| 1. |
- Vinterstare, Jerker, et al.
(författare)
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Antipredator phenotype in crucian carp altered by a psychoactive drug
- 2021
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Ingår i: Ecology and Evolution. - : John Wiley & Sons. - 2045-7758. ; 11:14, s. 9435-9446
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Tidskriftsartikel (refereegranskat)abstract
- Predator-inducible defenses constitute a widespread form of adaptive phenotypic plasticity, and such defenses have recently been suggested linked with the neuroendocrine system. The neuroendocrine system is a target of endocrine disruptors, such as psychoactive pharmaceuticals, which are common aquatic contaminants. We hypothesized that exposure to an antidepressant pollutant, fluoxetine, influences the physiological stress response in our model species, crucian carp, affecting its behavioral and morphological responses to predation threat. We examined short- and long-term effects of fluoxetine and predator exposure on behavior and morphology in crucian carp. Seventeen days of exposure to a high dose of fluoxetine (100 µg/L) resulted in a shyer phenotype, regardless of the presence/absence of a pike predator, but this effect disappeared after long-term exposure. Fluoxetine effects on morphological plasticity were context-dependent as a low dose (1 µg/L) only influenced crucian carp body shape in pike presence. A high dose of fluoxetine strongly influenced body shape regardless of predator treatment. Our results highlight that environmental pollution by pharmaceuticals could disrupt physiological regulation of ecologically important inducible defenses.
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| 2. |
- Björnerås, Caroline, et al.
(författare)
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Inland blue holes of The Bahamas - chemistry and biology in a unique aquatic environment
- 2020
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Ingår i: Fundamental and Applied Limnology. - : Schweizerbart science publishers. - 1863-9135. ; 194:2, s. 95-106
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Tidskriftsartikel (refereegranskat)abstract
- While lake systems in temperate regions have been extensively studied, tropical and subtropical systems have received less attention. Here, we describe the water chemistry and biota of ten inland blue holes on Andros Island, The Bahamas, representative of the morphological, abiotic, and biotic variation among Androsian inland blue holes. The majority of the studied blue holes were vertically stratified with oxic freshwater overlying anoxic saline groundwater of marine origin. Water chemistry (e.g. total phosphorus and nitrogen) in shallow waters was similar among blue holes, while turbidity and water color varied. Presence of hydrogen sulfide and reduced iron in and below the halocline indicate reducing conditions in all stratified blue holes. The biota above the halocline was also similar among blue holes with a few taxa dominating the phytoplankton community, and the zooplankton community consisting of copepods and rotifers. The Bahamas mosquitofish (Gambusia hubbsi) was present in all investigated blue holes, often accompanied by other small planktivorous fish, while the piscivorous bigmouth sleeper (Gobiomorus donnitor) was only present in some of the blue holes. Our field study reinforces that inland blue holes are highly interesting for biogeochemical research, and provide naturally replicated systems for evolutionary studies.
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| 3. |
- Hulthén, Kaj, et al.
(författare)
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A predation cost to bold fish in the wild
- 2017
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Ingår i: Scientific Reports. - : Nature Publishing Group. - 2045-2322. ; 7
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Tidskriftsartikel (refereegranskat)abstract
- Studies of predator-mediated selection on behaviour are critical for our understanding of the evolution and maintenance of behavioural diversity in natural populations. Consistent individual differences in prey behaviour, especially in the propensity to take risks (“boldness”), are widespread in the animal kingdom. Theory predicts that individual behavioural types differ in a cost-benefit trade-off where bolder individuals benefit from greater access to resources while paying higher predation-risk costs. However, explicitly linking predation events to individual behaviour under natural conditions is challenging and there is currently little data from the wild. We assayed individual behaviour and electronically tagged hundreds of fish (roach, Rutilus rutilus) before releasing them into their lake of origin, thereby exposing them to predation risk from avian apex predators (cormorants, Phalacrocorax carbo). Scanning for regurgitated tags at the cormorant roosting site provided data on individual predation events. We found that fish with higher boldness have a greater susceptibility to cormorant predation compared to relatively shy, risk-averse individuals. Our findings hereby provide unique and direct evidence of behavioural type-dependent predation vulnerability in the wild, i.e. that there is a predation cost to boldness, which is critical for our understanding of the evolution and maintenance of behavioural diversity in natural populations.
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| 4. |
- Lee, Marcus, et al.
