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  • 1.
    Agnvall, Beatrix
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biology. Linköping University, Faculty of Science & Engineering.
    Katajamaa, Rebecca
    Linköping University, Department of Physics, Chemistry and Biology, Biology.
    Altimiras, Jordi
    Linköping University, Department of Physics, Chemistry and Biology, Biology. Linköping University, Faculty of Science & Engineering.
    Jensen, Per
    Linköping University, Department of Physics, Chemistry and Biology, Biology. Linköping University, Faculty of Science & Engineering.
    Is domestication driven by reduced fear of humans? Boldness, metabolism and serotonin levels in divergently selected red junglefowl (Gallus gallus)2015In: Biology Letters, ISSN 1744-9561, E-ISSN 1744-957X, Vol. 11, no 9, article id 20150509Article in journal (Refereed)
    Abstract [en]

    Domesticated animals tend to develop a coherent set of phenotypic traits. Tameness could be a central underlying factor driving this, and we therefore selected red junglefowl, ancestors of all domestic chickens, for high or low fear of humans during six generations. We measured basal metabolic rate (BMR), feed efficiency, boldness in a novel object (NO) test, corticosterone reactivity and basal serotonin levels (related to fearfulness) in birds from the fifth and sixth generation of the high- and low-fear lines, respectively (44-48 individuals). Corticosterone response to physical restraint did not differ between selection lines. However, BMR was higher in low-fear birds, as was feed efficiency. Low-fear males had higher plasma levels of serotonin and both low-fear males and females were bolder in an NO test. The results show that many aspects of the domesticated phenotype may have developed as correlated responses to reduced fear of humans, an essential trait for successful domestication.

  • 2.
    Ahlgren, Johan
    et al.
    Lund Univ, Dept Biol Aquat Ecol, S-22362 Lund, Sweden..
    Chapman, Ben B.
    Lund Univ, Dept Biol Aquat Ecol, S-22362 Lund, Sweden.;Univ Nottingham, Sch Life Sci, Nottingham NG7 2RD, England..
    Nilsson, Anders P.
    Bronmark, Christer
    Lund Univ, Dept Biol Aquat Ecol, S-22362 Lund, Sweden..
    Individual boldness is linked to protective shell shape in aquatic snails2015In: Biology Letters, ISSN 1744-9561, E-ISSN 1744-957X, Vol. 11, no 4, article id UNSP 20150029Article in journal (Refereed)
    Abstract [en]

    The existence of consistent individual differences in behaviour ('animal personality') has been well documented in recent years. However, how such individual variation in behaviour is maintained over evolutionary time is an ongoing conundrum. A well-studied axis of animal personality is individual variation along a bold-shy continuum, where individuals differ consistently in their propensity to take risks. A predation-risk cost to boldness is often assumed, but also that the reproductive benefits associated with boldness lead to equivalent fitness outcomes between bold and shy individuals over a lifetime. However, an alternative or complementary explanation may be that bold individuals phenotypically compensate for their risky lifestyle to reduce predation costs, for instance by investing in more pronounced morphological defences. Here, we investigate the 'phenotypic compensation' hypothesis, i.e. that bold individuals exhibit more pronounced anti-predator defences than shy individuals, by relating shell shape in the aquatic snail Radix balthica to an index of individual boldness. Our analyses find a strong relationship between risk-taking propensity and shell shape in this species, with bolder individuals exhibiting a more defended shell shape than shy individuals. We suggest that this supports the 'phenotypic compensation' hypothesis and sheds light on a previously poorly studied mechanism to promote the maintenance of personality variation among animals.

  • 3.
    Alexander, Michelle
    et al.
    Univ York, York YO10 5DD, N Yorkshire, England.;Univ Aberdeen, Sch Geosci, Dept Archaeol, Aberdeen AB24 3UF, Scotland..
    Ho, Simon Y. W.
    Univ Sydney, Sch Biol Sci, Sydney, NSW 2006, Australia..
    Molak, Martyna
    Polish Acad Sci, Museum & Inst Zool, PL-00679 Warsaw, Poland..
    Barnett, Ross
    Palaeogen & Bioarchaeol Res Network, Res Lab Archaeol, Oxford OX1 3QY, England..
    Carlborg, Örjan
    Swedish University of Agricultural Sciences, Uppsala, Sweden.
    Dorshorst, Ben
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Biochemistry and Microbiology. Virginia Tech, Dept Anim & Poultry Sci, Blacksburg, VA 24061 USA..
    Honaker, Christa
    Virginia Tech, Dept Anim & Poultry Sci, Blacksburg, VA 24061 USA..
    Besnier, Francois
    Inst Marine Res, Sect Populat Genet, N-5024 Bergen, Norway..
    Wahlberg, Per
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Biochemistry and Microbiology. Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Sciences, Molecular Medicine.
    Dobney, Keith
    Univ Aberdeen, Sch Geosci, Dept Archaeol, Aberdeen AB24 3UF, Scotland..
    Siegel, Paul
    Virginia Tech, Dept Anim & Poultry Sci, Blacksburg, VA 24061 USA..
    Andersson, Leif
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Biochemistry and Microbiology. Swedish Univ Agr Sci, Dept Anim Breeding & Genet, S-75007 Uppsala, Sweden..
    Larson, Greger
    Palaeogen & Bioarchaeol Res Network, Res Lab Archaeol, Oxford OX1 3QY, England..
    Mitogenomic analysis of a 50-generation chicken pedigree reveals a rapid rate of mitochondrial evolution and evidence for paternal mtDNA inheritance2015In: Biology Letters, ISSN 1744-9561, E-ISSN 1744-957X, Vol. 11, no 10, article id 20150561Article in journal (Refereed)
    Abstract [en]

    Mitochondrial genomes represent a valuable source of data for evolutionary research, but studies of their short-term evolution have typically been limited to invertebrates, humans and laboratory organisms. Here we present a detailed study of 12 mitochondrial genomes that span a total of 385 transmissions in a well-documented 50-generation pedigree in which two lineages of chickens were selected for low and high juvenile body weight. These data allowed us to test the hypothesis of time-dependent evolutionary rates and the assumption of strict maternal mitochondrial transmission, and to investigate the role of mitochondrial mutations in determining phenotype. The identification of a non-synonymous mutation in ND4L and a synonymous mutation in CYTB, both novel mutations in Gallus, allowed us to estimate a molecular rate of 3.13 x 10(-7) mutations/site/year (95% confidence interval 3.75 x 10(-8)-1.12 x 10(-6)). This is substantially higher than avian rate estimates based upon fossil calibrations. Ascertaining which of the two novel mutations was present in an additional 49 individuals also revealed an instance of paternal inheritance of mtDNA. Lastly, an association analysis demonstrated that neither of the point mutations was strongly associated with the phenotypic differences between the two selection lines. Together, these observations reveal the highly dynamic nature of mitochondrial evolution over short time periods.

  • 4.
    Arnqvist, Göran
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Animal Ecology.
    Jones, Theresa M.
    Elgar, Mark A.
    Sex-role reversed nuptial feeding reduces male kleptoparasitism of females in Zeus bugs (Heteroptera: Veliidae)2006In: Biology Letters, ISSN 1744-9561, E-ISSN 1744-957X, Vol. 2, no 4, p. 491-493Article in journal (Refereed)
    Abstract [en]

    Males of a variety of taxa occasionally steal food secured by their mates. In some spiders and insects, males rely entirely on this form of intraspecific kleptoparasitism for their subsistence. However, this male strategy may be costly for females and a variety of different female counteradaptations have been proposed. In Zeus bugs ( Phoreticovelia spp.), males ride on the back of their mates for extended periods and females produce a gland secretion that males feed on. By experimentally occluding the dorsal glands in females and varying food availability, we show that nuptial feeding by females reduces the extent to which the males kleptoparasitize their mates. We suggest that females have, at least in part, evolved this unique form of nuptial feeding as a counteradaptation to reduce the rate of kleptoparasitism by males.

