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  • 1.
    Andersson, Jens
    et al.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Johansson, Frank
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Söderlund, Tony
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Interactions between predator- and diet-induced phenotypic changes in body shape of crucian carp2006In: Proceedings of the Royal Society of London. Biological Sciences, ISSN 0962-8452, E-ISSN 1471-2954, Vol. 273, no 1585, p. 431-437Article in journal (Refereed)
    Abstract [en]

    Predator cues and diet, when studied separately, have been shown to affect body shape of organisms. Previous studies show that the morphological responses to predator absence/presence and diet may be similar, and hence could confound the interpretation of the causes of morphological differences found between groups of individuals. In this study, we simultaneously examined the effect of these two factors on body shape and performance in crucian carp in a laboratory experiment. Crucian carp (Carassius carassius) developed a shallow body shape when feeding on zooplankton prey and a deep body shape when feeding on benthic chironomids. In addition, the presence of chemical cues from a pike predator affected body shape, where a shallow body shape was developed in the absence of pike and a deep body shape was developed in the presence of pike. Foraging activity was low in the presence of pike cues and when chironomids were given as prey. Our results thereby suggest that the change in body shape could be indirectly mediated through differences in foraging activity. Finally, the induced body shape changes affected the foraging efficiency, where crucians raised on a zooplankton diet or in the absence of pike cues had a higher foraging success on zooplankton compared to crucian raised on a chironomid diet or in the presence of pike. These results suggest that body changes in response to predators can be associated with a cost, in terms of competition for resources.

  • 2.
    Bokma, Folmer
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Problems detecting density-dependent diversification on phylogenies2009In: Proceedings of the Royal Society of London. Biological Sciences, ISSN 0962-8452, E-ISSN 1471-2954, Vol. 276, no 1659, p. 993-994Article in journal (Refereed)
  • 3.
    Calatayud, Joaquín
    et al.
    Umeå University, Faculty of Science and Technology, Department of Physics. Departamento de Ciencias de la Vida, Universidad de Alcala´, Edificio de Ciencias, Ctra. Madrid-Barcelona km. 33,6, Alcala´ de Henares, 28871 Madrid, Spain; Department of Biogeography and Global Change, Museo Nacional de Ciencias Naturales (MNCN-CSIC), C/Jose´ Gutie´rrez Abascal 2, 28006 Madrid, Spain.
    Angel Rodriguez, Miguel
    Molina-Venegas, Rafael
    Leo, Maria
    Luis Horreo, Jose
    Hortal, Joaquin
    Pleistocene climate change and the formation of regional species pools2019In: Proceedings of the Royal Society of London. Biological Sciences, ISSN 0962-8452, E-ISSN 1471-2954, Vol. 286, no 1905, article id 20190291Article in journal (Refereed)
    Abstract [en]

    Although the description of bioregions dates back to the origin of biogeography, the processes originating their associated species pools hive been seldom studied. Ancient historical events are thought to play a fundamental role in configuring bioregions, but the effects of more recent events on these regional biotas are largely unknown. We used a network approach to identify regional and sub-regional faunas of European Carabus beetles and developed a method to explore the relative contribution of dispersal barriers, niche similarities and phylogenetic history on their configuration. We identify a transition zone matching the limit of the ice sheets at the Last Glacial Maximum. While southern species pools are mostly separated by dispersal barriers, in the north species are mainly sorted by their environmental niches. Strikingly, most phylogenetic structuration of Carabus faunas occurred during the Pleistocene. Our results show how extreme recent historical events - such as Pleistocene climate cooling, rather than just deep-time evolutionary processes-can profoundly modify the composition and structure of geographical species pools.

  • 4. Chen, Xiaojie
    et al.
    Brännström, Åke
    Umeå University, Faculty of Science and Technology, Department of Mathematics and Mathematical Statistics. Evolution and Ecology Program, International Institute for Applied Systems Analysis (IIASA), Laxenburg, Austria.
    Dieckmann, Ulf
    Parent-preferred dispersal promotes cooperation in structured populations2019In: Proceedings of the Royal Society of London. Biological Sciences, ISSN 0962-8452, E-ISSN 1471-2954, Vol. 286, no 1895, article id 20181949Article in journal (Refereed)
    Abstract [en]