(författare)
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Low-latitude zooplankton pigmentation plasticity in response to multiple threats
- 2019
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Ingår i: Royal Society Open Science. - : Royal Society Open Science. - 2054-5703. ; 6:7, s. 1-10
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Tidskriftsartikel (refereegranskat)abstract
- Crustacean copepods in high-latitude lakes frequently alter their pigmentation facultatively to defend themselves against prevailing threats, such as solar ultraviolet radiation ( UVR) and visually oriented predators. Strong seasonality in those environments promotes phenotypic plasticity. To date, no one has investigated whether low-latitude copepods, experiencing continuous stress from UVR and predation threats, exhibit similar inducible defences. We here investigated the pigmentation levels of Bahamian 'blue hole' copepods, addressing this deficit. Examining several populations varying in predation risk, we found the lowest levels of pigmentation in the population experiencing the highest predation pressure. In a laboratory experiment, we found that, in contrast with our predictions, copepods from these relatively constant environments did show some changes in pigmentation subsequent to the removal of UVR; however, exposure to water from different predation regimes induced minor and idiosyncratic pigmentation change. Our findings suggest that low-latitude zooplankton in inland environments may exhibit reduced, but non-zero, levels of phenotypic plasticity compared with their high-latitude counterparts.
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| 5. |
- Naddafi, Rahmat, et al.
(författare)
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Developing management goals and associated assessment methods for Sweden’s nationally managed fish stocks : a project synthesis
- 2023
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Rapport (refereegranskat)abstract
- This report summarizes and synthesizes results from the Swedish Agency of Marine and Water Management (SwAM, or HaV) funded project “Förvaltningsmål för nationella arter (Management goals for nationally managed species)”. The objectives of the project have been to promote the development of management goals and associated status assessment methods and indicators, as well as reference points, for some nationally managed fish stocks both in coastal as well as freshwater areas. The report focusses largely on species and stocks that can be defined as data-poor. Such stocks are characterised by marked limitations in data availability and/or resources allocated to detailed analytical stock projections. Data-poor stocks also often lack carefully formulated management goals and associated methods and indicators for assessing stock status. In this report, we provide an overview of potential assessment methods and indicators and try to synthesise how they work and what the strengths and weaknesses are by applying them to selected data poor stocks such as pikeperch, pike, whitefish, and vendace. We also discuss how they relate to different potential management goals and provide recommendations for their application. We grouped the indicators and assessment methods by the three categories that are now used in the yearly status assessment framework provided by SLU Aqua (Resursöversikten/Fiskbarometern) – i) mortality, ii) abundance/biomass and iii) size/age structure. The results are also described for these three main categories of assessment indicators. Included is also a status report from a size- and age-based population dynamics model (Stock Synthesis 3) that is being developed for pikeperch in Lake Hjälmaren.An important experience from the project is that to improve the assessment methods for Swedish national fish stocks, it is important that managers develop both general as well as more detailed quantitative goals for the individual stocks. This should ideally be conducted in various forms of collaboration with the main stakeholders and scientists involved with assessment as participatory processes foster legitimacy. Carefully articulated management goals, which are possible to translate into quantitative targets, will facilitate the development of various approaches and methods to monitor stock statuses. Given the strong and complex interactions of fish and their environments it is also important to consider other pressures than fisheries when developing indicators and assessment methods.Our synthesis highlights a number of areas where the assessment of data-poor stocks can be improved:1. Apply precautionary principles for data-limited stocks, particularly ones that are known to be vulnerable to exploitation.2. Tailor approaches to how fisheries are managed in Sweden. Swedish nationally managed fish stocks are not managed by quotas (with one exception, vendace in the Bothnian Bay) and do not aim for maximum sustainable yield. Instead, the coastal and inland fisheries are managed by regulating the effort in the small-scale commercial fisheries (number of fishers/licenses and amount of gear). Regulation of recreational and subsistence fisheries effort, in terms of licenses or number of fishers) is not applied, nor possible since the fisheries is lacking obligatory notification and reporting systems. All national fisheries, however, are regulated by various technical measures (closed areas, size-limits, bag-limits, gear restrictions etc). Thus, goals and assessment methods that result in harvest limits or quota recommendations expressed in e.g. biomass/numbers are difficult to use as basis for management. Instead, there is a need for alternative management goals and associated assessment methods.3. Use best practice methods and indicators and adapt as scientific knowledge is developed. Data-limited methods are developing rapidly, and new methods/approaches are proposed in the scientific literature every year. It is thus important to be updated on the most recent developments. 