Journal: Proceedings of the Royal Society B: Biological Sciences

Abbreviation

Proc. R. Soc. B.

Publisher

Royal Society

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ISSN

1471-2954

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Publications1 - 10 of 173
  • Evidence for pollinator sharing in Mediterranean nectar-mimic orchids: absence of premating barriers?
    Item type: Journal Article
    Cozzolino, Salvatore; Schiestl, Florian P.; Müller, Andreas; et al. (2005)
    Proceedings of the Royal Society B: Biological Sciences
    Pollinator specificity has traditionally been considered the main reproductive isolation mechanism in orchids. Among Mediterranean orchids, however, many species attract and deceive pollinators by mimicking nectar-rewarding plants. To test the extent to which deceptive orchid species share pollinators, we collected and identified hemipollinaria-carrying insects, and used ribosomal sequences to identify the orchid species from which hemipollinaria were removed. We found that social and solitary bees, and also flies, carried hemipollinaria belonging to nine orchid species with different degrees of specialization. In particular, Anacamptis morio, Dactylorhiza romana and Orchis mascula used a large set of pollinator species, whereas others such as Orchis quadripunctata seemed to be pollinated by one pollinator species only. Out of the insects with hemipollinaria, 19% were found to carry hemipollinaria from more than one orchid species, indicating that sympatric food-deceptive orchids can share pollinators. This sharing was apparent even among orchid sister-species, thus revealing an effective overlap in pollinator sets among closely related species. These results suggest varying degrees of pollinator specificity in these orchids, and indicate that pollinator specificity cannot always act as the main isolation mechanism in food-deceptive temperate orchids.
  • Vocal contagion of emotions in non-human animals
    Item type: Review Article
    Briefer, Elodie F. (2018)
    Proceedings of the Royal Society B: Biological Sciences
  • Evolutionary implications of the adaptation to different immune systems in a parasite with a complex life cycle
    Item type: Journal Article
    Hammerschmidt, K.; Kurtz, J. (2005)
    Proceedings of the Royal Society B: Biological Sciences
  • Evolution of a predator-induced, nonlinear reaction norm
    Item type: Journal Article
    Carter, Mauricio J.; Lind, Martin I.; Dennis, Stuart R.; et al. (2017)
    Proceedings of the Royal Society B: Biological Sciences
    Inducible, anti-predator traits are a classic example of phenotypic plasticity. Their evolutionary dynamics depend on their genetic basis, the historical pattern of predation risk that populations have experienced and current selection gradients. When populations experience predators with contrasting hunting strategies and size preferences, theory suggests contrasting micro-evolutionary responses to selection. Daphnia pulex is an ideal species to explore the micro-evolutionary response of anti-predator traits because they face heterogeneous predation regimes, sometimes experiencing only invertebrate midge predators and other times experiencing vertebrate fish and invertebrate midge predators. We explored plausible patterns of adaptive evolution of a predator-induced morphological reaction norm. We combined estimates of selection gradients that characterize the various habitats that D. pulex experiences with detail on the quantitative genetic architecture of inducible morphological defences. Our data reveal a fine scale description of daphnid defensive reaction norms, and a strong covariance between the sensitivity to cues and the maximum response to cues. By analysing the response of the reaction norm to plausible, predator-specific selection gradients, we show how in the context of this covariance, micro-evolution may be more uniform than predicted from size-selective predation theory. Our results show how covariance between the sensitivity to cues and the maximum response to cues for morphological defence can shape the evolutionary trajectory of predator-induced defences in D. pulex.
  • Modes and mechanisms of a Daphnia invasion
    Item type: Journal Article
    Spaak, Piet; Fox, Jennifer; Hairston, Nelson G. (2012)
    Proceedings of the Royal Society B: Biological Sciences
    Whether exotic species invade new habitats successfully depends on (i) a change in the invaded habitat that makes it suitable for the invader and (ii) a genetic change in the invading taxon that enhances its fitness in the new habitat, or both. We dissect the causes of invasions of Swiss lakes, north of the Alps, byDaphnia galeata(a zooplankter typical of eutrophic lakes, e.g. those south of the Alps, which are also warmer) by comparing the fitness performance of eight geographically distributed clones that were fed algal-food typical of oligotrophic versus eutrophic conditions at two temperatures.Daphnia longispina, native to oligotrophic Swiss lakes, served as a reference.Daphnia galeatarequires eutrophic food to persist, whereasD. longispinasurvives and grows on oligotrophic food but does even better on eutrophic food. Invasion byD. galeatais further explained because invading clones from the north perform better on eutrophic food and at cooler temperatures than native clones from the south, suggesting a local response to countergradient selection. Our data support the hypothesis that populations of the invader in northern lakes are dominated by well-adapted genotypes. Our results illustrate how environmental change (i.e. eutrophication) and local adaptation can act together to drive a successful invasion.
  • Microbial community composition interacts with local abiotic conditions to drive colonization resistance in human gut microbiome samples
    Item type: Journal Article
    Baumgartner, Michael; Pfrunder Cardozo, Katia R.; Hall, Alex R. (2021)
    Proceedings of the Royal Society B: Biological Sciences