    Dispersal is a key process for the emergence of social and biological behaviours. Yet, little attention has been paid to dispersal's effects on the evolution of cooperative behaviour in structured populations. To address this issue, we propose two new dispersal modes, parent-preferred and offspring-preferred dispersal, incorporate them into the birth-death update rule, and consider the resultant strategy evolution in the prisoner's dilemma on random-regular, small-world, and scale-free networks, respectively. We find that parent-preferred dispersal favours the evolution of cooperation in these different types of population structures, while offspring-preferred dispersal inhibits the evolution of cooperation in homogeneous populations. On scale-free networks when the strength of parent-preferred dispersal is weak, cooperation can be enhanced at intermediate strengths of offspring-preferred dispersal, and cooperators can coexist with defectors at high strengths of offspring-preferred dispersal. Moreover, our theoretical analysis based on the pair-approximation method corroborates the evolutionary outcomes on random-regular networks. We also incorporate the two new dispersal modes into three other update rules (death-birth, imitation, and pairwise comparison updating), and find that similar results about the effects of parent-preferred and offspring-preferred dispersal can again be observed in the aforementioned different types of population structures. Our work, thus, unveils robust effects of preferential dispersal modes on the evolution of cooperation in different interactive environments.

  • 5.
    Cherif, Mehdi
    et al.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Loreau, Michel
    Plant - herbivore -decomposer stoichiometric mismatches and nutrientcycling in ecosystems2013In: Proceedings of the Royal Society of London. Biological Sciences, ISSN 0962-8452, E-ISSN 1471-2954, Vol. 280, no 1754, p. 20122453-Article in journal (Refereed)
    Abstract [en]

    Plant stoichiometry is thought to have a major influence on how herbivores affect nutrient availability in ecosystems. Most conceptual models predict that plants with high nutrient contents increase nutrient excretion by herbivores, in turn raising nutrient availability. To test this hypothesis, we built a stoichiometrically explicit model that includes a simple but thorough description of the processes of herbivory and decomposition. Our results challenge traditional views of herbivore impacts on nutrient availability in many ways. They show that the relationship between plant nutrient content and the impact of herbivores predicted by conceptual models holds only at high plant nutrient contents. At low plant nutrient contents, the impact of herbivores is mediated by the mineralization/immobilization of nutrients by decomposers and by the type of resource limiting the growth of decomposers. Both parameters are functions of the mismatch between plant and decomposer stoichiometries. Our work provides new predictions about the impacts of herbivores on ecosystemfertility that depend on critical interactions between plant, herbivore and decomposer stoichiometries in ecosystems.

  • 6.
    Cherif, Mehdi
    et al.
    Department of Biology, McGill University.
    Loreau, Michel
    Department of Biology, McGill University.
    When microbes and consumers determine the limiting nutrient of autotrophs: a theoretical analysis2009In: Proceedings of the Royal Society of London. Biological Sciences, ISSN 0962-8452, E-ISSN 1471-2954, Vol. 276, no 1656, p. 487-497Article in journal (Refereed)
    Abstract [en]

    Ecological stoichiometry postulates that differential nutrient recycling of elements such as nitrogen and phosphorus by consumers can shift the element that limits plant growth. However, this hypothesis has so far considered the effect of consumers, mostly herbivores, out of their food-web context. Microbial decomposers are important components of food webs, and might prove as important as consumers in changing the availability of elements for plants. In this theoretical study, we investigate how decomposers determine the nutrient that limits plants, both by feeding on nutrients and organic carbon released by plants and consumers, and by being fed upon by omnivorous consumers. We show that decomposers can greatly alter the relative availability of nutrients for plants. The type of limiting nutrient promoted by decomposers depends on their own elemental composition and, when applicable, on their ingestion by consumers. Our results highlight the limitations of previous stoichiometric theories of plant nutrient limitation control, which often ignored trophic levels other than plants and herbivores. They also suggest that detrital chains play an important role in determining plant nutrient limitation in many ecosystems.

