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  • 1.
    Betzholtz, Per-Eric
    et al.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Pettersson, Lars B
    Lund University.
    Ryrholm, Nils
    University of Gävle.
    Franzén, Markus
    Helmholtz Centre for Environmental Research, Germany.
    With that diet, you will go far: trait-based analysis reveals a link between rapid range expansion and a nitrogen-favoured diet.2013In: Proceedings of the Royal Society of London. Biological Sciences, ISSN 0962-8452, E-ISSN 1471-2954, Vol. 280, no 1750, article id 20122305Article in journal (Refereed)
    Abstract [en]

    Recent global change has had a substantial influence on the distribution of organisms, and many species are currently expanding their ranges. To evaluate the underlying processes, long-term data with good geographic resolution are essential. One important but generally overlooked data source is offered by the taxon-specific national catalogues of first provincial records that are kept in many countries. Here, we use such data to quantify trait-based influences on range expansion in Swedish butterflies and moths between 1973 and 2010. Of 282 species meeting pre-defined quality criteria, 170 expanded their northern range margin, with a mean expansion rate of 2.7 km per year. The analyses demonstrate that habitat and diet generalists, forest species and species active during warm conditions have expanded their ranges more rapidly than other species. Notably, range expansion in diet specialists was positively related to a nitrogen-favoured larval diet, an effect not found among oligo- or polyphagous species. In contrast to the general view, this shows that specialist species can undergo rapid range expansion. We suggest that increased areas of nitrogen-rich habitat, and increased availability of a nitrogen-favoured diet, are among the most important drivers of range expansions, potentially having far-reaching consequences for a wide variety of organisms.

  • 2.
    Broman, Elias
    et al.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Brüsin, Martin
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Dopson, Mark
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Hylander, Samuel
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Oxygenation of anoxic sediments triggers hatching of zooplankton eggs2015In: Proceedings of the Royal Society of London. Biological Sciences, ISSN 0962-8452, E-ISSN 1471-2954, Vol. 282, no 1817, article id 20152025Article in journal (Refereed)
    Abstract [en]

    Many coastal marine systems have extensive areas with anoxic sediments and it is not well known how these conditions affect the benthic-pelagic coupling. Zooplankton lay their eggs in the pelagic zone, and some sink and lie dormant in the sediment, before hatched zooplankton return to the water column. In this study, we investigated how oxygenation of long-term anoxic sediments affects the hatching frequency of dormant zooplankton eggs. Anoxic sediments from the brackish Baltic Sea were sampled and incubated for 26 days with constant aeration whereby, the sediment surface and the overlying water were turned oxic. Newly hatched rotifers and copepod nauplii (juveniles) were observed after 5 and 8 days, respectively. Approximately 1.5 × 105 nauplii per m-2 emerged from sediment turned oxic compared to 0.02 × 105 m-2 from controls maintained anoxic. This study demonstrated that re-oxygenation of anoxic sediments activated a large pool of buried zooplankton eggs, strengthening the benthic-pelagic coupling of the system. Modelling of the studied anoxic zone suggested that a substantial part of the pelagic copepod population can derive from hatching of dormant eggs. We suggest that this process should be included in future studies to understand population dynamics and carbon flows in marine pelagic systems.

  • 3.
    Broman, Elias
    et al.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Sachpazidou, Varvara
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Dopson, Mark
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Hylander, Samuel
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Diatoms dominate the eukaryotic metatranscriptome during spring in coastal 'dead zone' sediments2017In: Proceedings of the Royal Society of London. Biological Sciences, ISSN 0962-8452, E-ISSN 1471-2954, Vol. 284, no 1864, article id 20171617Article in journal (Refereed)
    Abstract [en]

    An important characteristic of marine sediments is the oxygen concentration that affects many central metabolic processes. There has been a widespread increase in hypoxia in coastal systems (referred to as 'dead zones') mainly caused by eutrophication. Hence, it is central to understand the metabolism and ecology of eukaryotic life in sediments during changing oxygen conditions. Therefore, we sampled coastal 'dead zone' Baltic Sea sediment during autumn and spring, and analysed the eukaryotic metatranscriptome from field samples and after incubation in the dark under oxic or anoxic conditions. Bacillariophyta (diatoms) dominated the eukaryotic metatranscriptome in spring and were also abundant during autumn. A large fraction of the diatom RNA reads was associated with the photosystems suggesting a constitutive expression in darkness. Microscope observation showed intact diatom cells and these would, if hatched, represent a significant part of the pelagic phytoplankton biomass. Oxygenation did not significantly change the relative proportion of diatoms nor resulted in any major shifts in metabolic 'signatures'. By contrast, diatoms rapidly responded when exposed to light suggesting that light is limiting diatom development in hypoxic sediments. Hence, it is suggested that diatoms in hypoxic sediments are on 'standby' to exploit the environment if they reach suitable habitats.

