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  • 1.
    Acerbi, Alberto
    et al.
    Department of Psychology, University of Bologna.
    Enquist, Magnus
    Stockholm University, Faculty of Humanities, Centre for the Study of Cultural Evolution. Stockholm University, Faculty of Science, Department of Zoology, Department of Ethology.
    Ghirlanda, Stefano
    Stockholm University, Faculty of Humanities, Centre for the Study of Cultural Evolution.
    Cultural evolution and individual development of openness and conservatism2009In: Proceedings of the National Academy of Sciences of the United States of America, ISSN 0027-8424, E-ISSN 1091-6490, Vol. 106, no 45, p. 18931-18935Article in journal (Refereed)
    Abstract [en]

    We present a model of cultural evolution in which an individual's propensity to engage in social learning is affected by social learning itself. We assume that individuals observe cultural traits displayed by others and decide whether to copy them based on their overall preference for the displayed traits. Preferences, too, can be transmitted between individuals. Our results show that such cultural dynamics tends to produce conservative individuals, i.e., individuals who are reluctant to copy new traits. Openness to new information, however, can be maintained when individuals need significant time to acquire the cultural traits that make them effective cultural models. We show that a gradual enculturation of young individuals by many models and a larger cultural repertoire to be acquired are favorable circumstances for the long-term maintenance of openness in individuals and groups. Our results agree with data about lifetime personality change, showing that openness to new information decreases with age. Our results show that cultural remodeling of cultural transmission is a powerful force in cultural evolution, i.e., that cultural evolution can change its own dynamics

  • 2.
    Acerbi, Alberto
    et al.
    Stockholm University, Faculty of Humanities, Centre for Cultural Evolution.
    Ghirlanda, Stefano
    Stockholm University, Faculty of Humanities, Centre for Cultural Evolution. Brooklyn College, US.
    Enquist, Magnus
    Stockholm University, Faculty of Humanities, Centre for Cultural Evolution. Stockholm University, Faculty of Science, Department of Zoology, Ethology.
    Regulatory Traits in Cultural Evolution2012In: Proceedings of WiVACE 2012, 2012, p. 1-9Conference paper (Refereed)
    Abstract [en]

    We call "regulatory traits" those cultural traits that are transmitted through cultural interactions and, at the same time, change individual behaviors directly influencing the outcome of future cultural interactions. The cultural dynamics of some of those traits are studied through simple simulations. In particular, we consider the cultural evolution of traits determining the propensity to copy, the number of potential demonstrators from whom one individual may copy, and conformist versus anti conformist attitudes. Our results show that regulatory traits generate peculiar dynamics that may explain complex human cultural phenomena. We discuss how the existence and importance of regulatory traits in cultural evolution impact on the analogy between genetic and cultural evolution and therefore on the possibility of using evolutionary biology inspired models to study human cultural dynamics.

  • 3.
    Almbro, Maria
    et al.
    Stockholm University, Faculty of Science, Department of Zoology, Ethology.
    Kullberg, Cecilia
    Stockholm University, Faculty of Science, Department of Zoology, Ethology.
    Impaired escape flight ability in butterflies due to low flight muscle ratio prior to hibernation2008In: Journal of Experimental Biology, ISSN 0022-0949, E-ISSN 1477-9145, Vol. 211, no 1, p. 24-28Article in journal (Refereed)
  • 4.
    Almbro, Maria
    et al.
    Centre for Evolutionary Biology, University of Western Australia.
    Kullberg, Cecilia
    Stockholm University, Faculty of Science, Department of Zoology, Ethology.
    Season, sex and flight muscle investment affect take-off performance in the hibernating small tortoiseshell butterfly Agalis urticae (Lepidoptera: Nymphalidae)2011In: The Journal of Research on the Lepidoptera, ISSN 0022-4324, Vol. 44, p. 77-84Article in journal (Refereed)
    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.

  • 5.
    Almbro, Maria
    et al.
    Stockholm University, Faculty of Science, Department of Zoology. Stockholm University, Faculty of Science, Department of Zoology, Department of Ethology.
    Kullberg, Cecilia
    Stockholm University, Faculty of Science, Department of Zoology. Stockholm University, Faculty of Science, Department of Zoology, Department of Ethology. Stockholm University.
    The downfall of mating: the effect of mate-carrying and flight muscle ratio on the escape ability of a pierid butterfly2009In: Behavioral Ecology and Sociobiology, ISSN 0340-5443, E-ISSN 1432-0762, Vol. 63, no 3, p. 413-420Article in journal (Refereed)
  • 6.
    Aronsson, Marianne
    et al.
    Stockholm University, Faculty of Science, Department of Zoology, Ethology.
    Gamberale-Stille, Gabriella
    Stockholm University, Faculty of Science, Department of Zoology, Ethology.
    Colour and pattern similarity in mimicry - evidence for a hierarchical discriminative learning of warning colour pattern components.Manuscript (preprint) (Other academic)
  • 7.
    Aronsson, Marianne
    et al.
    Stockholm University, Faculty of Science, Department of Zoology, Ethology.
    Gamberale-Stille, Gabriella
    Stockholm University, Faculty of Science, Department of Zoology, Ethology.
    Importance of internal pattern contrast and contrast against the background in aposematic signals.2009In: Behavioral Ecology, ISSN 1045-2249, E-ISSN 1465-7279, Vol. 20, no 6, p. 1356-1362Article in journal (Refereed)
    Abstract [en]

    Aposematic color patterns that signal prey unprofitability are suggested to work best when there is high contrast within the animal color pattern or between the animal and its background. Studies show that prey contrast against the background increases the signal efficiency. This has occasionally been extended to also explain the presence of internal patterns. We used domestic chicks, Gallus gallus domesticus, to investigate the relative importance for avoidance learning of within-prey pattern contrast and prey contrast against the background. In a series of trials, birds were first trained to avoid artificially made aposematic mealworms that were plain red or red with black stripes, and to discriminate them from palatable brown mealworms, on either a red or a brown background. Second, we investigated how the birds generalized between striped and nonstriped prey. The chicks showed faster avoidance learning when the basic color of the aposematic prey (red) contrasted with the background color (brown). However, there was no similar effect of internal pattern contrast. The generalization test showed a complete generalization between the nonstriped and the striped prey. We conclude that contrasting internal patterns do not necessarily affect predator avoidance learning the same way as shown for prey-to-background contrast in aposematic prey.