  • 7.
    Cote, Julien
    et al.
    Department of Environmental Science and Policy, University of California, Davis, CA, USA .
    Fogarty, Sean
    Brodin, Tomas
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Weinersmith, Kelly
    Sih, Andrew
    Personality-dependent dispersal in the invasive mosquitofish: group composition matters2011In: Proceedings of the Royal Society of London. Biological Sciences, ISSN 0962-8452, E-ISSN 1471-2954, Vol. 278, no 1712, p. 1670-1678Article in journal (Refereed)
    Abstract [en]

    Understanding/predicting ecological invasions is an important challenge in modern ecology because of their immense economical and ecological costs. Recent studies have revealed that within-species variation in behaviour (i.e. animal personality) can shed light on the invasion process. The general hypothesis is that individuals' personality type may affect their colonization success, suggesting that some individuals might be better invaders than others. We have recently shown that, in the invasive mosquitofish (Gambusia affinis), social personality trait was an important indicator of dispersal distance, with more asocial individuals dispersing further. Here, we tested how mean personality within a population, in addition to individual personality type, affect dispersal and settlement decisions in the mosquitofish. We found that individual dispersal tendencies were influenced by the population's mean boldness and sociability score. For example, individuals from populations with more asocial individuals or with more bold individuals are more likely to disperse regardless of their own personality type. We suggest that identifying behavioural traits facilitating invasions, even at the group level, can thus have direct applications in pest management.

  • 8. Cote, Julien
    et al.
    Fogarty, Sean
    Tymen, Blaise
    Sih, Andrew
    Brodin, Tomas
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Personality-dependent dispersal cancelled under predation risk2013In: Proceedings of the Royal Society of London. Biological Sciences, ISSN 0962-8452, E-ISSN 1471-2954, Vol. 280, no 1773, p. 20132349-Article in journal (Refereed)
    Abstract [en]

    Dispersal is a fundamental life-history trait for many ecological processes. Recent studies suggest that dispersers, in comparison to residents, display various phenotypic specializations increasing their dispersal inclination or success. Among them, dispersers are believed to be consistently more bold, exploratory, asocial or aggressive than residents. These links between behavioural types and dispersal should vary with the cause of dispersal. However, with the exception of one study, personality-dependent dispersal has not been studied in contrasting environments. Here, we used mosquitofish (Gambusia affinis) to test whether personality-dependent dispersal varies with predation risk, a factor that should induce boldness or sociability-dependent dispersal. Corroborating previous studies, we found that dispersing mosquitofish are less social than non-dispersing fish when there was no predation risk. However, personality-dependent dispersal is negated under predation risk, dispersers having similar personality types to residents. Our results suggest that adaptive dispersal decisions could commonly depend on interactions between phenotypes and ecological contexts.

  • 9. Cote, Julien
    et al.
    Fogarty, Sean
    Weinersmith, Kelly
    Brodin, Tomas
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Sih, Andrew
    Personality traits and dispersal tendency in the invasive mosquitofish (Gambusia affinis)2010In: Proceedings of the Royal Society of London. Biological Sciences, ISSN 0962-8452, E-ISSN 1471-2954, Vol. 277, no 1687, p. 1571-1579Article in journal (Refereed)
    Abstract [en]

    Ecological invasions, where non-native species spread to new areas, grow to high densities and have large, negative impacts on ecological communities, are a major worldwide problem. Recent studies suggest that one of the key mechanisms influencing invasion dynamics is personality-dependent dispersal: the tendency for dispersers to have a different personality type than the average from a source population. We examined this possibility in the invasive mosquitofish (Gambusia affinis). We measured individual tendencies to disperse in experimental streams and several personality traits: sociability, boldness, activity and exploration tendency before and three weeks after dispersal. We found that mosquitofish display consistent behavioural tendencies over time, and significant positive correlations between all personality traits. Most notably, sociability was an important indicator of dispersal distance, with more asocial individuals dispersing further, suggesting personality-biased dispersal on an invasion front. These results could have important ecological implications, as invasion by a biased subset of individuals is likely to have different ecological impacts than invasion by a random group of colonists.