4. Clearly describe limitations/assumptions of methods used. It is important to be aware of and critically evaluate the assumptions underlying the analyses, and to carefully communicate uncertainty together with the stock status assessment.5. Be particularly careful with low sample numbers. Many indicators and methods can be applied also on small sample sizes, however, the accuracy and precision of the estimates risk being low in such cases.6. Accept that there is no "gold standard" for fisheries assessment. Each case study is unique and needs to be balanced against data availability, local needs and other important factors. This also means that analysts need to be careful when using generic reference levels or “borrowing” data from other stocks.7. If possible, use several different methods/indicators. Although several indicators aim to measure similar aspects of the stock, small methodological differences can support the overall interpretation of individual indicator values. It is particularly important to incorporate many aspects and indicators (size/age/abundance/mortality) in order to produce a balanced assessment.8. Develop means of communication. Indicators and goals should be easy to understand. However, interpretation of results from multi-indicator frameworks can be challenging. There is thus a need for finding ways of communication that can convey complicated results in a simple-to-understand manner.9. For details on additional improvements, we refer the reader to the sub-header “recommendations for the future” found under each chapter.The implementation of Stock Synthesis for pikeperch in Lake Hjälmaren showed that it is possible to develop a more ambitious and detailed stock assessment model for a relatively data-poor stock. The model results partly support earlier interpretations of the development of the stock and the importance of the changes in regulations in 2001 (increased minimum size, increased mesh size and reduced mortality of undersized pikeperch). Before the model can be implemented and used for practical management, a number of actions for improvement are needed, which are highlighted in the relevant chapter. The most important next step is establishing management goals and reference levels for this stock. We recommend that such a dialogue is initiated by managers. The fisheries management goals should consider both biomass, fisheries mortality and size-based targets.To conclude, we stress the importance of improving all ongoing aspects related to the assessments of data-poor Swedish stocks. Strong local stocks and sustainable fisheries are vital for a variety of fisheries-related businesses and practices, particularly in rural areas, providing economical and societal value. Fishes also have important roles in aquatic food-webs and it is important that ecological values are managed wisely in order to reach targets for water quality, ecosystem structure and diversity. Given the strong and complex interactions of fish and their environments it is also important to consider other pressures than fisheries when developing indicators and assessment methods.
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| 6. |
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| 7. |
- Nilsson, Per Anders, 1968-, et al.
(författare)
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Species integrity enhanced by a predation cost to hybrids in the wild
- 2017
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Ingår i: Biology Letters. - : The Royal Society. - 1744-9561 .- 1744-957X. ; 13:7, s. 1-4
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Tidskriftsartikel (refereegranskat)abstract
- Species integrity can be challenged, and even eroded, if closely related species can hybridize and produce fertile offspring of comparable fitness to that of par- ental species. The maintenance of newly diverged or closely related species therefore hinges on the establishment and effectiveness of pre- and/or post- zygotic reproductive barriers. Ecological selection, including predation, is often presumed to contribute to reduced hybrid fitness, but field evidence for a predation cost to hybridization remains elusive. Here we provide proof-of- concept for predation on hybrids being a postzygotic barrier to gene flow in the wild. Cyprinid fishes commonly produce fertile, viable hybrid offspring and therefore make excellent study organisms to investigate ecological costs to hybrids. We electronically tagged two freshwater cyprinid fish species (roach Rutilus rutilus and bream Abramis brama) and their hybrids in 2005. Tagged fish were returned to their lake of origin, exposing them to natural predation risk from apex avian predators (great cormorant, Phalacrocorax carbo). Scanning for regurgitated tags under cormorant roosts 3–4 years later ident- ified cormorant-killed individual fish and allowed us to directly test for a predation cost to hybrids in the wild. Hybrid individuals were found significantly more susceptible to cormorant predation than individuals from either parental species. Such ecological selection against hybrids contributes to species integrity, and can enhance species diversification.
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| 8. |
- Palm, Stefan, et al.