  • 8.
    Aronsson, Marianne
    et al.
    Stockholm University, Faculty of Science, Department of Zoology, Ethology.
    Gamberale-Stille, Gabriella
    Stockholm University, Faculty of Science, Department of Zoology, Ethology.
    Why do aposematic prey often have contrasting internal patterns: Evidence of benefits through predator avoidance learning and generalization.Manuscript (preprint) (Other academic)
  • 9.
    Bergvall, Ulrika A.
    et al.
    Stockholm University, Faculty of Science, Department of Zoology, Ethology. University of Edinburgh, U.K..
    Schäpers, Alexander
    Stockholm University, Faculty of Science, Department of Zoology, Ethology.
    Kjellander, Petter
    Weiss, Alexander
    Personality and foraging decisions in fallow deer, Dama dama2011In: Animal Behaviour, ISSN 0003-3472, E-ISSN 1095-8282, Vol. 81, no 1, p. 101-112Article in journal (Refereed)
    Abstract [en]

    Recent studies have examined the ecological and evolutionary bases for variation in animal personality. However, only a few such studies have examined how foraging parameters are influenced by different personality domains. In wild ungulates, the trade-off between the time spent on food intake and antipredator behaviour differs between individuals, but the underlying reason for this is not yet well understood. One possibility is that this trade-off reflects personality dimensions such as boldness. To relate foraging decisions to personality we measured personality and performed feeding experiments with familiar and novel food in familiar and novel situations. We measured personality traits in 15 tame fallow deer, using novel object tests (NO), behavioural observations (BO) and personality ratings (PR). Boldness dimensions were found using PR and NO, dominance dimensions were found using BO and PR, and a flexibility dimension was found using BO. Multitrait–multimethod analysis showed that similar dimensions were significantly correlated across different methods and that different dimensions were not significantly correlated, even if measured using the same method. We also found that novel food eaten in familiar situations and familiar food eaten in novel situations were strongly related to boldness but not dominance, flexibility or age. Thus the trade-off between the benefits of gaining more food and the costs of reduced vigilance or increased toxin ingestion reflect boldness. These findings highlight the nature of personality dimensions in ungulates and how boldness impacts foraging behaviour.

  • 10.
    Bergvall, Ulrika Alm
    et al.
    Stockholm University, Faculty of Science, Department of Zoology, Department of Ethology.
    Balogh, Alexandra C.V.
    Stockholm University, Faculty of Science, Department of Zoology, Department of Ethology.
    Consummatory simultaneous positive and negative contrast in fallow deer: implications for selectivity2009In: Mammalian Biology, ISSN 1616-5047, E-ISSN 1618-1476, Vol. 74, no 3, p. 236-239Article in journal (Refereed)
  • 11.
    Berzins, Arnis
    et al.
    University of Daugavpils.
    Krama, Tatjana
    University of Daugavpils.
    Krams, Indrikis
    University of Turku.
    Freeberg, Todd
    University of Tennessee.
    Kivleniece, Inese
    University of Daugavpils.
    Kullberg, Cecilia
    Stockholm University, Faculty of Science, Department of Zoology, Ethology.
    Rantala, Markus J
    University of Turku.
    Mobbing as a tradeoff between safety and reproduction in a songbird2010In: Behavioral Ecology, ISSN 1045-2249, E-ISSN 1465-7279, Vol. 21, no 5, p. 1054-1060Article in journal (Refereed)
  • 12. Boström, Jannika E.
    et al.
    Kullberg, Cecilia
    Stockholm University, Faculty of Science, Department of Zoology, Ethology.
    Åkesson, Susanne
    Northern magnetic displacements trigger endogenous fuelling responses in a naive bird migrant2012In: Behavioral Ecology and Sociobiology, ISSN 0340-5443, E-ISSN 1432-0762, Vol. 66, no 5, p. 819-821Article in journal (Refereed)
    Abstract [en]

    In a previous study, we found that juvenile northern wheatears (Oenanthe oenanthe) exposed to a magnetic displacement to the west of their natural migration route increased their body mass. The total intensity and inclination used for the western displacement may also have been interpreted as northern compared to the experimental site (stronger total field intensity and steeper inclination angle). In order to investigate whether the fuelling response was a response to an unexpected magnetic field or specific to the northern magnetic field, we conducted a new experiment. Juvenile wheatears from the same study population were magnetically displaced to southwestern magnetic fields, exposing the birds to unexpected magnetic combinations, but eliminating the possible effect of a northern magnetic field. A control group was kept in the local geomagnetic field in Sweden for comparison. There was no difference in body mass increase between treatments, suggesting that the fuelling response previously found was not a simple response to an unexpected magnetic field, but rather a specific response to the northern magnetic field. Juvenile wheatears may have developed a fuelling response to northern magnetic fields in order to enable a successful flight towards the migration goal.

  • 13. Boström, Jannika
    et al.
    Fransson, Thord
    Henshaw, Ian
    Jakobsson, Sven
    Stockholm University, Faculty of Science, Department of Zoology, Ethology.
    Kullberg, Cecilia
    Stockholm University, Faculty of Science, Department of Zoology, Ethology.
    Åkesson, Susanne
    Autumn migratory fuelling: a response to simulated magnetic displacement in juvenile wheatears, Oenathe oenathe2010In: Behavioral Ecology and Sociobiology, ISSN 0340-5443, E-ISSN 1432-0762, Vol. 64, no 11, p. 1725-1732Article in journal (Refereed)
    Abstract [en]

    Recent experiments exposing migratory birds to altered magnetic fields simulating geographical displacements have shown that the geomagnetic field acts as an external cue affecting migratory fuelling behaviour. This is the first study investigating fuel deposition in relation to geomagnetic cues in long-distance migrants using the western passage of the Mediterranean region. Juvenile wheatears (Oenanthe oenanthe) were exposed to a magnetically simulated autumn migration from southern Sweden to West Africa. Birds displaced parallel to the west of their natural migration route, simulating an unnatural flight over the Atlantic Ocean, increased their fuel deposition compared to birds experiencing a simulated migration along the natural route. These birds, on the other hand, showed relatively low fuel loads in agreement with earlier data on wheatears trapped during stopover. The experimental displacement to the west, corresponding to novel sites in the Atlantic Ocean, led to a simulated longer distance to the wintering area, probably explaining the observed larger fuel loads. Our data verify previous results suggesting that migratory birds use geomagnetic cues for fuelling decisions and, for the first time, show that birds, on their first migration, can use geomagnetic cues to compensate for a displacement outside their normal migratory route, by adjusting fuel deposition.