  • 5. Backhouse, Amy
    et al.
    Sait, Steven M.
    Cameron, Tom C.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Multiple mating in the traumatically inseminating Warehouse pirate bug, Xylocoris flavipes: effects on fecundity and longevity2012In: Biology Letters, ISSN 1744-9561, E-ISSN 1744-957X, Vol. 8, no 5, p. 706-709Article in journal (Refereed)
    Abstract [en]

    Optimal mating frequencies differ between sexes as a consequence of the sexual differentiation of reproductive costs per mating, where mating is normally more costly to females than males. In mating systems where sexual reproduction is costly to females, sexual conflict may cause both direct (i.e. by reducing female fecundity or causing mortality) and indirect (i.e. increased risk of mortality, reduced offspring viability) reductions in lifetime reproductive success of females, which have individual and population consequences. We investigated the direct and indirect costs of multiple mating in a traumatically inseminating (TI) predatory Warehouse pirate bug, Xylocoris flavipes (Reuter) (Hemiptera: Anthocoridae), where the male penetrates the female's abdomen during copulation. This study aimed to quantify the effects of TI on female fecundity, egg viability, the lifetime fecundity schedule, longevity and prey consumption in this cosmopolitan biocontrol agent. We found no difference in the total reproductive output between mating treatments in terms of total eggs laid or offspring viability, but there were significant differences found in daily fecundity schedules and adult longevity. In terms of lifetime reproduction, female Warehouse pirate bugs appear to be adapted to compensate for the costs of TI mating to their longevity.

  • 6.
    Backström, Niclas
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Evolution, Genomics and Systematics, Evolutionary Biology.
    Qvarnström, Anna
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Evolution, Genomics and Systematics, Evolutionary Biology.
    Gustafsson, Lars
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Evolution, Genomics and Systematics, Evolutionary Biology.
    Ellegren, Hans
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Evolution, Genomics and Systematics, Evolutionary Biology.
    Levels of linkage disequilibrium in a wild bird population2006In: Biology Letters, ISSN 1744-9561, E-ISSN 1744-957X, Vol. 2, no 3, p. 435-438Article in journal (Refereed)
    Abstract [en]

    Population-based mapping approaches are attractive for tracing the genetic background to phenotypic traits in wild species, given that it is often difficult to gather extensive and well-defined pedigrees needed for quantitative trait locus analysis. However, the feasibility of association or hitch-hiking mapping is dependent on the degree of linkage disequilibrium. (LD) in the population, on which there is yet limited information for wild species. Here we use single nucleotide polymorphism (SNP) markers from 23 genes in a recently established linkage map of the Z chromosome of the collared flycatcher, to study the extent of LD in a natural bird population. In most but not all cases we find SNPs within the same intron (less than 500 bp) to be in perfect LD. However, LD then decays to background level at a distance 1 cM or 400-500 kb. Although LD seems more extensive than in other species, if the observed pattern is representative for other regions of the genome and turns out to be a general feature of natural bird populations, dense marker maps might be needed for genome scans aimed at identifying association between marker and trait loci.

  • 7. Barrett, Paul M.
    et al.
    Evans, David C.
    Campione, Nicolas E.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    Evolution of dinosaur epidermal structures2015In: Biology Letters, ISSN 1744-9561, E-ISSN 1744-957X, Vol. 11, no 6, article id 20150229Article in journal (Refereed)
    Abstract [en]

    Spectacularly preserved non-avian dinosaurs with integumentary filaments/feathers have revolutionized dinosaur studies and fostered the suggestion that the dinosaur common ancestor possessed complex integumentary structures homologous to feathers. This hypothesis has major implications for interpreting dinosaur biology, but has not been tested rigorously. Using a comprehensive database of dinosaur skin traces, we apply maximum-likelihood methods to reconstruct the phylogenetic distribution of epidermal structures and interpret their evolutionary history. Most of these analyses find no compelling evidence for the appearance of protofeathers in the dinosaur common ancestor and scales are usually recovered as the plesiomorphic state, but results are sensitive to the outgroup condition in pterosaurs. Rare occurrences of ornithischian filamentous integument might represent independent acquisitions of novel epidermal structures that are not homologous with theropod feathers.

  • 8.
    Belli, Phil R.
    et al.
    Univ New England, Armidale, NSW 2351, Australia..
    Campione, Nicolas E.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    Persons, W. Scott
    Univ Alberta, Edmonton, AB T6E 4S6, Canada..
    Currie, Philip J.
    Univ Alberta, Edmonton, AB T6E 4S6, Canada..
    Larson, Peter L.
    Geol Res Inc, Black Hills Inst, Hill City, SD 57745 USA..
    Tanke, Darren H.
    Royal Tyrrell Museum Palaeontol, Drumheller, AB, Canada..
    Bakker, Robert T.
    Houston Museum Nat Sci, Houston, TX 77030 USA..
    Tyrannosauroid integument reveals conflicting patterns of gigantism and feather evolution2017In: Biology Letters, ISSN 1744-9561, E-ISSN 1744-957X, Vol. 13, no 6, article id 20170092Article in journal (Refereed)
    Abstract [en]

    Recent evidence for feathers in theropods has led to speculations that the largest tyrannosaurids, including Tyrannosaurus rex, were extensively feathered. We describe fossil integument from Tyrannosaurus and other tyrannosaurids (Albertosaurus, Daspletosaurus, Gorgosaurus and Tarbosaurus), confirming that these large-bodied forms possessed scaly, reptilian-like skin. Body size evolution in tyrannosauroids reveals two independent occurrences of gigantism; specifically, the large sizes in Yutyrannus and tyrannosaurids were independently derived. These new findings demonstrate that extensive feather coverings observed in some early tyrannosauroids were lost by the Albian, basal to Tyrannosauridae. This loss is unrelated to palaeoclimate but possibly tied to the evolution of gigantism, although other mechanisms exist.

  • 9.
    Bennett, N. C.
    et al.
    Univ Pretoria, South Africa.
    Ganswindt, A.
    Univ Pretoria, South Africa.
    Ganswindt, S. B.
    Univ Pretoria, South Africa.
    Jarvis, J. U. M.
    Univ Cape Town, South Africa.
    Zöttl, Markus
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science. Univ Cambridge, UK.
    Faulkes, C. G.
    Queen Mary Univ London, UK.
    Evidence for contrasting roles for prolactin in eusocial naked mole-rats, Heterocephalus glaber and Damaraland mole-rats, Fukomys damarensis2018In: Biology Letters, ISSN 1744-9561, E-ISSN 1744-957X, Vol. 14, no 5, article id 20180150Article in journal (Refereed)
    Abstract [en]

    Elevated prolactin (PRL) has been associated with the expression of social and cooperative behaviours in a number of vertebrate species, as well as suppression of reproduction. As social mole-rats exhibit both of these traits, PRL is a prime candidate in mediating their social phenotype. While naked and Damaraland mole-rats (NMRs and DMRs) have evolved eusociality independently within their family, both species exhibit an extreme skew in lifetime reproductive success, with breeding restricted to a single female and one or two males. Non-breeding NMRs of both sexes are physiologically inhibited from reproducing, while in DMRs only the non-breeding females are physiologically suppressed. Newly emerging work has implicated the dopamine system and PRL as a component in socially induced reproductive suppression and eusociality in NMR, but the DMR remains unstudied in this context. To investigate evolutionary convergence in the role of PRL in shaping African mole-rat eusociality, we determined plasma PRL concentrations in breeders and non-breeders of both sexes, comparing DMRs with NMRs. Among samples from non-breeding NMRs 80% had detectable plasma PRL concentrations. As a benchmark, these often (37%) exceeding those considered clinically hyperprolactinaemic (25 ng ml(-1)) in humans: mean +/- s.e.m.: 34.81 +/- 5.87 ngml(-1); range 0.00-330.30 ng ml(-1). Conversely, 85% of non-breeding DMR samples had undetectable values and none had concentrations above 25 ng ml(-1): 0.71 +/- 0.38 ng ml(-1); 0.00-23.87 ngml(-1). Breeders in both species had the expected variance in plasma PRL concentrations as part of normal reproductive function, with lactating queens having significantly higher values. These results suggest that while elevated PRL in non-breeders is implicated in NMR eusociality, this may not be the case in DMRs, and suggests a lack of evolutionary convergence in the proximate control of the social phenotype in these mole-rats.

