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| 2. |
- Varg, Javier Edo, 1988-, et al.
(författare)
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Multi stress system : Microplastics in freshwater and their effects on host microbiota
- 2023
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Ingår i: Science of the Total Environment. - : Elsevier. - 0048-9697 .- 1879-1026. ; 856:Part 2
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Tidskriftsartikel (refereegranskat)abstract
- Microplastics are persistent and complex contaminants that have recently been found in freshwater systems, raising concerns about their presence in aquatic organisms. Plastics tend to be seen as an inert material; however, it is not well known if exposure to plastics for a prolonged time, in combination with organic chemicals, causes organism mortality. Ingestion of microplastics in combination with another pollutant may affect a host organism's fitness by altering the host microbiome. In this study, we investigated how microplastics interact with other pollutants in this multi-stress system, and whether they have a synergistic impact on the mortality of an aquatic organism and its microbiome. We used wild water boatmen Hemiptera (Corixidae) found at lake Erken located in east-central Sweden in a fully factorial two-way microcosm experiment designed with polystyrene microspheres and a commonly used detergent. The microplastic-detergent interaction is manifested as a significant increase in mortality compared to the other treatments at 48 h of exposure. The diversity of the microbial communities in the water was significantly affected by the combined treatment of microplastics and the detergent while the microbial communities in the host were affected by the treatments with microplastics and the detergent alone. Changes in relative abundance in Gammaproteobacteria (family Enterobacteriaceae), were observed in the perturbed treatments mostly associated with the presence of the detergent. This confirms that microplastics can interact with detergents having toxic effects on wild water boatmen. Furthermore, microplastics may impact wild organisms via changes in their microbial communities.
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| 3. |
- Varg, Javier Edo, 1988-, et al.
(författare)
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The stressful effects of microplastics associated with chromium (VI) on the microbiota of Daphnia Magna
- 2022
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Ingår i: Frontiers in Environmental Science. - : Frontiers Media S.A.. - 2296-665X. ; 10
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Tidskriftsartikel (refereegranskat)abstract
- Contamination by microplastics (particles < 1 mm) is a growing and alarming environmental problem in freshwater systems. Evidence suggests that industrial effluents could be one of the critical point sources of microplastics and other pollutants, and their interaction can cause organismal stress and affect host and environmental microbial communities. We tested the individual and combined effects of microplastics and other pollutants on host survival and host associated (commensal) bacterial diversity. We exposed Daphnia magna to 1 µm microplastic beads with a concentration of approximately 1820 particles/ml and chromium (VI) simultaneously with treatments of 2 and 5 ppm for 72 h. DNA extraction was done to amplify and sequence the ribosomal Bacterial 16S from both the water and the Daphnia. Daphnia experienced low mortality in treatments microplastics (13.3%) and 2 ppm chromium VI (30%) individually. However, the combination of microplastics and 2 ppm chromium (VI) increased the mortality to 74.4%. In the treatments with 5 ppm of chromium (VI) mortality rose to 100% after 30 h of exposure. Microbial diversity changed in response to microplastics, chromium (VI), and both combined exposure. Microplastics and toxic metals can cause dysbiosis of freshwater environmental microbiota, whole host microbiota, and host survival. This work stresses the importance to assess how pollutants’ individual and joint effects could affect organisms including their microbiome.
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| 4. |
- Corral-Lopez, Alberto, et al.
(författare)
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Field evidence for colour mimicry overshadowing morphological mimicry
- 2021
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Ingår i: Journal of Animal Ecology. - : John Wiley & Sons. - 0021-8790 .- 1365-2656. ; 90:3, s. 698-709
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Tidskriftsartikel (refereegranskat)abstract
- Imperfect mimicry may be maintained when the various components of an aposematic signal have different salience for predators. Experimental laboratory studies provide robust evidence for this phenomenon. Yet, evidence from natural settings remains scarce.We studied how natural bird predators assess multiple features in a multicomponent aposematic signal in the Neotropical ‘clear wing complex’ mimicry ring, dominated by glasswing butterflies.We evaluated two components of the aposematic signal, wing colouration and wing morphology, in a predation experiment based on artificial replicas of glasswing butterflies (model) and Polythoridae damselflies (mimics) in their natural habitat. We also studied the extent of the colour aposematic signal in the local insect community. Finally, we inspected the nanostructures responsible for this convergent colour signal, expected to highly differ between these phylogenetically distinct species.Our results provide direct evidence for a stronger salience of wing colouration than wing morphology, as well as stronger selection on imperfect than in perfect colour mimics. Additionally, investigations of how birds perceive wing colouration of the local insect community provides further evidence that a UV‐reflective white colouration is being selected as the colour aposematic signal of the mimicry ring. Using electron microscopy, we also suggest that damselflies have convergently evolved the warning colouration through a pre‐adaptation.These findings provide a solid complement to previous experimental evidence suggesting a key influence of the cognitive assessment of predators driving the evolution of aposematic signals and mimicry rings.