  • 14. Chen, Yu-Chia
    et al.
    Harrison, Peter W.
    Kotrschal, Alexander
    Stockholm University, Faculty of Science, Department of Zoology, Ethology. Uppsala University, Sweden.
    Kolm, Niclas
    Stockholm University, Faculty of Science, Department of Zoology, Ethology. Uppsala University, Sweden.
    Mank, Judith E.
    Panula, Pertti
    Expression change in Angiopoietin-1 underlies change in relative brain size in fish2015In: Proceedings of the Royal Society of London. Biological Sciences, ISSN 0962-8452, E-ISSN 1471-2954, Vol. 282, no 1810, article id 20150872Article in journal (Refereed)
    Abstract [en]

    Brain size varies substantially across the animal kingdom and is often associated with cognitive ability; however, the genetic architecture underpinning natural variation in these key traits is virtually unknown. In order to identify the genetic architecture and loci underlying variation in brain size, we analysed both coding sequence and expression for all the loci expressed in the telencephalon in replicate populations of guppies (Poecilia reticulata) artificially selected for large and small relative brain size. A single gene, Angiopoietin-1 (Ang-1), a regulator of angiogenesis and suspected driver of neural development, was differentially expressed between large-and small-brain populations. Zebra fish (Danio rerio) morphants showed that mild knock down of Ang-1 produces a small-brained phenotype that could be rescued with Ang-1 mRNA. Translation inhibition of Ang-1 resulted in smaller brains in larvae and increased expression of Notch-1, which regulates differentiation of neural stem cells. In situ analysis of newborn large-and small-brained guppies revealed matching expression patterns of Ang-1 and Notch-1 to those observed in zebrafish larvae. Taken together, our results suggest that the genetic architecture affecting brain size in our population may be surprisingly simple, and Ang-1 may be a potentially important locus in the evolution of vertebrate brain size and cognitive ability.

  • 15.
    Enquist, Magnus
    et al.
    Stockholm University, Faculty of Humanities, Centre for the Study of Cultural Evolution. Stockholm University, Faculty of Science, Department of Zoology, Ethology.
    Strimling, Pontus
    Stockholm University, Faculty of Humanities, Centre for the Study of Cultural Evolution.
    Eriksson, Kimmo
    Stockholm University, Faculty of Humanities, Centre for the Study of Cultural Evolution.
    Laland, Kevin
    School of Biology, University of St Andrews.
    Sjöstrand, Jonas
    Stockholm University, Faculty of Humanities, Centre for the Study of Cultural Evolution.
    One cultural parent makes no culture2010In: Animal Behaviour, ISSN 0003-3472, E-ISSN 1095-8282, Vol. 79, no 6, p. 1135-1162Article in journal (Refereed)
    Abstract [en]

    The ability to acquire knowledge and skills from others is widespread in animals and is commonly thought to be responsible for the behavioural traditions observed in many species. However, in spite of the extensive literature on theoretical analyses and empirical studies of social learning, little attention has been given to whether individuals acquire knowledge from a single individual or multiple models. Researchers commonly refer to instances of sons learning from fathers, or daughters from mothers, while theoreticians have constructed models of uniparental transmission, with little consideration of whether such restricted modes of transmission are actually feasible. We used mathematical models to demonstrate that the conditions under which learning from a single cultural parent can lead to stable culture are surprisingly restricted (the same reasoning applies to a single social-learning event). Conversely, we demonstrate how learning from more than one cultural parent can establish culture, and find that cultural traits will reach a nonzero equilibrium in the population provided the product of the fidelity of social learning and the number of cultural parents exceeds 1. We discuss the implications of the analysis for interpreting various findings in the animal social-learning literature, as well as the unique features of human culture.

  • 16. Fischer, Stefan
    et al.
    Bessert-Nettelbeck, Mathilde
    Kotrschal, Alexander
    Stockholm University, Faculty of Science, Department of Zoology, Ethology.
    Taborsky, Barbara
    Rearing-Group Size Determines Social Competence and Brain Structure in a Cooperatively Breeding Cichlid2015In: American Naturalist, ISSN 0003-0147, E-ISSN 1537-5323, Vol. 186, no 1, p. 123-140Article in journal (Refereed)
    Abstract [en]

    Social animals can greatly benefit from well-developed social skills. Because the frequency and diversity of social interactions often increase with the size of social groups, the benefits of advanced social skills can be expected to increase with group size. Variation in social skills often arises during ontogeny, depending on early social experience. Whether variation of social-group sizes affects development of social skills and related changes in brain structures remains unexplored. We investigated whether, in a cooperatively breeding cichlid, early group size (1) shapes social behavior and social skills and (2) induces lasting plastic changes in gross brain structures and (3) whether the development of social skills is confined to a sensitive ontogenetic period. Rearing-group size and the time juveniles spent in these groups interactively influenced the development of social skills and the relative sizes of four main brain regions. We did not detect a sensitive developmental period for the shaping of social behavior within the 2-month experience phase. Instead, our results suggest continuous plastic behavioral changes over time. We discuss how developmental effects on social behavior and brain architecture may adaptively tune phenotypes to their current or future environments.

  • 17. Fransson, Thord
    et al.
    Kullberg, Cecilia
    Stockholm University, Faculty of Science, Department of Zoology, Ethology.
    Stach, Robert
    Stockholm University, Faculty of Science, Department of Zoology, Ethology.
    Barboutis, Christos
    Extensive fuelling in great reed warblers following the trans-Sahara crossing in springManuscript (preprint) (Other academic)
    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.

  • 18.
    Gamberale-Stille, Gabriella
    et al.
    Stockholm University, Faculty of Science, Department of Zoology, Ethology.
    Bragée, Carolina
    Stockholm University, Faculty of Science, Department of Zoology.
    Tullberg, Birgitta S.
    Stockholm University, Faculty of Science, Department of Zoology, Animal Ecology.
    Higher survival of aposematic prey in close encounters with predators – an experimental study of detection distance.2009In: Animal Behaviour, ISSN 0003-3472, E-ISSN 1095-8282, Vol. 78, p. 111-116Article in journal (Refereed)
    Abstract [en]

    Aposematic animals are often conspicuous. It has been hypothesized that one function of conspicuousness in such prey is to be detected from afar by potential predators: the ‘detection distance hypothesis’. The hypothesis states that predators are less prone to attack at long detection range because more time is allowed for making the ‘correct’ decision not to attack the unprofitable prey. The detection distance hypothesis has gained some experimental support in that time-limited predators make more mistakes. To investigate effects of prey presentation distance we performed two experiments. First, in experiment 1, we investigated at what distance chicks, Gallus gallus domesticus, could see the difference in colour between aposematic and plain mealworms. Birds chose the correct track in a two-way choice when prey were at 20, 40 and 60 cm distance but not at 80 cm. Second, in experiment 2, fifth-instar larvae of the aposematic bug Lygaeus equestris were presented to experienced chicks at 2, 20 or 60 cm distance. We found no difference in attack probability between distances. However, prey mortality was significantly lower for the shortest presentation distance. In conclusion, we found no support for the hypothesis that aposematic prey benefit from long-range detection; in fact they benefit from shortdistance detection. This result, and others, suggests that the conspicuousness of aposematic prey at a distance may simply be a by-product of an efficient signalling function after detection.