  • 10.
    Bize, Pierre
    et al.
    Univ Aberdeen, Inst Biol & Environm Sci, Aberdeen, Scotland.;Univ Lausanne, Dept Ecol & Evolut, Lausanne, Switzerland..
    Daniel, Gregory
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal ecology. Univ Claude Bernard Lyon 1, Lab Biometrie & Biol Evolut, CNRS, Villeurbanne, France.
    Viblanc, Vincent A.
    Univ Lausanne, Dept Ecol & Evolut, Lausanne, Switzerland.;Univ Strasbourg, CNRS, UMR 7178, IPHC, F-67000 Strasbourg, France..
    Martin, Julien G. A.
    Univ Aberdeen, Inst Biol & Environm Sci, Aberdeen, Scotland..
    Doligez, Blandine
    Univ Claude Bernard Lyon 1, Lab Biometrie & Biol Evolut, CNRS, Villeurbanne, France..
    Negative phenotypic and genetic correlation between natal dispersal propensity and nest-defence behaviour in a wild bird2017In: Biology Letters, ISSN 1744-9561, E-ISSN 1744-957X, Vol. 13, no 7, article id 20170236Article in journal (Refereed)
    Abstract [en]

    Natural selection is expected to favour the integration of dispersal and phenotypic traits allowing individuals to reduce dispersal costs. Accordingly, associations have been found between dispersal and personality traits such as aggressiveness and exploration, which may facilitate settlement in a novel environment. However, the determinism of these associations has only rarely been explored. Here, we highlight the functional integration of individual personality in nest-defence behaviour and natal dispersal propensity in a long-lived colonial bird, the Alpine swift (Alms melba), providing insights into genetic constraints shaping the coevolution of these two traits. We report a negative association between natal dispersal and nest-defence (i.e. risk taking) behaviour at both the phenotypic and genetic level. This negative association may result from direct selection if risk-averseness benefits natal dispersers by reducing the costs of settlement in an unfamiliar environment, or from indirect selection if individuals with lower levels of nest defence also show lower levels of aggressiveness, reducing costs of settlement among unfamiliar neighbours in a colony. In both cases, these results highlight that risk taking is an important behavioural trait to consider in the study of dispersal evolution.

  • 11. Bomfleur, Benjamin
    et al.
    Mörs, Thomas
    Ferraguti, Marco
    Reguero, Marcelo A.
    McLoughlin, Stephen
    Fossilized spermatozoa preserved in a 50-Myr-old annelid cocoon from Antarctica2015In: Biology Letters, ISSN 1744-9561, E-ISSN 1744-957X, Vol. 11, no 7Article in journal (Refereed)
  • 12.
    Bomfleur, Benjamin
    et al.
    Swedish Museum of Natural History, Department of Paleobiology.
    Mörs, Thomas
    Swedish Museum of Natural History, Department of Paleobiology.
    Ferraguti, Marco
    Dipartimento di Bioscienze, Universita` degli Studi di Milano, Milano, Italy.
    Reguero, Marcelo
    Divisio´n Paleontologı´a de Vertebrados, Museo de La Plata, La Plata, Argentina.
    McLoughlin, Stephen
    Swedish Museum of Natural History, Department of Paleobiology.
    Fossilized spermatozoa preserved in a 50-myr-old annelid cocoon from Antarctica2015In: Biology Letters, ISSN 1744-9561, E-ISSN 1744-957X, Vol. 11, no 20150431, p. 1-5Article in journal (Refereed)
    Abstract [en]

    The origin and evolution of clitellate annelids—earthworms, leeches and their relatives—is poorly understood, partly because body fossils of these delicate organisms are exceedingly rare. The distinctive egg cases (cocoons) of Clitellata, however, are relatively common in the fossil record, although their potential for phylogenetic studies has remained largely unexplored. Here, we report the remarkable discovery of fossilized spermatozoa preserved within the secreted wall layers of a 50-Myr-old clitellate cocoon from Antarctica, representing the oldest fossil animal sperm yet known. Sperm characters are highly informative for the classification of extant Annelida. The Antarctic fossil spermatozoa have several features that point to affinities with the peculiar, leech-like ‘crayfish worms’ (Branchiobdellida). We anticipate that systematic surveys of cocoon fossils coupled with advances in non-destructive analytical methods may open a new window into the evolution of minute, soft-bodied life forms that are otherwise only rarely observed in the fossil record.

  • 13.
    Brodersen, Jakob
    et al.
    Lunds universitet.
    Nilsson, P. Anders
    Lunds universitet.
    Chapman, Ben B
    Lunds universitet.
    Skov, Christian
    Hansson, Lars-Anders
    Lunds universitet.
    Brönmark, Christer
    Lunds universitet.
    Variable individual consistency in timing and destination of winter migrating fish2012In: Biology Letters, ISSN 1744-9561, E-ISSN 1744-957X, Vol. 8, p. 21-23Article in journal (Refereed)
  • 14.
    Brown, Caleb M.
    et al.
    Tyrrell Museum of Paleontology.
    Campione, Nicolas E.
    Department of Ecology and Evolutionary Biology, University of Toronto, Ontario, Canada.
    Giacomini, Henrique C.
    University of Toronto.
    O'Brien, Lorna J.
    University of Toronto.
    Vavrek, Matthew J.
    Philip J. Currie Dinosaur Museum.
    Evans, David C.
    Royal Ontario Museum.
    Ecological modelling, size distributions and taphonomic size bias in dinosaur faunas: a comment on Codron et al. (2012)2013In: Biology Letters, ISSN 1744-9561, E-ISSN 1744-957X, Vol. 9, no 1, p. 20120582-Article in journal (Refereed)
  • 15.
    Chen, Hwei-yen
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal ecology.
    Zajitschek, Felix
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal ecology.
    Maklakov, Alexei A.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal ecology.
    Why ageing stops: heterogeneity explains late-life mortality deceleration in nematodes2013In: Biology Letters, ISSN 1744-9561, E-ISSN 1744-957X, Vol. 9, no 5, p. 20130217-Article in journal (Refereed)
    Abstract [en]

    While ageing is commonly associated with exponential increase in mortality with age, mortality rates paradoxically decelerate late in life resulting in distinct mortality plateaus. Late-life mortality plateaus have been discovered in a broad variety of taxa, including humans, but their origin is hotly debated. One hypothesis argues that deceleration occurs because the individual probability of death stops increasing at very old ages, predicting the evolution of earlier onset of mortality plateaus under increased rate of extrinsic mortality. By contrast, heterogeneity theory suggests that mortality deceleration arises from individual differences in intrinsic lifelong robustness and predicts that variation in robustness between populations will result in differences in mortality deceleration. We used experimental evolution to directly test these predictions by independently manipulating extrinsic mortality rate (high or low) and mortality source (random death or condition-dependent) to create replicate populations of nematodes, Caenorhabditis remanei that differ in the strength of selection in late-life and in the level of lifelong robustness. Late-life mortality deceleration evolved in response to differences in mortality source when mortality rate was held constant, while there was no consistent response to differences in mortality rate. These results provide direct experimental support for the heterogeneity theory of late-life mortality deceleration.