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| 5. |
- Varg, Javier Edo. 1988-
(författare)
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Host, its microbiota and their interactions
- 2018
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The development of sequencing technologies has advanced the field of host-associated microbiology by showing the huge diversity and functionality of the omnipresent microbes of all multicellular life. With these advances, new interesting questions have been raised with regards to microbial community composition, pollutants that can interact with the host microbial community, the factors that can affect the host microbial community and the processes that determine the enormous variety of the microbiota among hosts of the same species or genotype. However, conceptual disagreement regarding the ecology, genetics and evolutionary concepts regulating microbial diversity are frequently occurring in this field. Concepts such as symbiont, holobiont, and hologenome are generating discordances in the scientific community regarding microbial host associations and microbial communities. Then it is important to take into account the definitions and clarify the bases of these concepts: the holobiont refers to the host and their symbiotic microbes. Therefore, the hologenome are the genes of host plus the genes of their symbionts. However, the symbiont definition is wide open and when we use it at the holobiont level it can be misinterpreted as all microbes in a host. To separate symbionts from non-symbionts, it is necessary to search at the functional level for the emergence or enhancement of traits at the holobiont level. For that reason, not all of the microbiota are symbionts and, therefore the holobiont should only include the host and all the microbial symbionts that inhabit it. Consequently, host-associated microbes are part of the amalgam in the complex organisation of an organism and can also be explained by ecological associations. Understanding these complex interactions between host and its microbiota can, for instance, give us insight into how this community can influence the host’s regulatation of pollutants as stress factors. More important, to understand synergistic effects of pollutants such as microplastics and metals on the host and their microorganisms, constitute one of the new frontiers in toxicology. Finally, it is important to take into account how stress factors such as competition, environmental changes, pollution, and diet can influence the fitness, genome dynamics and diversification between organisms.
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| 6. |
- Varg, Javier Edo, 1988-, et al.
(författare)
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Microplastic exposure across trophic levels : effects on the host microbiota of freshwater organisms
- 2022
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Ingår i: Environmental Microbiome. - : Springer Nature. - 2524-6372. ; 17:1
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Tidskriftsartikel (refereegranskat)abstract
- BackgroundMicroplastics are a pervasive pollutant widespread in the sea and freshwater from anthropogenic sources, and together with the presence of pesticides, they can have physical and chemical effects on aquatic organisms and on their microbiota. Few studies have explored the combined effects of microplastics and pesticides on the host–microbiome, and more importantly, the effects across multiple trophic levels. In this work, we studied the effects of exposure to microplastics and the pesticide deltamethrin on the diversity and abundance of the host–microbiome across a three-level food chain: daphnids–damselfly–dragonflies. Daphnids were the only organism exposed to 1 µm microplastic beads, and they were fed to damselfly larvae. Those damselfly larvae were exposed to deltamethrin and then fed to the dragonfly larvae. The microbiotas of the daphnids, damselflies, and dragonflies were analyzed.ResultsExposure to microplastics and deltamethrin had a direct effect on the microbiome of the species exposed to these pollutants. An indirect effect was also found since exposure to the pollutants at lower trophic levels showed carry over effects on the diversity and abundance of the microbiome on higher trophic levels, even though the organisms at these levels where not directly exposed to the pollutants. Moreover, the exposure to deltamethrin on the damselflies negatively affected their survival rate in the presence of the dragonfly predator, but no such effects were found on damselflies fed with daphnids that had been exposed to microplastics.ConclusionsOur study highlights the importance of evaluating ecotoxicological effects at the community level. Importantly, the indirect exposure to microplastics and pesticides through diet can potentially have bottom-up effects on the trophic webs.
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| 7. |
- Varg, Javier Edo, 1988-, et al.