(författare)
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Reduced genetic diversity and low effective size in peripheral northern European catfish Silurus glanis populations
- 2019
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Ingår i: Journal of Fish Biology. - : Wiley. - 0022-1112 .- 1095-8649. ; 95:6, s. 1407-1421
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Tidskriftsartikel (refereegranskat)abstract
- Using 10 polymorphic microsatellites and 1251 individual samples (some dating back to the early 1980s), genetic structure and effective population size in all native and introduced Swedish populations of the European wels catfish or Silurus glanis were studied. Levels of genetic variability and phylogeographic relationships were compared with data from a previous study of populations in other parts of Europe. The genetically distinct Swedish populations displayed comparably low levels of genetic variability and according to one-sample estimates based on linkage disequilibrium and sib ship-reconstruction, current local effective population sizes were lower than minimum levels recommended for short-term genetic conservation. In line with a previous suggestion of postglacial colonisation from a single refugium, all Swedish populations were assembled on a common branch in a star-shaped dendrogram together with other European populations. Two distinct subpopulations were detected in upper and lower habitats of River Emån, indicating that even minor dispersal barriers may restrict gene flow for wels in running waters. Genetic assignment of specimens encountered in the brackish Baltic Sea and in lakes where the species does not occur naturally indicated presence of long-distance sea dispersal and confirmed unauthorised translocations, respectively.
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| 9. |
- Pärssinen, Varpu, et al.
(författare)
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Variation in predation regime drives sex-specific differences in mosquitofish foraging behaviour
- 2021
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Ingår i: Oikos. - : Wiley-Blackwell. - 0030-1299 .- 1600-0706. ; 130:5, s. 790-797
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Tidskriftsartikel (refereegranskat)abstract
- Predation is a well-studied driver of ecological selection on prey traits, which frequently drives divergence in anti-predator performance across environments that vary in predation risk. However, predation also alters prey mortality regimes, where low predation risk often results in higher prey densities and consequently higher intensities of intraspecific resource competition. In addition, predation risk alters the foraging context, as acquiring food can be risky in the presence of predators. Thus, different predation regimes can drive divergent selection on traits associated with resource competition, such as foraging behaviours. Moreover, because sexes often differ in susceptibility to predation and limitations to their reproductive output, the intensity of the tradeoff between predator avoidance and resource competition may depend on sex. We used a laboratory experiment to assess key aspects of foraging performance in a predator-free context in Bahamas mosquitofish Gambusia hubbsi wild-caught from multiple populations that experience either high or low levels of predation risk. When competing for limited food resources at a common density, females from low-predation regimes showed higher foraging and food consumption rates than females from high-predation regimes. Males showed fewer differences between predation regimes, and an opposite pattern from females. We suggest these sex-specific effects result from females facing a greater tradeoff between predation risk and resource competition, combined with males from high-predation environments elevating foraging behaviours in the absence of nearby predators and females. Females of this species are larger than males, bear live young and show higher foraging rates in the wild than males. On the other hand, males spend more time pursuing females in the wild, and may exhibit greater flexibility in foraging behaviours based on the immediate context. Our results show that varying levels of predation risk can lead to differences in behaviours associated with resource competition, but these effects can strongly differ between sexes.
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| 10. |
- Sha, Yongcui, et al.
(författare)
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Diel vertical migration of copepods and its environmental drivers in subtropical Bahamian blue holes
- 2021
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Ingår i: Aquatic Ecology. - : Springer. - 1386-2588 .- 1573-5125. ; 55:4, s. 1157-1169
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Tidskriftsartikel (refereegranskat)abstract
- Diel vertical migration (DVM) is the most common behavioral phenomenon in zooplankton, and numerous studies have evaluated DVM under strong seasonality at higher latitudes. Yet, our understanding of the environmental drivers of DVM at low latitudes, where seasonal variation is less pronounced, remains limited. Therefore, we here examined patterns of vertical distribution in copepods in six subtropical Bahamian blue holes with different food web structure and tested the role of several key environmental variables potentially affecting this behavior. Day and night samplings showed that copepods generally performed DVM, characterized by downward migration to deeper depths during the day and upward migration to surface waters at night. Across all blue holes, the daytime vertical depth distribution of calanoid copepods correlated positively with both predation risk and depth of food resources (Chlorophyll a), but was less affected by ultraviolet radiation (UVR). A potential explanation is that since UVR is a continuous threat across seasons, zooplankton have established photoprotective pigmentation making them less vulnerable to this threat. The copepods also showed a size-structured depth segregation, where larger individuals were found at deeper depths during the day, which further strengthens the suggestion that predation is a major driver of DVM in these systems. Hence, in contrast to studies performed at higher latitudes, we show that despite the constant exposure to UVR, predator avoidance and food availability are the most pronounced drivers of copepod DVM at those low latitudes, suggesting that the main driver of DVM may vary among systems, but also systematically by latitude.