  • 16. Cunningham, John A.
    et al.
    Ruecklin, Martin
    Blom, Henning
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Botella, Hector
    Donoghue, Philip C. J.
    Testing models of dental development in the earliest bony vertebrates, Andreolepis and Lophosteus2012In: Biology Letters, ISSN 1744-9561, E-ISSN 1744-957X, Vol. 8, no 5, p. 833-837Article in journal (Refereed)
    Abstract [en]

    Theories on the development and evolution of teeth have long been biased by the fallacy that chondrichthyans reflect the ancestral condition for jawed vertebrates. However, correctly resolving the nature of the primitive vertebrate dentition is challenged by a dearth of evidence on dental development in primitive osteichthyans. Jaw elements from the Silurian-Devonian stem-osteichthyans Lophosteus and Andreolepis have been described to bear a dentition arranged in longitudinal rows and vertical files, reminiscent of a pattern of successional development. We tested this inference, using synchrotron radiation X-ray tomographic microscopy (SRXTM) to reveal the pattern of skeletal development preserved in the sclerochronology of the mineralized tissues. The tooth-like tubercles represent focal elaborations of dentine within otherwise continuous sheets of the dermal skeleton, present in at least three stacked generations. Thus, the tubercles are not discrete modular teeth and their arrangement into rows and files is a feature of the dermal ornamentation that does not reflect a polarity of development or linear succession. These fossil remains have no bearing on the nature of the dentition in osteichthyans and, indeed, our results raise questions concerning the homologies of these bones and the phylogenetic classification of Andreolepis and Lophosteus.

  • 17.
    Ericson, Per G P
    et al.
    Swedish Museum of Natural History, Research Division.
    Anderson, Caisa Lisa
    Mayr, Gerald
    Hangin' on to our rocks 'n clocks: a reply to Brown et al2007In: Biology Letters, ISSN 1744-9561, E-ISSN 1744-957X, Vol. 3, no 3, p. 260-261Article in journal (Other academic)
  • 18.
    Ericson, Per G P
    et al.
    Swedish Museum of Natural History, Research Division.
    Anderson, Cajsa L
    Britton, Tom
    Elzanowski, Andrzej
    Johansson, Ulf S
    Swedish Museum of Natural History, Department of Zoology.
    Källersjö, Mari
    Ohlson, Jan I
    Swedish Museum of Natural History, Department of Bioinformatics and Genetics.
    Parsons, Thomas J
    Zuccon, Dario
    Mayr, Gerald
    Diversification of Neoaves: integration of molecular sequence data and fossils.2006In: Biology Letters, ISSN 1744-9561, E-ISSN 1744-957X, Vol. 2, no 4, p. 543-7Article in journal (Refereed)
    Abstract [en]

    Patterns of diversification and timing of evolution within Neoaves, which includes almost 95% of all bird species, are virtually unknown. On the other hand, molecular data consistently indicate a Cretaceous origin of many neoavian lineages and the fossil record seems to support an Early Tertiary diversification. Here, we present the first well-resolved molecular phylogeny for Neoaves, together with divergence time estimates calibrated with a large number of stratigraphically and phylogenetically well-documented fossils. Our study defines several well-supported clades within Neoaves. The calibration results suggest that Neoaves, after an initial split from Galloanseres in Mid-Cretaceous, diversified around or soon after the K/T boundary. Our results thus do not contradict palaeontological data and show that there is no solid molecular evidence for an extensive pre-Tertiary radiation of Neoaves.

  • 19. Ericson, Per G. P.
    et al.
    Anderson, Cajsa Lisa
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Evolution, Genomics and Systematics, Systematic Botany.
    Britton, Tom
    Elzanowski, Andrzej
    Johansson, Ulf S.
    Källersjö, Mari
    Ohlson, Jan I.
    Parsons, Thomas J.
    Zuccon, Dario
    Mayr, Gerald
    Diversification of Neoaves through time: Integration of molecular sequence data and fossils2006In: Biology Letters, ISSN 1744-9561, E-ISSN 1744-957X, Vol. 2, no 4, p. 543-547Article in journal (Refereed)
    Abstract [en]

    Patterns of diversification and timing of evolution within Neoaves, which includes almost 95% of all bird species, are virtually unknown. On the other hand, molecular data consistently indicate a Cretaceous origin of many neoavian lineages and the fossil record seems to support an Early Tertiary diversification. Here, we present the first well-resolved molecular phylogeny for Neoaves, together with divergence time estimates calibrated with a large number of stratigraphically and phylogenetically well-documented fossils. Our study defines several well-supported clades within Neoaves. The calibration results suggest that Neoaves, after an initial split from Galloanseres in Mid-Cretaceous, diversified around or soon after the K/T boundary. Our results thus do not contradict palaeontological data and show that there is no solid molecular evidence for an extensive pre-Tertiary radiation of Neoaves.

  • 20. Ericson, Per G. P.
    et al.
    Anderson, Cajsa Lisa
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Evolution, Genomics and Systematics.
    Mayr, Gerald
    Hangin’ on to our rocks ’n clocks: a reply to Brown et al.2007In: Biology Letters, ISSN 1744-9561, E-ISSN 1744-957X, Vol. 3, no 3, p. 260-261Article in journal (Refereed)
  • 21.
    Ettema, Thijs J. G.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Evolution, Genomics and Systematics, Molecular Evolution.
    Andersson, Siv G. E.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Evolution, Genomics and Systematics, Molecular Evolution.
    The alpha-proteobacteria: the Darwin finches of the bacterial world2009In: Biology Letters, ISSN 1744-9561, E-ISSN 1744-957X, Vol. 5, no 3, p. 429-432Article in journal (Refereed)
    Abstract [en]

    The alpha-proteobacteria represent one of the most diverse bacterial subdivisions, displaying extreme variations in lifestyle, geographical distribution and genome size. Species for which genome data are available have been classified into a species tree based on a conserved set of vertically inherited core genes. By mapping the variation in gene content onto the species tree, genomic changes can be associated with adaptations to specific growth niches. Genes for adaptive traits are mostly located in 'plasticity zones' in the bacterial genome, which also contain mobile elements and are highly variable across strains. By physically separating genes for information processing from genes involved in interactions with the surrounding environment, the rate of evolutionary change can be substantially enhanced for genes underlying adaptation to new growth habitats, possibly explaining the ecological success of the alpha-proteobacterial subdivision.

  • 22.
    Falck-Ytter, Terje
    Uppsala University, Disciplinary Domain of Humanities and Social Sciences, Faculty of Social Sciences, Department of Psychology.
    Young children with autism spectrum disorder use predictive eye movements in action observation2010In: Biology Letters, ISSN 1744-9561, E-ISSN 1744-957X, Vol. 6, no 3, p. 375-378Article in journal (Refereed)
    Abstract [en]

    Does a dysfunction in the mirror neuron system (MNS) underlie the social symptoms defining autism spectrum disorder (ASD)? Research suggests that the MNS matches observed actions to motor plans for similar actions, and that these motor plans include directions for predictive eye movements when observing goal-directed actions. Thus, one important question is whether children with ASD use predictive eye movements in action observation. Young children with ASD as well as typically developing children and adults were shown videos in which an actor performed object-directed actions (human agent condition). Children with ASD were also shown control videos showing objects moving by themselves (self-propelled condition). Gaze was measured using a corneal reflection technique. Children with ASD and typically developing individuals used strikingly similar goal-directed eye movements when observing others' actions in the human agent condition. Gaze was reactive in the self-propelled condition, suggesting that prediction is linked to seeing a hand-object interaction. This study does not support the view that ASD is characterized by a global dysfunction in the MNS.

  • 23. Fitzpatrick, Luisa J.
    et al.
    Gasparini, Clelia
    Fitzpatrick, John L.
    University of Manchester, UK.
    Evans, Jonathan P.
    Male-female relatedness and patterns of male reproductive investment in guppies2014In: Biology Letters, ISSN 1744-9561, E-ISSN 1744-957X, Vol. 10, no 5Article in journal (Refereed)
    Abstract [en]

    Inbreeding can cause reductions in fitness, driving the evolution of pre- and postcopulatory inbreeding avoidance mechanisms. There is now considerable evidence for such processes in females, but few studies have focused on males, particularly in the context of postcopulatory inbreeding avoidance. Here, we address this topic by exposing male guppies (Poecilia reticulata) to either full-sibling or unrelated females and determining whether they adjust investment in courtship and ejaculates. Our results revealed that males reduce their courtship but concomitantly exhibit short-term increases in ejaculate quality when paired with siblings. In conjunction with prior work reporting cryptic female preferences for unrelated sperm, our present findings reveal possible sexually antagonistic counter-adaptations that may offset postcopulatory inbreeding avoidance by females.