  • 19.
    Gillingham, M A F
    et al.
    Edward Grey Institute, University of Oxford.
    Richardson, D S
    School of Biological Sciences, University of East Anglia.
    Lovlie, H
    Stockholm University, Faculty of Science, Department of Zoology, Department of Ethology.
    Moynihan, A
    Department of Zoology, Edward Grey Institute.
    Worley, K
    School of Biological Sciences, University of East Anglia.
    Pizzari, T
    Edward Grey Institute, University of Oxford.
    Cryptic preference for MHC-dissimilar females inmale red junglefowl, Gallus gallus2009In: Proceedings of the Royal Society of London. Biological Sciences, ISSN 0962-8452, E-ISSN 1471-2954, p. 1083-1092Article in journal (Refereed)
  • 20.
    Hagman, Mattias
    et al.
    Stockholm University, Faculty of Science, Department of Zoology, Ethology.
    Hayes, Andrew
    Capon, Rob
    Shine, Richard
    Alarm cues experienced by cane toad tadpoles affect post-metamorphic morphology and chemical defences2009In: Functional Ecology, ISSN 0269-8463, E-ISSN 1365-2435, Vol. 23, p. 126-132Article in journal (Refereed)
    Abstract [en]

     Summary: In many anuran species, larvae modify their developmental trajectories and behaviour in response to chemical cues that predict predator risk. Recent reviews highlight a dearth of studies on delayed (post-metamorphic) consequences of larval experience.

  • 2 We raised cane toad (Bufo marinus) tadpoles either under control conditions or in the presence of non-lethal predator cues (crushed conspecifics).
  • 3 Exposure to these chemical cues massively reduced size at metamorphosis, as predicted by theory. Parotoid glands were larger relative to body size in post-metamorphic animals from the experimental treatment, suggesting higher investment in chemical defences.
  • 4 Exposure to chemical cues from crushed conspecifics during larval life reduced total bufadienolide content of metamorphs, but increased amounts of one specific bufadienolide (bufalin).
  • 5 Hence, cane toads respond to perceived predation risk in the aquatic environment by metamorphosing at a smaller size and modifying their investment in defensive toxins during post-metamorphic life.
  • 6 Phenotypically flexible responses to larval conditions vary among amphibian taxa, and can involve significant carry-over effects into post-metamorphic life.
  • 21.
    Hagman, Mattias
    et al.
    Stockholm University, Faculty of Science, Department of Zoology, Ethology.
    Phillips, Ben
    Shine, Richard
    Fatal attraction: adaptations to prey on native frogs imperil snakes after invasion of toxic toads.2009In: Proceedings of the Royal Society of London. Biological Sciences, ISSN 0962-8452, E-ISSN 1471-2954, Vol. 276, p. 2813-2818Article in journal (Refereed)
    Abstract [en]

    Adaptations that enhance fitness in one situation can become liabilities if circumstances change. In tropical Australia, native snake species are vulnerable to the invasion of toxic cane toads. Death adders (Acanthophis praelongus) are ambush foragers that (i) attract vertebrate prey by caudal luring and (ii) handle anuran prey by killing the frog then waiting until the frog's chemical defences degrade before ingesting it. These tactics render death adders vulnerable to toxic cane toads (Bufo marinus), because toads elicit caudal luring more effectively than do native frogs, and are more readily attracted to the lure. Moreover, the strategy of delaying ingestion of a toad after the strike does not prevent fatal poisoning, because toad toxins (unlike those of native frogs) do not degrade shortly after the prey dies. In our laboratory and field trials, half of the death adders died after ingesting a toad, showing that the specialized predatory behaviours death adders use to capture and process prey render them vulnerable to this novel prey type. The toads' strong response to caudal luring also renders them less fit than native anurans (which largely ignored the lure): all toads bitten by adders died. Together, these results illustrate the dissonance in behavioural adaptations that can arise following the arrival of invasive species, and reveal the strong selection that occurs when mutually naive species first interact.

  • 22.
    Hagman, Mattias
    et al.
    Stockholm University, Faculty of Science, Department of Zoology, Ethology.
    Shine, Richard
    Factors influencing responses to alarm pheromones by tadpoles of invasive cane toads (Bufo marinus)2009In: Journal of Chemical Ecology, ISSN 0098-0331, E-ISSN 1573-1561, Vol. 35, p. 265-271Article in journal (Refereed)
    Abstract [en]

    If pheromonal communication systems of invasive species differ from those of native biota, it may be possible to control the invader by exploiting that difference. When injured, the larvae of cane toads, Bufo marinus, an invasive species of major concern in tropical Australia, produce species-specific chemical cues that alert conspecific tadpoles to danger. Repeated exposure to the alarm chemical reduces tadpole survival rates and body sizes at metamorphosis and, thus, could help control toad populations. To evaluate the feasibility of this approach, we need to know how the intensity of toad tadpole response to the alarm chemical is affected by factors such as water temperature, time of day, larval stage and feeding history, geographic origin of the tadpoles, and habituation. Information on these topics may enable us to optimize deployment, so that tadpoles encounter pheromone at the times and places that confer maximum effect. In our studies, tadpole density, nutritional state, larval stage, and geographic origin had little effect on the intensity of the alarm response, but tadpoles reacted most strongly in higher water temperatures and during daylight hours. Repeated, once-daily exposure to pheromone did not induce habituation, but repeated exposure at 15-min interva

  • 23.
    Hagman, Mattias
    et al.
    Stockholm University, Faculty of Science, Department of Zoology, Ethology.
    Shine, Richard
    Species-specific communication systems in an introduced toad compared with native frogs in Australia2009In: Chemoecology, ISSN 0937-7409, E-ISSN 1423-0445, Vol. 19, no 4, p. 211-217Article in journal (Refereed)
    Abstract [en]

    Novel approaches to control invasive species are urgently needed. Cane toads (Bufo marinus) are large, highly toxic anurans that are spreading rapidly through tropical Australia. Injured toad larvae produce an alarm pheromone that elicits rapid avoidance by conspecifics but not by frog larvae. Experiments in outdoor ponds show that repeated exposure to the pheromone reduced toad tadpole survival rates (by >50%) and body mass at metamorphosis (by 20%). The alarm pheromone did not induce tadpoles to seek shelter, but accelerated ontogenetic differentiation. Perhaps reflecting mortality of weaker individuals during larval life, growth rates post-metamorphosis were higher in animals emerging from the pheromone exposure treatment than from the control treatment. Nonetheless, body size differentials established at metamorphosis persisted through the first 8 days of post-metamorphic life. We will need substantial additional research before evaluating whether the alarm pheromone provides a way to reduce cane toad recruitment in nature, but our field trials are encouraging in this respect.