  • 10. Goncalves, Ines Braga
    et al.
    Mobley, Kenyon B
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Ahnesjö, Ingrid
    Sagebakken, Gry
    Jones, Adam G
    Kvarnemo, Charlotta
    Reproductive compensation in broad-nosed pipefish females2010In: Proceedings of the Royal Society of London. Biological Sciences, ISSN 0962-8452, E-ISSN 1471-2954, Vol. 277, no 1687, p. 1581-1587Article in journal (Refereed)
    Abstract [en]

    The differential allocation hypothesis assumes that animals should weigh costs and benefits of investing into reproduction with a current mate against the expected quality of future mates, and predicts that they should invest more into reproduction when pairing with a high-quality mate. In the broad-nosed pipefish (Syngnathus typhle), males care for the embryos in a brood pouch and females compete for access to male mating partners. Both sexes prefer mating with large partners. In the present study, we show that the same female provides both large and small mating partners with eggs of similar size, weight and lipid content when mated to two males in succession. Importantly, however, eggs provided to small males (less preferred) had higher egg protein content (11% more) than those provided to large males (preferred). Thus, contrary to the differential allocation hypothesis, eggs did not contain more resources when females mated with a larger male. Instead, the pattern observed in our results is consistent with a compensatory reproductive strategy.

  • 11.
    Hein, Catherine L.
    et al.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences. Climate Impacts Research Centre, Abisko Scientific Research Station, Abisko, Sweden .
    Öhlund, Gunnar
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Englund, Göran
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Fish introductions reveal the temperature dependence of species interactions2014In: Proceedings of the Royal Society of London. Biological Sciences, ISSN 0962-8452, E-ISSN 1471-2954, Vol. 281, no 1775, p. 20132641-Article in journal (Refereed)
    Abstract [en]

    A major area of current research is to understand how climate change will impact species interactions and ultimately biodiversity. A variety of environmental conditions are rapidly changing owing to climate warming, and these conditions often affect both the strength and outcome of species interactions. We used fish distributions and replicated fish introductions to investigate environmental conditions influencing the coexistence of two fishes in Swedish lakes: brown trout (Salmo trutta) and pike (Esox lucius). A logistic regression model of brown trout and pike coexistence showed that these species coexist in large lakes (more than 4.5 km(2)), but not in small, warm lakes (annual air temperature more than 0.9-1.5 degrees C). We then explored how climate change will alter coexistence by substituting climate scenarios for 2091-2100 into our model. The model predicts that brown trout will be extirpated from approximately half of the lakes where they presently coexist with pike and from nearly all 9100 lakes where pike are predicted to invade. Context dependency was critical for understanding pike-brown trout interactions, and, given the widespread occurrence of context-dependent species interactions, this aspect will probably be critical for accurately predicting climate impacts on biodiversity.

  • 12.
    Lind, Martin
    et al.
    Umeå University, Faculty of Science and Technology, Ecology and Environmental Science.
    Persbo, Frida
    Johansson, Frank
    Umeå University, Faculty of Science and Technology, Ecology and Environmental Science.
    Pool desiccation and developmental thresholds in the common frog, Rana temporaria.2008In: Proceedings of the Royal Society of London. Biological Sciences, ISSN 0962-8452, E-ISSN 1471-2954, Vol. 275, no 1638, p. 1073-80Article in journal (Refereed)
    Abstract [en]

    The developmental threshold is the minimum size or condition that a developing organism must have reached in order for a life-history transition to occur. Although developmental thresholds have been observed for many organisms, inter-population variation among natural populations has not been examined. Since isolated populations can be subjected to strong divergent selection, population divergence in developmental thresholds can be predicted if environmental conditions favour fast or slow developmental time in different populations. Amphibian metamorphosis is a well-studied life-history transition, and using a common garden approach we compared the development time and the developmental threshold of metamorphosis in four island populations of the common frog Rana temporaria: two populations originating from islands with only temporary breeding pools and two from islands with permanent pools. As predicted, tadpoles from time-constrained temporary pools had a genetically shorter development time than those from permanent pools. Furthermore, the variation in development time among females from temporary pools was low, consistent with the action of selection on rapid development in this environment. However, there were no clear differences in the developmental thresholds between the populations, indicating that the main response to life in a temporary pool is to shorten the development time.

  • 13.
    Nordahl, Oscar
    et al.
    Linnéuniversitetet, Institutionen för biologi och miljö (BOM).
    Tibblin, Petter
    Linnéuniversitetet, Institutionen för biologi och miljö (BOM).
    Koch-Schmidt, Per
    Linnéuniversitetet, Institutionen för biologi och miljö (BOM).
    Berggren, Hanna
    Linnéuniversitetet, Institutionen för biologi och miljö (BOM).
    Larsson, Per
    Linnéuniversitetet, Institutionen för biologi och miljö (BOM).
    Forsman, Anders
    Linnéuniversitetet, Institutionen för biologi och miljö (BOM).
    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.