  • 24. Freeman, Robin
    et al.
    Mann, Richard
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Mathematics, Analysis and Applied Mathematics.
    Guilford, Tim
    Biro, Dora
    Group decisions and individual differences: route fidelity predicts flight leadership in homing pigeons (Columba livia)2011In: Biology Letters, ISSN 1744-9561, E-ISSN 1744-957X, Vol. 7, no 1, p. 63-66Article in journal (Refereed)
    Abstract [en]

    How social-living animals make collective decisions is currently the subject of intense scientific interest, with increasing focus on the role of individual variation within the group. Previously, we demonstrated that during paired flight in homing pigeons, a fully transitive leadership hierarchy emerges as birds are forced to choose between their own and their partner's habitual routes. This stable hierarchy suggests a role for individual differences mediating leadership decisions within homing pigeon pairs. What these differences are, however, has remained elusive. Using novel quantitative techniques to analyse habitual route structure, we show here that leadership can be predicted from prior route-following fidelity. Birds that are more faithful to their own route when homing alone are more likely to emerge as leaders when homing socially. We discuss how this fidelity may relate to the leadership phenomenon, and propose that leadership may emerge from the interplay between individual route confidence and the dynamics of paired flight.

  • 25.
    Friberg, Urban
    et al.
    Department of Evolutionary Biology, Uppsala University, Uppsala, Sweden.
    Stewart, Andrew D.
    Department of Ecology, Evolution and Marine Biology, University of California, Santa Barbara, USA.
    Rice, William R.
    Department of Ecology, Evolution and Marine Biology, University of California, Santa Barbara, USA.
    X- and Y-chromosome linked paternal effects on a life-history trait2012In: Biology Letters, ISSN 1744-9561, E-ISSN 1744-957X, Vol. 8, no 1, p. 71-73Article in journal (Refereed)
    Abstract [en]

    Males and females usually invest asymmetrically in offspring. In species lacking parental care, females influence offspring in many ways, while males only contribute genetic material via their sperm. For this reason, maternal effects have long been considered an important source of phenotypic variation, while paternal effects have been presumed to be absent or negligible. The recent surge of studies showing trans-generational epigenetic effects questions this assumption, and indicates that paternal effects may be far more important than previously appreciated. Here, we test for sex-linked paternal effects in Drosophila melanogaster on a life-history trait, and find substantial support for both X- and Y-linked effects.

  • 26.
    Friberg, Urban
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Evolutionary Biology.
    Stewart, Andrew D.
    Rice, William R.
    X- and Y-chromosome linked paternal effects on a life-history trait2012In: Biology Letters, ISSN 1744-9561, E-ISSN 1744-957X, Vol. 8, no 1, p. 71-73Article in journal (Refereed)
    Abstract [en]

    Males and females usually invest asymmetrically in offspring. In species lacking parental care, females influence offspring in many ways, while males only contribute genetic material via their sperm. For this reason, maternal effects have long been considered an important source of phenotypic variation, while paternal effects have been presumed to be absent or negligible. The recent surge of studies showing trans-generational epigenetic effects questions this assumption, and indicates that paternal effects may be far more important than previously appreciated. Here, we test for sex-linked paternal effects in Drosophila melanogaster on a life-history trait, and find substantial support for both X- and Y-linked effects.

  • 27. Gundale, Michael J.
    et al.
    Bach, Lisbet H.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Nordin, Annika
    The impact of simulated chronic nitrogen deposition on the biomass and N-2-fixation activity of two boreal feather moss-cyanobacteria associations2013In: Biology Letters, ISSN 1744-9561, E-ISSN 1744-957X, Vol. 9, no 6, p. 20130797-Article in journal (Refereed)
    Abstract [en]

    Bryophytes achieve substantial biomass and play several key functional roles in boreal forests that can influence how carbon (C) and nitrogen (N) cycling respond to atmospheric deposition of reactive nitrogen (N-r). They associate with cyanobacteria that fix atmospheric N-2, and downregulation of this process may offset anthropogenic Nr inputs to boreal systems. Bryophytes also promote soil C accumulation by thermally insulating soils, and changes in their biomass influence soil C dynamics. Using a unique large-scale (0.1 ha forested plots), long-term experiment (16 years) in northern Sweden where we simulated anthropogenic Nr deposition, we measured the biomass and N-2-fixation response of two bryophyte species, the feather mosses Hylocomium splendens and Pleurozium schreberi. Our data show that the biomass declined for both species; however, N-2-fixation rates per unit mass and per unit area declined only for H. splendens. The low and high treatments resulted in a 29% and 54% reduction in total feather moss biomass, and a 58% and 97% reduction in total N-2-fixation rate per unit area, respectively. These results help to quantify the sensitivity of feather moss biomass and N-2 fixation to chronic Nr deposition, which is relevant for modelling ecosystem C and N balances in boreal ecosystems.

  • 28.
    Hailer, Frank
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Evolution, Genomics and Systematics, Evolutionary Biology.
    Helander, B.
    Folkestad, A. O.
    Ganusevich, S. A.
    Garstad, S.
    Hauff, P.
    Koren, C.
    Nygård, T.
    Volke, V.
    Vilà, Carles
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Evolution, Genomics and Systematics, Evolutionary Biology.
    Ellegren, Hans
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Evolution, Genomics and Systematics, Evolutionary Biology.
    Bottlenecked but long-lived: high genetic diversity retained in white-tailed eagles upon recovery from population decline2006In: Biology Letters, ISSN 1744-9561, E-ISSN 1744-957X, Vol. 2, no 2, p. 316-319Article in journal (Refereed)
    Abstract [en]

    Most of the white-tailed eagle (Haliaeetus albicilla) populations in Europe experienced dramatic declines during the twentieth century. However, owing to intense conservation actions and the ban of DDT and other persistent pollutants, populations are currently recovering. We show that despite passing through demographic bottlenecks, white-tailed eagle populations have retained significant levels of genetic diversity. Both genetic and ringing data indicate that migration between populations has not been a major factor for the maintenance of genetic variability. We argue that the long generation time of eagles has acted as an intrinsic buffer against loss of genetic diversity, leading to a shorter effective time of the experienced bottleneck. Notably, conservation actions taken in several small sub-populations have ensured the preservation of a larger proportion of the total genetic diversity than if conservation had focused on the population stronghold in Norway. For conservation programmes targeting other endangered, long-lived species, our results highlight the possibility for local retention of high genetic diversity in isolated remnant populations.

  • 29.
    Herbert-Read, James E.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Mathematics.
    Romenskyy, Maxym
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Mathematics.
    Sumpter, David J. T.
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Mathematics.
    A Turing test for collective motion2015In: Biology Letters, ISSN 1744-9561, E-ISSN 1744-957X, Vol. 11, no 12, article id 20150674Article in journal (Refereed)
    Abstract [en]

    A widespread problem in biological research is assessing whether a model adequately describes some real-world data. But even if a model captures the large-scale statistical properties of the data, should we be satisfied with it? We developed a method, inspired by Alan Turing, to assess the effectiveness of model fitting. We first built a self-propelled particle model whose properties (order and cohesion) statistically matched those of real fish schools. We then asked members of the public to play an online game (a modified Turing test) in which they attempted to distinguish between the movements of real fish schools or those generated by the model. Even though the statistical properties of the real data and the model were consistent with each other, the public could still distinguish between the two, highlighting the need for model refinement. Our results demonstrate that we can use 'citizen science' to cross-validate and improve model fitting not only in the field of collective behaviour, but also across a broad range of biological systems.

  • 30.
    Heuschele, Jan
    et al.
    Department of Biological and Environmental Sciences, University of Helsinki.
    Candolin, Ulrika
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Limnology.
    An increase in pH boosts olfactory communication in sticklebacks2007In: Biology Letters, ISSN 1744-9561, E-ISSN 1744-957X, Vol. 3, no 4, p. 411-413Article in journal (Refereed)
    Abstract [en]

    Human-induced eutrophication is a serious environmental problem that constrains visual communication and influences the mate choice process in fishes. Eutrophication also changes the chemical environment and the pH of the water, which could influence the use of olfactory cues in mate choice. Here, we show that an increase in pH enhances the use of male olfactory cues in mate choice in three-spined sticklebacks, Gasterosteus aculeatus. In a laboratory choice experiment, gravid females were more attracted to male olfactory cues when pH was raised. This could compensate for impaired visual communication in eutrophied waters and facilitate adaptive mate choice.