  • 24.
    Henshaw, Ian
    et al.
    Stockholm University, Faculty of Science, Department of Zoology, Ethology.
    Fransson, Thord
    Naturhistoriska riksmuseet, Ringmärkningscentralen.
    Jakobsson, Sven
    Stockholm University, Faculty of Science, Department of Zoology, Ethology.
    Jenni-Eiermann, Susanne
    Swiss ornithological Institute.
    Kullberg, Cecilia
    Stockholm University, Faculty of Science, Department of Zoology, Ethology.
    Information from the geomagnetic field triggers a reduced adrenocortical response in a migratory bird2009In: Journal of Experimental Biology, ISSN 0022-0949, E-ISSN 1477-9145, Vol. 212, p. 2902-2907Article in journal (Refereed)
    Abstract [en]

    Long-distance migrants regularly pass ecological barriers, like the Sahara desert, where extensive fuel loads are necessary for a successful crossing. A central question is how inexperienced migrants know when to put on extensive fuel loads. Beside the endogenous rhythm, external cues have been suggested to be important. Geomagnetic information has been shown to trigger changes in foraging behaviour and fuel deposition rate in migratory birds. The underlying mechanism for these adjustments, however, is not well understood. As the glucocorticoid hormone corticosterone is known to correlate with behaviour and physiology related to energy regulation in birds, we here investigated the effect of geomagnetic cues on circulating corticosterone levels in a long-distance migrant. Just as in earlier studies, juvenile thrush nightingales (Luscinia luscinia) caught during autumn migration and exposed to the simulated geomagnetic field of northern Egypt increased food intake and attained higher fuel loads than control birds experiencing the ambient magnetic field of southeast Sweden. Our results further show that experimental birds faced a reduced adrenocortical response compared with control birds, thus for the first time implying that geomagnetic cues trigger changes in hormonal secretion enabling appropriate behaviour along the migratory route.

  • 25.
    Henshaw, Ian
    et al.
    Uppsala universitet.
    Fransson, Thord
    Naturhistoriska riksmuseet, ringmärkningscentralen.
    Jakobsson, Sven
    Stockholm University, Faculty of Science, Department of Zoology, Ethology.
    Kullberg, Cecilia
    Stockholm University, Faculty of Science, Department of Zoology, Ethology.
    Geomagnetic field affects spring migratory direction in a long distance migrant2010In: Behavioral Ecology and Sociobiology, ISSN 0340-5443, E-ISSN 1432-0762, Vol. 64, no 8, p. 1317-1323Article in journal (Refereed)
  • 26.
    Kotrschal, Alexander
    et al.
    Stockholm University, Faculty of Science, Department of Zoology, Ethology. University of Veterinary Medicine, Austria.
    Buechel, Séverine D.
    Stockholm University, Faculty of Science, Department of Zoology, Ethology. University of Veterinary Medicine, Austria.
    Zala, Sarah M.
    Corral Lopez, Alberto
    Stockholm University, Faculty of Science, Department of Zoology, Ethology.
    Penn, Dustin J.
    Kolm, Niclas
    Stockholm University, Faculty of Science, Department of Zoology, Ethology.
    Brain size affects female but not male survival under predation threat2015In: Ecology Letters, ISSN 1461-023X, E-ISSN 1461-0248, Vol. 18, no 7, p. 646-652Article in journal (Refereed)
    Abstract [en]

    There is remarkable diversity in brain size among vertebrates, but surprisingly little is known about how ecological species interactions impact the evolution of brain size. Using guppies, artificially selected for large and small brains, we determined how brain size affects survival under predation threat in a naturalistic environment. We cohoused mixed groups of small- and large-brained individuals in six semi-natural streams with their natural predator, the pike cichlid, and monitored survival in weekly censuses over 5 months. We found that large-brained females had 13.5% higher survival compared to small-brained females, whereas the brain size had no discernible effect on male survival. We suggest that large-brained females have a cognitive advantage that allows them to better evade predation, whereas large-brained males are more colourful, which may counteract any potential benefits of brain size. Our study provides the first experimental evidence that trophic interactions can affect the evolution of brain size.

  • 27.
    Kotrschal, Alexander
    et al.
    Stockholm University, Faculty of Science, Department of Zoology, Ethology. Uppsala University, Sweden.
    Corral-Lopez, Alberto
    Stockholm University, Faculty of Science, Department of Zoology, Ethology.
    Amcoff, Mirjam
    Kolm, Niclas
    Stockholm University, Faculty of Science, Department of Zoology, Ethology. Uppsala University, Sweden.
    A larger brain confers a benefit in a spatial mate search learning task in male guppies2015In: Behavioral Ecology, ISSN 1045-2249, E-ISSN 1465-7279, Vol. 26, no 2, p. 527-532Article in journal (Refereed)
    Abstract [en]

    Brain size varies dramatically among vertebrates, and selection for increased cognitive abilities is thought to be the key force underlying the evolution of a large brain. Indeed, numerous comparative studies suggest positive relationships between cognitively demanding aspects of behavior and brain size controlled for body size. However, experimental evidence for the link between relative brain size and cognitive ability is surprisingly scarce and to date stems from a single study on brain size selected guppies (Poecilia reticulata), where large-brained females were shown to outperform small-brained females in a numerical learning assay. Because the results were inconclusive for males in that study, we here use a more ecologically relevant test of male cognitive ability to investigate whether or not a relatively larger brain increases cognitive ability also in males. We compared mate search ability of these artificially selected large-and small-brained males in a maze and found that large-brained males were faster at learning to find a female in a maze. Large-brained males decreased the time spent navigating the maze faster than small-brained males and were nearly twice as fast through the maze after 2 weeks of training. Our results support that relatively larger brains are better also for males in some contexts, which further substantiates that variation in vertebrate brain size is generated through the balance between energetic costs and cognitive benefits.

  • 28.
    Kotrschal, Alexander
    et al.
    Stockholm University, Faculty of Science, Department of Zoology, Ethology.
    Corral-Lopez, Alberto
    Stockholm University, Faculty of Science, Department of Zoology, Ethology.
    Szidat, Soenke
    Kolm, Niclas
    Stockholm University, Faculty of Science, Department of Zoology, Ethology.
    The effect of brain size evolution on feeding propensity, digestive efficiency, and juvenile growth2015In: Evolution, ISSN 0014-3820, E-ISSN 1558-5646, Vol. 69, no 11, p. 3013-3020Article in journal (Refereed)
    Abstract [en]

    One key hypothesis in the study of brain size evolution is the expensive tissue hypothesis; the idea that increased investment into the brain should be compensated by decreased investment into other costly organs, for instance the gut. Although the hypothesis is supported by both comparative and experimental evidence, little is known about the potential changes in energetic requirements or digestive traits following such evolutionary shifts in brain and gut size. Organisms may meet the greater metabolic requirements of larger brains despite smaller guts via increased food intake or better digestion. But increased investment in the brain may also hamper somatic growth. To test these hypotheses we here used guppy (Poecilia reticulata) brain size selection lines with a pronounced negative association between brain and gut size and investigated feeding propensity, digestive efficiency (DE), and juvenile growth rate. We did not find any difference in feeding propensity or DE between large-and small-brained individuals. Instead, we found that large-brained females had slower growth during the first 10 weeks after birth. Our study provides experimental support that investment into larger brains at the expense of gut tissue carries costs that are not necessarily compensated by a more efficient digestive system.