  • 4.
    Forsman, Anders
    et al.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Betzholtz, Per-Eric
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Franzén, Markus
    Helmholtz Centre for Environmental Research, Germany.
    Variable coloration is associated with dampened population fluctuations in noctuid moths2015In: Proceedings of the Royal Society of London. Biological Sciences, ISSN 0962-8452, E-ISSN 1471-2954, Vol. 282, no 1808, p. 1-9, article id 20142922Article in journal (Refereed)
    Abstract [en]

    Theory and recent reviews state that greater genetic and phenotypic variation should be beneficial for population abundance and stability. Experimental evaluations of this prediction are rare, of short duration and conducted under controlled environmental settings. The question whether greater diversity in functionally important traits stabilizes populations under more complex ecological conditions in the wild has not been systematically evaluated. Moths are mainly nocturnal, with a large variation in colour patterns among species, and constitute an important food source for many types of organisms. Here, we report the results of a long-term (2003-2013) monitoring study of 115 100 noctuid moths from 246 species. Analysis of time-series data provide rare evidence that species with higher levels of inter-individual variation in colour pattern have higher average abundances and undergo smaller between-year fluctuations compared with species having less variable colour patterns. The signature of interspecific temporal synchronization of abundance fluctuations was weak, suggesting that the dynamics were driven by species-specific biotic interactions rather than by some common, density-independent factor(s). We condude that individual variation in colour patterns dampens population abundance fluctuations, and suggest that this may partly reflect that colour pattern polymorphism provides protection from visually oriented predators and parasitoids.

  • 5.
    Forsman, Anders
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Merilä, Juha
    University of Helsinki.
    Ebenhard, Torbjörn
    Swedish Biodiversity Centre.
    Phenotypic evolution of dispersal-enhancing traits in insular voles2011In: Proceedings of the Royal Society of London. Biological Sciences, ISSN 0962-8452, E-ISSN 1471-2954, Vol. 278, no 1703, p. 225-232Article in journal (Refereed)
    Abstract [en]

    Evolutionary theory predicts that in metapopulations subject to rapid extinction-recolonization dynamics, natural selection should favour evolution of traits that enhance dispersal and recolonization ability. Metapopulations of field voles (Microtus agrestis) on islands in the Stockholm archipelago, Sweden, are characterized by frequent local extinction and recolonization of subpopulations. Here, we show that voles on the islands were larger and had longer feet than expected for their body size, compared with voles from the mainland; that body size and size-specific foot length increased with increasing geographical isolation and distance from mainland; and that the differences in body size and size-specific foot length were genetically based. These findings provide rare evidence for relatively recent (less than 1000 years) and rapid (corresponding to 100-250 darwins) evolution of traits facilitating dispersal and recolonization in island metapopulations.

  • 6.
    Forsman, Anders
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Wennersten, Lena
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Karlsson, Magnus
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Caesar, Sofia
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Variation in founder groups promotes establishment success in the wild2012In: Proceedings of the Royal Society of London. Biological Sciences, ISSN 0962-8452, E-ISSN 1471-2954, Vol. 279, no 1739, p. 2800-2806Article in journal (Refereed)
    Abstract [en]

    Environmental changes currently pose severe threats to biodiversity, and reintroductions and translocations are increasingly used to protect declining populations and species from extinction. Theory predicts that establishment success should be higher for more variable groups of dissimilar individuals. To test this ‘diversity promotes establishment’ hypothesis, we introduced colour polymorphic pygmy grasshoppers (Tetrix subulata) to different sites in the wild. The number of descendants found at the release sites the subsequent year increased with increasing number of colour morphs in the founder group, and variation in founder groups also positively affected colour morph diversity in the established populations. Since colour morphs differ in morphology, physiology, behaviour, reproductive life history and types of niche used, these findings demonstrate that variation among individuals in functionally important traits promotes establishment success under natural conditions, and further indicate that founder diversity may contribute to evolutionary rescue and increased population persistence.