  • 31. Ho, Simon Y. W.
    et al.
    Larson, Greger
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Biochemistry and Microbiology.
    Edwards, Ceiridwen J.
    Heupink, Tim H.
    Lakin, Kay E.
    Holland, Peter W. H.
    Shapiro, Beth
    Correlating Bayesian date estimates with climatic events and domestication using a bovine case study.2008In: Biology Letters, ISSN 1744-9561, E-ISSN 1744-957X, Vol. 4, no 4, p. 370-374Article in journal (Refereed)
    Abstract [en]

    The tribe Bovini contains a number of commercially and culturally important species, such as cattle. Understanding their evolutionary time scale is important for distinguishing between post-glacial and domestication-associated population expansions, but estimates of bovine divergence times have been hindered by a lack of reliable calibration points. We present a Bayesian phylogenetic analysis of 481 mitochondrial D-loop sequences, including 228 radiocarbon-dated ancient DNA sequences, using a multi-demographic coalescent model. By employing the radiocarbon dates as internal calibrations, we co-estimate the bovine phylogeny and divergence times in a relaxed-clock framework. The analysis yields evidence for significant population expansions in both taurine and zebu cattle, European aurochs and yak clades. The divergence age estimates support domestication-associated expansion times (less than 12 kyr) for the major haplogroups of cattle. We compare the molecular and palaeontological estimates for the Bison-Bos divergence.

  • 32.
    Holmer, Lars Erik
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    Skovsted, C.B.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    Brock, G.A.
    Paterson, J.A.
    The Early Cambrian tommotiid Micrina, a sessile bivalved stem group brachiopod2008In: Biology Letters, ISSN 1744-9561, E-ISSN 1744-957X, Vol. 4, no 6, p. 724-728Article in journal (Refereed)
    Abstract [en]

    The tannuolinid Micrina belongs to the tommotiids—a common and widely distributed, but poorly understood, group of Early Cambrian fossil metazoans with multiple external organophosphatic sclerites. Recent findings of sessile articulated tommotiid scleritomes indicate that previous reconstructions of tommotiids as slug-like bilaterians with a dorsal cover of sclerites require detailed re-evaluation. Comparative ultrastructural work has already indicated that the tommotiids might be a sister group to the Brachiopoda, with Micrina representing the most derived and brachiopod-like bimembrate tommotiid. Here we further develop and strengthen this controversial phylogenetic model with a new reconstruction of Micrina, where the two types of sclerites—mitral and sellate—belong to a near bilaterally symmetrical bivalved sessile organism. This new scleritome configuration was tested by recreating an articulated bivalved Micrina from isolated mitral and sellate sclerites; both sclerites have muscles that would have enabled movement of the sclerites. The mitral and sellate sclerites of Micrina are considered to be homologous with the ventral and dorsal valves, respectively, of organophosphatic linguliform brachiopods, indicating that a simple type of filter-feeding within an enclosed bivalved shell had started to evolve in derived tannuolinids. The new reconstruction also indicates that the phylogenetic range of ‘bivalved’, sessile lophophorates is larger than previously suspected.

  • 33.
    Hornborg, Sara
    et al.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, SIK – Institutet för livsmedel och bioteknik.
    Belgrano, A.
    Bartolino, V.
    Valentinsson, D.
    Ziegler, Friederike
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, SIK – Institutet för livsmedel och bioteknik.
    Trophic indicators in fisheries: A call for re-evaluation2013In: Biology Letters, ISSN 1744-9561, E-ISSN 1744-957X, Vol. 9, no 1, p. 1050-Article in journal (Refereed)
    Abstract [en]

    Mean trophic level (MTL) of landings and primary production required (PPR) by fisheries are increasingly used in the assessment of sustainability in fisheries. However, in their present form, MTL and PPR are prone to misinterpretation. We show that it is important to account for actual catch data, define an appropriate historical and spatial domain, and carefully consider the effects of fisheries management, based on results from a case study of Swedish fisheries during the past century. © 2012 The Author(s) Published by the Royal Society. All rights reserved.

  • 34. Hulthén, K.
    et al.
    Chapman, B.B.
    Nilsson, Anders
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Environmental and Life Sciences.
    Vinterstare, J.
    Hansson, L-A.
    Skov, C.
    Brodersen, J.
    Baktoft, H.
    Brönmark, C.
    Escaping peril: perceived predation risk affects migratory propensity2015In: Biology Letters, ISSN 1744-9561, E-ISSN 1744-957X, Vol. 11, article id 20150466Article in journal (Refereed)
  • 35.
    Immler, Simone
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Evolutionary Biology.
    Hotzy, Cosima
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Evolutionary Biology.
    Alavioon, Ghazal
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Evolutionary Biology.
    Petersson, Erik
    Arnqvist, Goran
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal ecology.
    Sperm variation within a single ejaculate affects offspring development in Atlantic salmon2014In: Biology Letters, ISSN 1744-9561, E-ISSN 1744-957X, Vol. 10, no 2, p. 20131040-Article in journal (Refereed)
    Abstract [en]

    It is generally believed that variation in sperm phenotype within a single ejaculate has no consequences for offspring performance, because sperm phenotypes are thought not to reflect sperm genotypes. We show that variation in individual sperm function within an ejaculate affects the performance of the resulting offspring in the Atlantic salmon Salmo salar. We experimentally manipulated the time between sperm activation and fertilization in order to select for sperm cohorts differing in longevity within single ejaculates of wild caught male salmon. We found that within-ejaculate variation in sperm longevity significantly affected offspring development and hence time until hatching. Whether these effects have a genetic or epigenetic basis needs to be further evaluated. However, our results provide experimental evidence for transgenerational effects of individual sperm function.

  • 36.
    Johansson, Ulf S.
    et al.
    Swedish Museum of Natural History, Department of Zoology.
    Bowie, Rauri C.K.
    Hackett, Shannon J.
    Schulenberg, Thomas S.
    The Phylogenetic affinities of Crossley's Babbler (Mystacornis crossleyi): adding a new niche to the vanga radiation of Madagascar.2008In: Biology Letters, ISSN 1744-9561, E-ISSN 1744-957X, Vol. 4, no 6, p. 677-680Article in journal (Refereed)
  • 37. Johnson, Steven D.
    et al.
    Torninger, Erica
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Ecological Botany.
    Ågren, Jon
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Ecological Botany.
    Relationships between population size and pollen fates in a moth-pollinated orchid2009In: Biology Letters, ISSN 1744-9561, E-ISSN 1744-957X, Vol. 5, no 2, p. 282-285Article in journal (Refereed)
    Abstract [en]

    Management of small plant populations requires an understanding of their reproductive ecology, particularly in terms of sensitivity to Allee effects. To address this issue, we explored how components of pollen transfer and pollination success of individual plants varied among 36 populations of the self-compatible moth-pollinated orchid Satyrium longicauda in South Africa. Mean fruit set, seed production, proportion of flowers with pollen deposited or removed and proportion of removed pollen that reached stigmas (approx. 8% in this species) were not significantly related to population size (range: 1–450 flowering individuals), density or isolation. Plants in small populations did, however, have significantly higher levels of pollinator-mediated self-pollination (determined using colour-labelled pollen) than those in larger populations. Our results suggest that small populations of this orchid species are resilient to Allee effects in terms of overall pollination success, although the higher levels of pollinator-mediated self-pollination in small populations may lead to inbreeding depression and long-term erosion of genetic diversity.