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| 11. |
- Vinterstare, Jerker
(författare)
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Defence on Demand : A physiological perspective on phenotypic plasticity in anti-predator traits
- 2021
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Almost all species face some degree of predation risk, and, hence, evolution has produced a plethora of anti-predator defences. However, anti-predator strategies require resources, and the prevailing risk of becoming prey is influenced by many factors and rarely constant across time and space. Evolution has therefore favoured the development of phenotypic plasticity in anti-predator defences. The capacity of a single genotype to fine-tune its phenotype according to the prevailing risk of predation results in a closer phenotype-environment match in the mercurial environments of the natural world. Interest in the ecology and evolution of inducible defences has progressed the development of its theoretical underpinnings, along with empirical tests of theoretical predictions. Inter-individual differences in the expression of inducible traits are nowadays understood ubiquitous, and this intriguing variation holds possibility to bridge our current knowledge gap on the proximate, physiological mechanisms underlying inducible morphological defence regulation. In this thesis, I address unanswered questions on the proximate, physiological processes behind phenotypic plasticity in morphological defences. I first examine classic resource-allocation trade-offs to search for hidden physiological costs coupled with perceived predation risk and investment into a morphological defence. I further employ a recent hypothesis of physiological stress being the mechanism driving morphological defence regulation. To test my predictions, I have used a well-established model system for the study of inducible morphological defences, the crucian carp (Carassius carassius). I show that innate immune functions are altered by predator exposure, and that the defence against pathogens is correlated with the morphological defence against larger-sized enemies (predators). Second, from a series of laboratory experiments and field studies, I demonstrate support for the hypothesis of stress physiology being involved in plastic defence expression, and that crucian carp display clear sexual dimorphism in the anti-predator phenotype. I suggest that this is due to sex-specific trade-off dynamics, where females invest more into reproduction, resulting in less resources for anti-predator protection. Finally, I present novel trait changes (changes in body colour, diel activity and eye morphology) in response to non-lethal predation risk that may act in synergy to produce an integrated anti-predator phenotype. In summary, my results illustrate a potential causality from the vertebrate stress axis to the regulation of morphological defence expression. Further, my thesis highlights variation and complexity on the route to producing optimal anti-predator phenotypes under competing demands from other interests.
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| 12. |
- Vinterstare, Jerker, et al.
(författare)
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Defence versus defence : Are crucian carp trading off immune function against predator-induced morphology?
- 2019
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Ingår i: Journal of Animal Ecology. - : John Wiley & Sons. - 0021-8790 .- 1365-2656. ; 88:10, s. 1510-1521
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Tidskriftsartikel (refereegranskat)abstract
- Numerous species adopt inducible defence strategies; that is, they have phenotypically plastic traits that decrease the risk of capture and consumption by potential predators. The benefits of expressing alternative phenotypes in high- vs. low-risk environments are well documented. However, inducible anti-predator traits are also expected to incur costs, as they are not expressed when predators are absent, yet empirical evidence of such costs remains scarce. Virtually, all animals in nature are simultaneously under strong selection to evade both capture by predators and infection by parasites or pathogens and, hence, display a diverse arsenal of defences to combat these threats, raising the possibility of trade-offs between defences. A classic example of a predator-induced morphological defence is the deep-bodied shape of crucian carp that reduces risk of predation from gape-size-limited predators. The goal of this study was to examine whether predator exposure affects also immune function in crucian carp, and whether the degree of expressed morphological defence is traded off against immune function in individuals. Following exposure to manipulations of perceived risk (predator presence/absence) in a long-term experiment (8 months), key aspects of innate immune function and individual differences in the expression of inducible morphological defence were quantified. Predator-exposed individuals showed lower haptoglobin levels and complement activity, but higher natural antibody titres than fish from predator-free conditions. When experimentally challenged with a mimicked bacterial infection (LPS injection), fish reared in the presence of a natural predator showed a weaker immune response. Moreover, among predator-exposed individuals, the magnitude of morphological defence expression correlated with both baseline immune function and the ability to mount an immune response. However, these relationships were not consistently supportive of a general trade-off among defences. Our results suggest that fish exposed to predators on average reduce investment in immune function, and, further, the observed relationships among defences in predator-exposed individuals can best be explained from individual fitness and pace-of-life perspectives.
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| 13. |
- Vinterstare, Jerker, et al.