  • 7.
    Hansson, Lars-Anders
    et al.
    Lunds universitet.
    Hylander, Samuel
    Lunds universitet.
    Size-structured risk assessments govern Daphnia migration2009In: Proceedings of the Royal Society of London. Biological Sciences, ISSN 0962-8452, E-ISSN 1471-2954, Vol. 276, no 1655, p. 331-336Article in journal (Refereed)
    Abstract [en]

    One of the more fascinating phenomena in nature is animal mass migrations and in oceans and freshwaters, diel variations in depth distribution of zooplankton are a phenomenon that has intrigued scientists for more than a century. In our study, we show that zooplankton are able to assess the threat level of ultraviolet radiation and adjust their depth distribution to this level at a very fine tuned scale. Moreover, predation risk induces a size-structured depth separation, such that small individuals, which we show are less vulnerable to predation than larger, make a risk assessment and continue feeding in surface waters during day, offering a competitive release from down-migrating larger animals. Hence, we mechanistically show that such simple organisms as invertebrate zooplankton are able to make individual, size-specific decisions regarding how to compromise between threats from both predators and UV radiation, and adjust their diel migratory patterns accordingly.

  • 8.
    Hylander, Samuel
    et al.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Ekvall, Mikael T
    Lund University.
    Bianco, Giuseppe
    Lund University.
    Yang, Xi
    Lund University.
    Hansson, Lars-Anders
    Lund University.
    Induced tolerance expressed as relaxed behavioural threat response in millimetre-sized aquatic organisms2014In: Proceedings of the Royal Society of London. Biological Sciences, ISSN 0962-8452, E-ISSN 1471-2954, Vol. 281, no 1788, p. Article ID: 20140364-Article in journal (Refereed)
    Abstract [en]

    Natural selection shapes behaviour in all organisms, but this is difficult to study in small, millimetre-sized, organisms. With novel labelling and tracking techniques, based on nanotechnology, we here show how behaviour in zooplankton (Daphnia magna) is affected by size, morphology and previous exposure to detrimental ultraviolet radiation (UVR). All individuals responded with immediate downward swimming to UVR exposure, but when released from the threat they rapidly returned to the surface. Large individuals swam faster and generally travelled longer distances than small individuals. Interestingly, individuals previously exposed to UVR (during several generations) showed a more relaxed response to UVR and travelled shorter total distances than those that were naive to UVR, suggesting induced tolerance to the threat. In addition, animals previously exposed to UVR also had smaller eyes than the naive ones, whereas UVR-protective melanin pigmentation of the animals was similar between populations. Finally, we show that smaller individuals have lower capacity to avoid UVR which could explain patterns in natural systems of lower migration amplitudes in small individuals. The ability to change behavioural patterns in response to a threat, in this case UVR, adds to our understanding of how organisms navigate in the ‘landscape of fear’, and this has important implications for individual fitness and for interaction strengths in biotic interactions.

  • 9.
    Härlin, Mikael
    Växjö University, Faculty of Mathematics/Science/Technology, Institutionen för biovetenskaper och processteknik.
    Phylogenetic approaches to nomenclature: a comparison based on a nemertean case study.1999In: Proceedings of the Royal Society of London. Biological Sciences, ISSN 0962-8452, E-ISSN 1471-2954, Vol. 266, no 1434, p. 2201-2207Article in journal (Refereed)
    Abstract [en]

    Phylogenetic approaches to biological nomenclature are becoming increasingly common. Here I compare the behaviour of two such approaches, the phylogenetic system of definition and the phylogenetic system of reference, when there is a shift in the preference of phylogenetic hypotheses. The comparison is based on a case study from nemertean systematics and is the first to compare two different phylogenetic approaches throughout three stages of change, including two stages of phylogenetic nomenclature. It is concluded that a phylogenetic system of reference in combination with uninomials is superior in conveying phylogenetic information.