  • 38. Jønsson, Knud A
    et al.
    Fjeldså, Jon
    Ericson, Per G P
    Swedish Museum of Natural History, Research Division.
    Irestedt, Martin
    Swedish Museum of Natural History, Department of Bioinformatics and Genetics.
    Systematic placement of an enigmatic Southeast Asian taxon Eupetes macrocerus and implications for the biogeography of a main songbird radiation, the Passerida.2007In: Biology Letters, ISSN 1744-9561, E-ISSN 1744-957X, Vol. 3, no 3, p. 323-6Article in journal (Refereed)
    Abstract [en]

    Biogeographic connections between Australia and other continents are still poorly understood although the plate tectonics of the Indo-Pacific region is now well described. Eupetes macrocerus is an enigmatic taxon distributed in a small area on the Malay Peninsula and on Sumatra and Borneo. It has generally been associated with Ptilorrhoa in New Guinea on the other side of Wallace's Line, but a relationship with the West African Picathartes has also been suggested. Using three nuclear markers, we demonstrate that Eupetes is the sister taxon of the South African genus Chaetops, and their sister taxon in turn being Picathartes, with a divergence in the Eocene. Thus, this clade is distributed in remote corners of Africa and Asia, which makes the biogeographic history of these birds very intriguing. The most parsimonious explanation would be that they represent a relictual basal group in the Passerida clade established after a long-distance dispersal from the Australo-Papuan region to Africa. Many earlier taxonomic arrangements may have been based on assumptions about relationships with similar-looking forms in the same, or adjacent, biogeographic regions, and revisions with molecular data may uncover such cases of neglect of ancient relictual patterns reflecting past connections between the continents.

  • 39. Kallio, Eva R.
    et al.
    Henttonen, Heikki
    Koskela, Esa
    Lundkvist, Åke
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Biochemistry and Microbiology.
    Mappes, Tapio
    Vapalahti, Olli
    Maternal antibodies contribute to sex-based difference in hantavirus transmission dynamics2013In: Biology Letters, ISSN 1744-9561, E-ISSN 1744-957X, Vol. 9, no 6, p. 20130887-Article in journal (Refereed)
    Abstract [en]

    Individuals often differ in their ability to transmit disease and identifying key individuals for transmission is a major issue in epidemiology. Male hosts are often thought to be more important than females for parasite transmission and persistence. However, the role of infectious females, particularly the transient immunity provided to offspring through maternal antibodies (MatAbs), has been neglected in discussions about sex-biased infection transmission. We examined the effect of host sex upon infection dynamics of zoonotic Puumala hantavirus (PUUV) in semi-natural, experimental populations of bank vole (Myodes glareolus). Populations were founded with either females or males that were infected with PUUV, whereas the other sex was immunized against PUUV infection. The likelihood of the next generation being infected was lower when the infected founders were females, underlying the putative importance of adult males in PUUV transmission and persistence in host populations. However, we show that this effect probably results from transient immunity that infected females provide to their offspring, rather than any sex-biased transmission efficiency per se. Our study proposes a potential contrasting nature of female and male hosts in the transmission dynamics of hantaviruses.

  • 40. Koblmueller, Stephan
    et al.
    Wayne, Robert K.
    Leonard, Jennifer A.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Evolutionary Biology.
    Impact of Quaternary climatic changes and interspecific competition on the demographic history of a highly mobile generalist carnivore, the coyote2012In: Biology Letters, ISSN 1744-9561, E-ISSN 1744-957X, Vol. 8, no 4, p. 644-647Article in journal (Refereed)
    Abstract [en]

    Recurrent cycles of climatic change during the Quaternary period have dramatically affected the population genetic structure of many species. We reconstruct the recent demographic history of the coyote (Canis latrans) through the use of Bayesian techniques to examine the effects of Late Quaternary climatic perturbations on the genetic structure of a highly mobile generalist species. Our analysis reveals a lack of phylogeographic structure throughout the range but past population size changes correlated with climatic changes. We conclude that even generalist carnivorous species are very susceptible to environmental changes associated with climatic perturbations. This effect may be enhanced in coyotes by interspecific competition with larger carnivores.

  • 41.
    Kotrschal, Alexander
    et al.
    Stockholm University, Faculty of Science, Department of Zoology.
    Corral-Lopez, Alberto
    Stockholm University, Faculty of Science, Department of Zoology.
    Kolm, Niclas
    Stockholm University, Faculty of Science, Department of Zoology.
    Large brains, short life: selection on brain size impacts intrinsic lifespan2019In: Biology Letters, ISSN 1744-9561, E-ISSN 1744-957X, Vol. 15, no 5, article id 20190137Article in journal (Refereed)
    Abstract [en]

    The relationship between brain size and ageing is a paradox. The cognitive benefits of large brains should protect from extrinsic mortality and thus indirectly select for slower ageing. However, the substantial energetic cost of neural tissue may also impact the energetic budget of large-brained organisms, causing less investment in somatic maintenance and thereby faster ageing. While the positive association between brain size and survival in the wild is well established, no studies exist on the direct effects of brain size on ageing. Here we test how brain size influences intrinsic ageing in guppy (Poecilia reticulata) brain size selection lines with 12% difference in relative brain size. Measuring survival under benign conditions, we find that large-brained animals live 22% shorter than small-brained animals and the effect is similar in both males and females. Our results suggest a trade-off between investment into brain size and somatic maintenance. This implies that the link between brain size and ageing is contingent on the mechanism of mortality, and selection for positive correlations between brain size and ageing should occur mainly under cognition-driven survival benefits from increased brain size. We show that accelerated ageing can be a cost of evolving a larger brain.

  • 42.
    Lehmann, Philipp
    et al.
    Stockholm University, Faculty of Science, Department of Zoology. Stellenbosch University, South Africa .
    Javal, Marion
    Terblanche, John S.
    Oxygen limitation is not the cause of death during lethal heat exposure in an insect2019In: Biology Letters, ISSN 1744-9561, E-ISSN 1744-957X, Vol. 15, no 1, article id 20180701Article in journal (Refereed)
    Abstract [en]

    Oxygen- and capacity-limited thermal tolerance (OCLTT) is a controversial hypothesis claiming to explain variation in, and mechanistically determine, animal thermal limits. The lack of support from Insecta is typically argued to be a consequence of their high-performance respiratory systems. However, no studies have reported internal body oxygen levels during thermal ramping so it is unclear if changes in ambient gas are partially or fully offset by a compensatory respiratory system. Here we provide such an assessment by simultaneously recording haemolymph oxygen (pO(2)) levels-as an approximation of tissue oxygenation-while experimentally manipulating ambient oxygen and subjecting organisms to thermal extremes in a series of thermolimit respirometry experiments using pupae of the butterfly Pieris napi. The main results are that while P. napi undergo large changes in haemolymph pO(2) that are positively correlated with experimental oxygen levels, haemolymph pO(2) is similar pre-and post-death during thermal assays. OCLTT predicts that reduction in body oxygen level should lead to a reduction in CTmax. Despite finding the former, there was no change in CTmax across a wide range of body oxygen levels. Thus, we argue that oxygen availability is not a functional determinant of the upper thermal limits in pupae of P. napi.

  • 43.
    Leonard, Jennifer A
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Evolution, Genomics and Systematics, Evolutionary Biology.
    Wayne, Robert K
    Native Great Lakes wolves were not restored2008In: Biology Letters, ISSN 1744-9561, E-ISSN 1744-957X, Vol. 4, no 1, p. 95-98Article in journal (Refereed)
    Abstract [en]

    Wolves from the Great Lakes area were historically decimated due to habitat loss and predator control programmes. Under the protection of the US Endangered Species Act, the population has rebounded to approximately 3000 individuals. We show that the pre-recovery population was dominated by mitochondrial DNA haplotypes from an endemic American wolf referred to here as the Great Lakes wolf. In contrast, the recent population is admixed, and probably derives also from the grey wolf (Canis lupus) of Old World origin and the coyote (Canis latrans). Consequently, the pre-recovery population has not been restored, casting doubt on delisting actions.