  • 14.
    Pontarp, Mikael
    et al.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences. Univ Zurich, Dept Evolutionary Biol & Environm Studies, Winterthurerstr 190, CH-8057 Zurich, Switzerland.
    Petchey, Owen L.
    Community trait overdispersion due to trophic interactions: concerns for assembly process inference2016In: Proceedings of the Royal Society of London. Biological Sciences, ISSN 0962-8452, E-ISSN 1471-2954, Vol. 283, no 1840, article id 20161729Article in journal (Refereed)
    Abstract [en]

    The expected link between competitive exclusion and community trait over-dispersion has been used to infer competition in local communities, and trait clustering has been interpreted as habitat filtering. Such community assembly process inference has received criticism for ignoring trophic interactions, as competition and trophic interactions might create similar trait patterns. While other theoretical studies have generally demonstrated the importance of predation for coexistence, ours provides the first quantitative demonstration of such effects on assembly process inference, using a trait-based ecological model to simulate the assembly of a competitive primary consumer community with and without the influence of trophic interactions. We quantified and contrasted trait dispersion/clustering of the competitive communities with the absence and presence of secondary consumers. Trophic interactions most often decreased trait clustering (i.e. increased dispersion) in the competitive communities due to evenly distributed invasions of secondary consumers and subsequent competitor extinctions over trait space. Furthermore, effects of trophic interactions were somewhat dependent on model parameters and clustering metric. These effects create considerable problems for process inference from trait distributions; one potential solution is to use more process-based and inclusive models in inference.

  • 15.
    Pontarp, Mikael
    et al.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences. Department of Evolutionary Biology and Environmental Studies, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland.
    Petchey, Owen L.
    Ecological opportunity and predator-prey interactions: linking eco-evolutionary processes and diversification in adaptive radiations2018In: Proceedings of the Royal Society of London. Biological Sciences, ISSN 0962-8452, E-ISSN 1471-2954, Vol. 285, no 1874, article id 20172550Article in journal (Refereed)
    Abstract [en]

    Much of life's diversity has arisen through ecological opportunity and adaptive radiations, but the mechanistic underpinning of such diversification is not fully understood. Competition and predation can affect adaptive radiations, but contrasting theoretical and empirical results show that they can both promote and interrupt diversification. A mechanistic understanding of the link between microevolutionary processes and macroevolutionary patterns is thus needed, especially in trophic communities. Here, we use a trait-based eco-evolutionary model to investigate the mechanisms linking competition, predation and adaptive radiations. By combining available micro-evolutionary theory and simulations of adaptive radiations we show that intraspecific competition is crucial for diversification as it induces disruptive selection, in particular in early phases of radiation. The diversification rate is however decreased in later phases owing to interspecific competition as niche availability, and population sizes are decreased. We provide new insight into how predation tends to have a negative effect on prey diversification through decreased population sizes, decreased disruptive selection and through the exclusion of prey from parts of niche space. The seemingly disparate effects of competition and predation on adaptive radiations, listed in the literature, may thus be acting and interacting in the same adaptive radiation at different relative strength as the radiation progresses.

  • 16. Saaristo, Minna
    et al.
    Brodin, Tomas
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences. Department of Wildlife, Fish, and Environmental Studies, SLU, Umeå, Sweden .
    Balshine, Sigal
    Bertram, Michael G.
    Brooks, Bryan W.
    Ehlman, Sean M.
    McCallum, Erin S.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Sih, Andrew
    Sundin, Josefin
    Wong, Bob B. M.
    Arnold, Kathryn E.
    Direct and indirect effects of chemical contaminants on the behaviour, ecology and evolution of wildlife2018In: Proceedings of the Royal Society of London. Biological Sciences, ISSN 0962-8452, E-ISSN 1471-2954, Vol. 285, no 1885, article id 20181297Article, review/survey (Refereed)
    Abstract [en]