  • 29.
    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
    Stockholm University, Faculty of Science, Department of Zoology, Ethology.
    Artificial selection on relative brain size reveals a positive genetic correlation between brain size and proactive personality in the guppy2014In: Evolution, ISSN 0014-3820, E-ISSN 1558-5646, Vol. 68, no 4, p. 1139-1149Article in journal (Refereed)
    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.

  • 30.
    Laikre, Linda
    et al.
    Stockholm University, Faculty of Science, Department of Zoology, Population Genetics.
    Jansson, Mija
    Stockholm University, Faculty of Science, Department of Zoology, Population Genetics.
    Allendorf, Fred W.
    Jakobsson, Sven
    Stockholm University, Faculty of Science, Department of Zoology, Ethology.
    Ryman, Nils
    Stockholm University, Faculty of Science, Department of Zoology, Population Genetics.
    Hunting Effects on Favourable Conservation Status of Highly Inbred Swedish Wolves2013In: Conservation Biology, ISSN 0888-8892, E-ISSN 1523-1739, Vol. 27, no 2, p. 248-253Article in journal (Refereed)
    Abstract [en]

    The wolf (Canis lupus) is classified as endangered in Sweden by the Swedish Species Information Centre, which is the official authority for threat classification. The present population, which was founded in the early 1980s, descends from 5 individuals. It is isolated and highly inbred, and on average individuals are more related than siblings. Hunts have been used by Swedish authorities during 2010 and 2011 to reduce the population size to its upper tolerable level of 210 wolves. European Union (EU) biodiversity legislation requires all member states to promote a concept called “favourable conservation status” (FCS) for a series of species including the wolf. Swedish national policy stipulates maintenance of viable populations with sufficient levels of genetic variation of all naturally occurring species. Hunting to reduce wolf numbers in Sweden is currently not in line with national and EU policy agreements and will make genetically based FCS criteria less achievable for this species. We suggest that to reach FCS for the wolf in Sweden the following criteria need to be met: (1) a well-connected, large, subdivided wolf population over Scandinavia, Finland, and the Russian Karelia-Kola region should be reestablished, (2) genetically effective size (Ne) of this population is in the minimum range of Ne = 500–1000, (3) Sweden harbors a part of this total population that substantially contributes to the total Ne and that is large enough to not be classified as threatened genetically or according to IUCN criteria, and (4) average inbreeding levels in the Swedish population are <0.1.

  • 31.
    Leimar, Olof
    Stockholm University, Faculty of Science, Department of Zoology, Ethology.
    Multidimensional convergence stability2009In: Evolutionary Ecology Research, ISSN 1522-0613, E-ISSN 1937-3791, Vol. 11, p. 191-208Article in journal (Refereed)
    Abstract [en]

    Questions: Are there general stability conditions for the evolution Of Multidimensional traits, regardless of genetic correlations between traits? Can genetic correlations influence whether evolution converges to a stable trait vector?

    Mathematical methods: Adaptive dynamics theory and the weak selection limit of quantitative genetics.

    Key assumptions: Evolutionary change is represented as either (i) any gradualistic adaptive path in trait space, consisting of a sequence of small-effect mutant invasions, allowing for pleiotropic mutants, or (ii) a solution to the 'canonical equation' of adaptive dynamics with a gradually varying mutational covariance matrix. Assumption (ii) is a special case of (i).

    Conclusions: It is possible to formulate robust stability conditions for multidimensional traits, but most evolutionary equilibria will not satisfy these conditions. Under the liberal assumption (i), there will in general be no 'absolutely convergence stable' equilibria in multidimensional trait spaces (except for simplified models). Under the more restrictive assumption (ii), a Much larger proportion of evolutionary equilibria is 'strongly convergence stable', i.e. are stable irrespective of genetic correlations.

  • 32.
    Leimar, Olof
    et al.
    Stockholm University, Faculty of Science, Department of Zoology, Ethology.
    Norberg, Ulf
    Stockholm University, Faculty of Science, Department of Zoology, Animal Ecology.
    Metapopulation extinction and genetic variation in dispersal-related traits1997In: Oikos, ISSN 0030-1299, E-ISSN 1600-0706, Vol. 80, p. 448-458Article in journal (Refereed)
  • 33.
    Leimar, Olof
    et al.
    Stockholm University, Faculty of Science, Department of Zoology, Ethology.
    Norberg, Ulf
    Stockholm University, Faculty of Science, Department of Zoology, Ethology.
    Wiklund, Christer
    Stockholm University, Faculty of Science, Department of Zoology, Animal Ecology.
    Habitat preference and habitat exploration in two species of satyrine butterflies2003In: Ecography, ISSN 0906-7590, E-ISSN 1600-0587, Vol. 26, p. 474-480Article in journal (Refereed)
  • 34.
    Lind, Johan
    Stockholm University, Faculty of Science, Department of Zoology, Ethology.
    Book review of Sturkie's Avian Physiology, 2000 (ed) G.C. Whittow2001In: Ornis Svecica, ISSN 1102-6812, Vol. 11, no 4, p. 268-270Article, book review (Other (popular science, discussion, etc.))
  • 35.
    Lind, Johan
    Stockholm University, Faculty of Science, Department of Zoology, Ethology.
    Book review of Wings over Falsterbo, 2004, (ed) L. Karlsson2005In: Ibis, ISSN 0019-1019, E-ISSN 1474-919X, Vol. 147, p. 428-Article, book review (Other (popular science, discussion, etc.))
  • 36.
    Lind, Johan
    Stockholm University, Faculty of Science, Department of Zoology, Ethology.
    Escape flight in moulting tree sparrows (Passer montanus)2001In: Functional Ecology, ISSN 0269-8463, E-ISSN 1365-2435, Vol. 15, no 1, p. 29-35Article in journal (Refereed)
    Abstract [en]
    • 1 Impaired predator evasion in birds as a cost in different life-history periods has received increasing attention in the last decade. Evasive abilities in birds have been found to be detrimentally affected by migratory fuel load, reproduction and moult. These results suggest that during these periods of their lives birds suffer from increased predation risk due to impaired evasive abilities.
    • 2 Theoretically, moult should have a detrimental effect on flight, and empirical work on starlings has shown impaired escape ability due to moult. However, a recent theoretical investigation found a surprisingly small effect of moult on flight in birds.
    • 3 In this study, 31 Tree Sparrows, a sedentary species with a slow moult, were used to investigate the effect of natural and manipulated moult on escape ability. No effect was found due to natural moult, however, when experimentally increasing moult gap size a strong negative effect was found.
    • 4  With support from empirical and theoretical work, this is the first study to suggest that slow moult may not increase predation risk due to impaired evasive abilities. Compensatory physiological adaptations probably cause this result and may be very important during moult.
    • 5 Predation risk is probably an important factor in the evolution of moult patterns and moult strategies.
  • 37.
    Lind, Johan
    Stockholm University, Faculty of Science, Department of Zoology, Ethology.
    Reduced take-off ability in robins due to migratory fuel load1999In: Behavioral Ecology and Sociobiology, ISSN 0340-5443, E-ISSN 1432-0762, Vol. 46, no 1, p. 65-70Article in journal (Refereed)
    Abstract [en]