  • 10.
    Latorre-Margalef, Neus
    et al.
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Gunnarsson, Gunnar
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Munster, V J
    Fouchier, R A M
    Osterhaus, A D M E
    Elmberg, J
    Olsen, Björn
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Wallensten, Anders
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Fransson, T
    Brudin, Lars
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Waldenström, Jonas
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Does Influenza A affect body condition of wild mallard ducks, or vice versa? A reply to Flint & Franson2009In: Proceedings of the Royal Society of London. Biological Sciences, ISSN 0962-8452, E-ISSN 1471-2954, Vol. 276, no 1666, p. 2347-2349Article in journal (Refereed)
  • 11.
    Latorre-Margalef, Neus
    et al.
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Gunnarsson, Gunnar
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Munster, V.J.
    Fouchier, R.A.M.
    Osterhaus, A.D.M.E.
    Elmberg, Johan
    Olsen, Björn
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Wallensten, Anders
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Haemig, Paul D.
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Fransson, Thord
    Brudin, Lars
    University of Kalmar, School of Pure and Applied Natural Sciences. Kalmar County Hospital.
    Waldenström, Jonas
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Effects of influenza A virus infection on migrating mallard ducks2009In: Proceedings of the Royal Society of London. Biological Sciences, ISSN 0962-8452, E-ISSN 1471-2954, Vol. 276, no 1659, p. 1029-1036Article in journal (Refereed)
    Abstract [en]

    The natural reservoir of influenza A virus is waterfowl, particularly dabbling ducks (genus Anas). Although it has long been assumed that waterfowl are asymptomatic carriers of the virus, a recent study found that low-pathogenic avian influenza (LPAI) infection in Bewick's swans (Cygnus columbianus bewickii) negatively affected stopover time, body mass and feeding behaviour. In the present study, we investigated whether LPAI infection incurred ecological or physiological costs to migratory mallards (Anas platyrhynchos) in terms of body mass loss and staging time, and whether such costs could influence the likelihood for long-distance dispersal of the avian influenza virus by individual ducks. During the autumn migrations of 2002-2007, we collected faecal samples (n = 10 918) and biometric data from mallards captured and banded at Ottenby, a major staging site in a flyway connecting breeding and wintering areas of European waterfowl. Body mass was significantly lower in infected ducks than in uninfected ducks (mean difference almost 20 g over all groups), and the amount of virus shed by infected juveniles was negatively correlated with body mass. There was no general effect of infection on staging time, except for juveniles in September, in which birds that shed fewer viruses stayed shorter than birds that shed more viruses. LPAI infection did not affect speed or distance of subsequent migration. The data from recaptured individuals showed that the maximum duration of infection was on average 8.3 days (s.e. 0.5), with a mean minimum duration of virus shedding of only 3.1 days (s.e. 0.1). Shedding time decreased during the season, suggesting that mallards acquire transient immunity for LPAI infection. In conclusion, deteriorated body mass following infection was detected, but it remains to be seen whether this has more long-term fitness effects. The short virus shedding time suggests that individual mallards are less likely to spread the virus at continental or intercontinental scales.

  • 12.
    Latorre-Margalef, Neus
    et al.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science. Univ Georgia, Dept Populat Hlth, Coll Vet Med, Southeastern Cooperat Wildlife Dis Study, Athens, GA 30602 USA.
    Tolf, Conny
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Grosbois, Vladimir
    Int Res Ctr Agr Dev CIRAD UPR AGIRs, Anim & Integrate Risk Management, F-34398 Montpellier, France.
    Avril, Alexis
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Bengtsson, Daniel
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Wille, Michelle
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Osterhaus, Albert D M E
    Erasmus MC, Dept Virol, Rotterdam, Netherlands.
    Fouchier, Ron A M
    Erasmus MC, Dept Virol, Rotterdam, Netherlands.
    Olsen, Björn
    Uppsala Univ.
    Waldenström, Jonas
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Long-term variation in influenza A virus prevalence and subtype diversity in migratory mallards in northern Europe.2014In: Proceedings of the Royal Society of London. Biological Sciences, ISSN 0962-8452, E-ISSN 1471-2954, Vol. 281, no 1781, p. Article ID: UNSP 20140098-Article in journal (Refereed)
    Abstract [en]