  • 44.
    Leonard, Jennifer A.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Evolutionary Biology.
    Wayne, Robert K.
    University of California.
    Wishful thinking: Imagining that the current Great Lakes wolf is the same entity that existed historically2009In: Biology Letters, ISSN 1744-9561, E-ISSN 1744-957X, Vol. 5, no 1, p. 67-68Article in journal (Refereed)
  • 45.
    Lindenfors, Patrik
    Stockholm University, Faculty of Science, Department of Zoology, Animal Ecology. Stockholm University, Faculty of Humanities, Centre for the Study of Cultural Evolution.
    Neocortex evolution in primates: the 'social brain' is for females2005In: Biology Letters, ISSN 1744-9561, E-ISSN 1744-957X, Vol. 1, p. 407-410Article in journal (Refereed)
    Abstract [en]

    According to the social intelligence hypothesis, relative neocortex size should be directly related to the degree of social complexity. This hypothesis has found support in a number of comparative studies of group size. The relationship between neocortex and sociality is thought to exist either because relative neocortex size limits group size or because a larger group size selects for a larger neocortex. However, research on primate social evolution has indicated that male and female group sizes evolve in relation to different demands. While females mostly group according to conditions set by the environment, males instead simply go where the females are. Thus, any hypothesis relating to primate social evolution has to analyse its relationship with male and female group sizes separately. Since sex-specific neocortex sizes in primates are unavailable in sufficient quantity, I here instead present results from phylogenetic comparative analyses of unsexed relative neocortex sizes and female and male group sizes. These analyses show that while relative neocortex size is positively correlated with female group size, it is negatively, or not at all correlated with male group size. This indicates that the social intelligence hypothesis only applies to female sociality.

  • 46. Lohmus, Mare
    et al.
    Moalem, Sharon
    Björklund, Mats
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal Ecology.
    Leptin, a tool of parasites?2012In: Biology Letters, ISSN 1744-9561, E-ISSN 1744-957X, Vol. 8, no 5, p. 849-852Article in journal (Refereed)
    Abstract [en]

    One common physiological phenomenon that is involved both in infectious and in malignant processes is the reduction in appetite: disease anorexia. An increase in plasma levels of leptin with inflammation is thought to be involved in this process. However, from an evolutionary perspective, in certain cases, it would be more adaptive for an internal parasite to stimulate the appetite of the host instead of causing its suppression. We tested whether a parasitic infection with the larvae of the helminth parasite Taenia taeniaformis affects the levels of appetite-regulating proteins, such as leptin, ghrelin and neuropeptide-Y (NPY) in wild yellow-necked mouse (Apodemus flavicollis). We found that infected mice had lower plasma levels of leptin and increased levels of NPY than the uninfected subjects. Ghrelin levels were not associated with the occurrence of the parasites; however, these levels strongly correlated with the levels of NPY. This study suggests a possible manipulation by parasitic larvae of appetite regulation in infected subjects.

  • 47.
    Maklakov, Alexei A.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal Ecology.
    Immler, Simone
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Evolutionary Biology.
    Gonzalez-Voyer, Alejandro
    Rönn, Johanna
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal ecology.
    Kolm, Niclas
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal Ecology.
    Brains and the city: big-brained passerine birds succeed in urban environments2011In: Biology Letters, ISSN 1744-9561, E-ISSN 1744-957X, Vol. 7, no 5, p. 730-732Article in journal (Refereed)
    Abstract [en]

    Urban regions are among the most human-altered environments on Earth and they are poised for rapid expansion following population growth and migration. Identifying the biological traits that determine which species are likely to succeed in urbanized habitats is important for predicting global trends in biodiversity. We provide the first evidence for the intuitive yet untested hypothesis that relative brain size is a key factor predisposing animals to successful establishment in cities. We apply phylogenetic mixed modelling in a Bayesian framework to show that passerine species that succeed in colonizing at least one of 12 European cities are more likely to belong to big-brained lineages than species avoiding these urban areas. These data support findings linking relative brain size with the ability to persist in novel and changing environments in vertebrate populations, and have important implications for our understanding of recent trends in biodiversity.

  • 48. Maklakov, Alexei A.
    et al.
    Immler, Simone
    Gonzalez-Voyer, Alejandro
    Rönn, Johanna
    Kolm, Niclas
    Uppsala universitet, Zooekologi.
    Brains and the city in passerine birds: re-analysis and confirmation of the original result2013In: Biology Letters, ISSN 1744-9561, E-ISSN 1744-957X, Vol. 9, no 6, article id 20130859Article in journal (Refereed)
    Abstract [en]

    Our original paper [1] included two Bayesian analyses [2] of the association between brain size and the probability of a passerine species of bird breeding in the city centre—at the level of families and at the level of individual species—with both analyses suggesting the same pattern. It has since been brought to our attention that in one of the analyses at the level of individual species, the residual variance was not fixed to 1 resulting in overestimation of the variance. We re-ran the analysis using fixed residual variance and the results support the original conclusion that relative brain size is associated with breeding in the city centre (ln brain size: posterior mean, 324.53, 95% credibility interval, 52.61–601.35; ln body size: posterior mean, −276.22, 95% credibility interval, −490.60 to −70.32). Furthermore, we applied a complimentary approach using logistic regression to test whether brain size predicts breeding in the city centre (yes/no) without accounting for phylogeny. This analysis also resulted in a significant positive association between brain size and breeding in city centres (likelihood ratio tests: ln brain size: d.f. = 1, χ2 = 11.08, p = 0.0009; ln body size: d.f. = 1, χ2 = 11.26, p = 0.0008). Thus, our results are confirmed by both phylogenetic and non-phylogenetic analyses.

  • 49.
    Maklakov, Alexei A.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal ecology.
    Immler, Simone
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Evolutionary Biology.
    Gonzalez-Voyer, Alejandro
    Rönn, Johanna
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal ecology.
    Kolm, Niclas
    Brains and the city in passerine birds: re-analysis and confirmation of the original result2013In: Biology Letters, ISSN 1744-9561, E-ISSN 1744-957X, Vol. 9, no 6, p. 20130859-Article in journal (Refereed)
    Abstract [en]

    Our original paper [1] included two Bayesian analyses [2] of the association between brain size and the probability of a passerine species of bird breeding in the city centre—at the level of families and at the level of individual species—with both analyses suggesting the same pattern. It has since been brought to our attention that in one of the analyses at the level of individual species, the residual variance was not fixed to 1 resulting in overestimation of the variance. We re-ran the analysis using fixed residual variance and the results support the original conclusion that relative brain size is associated with breeding in the city centre (ln brain size: posterior mean, 324.53, 95% credibility interval, 52.61–601.35; ln body size: posterior mean, −276.22, 95% credibility interval, −490.60 to −70.32). Furthermore, we applied a complimentary approach using logistic regression to test whether brain size predicts breeding in the city centre (yes/no) without accounting for phylogeny. This analysis also resulted in a significant positive association between brain size and breeding in city centres (likelihood ratio tests: ln brain size: d.f. = 1, χ2 = 11.08, p = 0.0009; ln body size: d.f. = 1, χ2 = 11.26, p = 0.0008). Thus, our results are confirmed by both phylogenetic and non-phylogenetic analyses.

  • 50.
    Maklakov, Alexei A.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Animal Ecology.
    Kremer, Natacha
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Animal Ecology.
    Arnqvist, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Animal Ecology.
    Ageing and the evolution of female resistance to remating in seed beetles2006In: Biology Letters, ISSN 1744-9561, E-ISSN 1744-957X, Vol. 2, no 1, p. 62-64Article in journal (Refereed)
    Abstract [en]

    Female remating behaviour is a key mating system parameter that is predicted to evolve according to the net effect of remating on female fitness. In many taxa, females commonly resist male remating attempts because of the costs of mating. Here, we use replicated populations of the seed beetle Acanthoscelides obtectus selected for either early or late life reproduction and show that 'Early' and 'Late' females evolved different age-specific rates of remating. Early females were more likely to remate with control males as they aged, while Late females were more resistant to remating later in life. Thus, female remating rate decreases with age when direct selection on late-life fitness is operating and increases when such selection is relaxed. Our findings not only demonstrate that female resistance to remating can evolve rapidly, but also that such evolution is in accordance with the genetic interests of females.

12 1 - 50 of 82
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