    Chemical contaminants (e.g. metals, pesticides, pharmaceuticals) are changing ecosystems via effects on wildlife. Indeed, recent work explicitly performed under environmentally realistic conditions reveals that chemical contaminants can have both direct and indirect effects at multiple levels of organization by influencing animal behaviour. Altered behaviour reflects multiple physiological changes and links individual-to population-level processes, thereby representing a sensitive tool for holistically assessing impacts of environmentally relevant contaminant concentrations. Here, we show that even if direct effects of contaminants on behavioural responses are reasonably well documented, there are significant knowledge gaps in understanding both the plasticity (i.e. individual variation) and evolution of contaminant-induced behavioural changes. We explore implications of multi-level processes by developing a conceptual framework that integrates direct and indirect effects on behaviour under environmentally realistic contexts. Our framework illustrates how sublethal behavioural effects of contaminants can be both negative and positive, varying dynamically within the same individuals and populations. This is because linkages within communities will act indirectly to alter and even magnify contaminant-induced effects. Given the increasing pressure on wildlife and ecosystems from chemical pollution, we argue there is a need to incorporate existing knowledge in ecology and evolution to improve ecological hazard and risk assessments.

  • 17. Sagebakken, Gry
    et al.
    Ahnesjö, Ingrid
    Mobley, Kenyon B
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Gonçalves, Inês Braga
    Kvarnemo, Charlotta
    Brooding fathers, not siblings, take up nutrients from embryos.2010In: Proceedings of the Royal Society of London. Biological Sciences, ISSN 0962-8452, E-ISSN 1471-2954, Vol. 277, no 1683, p. 971-977Article in journal (Refereed)
    Abstract [en]

    It is well known that many animals with placenta-like structures provide their embryos with nutrients and oxygen. However, we demonstrate here that nutrients can pass the other way, from embryos to the parent. The study was done on a pipefish, Syngnathus typhle, in which males brood fertilized eggs in a brood pouch for several weeks. Earlier research has found a reduction of embryo numbers during the brooding period, but the fate of the nutrients from these 'reduced' embryos has been unknown. In this study, we considered whether (i) the brooding male absorbs the nutrients, (ii) siblings absorb them, or (iii) a combination of both. Males were mated to two sets of females, one of which had radioactively labelled eggs (using (14)C-labelled amino acids), such that approximately half the eggs in the brood pouch were labelled. This allowed us to trace nutrient uptake from these embryos. We detected that (14)C-labelled amino acids were transferred to the male brood pouch, liver and muscle tissue. However, we did not detect any significant (14)C-labelled amino-acid absorption by the non-labelled half-siblings in the brood pouch. Thus, we show, to our knowledge, for the first time, that males absorb nutrients derived from embryos through their paternal brood pouch.

  • 18.
    Sjödin, Henrik
    et al.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences. Evolution and Ecology Program, International Institute for Applied Systems Analysis, 2361 Laxenburg, Austria.
    Brännström, Åke
    Umeå University, Faculty of Science and Technology, Department of Mathematics and Mathematical Statistics. Evolution and Ecology Program, International Institute for Applied Systems Analysis, 2361 Laxenburg, Austria.
    Englund, Göran
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Space race functional responses2015In: Proceedings of the Royal Society of London. Biological Sciences, ISSN 0962-8452, E-ISSN 1471-2954, Vol. 282, no 1801, article id 20142121Article in journal (Refereed)
    Abstract [en]

    We derive functional responses under the assumption that predators and prey are engaged in a space race in which prey avoid patches with many predators and predators avoid patches with few or no prey. The resulting functional response models have a simple structure and include functions describing how the emigration of prey and predators depend on interspecific densities. As such, they provide a link between dispersal behaviours and community dynamics. The derived functional response is general but is here modelled in accordance with empirically documented emigration responses. We find that the prey emigration response to predators has stabilizing effects similar to that of the DeAngelis-Beddington functional response, and that the predator emigration response to prey has destabilizing effects similar to that of the Holing type 11 response. A stability criterion describing the net effect of the two emigration responses on a Lotka-Volterra predator-prey system is presented. The winner of the space race (i.e. whether predators or prey are favoured) is determined by the relationship between the slopes of the species' emigration responses. It is predicted that predators win the space race in poor habitats, where predator and prey densities are low, and that prey are more successful in richer habitats.