    Recent studies have shown that large fuel loads in small birds impair flying ability. This is the first study to show how migratory fuel load affects flying ability, such as velocity and height gained at take-off in a predator escape situation, in a medium-distance migrant, and whether they adjust their take-off according to predator attack angle. First-year robins (Erithacus rubecula) were subjected to simulated attacks from a model merlin (Falco columbarius), and take-off velocity and angle were analysed. Robins with a wing load of 0.19 g cm−2 took off at a 39% lower angle than robins with a wing load of 0.13 g cm−2, while velocity remained unaffected. The robins did not adjust their angle of ascent in accordance with the predator's angle of attack. Since many predators rely on surprise attacks, a difference in flight ability due to varying fuel loads found in migrating robins can be important for birds' chances of survival when actually attacked.

  • 38.
    Lind, Johan
    Stockholm University, Faculty of Science, Department of Zoology, Ethology.
    To eat or not to eat, that is the question: Being too heavy may make a bird vulnerable to predators2000In: Interpretive Birding Bulletin, Vol. 1, p. 12-14Article in journal (Other (popular science, discussion, etc.))
  • 39.
    Lind, Johan
    Stockholm University, Faculty of Science, Department of Zoology, Ethology.
    Tree sparrow, Passer montanus, freezing in the presence of a sparrowhawk, Accipiter nisus2002In: Ornis Svecica, Vol. 12, p. 214-215Article in journal (Refereed)
  • 40.
    Lind, Johan
    Stockholm University, Faculty of Science, Department of Zoology, Ethology.
    Varför bry sig om sin vikt?2002In: Fåglar i Stockholmstrakten, Vol. 31, p. 28-33Article in journal (Other (popular science, discussion, etc.))
  • 41.
    Lind, Johan
    Stockholm University, Faculty of Science, Department of Zoology, Ethology.
    What determines the probability of surviving predator attacks in bird migration?: The relative importance of vigilance and fuel load2004In: Journal of Theoretical Biology, ISSN 0022-5193, E-ISSN 1095-8541, Vol. 231, no 2, p. 223-227Article in journal (Refereed)
    Abstract [en]

    Migrating birds must accumulate fuel during their journeys and this fuel load should incur an increased risk of predation. Migratory fuelling should increase individual mass-dependent predation risk for two reasons. First, acquisition costs are connected to the increased time a bird must spend foraging to accumulate the fuel loads and the reduced predator detection that accompanies foraging. Second, birds with large fuel loads have been shown to suffer from impaired predator evasion which makes them more vulnerable when actually attacked. Here, I investigate the relative importance of these two aspects of mass-dependent predation risk and I have used published data and a hypothetical situation for a foraging bird to investigate how much migratory fuelling in terms of escape performance and natural variation in predator detection contribute to individual risk during foraging. Results suggest that for birds foraging close to protective cover the negative impact of fuel load on flight performance is very small, whereas variation in time to predator detection is of great importance for a bird's survival. However, the importance of flight performance for predation risk increases as the distance to cover increases. Hence, variation in predator detection (and vigilance) probably influences individual survival much more than migratory fuel load and consequently, to understand risk management during migration studies that focus on vigilance and predator detection during fuelling are much needed

  • 42.
    Lind, Johan
    et al.
    Stockholm University, Faculty of Humanities, Centre for the Study of Cultural Evolution. Stockholm University, Faculty of Science, Department of Zoology, Ethology.
    Enqvist, Magnus
    Stockholm University, Faculty of Humanities, Centre for the Study of Cultural Evolution. Stockholm University, Faculty of Science, Department of Zoology, Ethology.
    Insight Learning and Shaping.2012In: Encyclopedia of the Sciences of Learning, Springer Publishing Company, 2012, p. 1574-1577Chapter in book (Refereed)
  • 43.
    Lind, Johan
    et al.
    Stockholm University, Faculty of Science, Department of Zoology, Ethology.
    Gustin, Marco
    LIPU.
    Sorace, Alberto
    Instituto Superiore di Sanità.
    Compensatory bodily changes during moult in tree sparrows, Passer montanus, in Italy2004In: Ornis Fennica, ISSN 0030-5685, Vol. 81, no 2, p. 75-83Article in journal (Refereed)
    Abstract [en]

    To cope with fluctuating environments animals have evolved reversible phenotypic flexibility.Some birds demonstrate this phenomenon by changing mass and flight muscle according to changes in wing loading. During moult, birds suffer from reduced wing area because feathers are shed and replaced, resulting in a wing loading increase. Moult is rather well studied in birds, but the perspective of phenotypic flexibility has been neglected. Therefore,we tested predictions generated from experimental studies by collecting information about bodymass, flightmuscle size and fat stores from an Italian population of Tree Sparrows (Passer montanus) to investigate if they compensate physiologically for the wing area reductions they suffer from during moult. Our results did not corroborate predictions based on experimental studies; that is, the Tree Sparrows did not reduce body mass and increase in flight muscle size as a response to wing area reductions during midmoult. Instead, body mass increased throughout moult, flight muscle size did not change, and fat stores decreased asmoult progressed. To further investigate compensatory changes, we analysed bodily differences in midmoult between birds differing in moult gap size. Again, contrary to predictions from experimental studies, birds having larger moult gaps were found to have higher body mass. These birds were also found to keep the ratio between flight muscle size and body mass constant over the day whereas birds with small moult gaps reduced this ratio over the day. Birds with large moult gaps ere also found to store less fat than birdswith small gaps. Physiological constraints may help to explain these results and underlying reasons for the observed variation in bodily regulation in birds are discussed.

