predatorsManuskript (preprint) (Annet vitenskapelig)
    Abstract [en]

    Crypsis and aposematism are strategies used to avoid predation. Cryptic coloration helps prey to avoid detection and aposematic coloration signals unpalatability to the predator. In the Swedish populations of striated shieldbug Graphosoma lineatum there is a change in coloration and presumably protective strategy that coincides with a change of season and the natural background in the environment. We have compared effectiveness of warning function of colour patterns and chemical defence of three consecutive instars of G. lineatum: the cryptic fifth-instar larvae, the cryptic pale brown and black pre-hibernation adults and the aposematic red and black post-hibernation adults. In experiments with hand reared great tits (Parus major) we investigated the birds’ initial response, avoidance learning and generalisation between forms. We also noted if bugs used their scent glands on attack and if they survived attacks or not. Birds attacked the larvae faster and to a higher extent than the adults, both in naïve birds and after experience, but we found no difference between the adult colour forms in this regard. However, birds generalised asymmetrically between adults and larvae. Previous experience of adults benefited the larvae, but previous experience with larvae increased attack risk on adults and significantly more on the pale than the red adults. Spraying the defensive secretion increased the survival of adults but not the larvae. We conclude that the life stages of G. lineatum differ in defensive strategy against bird predators so that larvae rely on crypsis and the red adults rely mainly on aposematism, whereas the pale adult form seems to do both.

  • 34.
    Johansen, Aleksandra I.
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen.
    Tullberg, Birgitta S.
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen.
    Gamberale-Stille, Gabriella
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen.
    Motion level in Graphosoma lineatum coincides with ontogenetic change in defensive colorationInngår i: Entomologia Experimentalis et Applicata, ISSN 0013-8703, E-ISSN 1570-7458Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Crypsis and aposematism are two different approaches to predation avoidance. Theoretically, the chosen strategy depends on the prevailing possibilities and constraints to the animal. Consequently, insects often change strategy between life stages, but a switch in strategy within a life stage is quite uncommon. In the Swedish shieldbug, Graphosoma lineatum L. (Heteroptera: Pentatomidae), there is a colour change from the pre-hibernating to the post-hibernating adults that alters their protective strategy from effective crypsis to aposematism, although both stages are distasteful to predators. The change in colour occurs as there is a shift of seasons, which alters the environmental background. Here we investigate if there is a change in behaviour in G. lineatum connected to the change in coloration and protective strategy. We therefore measured the motion levels in the two different colour forms of G. lineatum, both in the field and in a more controlled laboratory set up. Our result clearly shows that there is a change in behaviour connected to the change in colour. Thus, we found that the cryptic pre-hibernation form has a significantly lower motion level than the aposematic post-hibernation form, which is in line with the expectation from the fact that motion disrupts crypsis, but not aposematism. 

  • 35.
    Johansen, Aleksandra Irene
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen.
    Seasonal change in defensive coloration in a shieldbug2011Annet (Annet vitenskapelig)
    Abstract [en]

    Protective coloration such as aposematism and crypsis occurs in many insects but only a few species alter their defensive strategy during the same instar. We hypothesize the adult shield bug Graphosoma lineatum with an alternating black and non-melanised longitudinal striation exhibit such a change in defensive coloration. In Sweden, the non-melanised stripes of the pre-hibernation G. lineatum are pale brown and cryptic but they change during hibernation to red and aposematic. We have tested the adaptive functions of coloration of the two G. lineatum forms against bird predators. In Paper I we used great tits as predators and measured detection time of the two forms against a background of dry grass and plants, simulating late-summer conditions. We found that the birds took longer time to find the pale than the red form. Thus, the pale form of G. lineatum is more cryptic in a dry environment than the red form. In Paper II and III we used naïve predators and measured attack rate/latency on red and pale adults and fifth-instar larvae (black and brown) to investigate avoidance and generalisation between the stages. In Paper II domestic chicks initially found the red form most intimidating, but both adult forms are more intimidating than the larva. Moreover, there was a broad generalisation among forms. In Paper III naïve great tits did not find the red form significantly more aversive than the pale adult. Neither the chicks nor the tits shoved any difference in the speed of avoidance learning between the two adult colour forms. In Paper IV the shieldbugs themselves were the main focus as we compared activity levels in the different colour forms and found that G. lineatum alters behaviour in accordance to their protective strategy. Thus they were significantly less active during the cryptic phase. Taken together, these experiments suggest that the pale brown adult invests in a cryptic strategy at the cost of reduced protection from aposematism, whereas the red adult benefits from aposematism at the cost of reduced camouflage.    