    Data on long-term circulation of pathogens in wildlife populations are seldom collected, and hence understanding of spatial-temporal variation in prevalence and genotypes is limited. Here, we analysed a long-term surveillance series on influenza A virus (IAV) in mallards collected at an important migratory stopover site from 2002 to 2010, and characterized seasonal dynamics in virus prevalence and subtype diversity. Prevalence dynamics were influenced by year, but retained a common pattern for all years whereby prevalence was low in spring and summer, but increased in early autumn with a first peak in August, and a second more pronounced peak during October-November. A total of 74 haemagglutinin (HA)/neuraminidase (NA) combinations were isolated, including all NA and most HA (H1-H12) subtypes. The most common subtype combinations were H4N6, H1N1, H2N3, H5N2, H6N2 and H11N9, and showed a clear linkage between specific HA and NA subtypes. Furthermore, there was a temporal structuring of subtypes within seasons based on HA phylogenetic relatedness. Dissimilar HA subtypes tended to have different temporal occurrence within seasons, where the subtypes that dominated in early autumn were rare in late autumn, and vice versa. This suggests that build-up of herd immunity affected IAV dynamics in this system.

  • 13.
    Malmström, Helena
    et al.
    Uppsala University, Sweden;Univ Johannesburg, South Africa.
    Gunther, Torsten
    Uppsala University, Sweden.
    Svensson, Emma M.
    Uppsala University, Sweden.
    Juras, Anna
    Adam Mickiewia Univ Poznan, Poland.
    Fraser, Magdalena
    Uppsala University, Sweden.
    Munters, Arielle R.
    Uppsala University, Sweden.
    Pospieszny, Lukasz
    Univ Bristol, UK;Polish Acad Sci, Poland.
    Torv, Mari
    Univ Tartu, Estonia.
    Lindström, Jonathan
    Linnaeus University, Faculty of Arts and Humanities, Department of Cultural Sciences.
    Gotherström, Anders
    Stockholm University, Sweden.
    Stora, Jan
    Stockholm University, Sweden.
    Jakobsson, Mattias
    Uppsala University, Sweden;Univ Johannesburg, South Africa.
    The genomic ancestry of the Scandinavian Battle Axe Culture people and their relation to the broader Corded Ware horizon2019In: Proceedings of the Royal Society of London. Biological Sciences, ISSN 0962-8452, E-ISSN 1471-2954, Vol. 286, no 1912, p. 1-8, article id 20191528Article in journal (Refereed)
    Abstract [en]

    The Neolithic period is characterized by major cultural transformations and human migrations, with lasting effects across Europe. To understand the population dynamics in Neolithic Scandinavia and the Baltic Sea area, we investigate the genomes of individuals associated with the Battle Axe Culture (BAC), a Middle Neolithic complex in Scandinavia resembling the continental Corded Ware Culture (CWC). We sequenced 11 individuals (dated to 3330-1665 calibrated before common era (cal BCE)) from modern-day Sweden, Estonia, and Poland to 0.26-3.24x coverage. Three of the individuals were from CWC contexts and two from the central-Swedish BAC burial 'Bergsgraven'. By analysing these genomes together with the previously published data, we show that the BAC represents a group different from other Neolithic populations in Scandinavia, revealing stratification among cultural groups. Similar to continental CWC, the BAC-associated individuals display ancestry from the Pontic-Caspian steppe herders, as well as smaller components originating from hunter-gatherers and Early Neolithic farmers. Thus, the steppe ancestry seen in these Scandinavian BAC individuals can be explained only by migration into Scandinavia. Furthermore, we highlight the reuse of megalithic tombs of the earlier Funnel Beaker Culture (FBC) by people related to BAC. The BAC groups likely mixed with resident middle Neolithic farmers (e.g. FBC) without substantial contributions from Neolithic foragers.

  • 14.
    Nordahl, Oscar
    et al.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Tibblin, Petter
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Koch-Schmidt, Per
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Berggren, Hanna
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Larsson, Per
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Forsman, Anders
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Sun-basking fish benefit from body temperatures that are higher than ambient water2018In: Proceedings of the Royal Society of London. Biological Sciences, ISSN 0962-8452, E-ISSN 1471-2954, Vol. 285, no 1879, article id 20180639Article in journal (Refereed)
    Abstract [en]