  • 19. Van der Merwe, MM
    et al.
    Kinnear, MW
    Barrett, LG
    Dodds, PN
    Ericson, Lars
    Umeå University, Faculty of Science and Technology, Ecology and Environmental Science.
    Thrall, PH
    Burdon, JJ
    Positive selection in AvrP4 avirulence gene homologues across the genus Melampsora2009In: Proceedings of the Royal Society of London. Biological Sciences, ISSN 0962-8452, E-ISSN 1471-2954, Vol. 276, no 1669, p. 2913-2922Article in journal (Refereed)
    Abstract [en]

    Pathogen genes involved in interactions with their plant hosts are expected to evolve under positive Darwinian selection or balancing selection. In this study a single copy avirulence gene, AvrP4, in the plant pathogen Melampsora lini, was used to investigate the evolution of such a gene across species. Partial translation elongation factor 1-alpha sequences were obtained to establish phylogenetic relationships among the Melampsora species. We amplified AvrP4 homologues from species pathogenic on hosts from different plant families and orders, across the inferred phylogeny. Translations of the AvrP4 sequences revealed a predicted signal peptide and towards the C-terminus of the protein, six identically spaced cysteines were identified in all sequences. Maximum likelihood analysis of synonymous versus non-synonymous substitution rates indicated that positive selection played a role in the evolution of the gene during the diversification of the genus. Fourteen codons under significant positive selection reside in the C-terminal 28 amino acid region, suggesting that this region interacts with host molecules in most sequenced accessions. Selection pressures on the gene may be either due to the pathogenicity or avirulence function of the gene or both.

  • 20.
    Zhang, Lai
    et al.
    Umeå University, Faculty of Science and Technology, Department of Mathematics and Mathematical Statistics. School of Mathematical Science, Yangzhou University, Si Wang Ting Road, Yangzhou 225002, People’s Republic of China.
    Takahashi, Daisuke
    Umeå University, Faculty of Science and Technology, Department of Mathematics and Mathematical Statistics.
    Hartvig, Martin
    Andersen, Ken H.
    Food-web dynamics under climate change2017In: Proceedings of the Royal Society of London. Biological Sciences, ISSN 0962-8452, E-ISSN 1471-2954, Vol. 284, no 1867, article id 20171772Article in journal (Refereed)
    Abstract [en]

    Climate change affects ecological communities through its impact on the physiological performance of individuals. However, the population dynamic of species well inside their thermal niche is also determined by competitors, prey and predators, in addition to being influenced by temperature changes. We use a trait-based food-web model to examine how the interplay between the direct physiological effects from temperature and the indirect effects due to changing interactions between populations shapes the ecological consequences of climate change for populations and for entire communities. Our simulations illustrate how isolated communities deteriorate as populations go extinct when the environment moves outside the species' thermal niches. High-trophic-level species are most vulnerable, while the ecosystem function of lower trophic levels is less impacted. Open communities can compensate for the loss of ecosystem function by invasions of new species. Individual populations show complex responses largely uncorrelated with the direct impact of temperature change on physiology. Such complex responses are particularly evident during extinction and invasion events of other species, where climaticallywell-adapted species may be brought to extinction by the changed food-web topology. Our results highlight that the impact of climate change on specific populations is largely unpredictable, and apparently well-adapted species may be severely impacted.

  • 21.
    Öhlund, Gunnar
    et al.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Hedström, Per
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Norman, Sven
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Hein, Catherine L.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Englund, Göran
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Temperature dependence of predation depends on the relative performance of predators and prey2015In: Proceedings of the Royal Society of London. Biological Sciences, ISSN 0962-8452, E-ISSN 1471-2954, Vol. 282, no 1799, article id 20142254Article in journal (Refereed)
    Abstract [en]

    The temperature dependence of predation rates is a key issue for understanding and predicting the responses of ecosystems to climate change. Using a simple mechanistic model, we demonstrate that differences in the relative performances of predator and prey can cause strong threshold effects in the temperature dependence of attack rates. Empirical data on the attack rate of northern pike (Esox lucius) feeding on brown trout (Salmo trutta) confirm this result. Attack rates fell sharply below a threshold temperature of +11 degrees C, which corresponded to a shift in relative performance of pike and brown trout with respect to maximum attack and escape swimming speeds. The average attack speed of pike was an order of magnitude lower than the escape speed of brown trout at 5 degrees C, but approximately equal at temperatures above 11 degrees C. Thresholds in the temperature dependence of ecological rates can create tipping points in the responses of ecosystems to increasing temperatures. Thus, identifying thresholds is crucial when predicting future effects of climate warming.

1 - 21 of 21
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