    Fulltekst (pdf)
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  • 36.
    Kazemi, Baharan
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen.
    Evolution of Mimicry and Aposematism Explained: Salient Traits and Predator Psychology2017Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    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.

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    Evolution of Mimicry and Aposematism Explained: Salient Traits and Predator Psychology
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  • 37. Kessler, Kat
    et al.
    Giannisis, Andreas
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för biokemi och biofysik.
    Bial, Greg
    Foquet, Lander
    Nielsen, Henrietta M.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för biokemi och biofysik.
    Raber, Jacob
    Behavioral and cognitive performance of humanized APOEε3/ε3 liver mice in relation to plasma apolipoprotein E levels2023Inngår i: Scientific Reports, E-ISSN 2045-2322, Vol. 13, artikkel-id 1728Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Plasma apolipoprotein E levels were previously associated with the risk of developing Alzheimer’s disease (AD), levels of cerebrospinal fluid AD biomarkers, cognition and imaging brain measures. Outside the brain, the liver is the primary source of apoE and liver transplantation studies have demonstrated that liver-derived apoE does not cross the blood–brain-barrier. How hepatic apoE may be implicated in behavioral and cognitive performance is not clear. In the current study, we behaviorally tested FRGN mice with humanized liver harboring the ε3/ε3 genotype (E3-human liver (HL)) and compared their behavioral and cognitive performance with that of age-matched ε3/ε3 targeted replacement (E3-TR) mice, the latter produces human apoE3 throughout the body whereas the E3-HL mice endogenously produce human apoE3 only in the liver. We also compared the liver weights and plasma apoE levels, and assessed whether plasma apoE levels were correlated with behavioral or cognitive measures in both models. E3-HL were more active but performed cognitively worse than E3-TR mice. E3-HL mice moved more in the open field containing objects, showed higher activity levels in the Y maze, showed higher activity levels during the baseline period in the fear conditioning test than E3-TR mice, and swam faster than E3-TR mice during training to locate the visible platform in the water maze. However, E3-HL mice showed reduced spatial memory retention in the water maze and reduced fear learning and contextual and cued fear memory than E3-TR mice. Liver weights were greater in E3-HL than E3-TR mice and sex-dependent only in the latter model. Plasma apoE3 levels were similar to those found in humans and comparable in female and male E3-TR mice but higher in female E3-HL mice. Finally, we found correlations between plasma apoE levels and behavioral and cognitive measures which were predominantly model-dependent. Our study demonstrates mouse-model dependent associations between plasma apoE levels, behavior and cognition in an ‘AD-neutral’ setting and suggests that a humanized liver might be sufficient to induce mouse behavioral and cognitive phenotypes.

  • 38. Koekemoer, L. L.
    et al.
    Hajkazemian, Melika
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för molekylär biovetenskap, Wenner-Grens institut.
    Zawada, J. W.
    Mirzaie, M.
    Dahan‑Moss, Y. L.
    Emami, S. Noushin
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för molekylär biovetenskap, Wenner-Grens institut. Molecular Attraction AB, Sweden; University of Greenwich, UK.
    Data-driven networking of global transcriptomics and male sexual development in the main malaria vector, Anopheles funestus2023Inngår i: Scientific Reports, E-ISSN 2045-2322, Vol. 13, artikkel-id 16798Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