    In terrestrial environments, cold-blooded animals can attain higher bodytemperatures by sun basking, and thereby potentially benefit from broaderniches, improved performance and higher fitness. The higher heat capacityand thermal conductivity of water compared with air have been universallyassumed to render heat gain from sun basking impossible for aquaticectotherms, such that their opportunities to behaviourally regulate body temperatureare largely limited to choosing warmer or colder habitats. Here wechallenge this paradigm. Using physical modelswe first showthat submergedobjects exposed to natural sunlight attain temperatures in excess of ambientwater. We next demonstrate that free-ranging carp (Cyprinus carpio) canincrease their body temperature during aquatic sun basking close to thesurface. The temperature excess gained by basking was larger in dark thanin pale individuals, increased with behavioural boldness, and was associatedwith faster growth. Overall, our results establish aquatic sun basking as a novelecologically significant mechanism for thermoregulation in fish. The discoveryof this previously overlooked process has practical implications for aquaculture,offers alternative explanations for behavioural and phenotypicadaptations, will spur future research in fish ecology, and calls for modificationsof models concerning climate change impacts on biodiversity inmarine and freshwater environments.

  • 15.
    Thorley, Jack
    et al.
    Univ Cambridge, UK;Kalahari Res Ctr, South Africa.
    Katlein, Nathan
    Kalahari Res Ctr, South Africa;Univ S Alabama, USA.
    Goddard, Katy
    Kalahari Res Ctr, South Africa;Univ Lincoln, UK.
    Zöttl, Markus
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science. Univ Cambridge, UK;Kalahari Res Ctr, South Africa.
    Clutton-Brock, Tim
    Univ Cambridge, UK;Kalahari Res Ctr, South Africa;Univ Pretoria, South Africa.
    Reproduction triggers adaptive increases in body size in female mole-rats2018In: Proceedings of the Royal Society of London. Biological Sciences, ISSN 0962-8452, E-ISSN 1471-2954, Vol. 285, no 1880, article id 20180897Article in journal (Refereed)
    Abstract [en]

    In social mole-rats, breeding females are larger and more elongated than non-breeding female helpers. This status-related morphological divergence is thought to arise from modifications of skeletal growth following the death or removal of the previous breeder and the transition of their successors from a non-breeding to a breeding role. However, it is not clear what changes in growth are involved, whether they are stimulated by the relaxation of reproductive suppression or by changes in breeding status, or whether they are associated with fecundity increases. Here, we show that, in captive Damaraland mole-rats (Fukomys damarensis), where breeding was experimentally controlled in age-matched siblings, individuals changed in size and shape through a lengthening of the lumbar vertebrae when they began breeding. This skeletal remodelling results from changes in breeding status because (i) females removed from a group setting and placed solitarily showed no increases in growth and (ii) females dispersing from natural groups that have not yet bred do not differ in size and shape from helpers in established groups. Growth patterns consequently resemble other social vertebrates where contrasts in size and shape follow the acquisition of the breeding role. Our results also suggest that the increases in female body size provide fecundity benefits. Similar forms of socially responsive growth might be more prevalent in vertebrates than is currently recognized, but the extent to which this is the case, and the implications for the structuring of mammalian dominance hierarchies, are as yet poorly understood.

  • 16.
    Wennersten, Lena
    et al.
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Forsman, Anders
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Does colour polymorphism enhance survival of prey populations?2009In: Proceedings of the Royal Society of London. Biological Sciences, ISSN 0962-8452, E-ISSN 1471-2954, Vol. 276, no 1665, p. 2187-2194Article in journal (Refereed)
    Abstract [en]

    That colour polymorphism may protect prey populations from predation is an old but rarely tested hypothesis. We examine whether colour polymorphic populations of prey exposed to avian predators in an ecologically valid visual context were exposed to increased extinction risk compared with monomorphic populations. We made 2976 artificial pastry prey, resembling Lepidoptera larvae, in four different colours and presented them in 124 monomorphic and 124 tetramorphic populations on tree trunks and branches such that they would be exposed to predation by free-living birds, and monitored their 'survival'. Among monomorphic populations, there was a significant effect of prey coloration on survival, confirming that coloration influenced susceptibility to visually oriented predators. Survival of polymorphic populations was inferior to that of monomorphic green populations, but did not differ significantly from monomorphic brown, yellow or red populations. Differences in survival within polymorphic populations paralleled those seen among monomorphic populations; the red morph most frequently went extinct first and the green morph most frequently survived the longest. Our findings do not support the traditional protective polymorphism hypothesis and are in conflict with those of earlier studies. As a possible explanation to our findings, we offer a competing 'giveaway cue' hypothesis: that polymorphic populations may include one morph that attracts the attention of predators and that polymorphic populations therefore may suffer increased predation compared with some monomorphic populations.

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