    Biological invasions can alter ecosystem stability and function, and predicting what happens when a new species or strain arrives remains a major challenge in ecology. In the mammalian gastrointestinal tract, susceptibility of the resident microbial community to invasion by pathogens has important implications for host health. However, at the community level, it is unclear whether susceptibility to invasion depends mostly on resident community composition (which microbes are present), or also on local abiotic conditions (such as nutrient status). Here, we used a gut microcosm system to disentangle some of the drivers of susceptibility to invasion in microbial communities sampled from humans. We found resident microbial communities inhibited an invading Escherichia coli strain, compared to community-free control treatments, sometimes excluding the invader completely (colonization resistance). These effects were stronger at later time points, when we also detected altered community composition and nutrient availability. By separating these two components (microbial community and abiotic environment), we found taxonomic composition played a crucial role in suppressing invasion, but this depended critically on local abiotic conditions (adapted communities were more suppressive in nutrient-depleted conditions). This helps predict when resident communities will be most susceptible to invasion, with implications for optimizing treatments based on microbiota management.
  • Interactions among bacterial strains and fluke genotypes shape virulence of co-infection
    Item type: Journal Article
    Louhi, Katja-Riikka; Sundberg, Lotta-Riina; Jokela, Jukka; et al. (2015)
    Proceedings of the Royal Society B: Biological Sciences
    Most studies of virulence of infection focus on pairwise host–parasite interactions. However, hosts are almost universally co-infected by several parasite strains and/or genotypes of the same or different species. While theory predicts that co-infection favours more virulent parasite genotypes through intensified competition for host resources, knowledge of the effects of genotype by genotype (G × G) interactions between unrelated parasite species on virulence of co-infection is limited. Here, we tested such a relationship by challenging rainbow trout with replicated bacterial strains and fluke genotypes both singly and in all possible pairwise combinations. We found that virulence (host mortality) was higher in co-infections compared with single infections. Importantly, we also found that the overall virulence was dependent on the genetic identity of the co-infecting partners so that the outcome of co-infection could not be predicted from the respective virulence of single infections. Our results imply that G × G interactions among co-infecting parasites may significantly affect host health, add to variance in parasite fitness and thus influence evolutionary dynamics and ecology of disease in unexpected ways.
  • Experimental taphonomy of giant sulphur bacteria
    Item type: Journal Article
    Cunningham, J.A.; Thomas, C.-W.; Bengtson, S.; et al. (2012)
    Proceedings of the Royal Society B: Biological Sciences
    The Ediacaran Doushantuo biota has yielded fossils interpreted as eukaryotic organisms, either animal embryos or eukaryotes basal or distantly related to Metazoa. However, the fossils have been interpreted alternatively as giant sulphur bacteria similar to the extant Thiomargarita . To test this hypothesis, living and decayed Thiomargarita were compared with Doushantuo fossils and experimental taphonomic pathways were compared with modern embryos. In the fossils, as in eukaryotic cells, subcellular structures are distributed throughout cell volume; in Thiomargarita, a central vacuole encompasses approximately 98 per cent cell volume. Key features of the fossils, including putative lipid vesicles and nuclei, complex envelope ornament, and ornate outer vesicles are incompatible with living and decay morphologies observed in Thiomargarita. Microbial taphonomy of Thiomargarita also differed from that of embryos. Embryo tissues can be consumed and replaced by bacteria, forming a replica composed of a three-dimensional biofilm, a stable fabric for potential fossilization. Vacuolated Thiomargarita cells collapse easily and do not provide an internal substrate for bacteria. The findings do not support the hypothesis that giant sulphur bacteria are an appropriate interpretative model for the embryo-like Doushantuo fossils. However, sulphur bacteria may have mediated fossil mineralization and may provide a potential bacterial analogue for other macroscopic Precambrian remains.
  • Protein-poor diet reduces host-specific immune gene expression in Bombus terrestris
    Item type: Journal Article
    Brunner, Franziska S.; Schmid-Hempel, Paul; Barribeau, Seth M. (2014)
    Proceedings of the Royal Society B: Biological Sciences
  • Extreme heterochiasmy and nascent sex chromosomes in European tree frogs
    Item type: Journal Article
    Berset-Brändli, Laura; Jaquiéry, Julie; Broquet, Thomas; et al. (2008)
    Proceedings of the Royal Society B: Biological Sciences
    We investigated sex-specific recombination rates in Hyla arborea, a species with nascent sex chromosomes and male heterogamety. Twenty microsatellites were clustered into six linkage groups, all showing suppressed or very low recombination in males. Seven markers were sex linked, none of them showing any sign of recombination in males (r=0.00 versus 0.43 on average in females). This opposes classical models of sex chromosome evolution, which envision an initially small differential segment that progressively expands as structural changes accumulate on the Y chromosome. For autosomes, maps were more than 14 times longer in females than in males, which seems the highest ratio documented so far in vertebrates. These results support the pleiotropic model of Haldane and Huxley, according to which recombination is reduced in the heterogametic sex by general modifiers that affect recombination on the whole genome.
Publications1 - 10 of 173