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

  • 39.
    Kotrschal, Alexander
    et al.
    Department of Ecology & Genetics/Animal Ecology, Uppsala University, Sweden.
    Lievens, Eva J. P.
    Dahlbom, Josefin
    Bundsen, Andreas
    Semenova, Svetlana
    Sundvik, Maria
    Maklakov, Alexei A.
    Winberg, Svante
    Panula, Pertti
    Kolm, Niclas
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för etologi.
    Artificial selection on relative brain size reveals a positive genetic correlation between brain size and proactive personality in the guppy2014Inngår i: Evolution, ISSN 0014-3820, E-ISSN 1558-5646, Vol. 68, nr 4, s. 1139-1149Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Animal personalities range from individuals that are shy, cautious, and easily stressed (a reactive personality type) to individuals that are bold, innovative, and quick to learn novel tasks, but also prone to routine formation (a proactive personality type). Although personality differences should have important consequences for fitness, their underlying mechanisms remain poorly understood. Here, we investigated how genetic variation in brain size affects personality. We put selection lines of large- and small-brained guppies (Poecilia reticulata), with known differences in cognitive ability, through three standard personality assays. First, we found that large-brained animals were faster to habituate to, and more exploratory in, open field tests. Large-brained females were also bolder. Second, large-brained animals excreted less cortisol in a stressful situation (confinement). Third, large-brained animals were slower to feed from a novel food source, which we interpret as being caused by reduced behavioral flexibility rather than lack of innovation in the large-brained lines. Overall, the results point toward a more proactive personality type in large-brained animals. Thus, this study provides the first experimental evidence linking brain size and personality, an interaction that may affect important fitness-related aspects of ecology such as dispersal and niche exploration.

  • 40.
    Leimar, Olof
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för etologi.
    Norberg, Ulf
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för etologi.
    Wiklund, Christer
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för zoologisk ekologi.
    Habitat preference and habitat exploration in two species of satyrine butterflies2003Inngår i: Ecography, ISSN 0906-7590, E-ISSN 1600-0587, Vol. 26, s. 474-480Artikkel i tidsskrift (Fagfellevurdert)
  • 41.
    Lind, Johan
    Stockholms universitet, Humanistiska fakulteten, Institutionen för arkeologi och antikens kultur, Centrum för evolutionär kulturforskning.
    Inget stöd för att kråkfåglar kan resonera2017Inngår i: Sans, ISSN 2000-9690, nr 3, s. 10-15Artikkel i tidsskrift (Annet (populærvitenskap, debatt, mm))
  • 42.
    Lind, Johan
    Stockholms universitet, Humanistiska fakulteten, Institutionen för arkeologi och antikens kultur, Centrum för evolutionär kulturforskning.
    Nobelkommittén gjorde inte hemläxan inför medicinpriset2014Inngår i: Svenska dagbladet, ISSN 1101-2412, nr 22 novemberArtikkel i tidsskrift (Annet (populærvitenskap, debatt, mm))
    Abstract [sv]

    Har Nobelkommittén missat ett sekel av beteendeforskning när de motiverar årets pris med uttalanden om råttors höga intelligens? Den frågar ställer Johan Lind, docent i etologi vid Stockholms universitet.

  • 43.
    Lind, Johan
    et al.
    Stockholms universitet, Humanistiska fakulteten, Centrum för evolutionär kulturforskning. Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för etologi.
    Enqvist, Magnus
    Stockholms universitet, Humanistiska fakulteten, Centrum för evolutionär kulturforskning. Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för etologi.
    Insight Learning and Shaping2012Inngår i: Encyclopedia of the Sciences of Learning / [ed] Norbert M. Seel, Springer Publishing Company, 2012, s. 1574-1577Kapittel i bok, del av antologi (Fagfellevurdert)
  • 44.
    Lind, Johan
    et al.
    Stockholms universitet, Humanistiska fakulteten, Institutionen för arkeologi och antikens kultur, Centrum för evolutionär kulturforskning. Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen.
    Ghirlanda, Stefano
    Enquist, Magnus
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen.
    Social learning through associative processes: a computational theory2019Inngår i: Royal Society Open Science, E-ISSN 2054-5703, Vol. 6, nr 3, artikkel-id 181777Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Social transmission of information is a key phenomenon in the evolution of behaviour and in the establishment of traditions and culture. The diversity of social learning phenomena has engendered a diverse terminology and numerous ideas about underlying learning mechanisms, at the same time that some researchers have called for a unitary analysis of social learning in terms of associative processes. Leveraging previous attempts and a recent computational formulation of associative learning, we analyse the following learning scenarios in some generality: learning responses to social stimuli, including learning to imitate; learning responses to non-social stimuli; learning sequences of actions; learning to avoid danger. We conceptualize social learning as situations in which stimuli that arise from other individuals have an important role in learning. This role is supported by genetic predispositions that either cause responses to social stimuli or enable social stimuli to reinforce specific responses. Simulations were performed using a new learning simulator program. The simulator is publicly available and can be used for further theoretical investigations and to guide empirical research of learning and behaviour. Our explorations show that, when guided by genetic predispositions, associative processes can give rise to a wide variety of social learning phenomena, such as stimulus and local enhancement, contextual imitation and simple production imitation, observational conditioning, and social and response facilitation. In addition, we clarify how associative mechanisms can result in transfer of information and behaviour from experienced to naive individuals.