(författare)
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Single and combined effects of microplastics, pyrethroid and food resources on the life-history traits and microbiome of Chironomus riparius
- 2021
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Ingår i: Environmental Pollution. - : Elsevier. - 0269-7491 .- 1873-6424. ; 289
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Tidskriftsartikel (refereegranskat)abstract
- There is growing evidence of widespread contamination of freshwater ecosystems with microplastics. However, the effects of chronic microplastic ingestion and its interaction with other pollutants and stress factors on the life history traits and the host-microbiome of aquatic invertebrates are not well understood. This study investigates the effects of exposure to sediment spiked with 1 mu m polystyrene-based latex microplastic spheres, an environmentally realistic concentration of a pyrethroid pesticide (esfenvalerate), and a combination of both treatments on the life-history traits of the benthic-dwelling invertebrate, Chironomus riparius and its microbial community. The chironomid larvae were also exposed to two food conditions: abundant or limited food in the sediment, monitored for 28 and 34 days respectively. The microplastics and esfenvalerate had negative effects on adult emergence and survival, and these effects differed between the food level treatments. The microbiome diversity was negatively affected by the exposure to microplastics, while the relative abundances of the four top phyla were significantly affected only in the high food level treatment. Although the combined exposure to microplastics and esfenvalerate showed some negative effects on survival and emergence, there was little evidence for synergistic effects when compared to the single exposure. The food level affected all life-history traits and the microbiota, and lower food levels intensified the negative effects of the exposure to microplastics, esfenvalerate and their combination. We argue that these pollutants can affect crucial life-history traits such as successful metamorphosis and the host-microbiome. Therefore, it should be taken into consideration for toxicological assessment of pollutant acceptability. Our study highlights the importance of investigating possible additive and synergic activities between stressors to understand the effects of pollutants in the life story traits and host-microbiome.
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| 8. |
- Varg, Javier Edo, 1988-
(författare)
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The effects of exposure to microplastics and pollutants on the arthropod microbiome
- 2021
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Anthropogenic pollution is widespread across various ecosystems. This disturbance can alter the interaction between a host and its associated microbiome, with repercussions for hosts traits such as health, behavior, and host evolution. The thesis aim is to understand the effects of inert microplastics and other pollutants, as pesticides, detergents, and toxic metals, on the host-microbiota of different freshwater invertebrates. Specifically, this thesis explores the secondary effects of stress factors on the host, trophic interactions, and free-living microbes. Chapter I tested the effects of microplastics and the pesticide esfenvalerate on Chironomus riparius survival, emergence, and its microbiome. Chapter II tested the effects of microplastics and the pesticide deltamethrin on a trophic chain of three organisms: Daphnia magna, damselfly larva Ischnura elegans, and wild dragonfly larva Aeshna cyanea. Chapter III tested the effects of microplastics and sodium dodecyl sulfate on the microbiome of wild water boatman from the family Corixidae. Chapter IV tested the effects of microplastics and Chromium VI on Daphnia magna mortality and its microbiome. The thesis used metagenomic tools to characterize both the host microbiome and its surrounding microcosms. Our results showed that microplastics interact with additive toxicants to affect the host microbiome, however, these effects depend on the type of toxicant, the size of the microplastic, and the host itself.
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| 9. |
- Ålund, Murielle, et al.
(författare)
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Sensory environment affects Icelandic threespine stickleback's anti-predator escape behaviour
- 2022
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Ingår i: Proceedings of the Royal Society of London. Biological Sciences. - : The Royal Society. - 0962-8452 .- 1471-2954. ; 289:1972
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Tidskriftsartikel (refereegranskat)abstract
- Human-induced changes in climate and habitats push populations to adapt to novel environments, including new sensory conditions, such as reduced visibility. We studied how colonizing newly formed glacial lakes with turbidity-induced low-visibility affects anti-predator behaviour in Icelandic threespine sticklebacks. We tested nearly 400 fish from 15 populations and four habitat types varying in visibility and colonization history in their reaction to two predator cues (mechano-visual versus olfactory) in high versus low-visibility light treatments. Fish reacted differently to the cues and were affected by lighting environment, confirming that cue modality and light levels are important for predator detection and evasion. Fish from spring-fed lakes, especially from the highlands (likely more diverged from marine fish than lowland fish), reacted fastest to mechano-visual cues and were generally most active. Highland glacial fish showed strong responses to olfactory cues and, counter to predictions from the flexible stem hypothesis, the greatest plasticity in response to light levels. This study, leveraging natural, repeated invasions of novel sensory habitats, (i) illustrates rapid changes in anti-predator behaviour that follow due to adaptation, early life experience, or both, and (ii) suggests an additional role for behavioural plasticity enabling population persistence in the face of frequent changes in environmental conditions.
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