  • 44.
    Lind, Johan
    et al.
    Stockholm University, Faculty of Science, Department of Zoology, Ethology.
    Jakobsson, Sven
    Stockholm University, Faculty of Science, Department of Zoology.
    Body-building and concurrent mass loss: flight adaptations in tree sparrows2001In: Proceedings of the Royal Society of London. Biological Sciences, ISSN 0962-8452, E-ISSN 1471-2954, Vol. 268, no 1479, p. 1915-1919Article in journal (Refereed)
    Abstract [en]

    Environmental changes are responsible for the evolution of flexible physiology and the extent of phenotypic plasticity in the regulation of birds' organ size has not been appreciated until recently. Rapid reversible physiological changes during different life–history stages are virtually only known from long–distance migrants, and few studies have focused on less extreme aspects of organ flexibility. During moult, birds suffer from increased wing loading due to wing–area reductions, which may impair flight ability. A previous study found that tree sparrows' escape flight (Passer montanus) is unaffected during moult, suggesting compensatory aptness. We used non–invasive techniques to study physiological adaptations to increased wing loading in tree sparrows. As wing area was reduced during natural moult the ratio of pectoral–muscle size to body mass increased. When moult was completed this ratio decreased. We show experimentally a novel, strategic, organ–flexibility pattern. Unlike the general pattern, where body mass is positively coupled to pectoral–muscle size, tree sparrows responded within 7 days to reductions in wing area by reducing body mass concurrently with an increase in pectoral–muscle size. This rapid flexibility in a non–migratory species probably reflects the paramount importance and long history of flight in birds.

  • 45.
    Lind, Johan
    et al.
    Stockholm University, Faculty of Humanities, Centre for the Study of Cultural Evolution. Stockholm University, Faculty of Science, Department of Zoology, Ethology. Stockholm University, Faculty of Science, Department of Zoology.
    Jakobsson, Sven
    Stockholm University. Stockholm University, Faculty of Science, Department of Zoology. Stockholm University, Faculty of Science, Department of Zoology, Ethology.
    Kullberg, Cecilia
    Stockholm University. Stockholm University, Faculty of Science, Department of Zoology. Stockholm University, Faculty of Science, Department of Zoology, Ethology.
    Impaired predator evasion in the life-history of birds: behavioral and physiological adaptations to reduced flight ability.2010In: Current Ornithology, Vol. 17, p. 1-30Article in journal (Refereed)
  • 46.
    Lindström, Åke
    et al.
    Lund University.
    Lind, Johan
    Stockholm University, Faculty of Science, Department of Zoology, Ethology.
    Fuel deposition and speed of early autumn migration of juvenile bluethroats Luscinia s. svecica leaving their natal area in Swedish Lapland2002In: Ornis Svecica, Vol. 11, p. 253-264Article in journal (Refereed)
  • 47.
    Lovlie, Hanne
    et al.
    Stockholm University, Faculty of Science, Department of Zoology, Department of Ethology.
    Cornwallis, C K
    Department of Animal and Plant Sciences, University of Sheffield.
    Pizzari, T
    Edward Grey Institute, University of Oxford.
    Male Mounting Alone Reduces Female Promiscuity in the Fowl2005In: Current Biology, ISSN 0960-9822, E-ISSN 1879-0445, Vol. 15, p. 1222-1227Article in journal (Refereed)
  • 48.
    Norberg, Ulf
    et al.
    Stockholm University, Faculty of Science, Department of Zoology, Ethology.
    Leimar, Olof
    Stockholm University, Faculty of Science, Department of Zoology, Ethology.
    Spatial and temporal variation in flight morphology in the butterfly Melitaea cixia (Lepidoptera: Nymphalidae)2002In: Biological Journal of the Linnean Society, ISSN 0024-4066, E-ISSN 1095-8312, Vol. 77, p. 445-453Article in journal (Refereed)
  • 49.
    Nylin, Sören
    et al.
    Stockholm University, Faculty of Science, Department of Zoology, Animal Ecology.
    Söderlind, Lina
    Stockholm University, Faculty of Science, Department of Zoology, Animal Ecology.
    Gamberale-Stille, Gabriella
    Stockholm University, Faculty of Science, Department of Zoology, Ethology.
    Audusseau, Hélène
    Stockholm University, Faculty of Science, Department of Zoology, Animal Ecology.
    Celorio-Mancera, Maria de la Paz
    Stockholm University, Faculty of Science, Department of Zoology, Animal Ecology.
    Janz, Niklas
    Stockholm University, Faculty of Science, Department of Zoology, Animal Ecology.
    Sperling, Felix A. H.
    Vestiges of an ancestral host plant: preference and performance in the butterfly Polygonia faunus and its sister species P. c-album2015In: Ecological Entomology, ISSN 0307-6946, E-ISSN 1365-2311, Vol. 40, no 3, p. 307-315Article in journal (Refereed)
    Abstract [en]

    1. In the study of the evolution of insect-host plant interactions, important information is provided by host ranking correspondences among female preference, offspring preference, and offspring performance. Here, we contrast such patterns in two polyphagous sister species in the butterfly family Nymphalidae, the Nearctic Polygonia faunus, and the Palearctic P. c-album. 2. These two species have similar host ranges, but according to the literature P. faunus does not use the ancestral host plant clade-the urticalean rosids'. Comparisons of the species can thus test the effects of a change in insect-plant associations over a long time scale. Cage experiments confirmed that P. faunus females avoid laying eggs on Urtica dioica (the preferred host of P. c-album), instead preferring Salix, Betula, and Ribes.3. However, newly hatched larvae of both species readily accept and grow well on U. dioica, supporting the general theory that evolutionary changes in host range are initiated through shifts in female host preferences, whereas larvae are more conservative and also can retain the capacity to perform well on ancestral hosts over long time spans.4. Similar rankings of host plants among female preference, offspring preference, and offspring performance were observed in P. c-album but not in P. faunus. This is probably a result of vestiges of larval adaptations to the lost ancestral host taxon in the latter species. 5. Female and larval preferences seem to be largely free to evolve independently, and consequently larval preferences warrant more attention.

  • 50.
    Pizzari, T
    et al.
    Department of Animal Environment & Health, Swedish University of Agricultural Science.
    Cornwallis, C K
    Department of Animal & Plant Sciences, University of Sheffield.
    Lovlie, H
    Stockholm University, Faculty of Science, Department of Zoology, Department of Ethology.
    Jakobsson, S
    Stockholm University, Faculty of Science, Department of Zoology, Department of Ethology.
    Birkhead, T R
    Department of Animal & Plant Sciences, University of Sheffield.
    Sophisticated sperm allocation in male fowl2003In: Nature, ISSN 0028-0836, E-ISSN 1476-4687, Vol. 426, p. 70-74Article in journal (Refereed)
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