  • 45.
    Lind, Johan
    et al.
    Stockholms universitet, Humanistiska fakulteten, Institutionen för arkeologi och antikens kultur, Centrum för evolutionär kulturforskning. Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen.
    Lönnberg, Sofie
    Stockholms universitet, Humanistiska fakulteten, Institutionen för arkeologi och antikens kultur, Centrum för evolutionär kulturforskning.
    Persson, Tomas
    Enquist, Magnus
    Stockholms universitet, Humanistiska fakulteten, Institutionen för arkeologi och antikens kultur, Centrum för evolutionär kulturforskning. Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen.
    Time Does Not Help Orangutans Pongo abelii Solve Physical Problems2017Inngår i: Frontiers in Psychology, E-ISSN 1664-1078, Vol. 8, artikkel-id 161Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Many questions in animal intelligence and cognition research are challenging. One challenge is to identify mechanisms underlying reasoning in experiments. Here, we provide a way to design such tests in non-human animals. We know from research in skill acquisition in humans that reasoning and thinking can take time because some problems are processed in multiple steps before a solution is reached (e.g., during mental arithmetics). If animals are able to learn through similar processes their decision making can be time consuming, and most importantly improve if more time to process information is allowed. We tested if performance of two Sumatran orangutans (Pongo abelii) increased in a two-choice experiment when they were allowed extra time before making their decisions, compared to when they were forced to decide immediately. We found that the performance of the orangutans did not depend on the time they were allowed to process the information before making their decisions. This methodology provides a potential avenue for empirical tests of mechanisms underlying reasoning in non-human animals.

    Fulltekst (pdf)
    fulltext
  • 46.
    Lindenfors, Patrik
    Stockholms universitet, Humanistiska fakulteten, Institutionen för arkeologi och antikens kultur, Centrum för evolutionär kulturforskning. Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen. Naturvårdsverket, Sverige; Institutet för Framtidsstudier, Sverige.
    Det kulturella djuret: om människans evolution och tänkandets utveckling2019Bok (Annet vitenskapelig)
    Abstract [sv]

    För några miljoner år sedan tillverkade våra förfäder de första stenverktygen. Sedan hände märkligt lite på två och en halv miljoner år. Det är först de senaste tusentals åren som den teknologiska utvecklingen tagit ett rejält språng. Vi har skapat städer, skrivit symfonier, byggt månraketer, internet och Nya Söderstadion samtidigt som höjdpunkten på den kulturella utvecklingen i övriga djurriket fortfarande är att använda två stenar för att knäcka nötter. Vad var det som hände?

    I Det kulturella djuret får du ta del av den senaste forskningen om hjärnan, inlärning och den informationshantering som är unik för människan, och med vilken vi förändrat både världen och oss själva. På vägen får du också lära dig en hel del om övriga djurriket: Är kråkor verkligen smartare än femåringar? Har encelliga toffeldjur ett minne? Och vad är likheten mellan en myrstack och en mänsklig hjärna? Framför allt får du lära dig allt om den biologiska och kulturella evolution som gjort oss till dem vi är idag.

  • 47.
    Lindenfors, Patrik
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen. Stockholms universitet, Humanistiska fakulteten, Centrum för evolutionär kulturforskning.
    Om djurs tänkande2017Inngår i: Folkvett, ISSN 0283-0795, nr 1, s. 62-75Artikkel i tidsskrift (Annet (populærvitenskap, debatt, mm))
    Abstract [sv]

    Den här artikeln har en historia. Från början skrevs den på uppdrag av Forskning & Framsteg, Sveriges främsta populärvetenskapliga tidskrift. Men eftersom den beskri-ver analyser som går på tvärs med andras forskares verk-samhet uppstod det diskussioner. Tidskriften kom därför fram till att det vore bättre om en neutral journalist skrev artikeln än jag, som är part i målet. Artikeln handlar näm-ligen om ny forskning vid min arbetsplats: Centrum för evolutionär kulturforskning vid Stockholms universitet. Ett klokt redaktionellt beslut av Forskning & Framsteg, tveklöst. Men det vore synd om texten hamnade i pap-perskorgen. Här kommer därför en (partisk) skildring av ny forskning kring djurs tänkande.

  • 48.
    Lindenfors, Patrik
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för zoologisk ekologi. Stockholms universitet, Humanistiska fakulteten, Institutionen för arkeologi och antikens kultur, Centrum för evolutionär kulturforskning. Institute for Future Studies, Sweden.
    Primate Social Evolution2018Inngår i: The International Encyclopedia of Anthropology, John Wiley & Sons, 2018Kapittel i bok, del av antologi (Fagfellevurdert)
    Abstract [en]

    Primates display a remarkable diversity of types of social organization—a diversity that, according to the socioecological model of social evolution, is ultimately determined by ecological factors limiting female fitness and the number of matings limiting male fitness. The foremost ecological determinants of female sociality are the degree to which food resources are defendable, either alone or in a group, and the level of protection from predators gained from being part of a group. Further factors that have been proposed are the presence of infanticide, coalitions, and dominance hierarchies; general population density and habitat saturation; whether competition is mainly intra‐ or intergroup; and which sex disperses. Male sociality is instead mainly determined by the spatiotemporal spacing of mating opportunities with females. Some researchers have also proposed that cognitive abilities impose a limit on group size, since primate sociality demands competent navigation of social networks.

    Fulltekst (pdf)
    fulltext
  • 49.
    Norberg, Ulf
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen.
    Enfjäll, Karin
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen.
    Leimar, Olof
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen.
    Habitat exploration in butterflies - an outdoor cage experiment2002Inngår i: Evolutionary ecology, Vol. 16, s. 1-14Artikkel i tidsskrift (Fagfellevurdert)
  • 50.
    Olofsson, Martin
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen.
    Løvlie, Hanne
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen.
    Tibblin, Jessika
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen.
    Jakobsson, Sven
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen.
    Wiklund, Christer
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen.
    Eyespot display in the peacock butterfly triggers antipredator behaviors in naive adult fowl2013Inngår i: Behavioral Ecology, ISSN 1045-2249, E-ISSN 1465-7279, Vol. 24, nr 1, s. 305-310Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Large conspicuous eyespots have evolved in multiple taxa and presumably function to thwart predator attacks. Traditionally, large eyespots were thought to discourage predator attacks because they mimicked eyes of the predators' own predators. However, this idea is controversial and the intimidating properties of eyespots have recently been suggested to Amply be a consequence of their conspicuousness. Some lepidopteran species include large eyespots in their antipredation repertoire. In the peacock butterfly, Mathis io, eyespots are typically hidden during rest and suddenly exposed by the butterfly when disturbed. Previous experiments have shown that small wild passerines are intimidated by this display. Here, we test whether eyespots also intimidate a considerably larger bird, domestic fowl, Gallus gallus domesticus, by staging interactions between birds and peacock butterflies that were sham-painted or had their eyespots painted oven Our results show that birds typically fled when peacock butterflies performed their display regardless of whether eyespots were visible or painted over. However, birds confronting butterflies with visible eyespots delayed their return to the butterfly, were more vigilant, and more likely to utter alarm calls associated with detection of ground-based predators, compared with birds confronting butterflies with eyespots painted over. Because production of alarm calls and increased vigilance are antipredation behaviors in the fowl, their reaction suggests that eyespots may elicit fear rather than just an aversion to conspicuous patterns. Our results, therefore, suggest that predators perceive large lepidopteran eyespots as belonging to the eyes of a potential predator.

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