(författare)
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Experimental manipulation of perceived predation risk and cortisol generates contrasting trait trajectories in plastic crucian carp
- 2020
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Ingår i: Journal of Experimental Biology. - : COMPANY BIOLOGISTS LTD. - 0022-0949 .- 1477-9145. ; 223:4
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Tidskriftsartikel (refereegranskat)abstract
- Most animals constitute potential prey and must respond appropriately to predator-mediated stress in order to survive. Numerous prey also adaptively tailor their response to the prevailing level of risk and stress imposed by their natural enemies, i.e. they adopt an inducible defence strategy. Predator exposure may activate the stress axis, and drive the expression of anti-predator traits that facilitate survival in a high-risk environment (the predation-stress hypothesis). Here, we quantified two key morphological anti-predator traits, body morphology and coloration, in crucian carp reared in the presence or absence of a predator ( pike) in addition to experimental manipulation of physiological stress via implants containing either cortisol or a cortisol inhibitor. We found that predator-exposed fish expressed a deeper-bodied phenotype and darker body coloration as compared with non-exposed individuals. Skin analyses revealed that an increase in the amount of melanophores caused the dramatic colour change in predator-exposed fish. Increased melanization is costly, and the darker body coloration may act as an inducible defence against predation, via a conspicuous signal of the morphological defence or by crypsis towards dark environments and a nocturnal lifestyle. By contrast, the phenotype of individuals carrying cortisol implants did not mirror the phenotype of predatorexposed fish but instead exhibited opposite trajectories of trait change: a shallow-bodied morphology with a lighter body coloration as compared with sham-treated fish. The cortisol inhibitor did not influence the phenotype of fish i.e. neither body depth nor body coloration differed between this group and predator-exposed fish with a sham implant. However, our results illuminate a potential link between stress physiology and morphological defence expression.
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| 14. |
- Vinterstare, Jerker, et al.
(författare)
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More than meets the eye : Predator-induced pupil size plasticity in a teleost fish
- 2020
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Ingår i: Journal of Animal Ecology. - : Wiley-Blackwell. - 0021-8790 .- 1365-2656. ; 89:10, s. 2258-2267
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Tidskriftsartikel (refereegranskat)abstract
- Most animals are visually oriented, and their eyes provide their ‘window to the world’. Eye size correlates positively with visual performance, because larger eyes can house larger pupils that increase photon catch and contrast discrimination, particularly under dim light, which have positive effects on behaviours that enhance fitness, including predator avoidance and foraging. Recent studies have linked predation risk to selection for larger eyes and pupils, and such changes should be of importance for the majority of teleost fishes as they have a pupil that is fixed in size (eyes lack a pupillary sphincter muscle) and, hence, do not respond to changes in light conditions. Here, we quantify eye and pupil size of individual crucian carp, a common freshwater fish, following controlled manipulations of perceived predation risk (presence/absence). We also tested if crucian carp responded to increased predation risk by shifts in diel activity patterns. We found that crucian carp show phenotypic plasticity with regards to pupil size, but not eye size, as pupil size increased when exposed to predators (pike). Predator-exposed crucian carp also shifted from diurnal to nocturnal activity. Using a modelling exercise, we moreover show that the plastically enlarged pupils significantly increase visual range, especially for small objects under dim light conditions. Overall, our results provide compelling evidence for predator-induced pupil enlargement resulting in enhanced visual capabilities in a teleost fish. Pupil size plasticity in combination with the observed shift towards nocturnal activity may allow for efficient foraging also under dark conditions when predation risk from diurnal and visually oriented predators is reduced. The data highlight the powerful role of predation risk for eye development and evolution.
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| 15. |
- Vinterstare, Jerker, et al.
(författare)
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Predation risk and the evolution of a vertebrate stress response : Parallel evolution of stress reactivity and sexual dimorphism
- 2021
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Ingår i: Journal of Evolutionary Biology. - : John Wiley & Sons. - 1010-061X .- 1420-9101. ; 34:10, s. 1554-1567
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Tidskriftsartikel (refereegranskat)abstract
- Predation risk is often invoked to explain variation in stress responses. Yet, the answers to several key questions remain elusive, including the following: (1) how predation risk influences the evolution of stress phenotypes, (2) the relative importance of environmental versus genetic factors in stress reactivity and (3) sexual dimorphism in stress physiology. To address these questions, we explored variation in stress reactivity (ventilation frequency) in a post-Pleistocene radiation of live-bearing fish, where Bahamas mosquitofish (Gambusia hubbsi) inhabit isolated blue holes that differ in predation risk. Individuals of populations coexisting with predators exhibited similar, relatively low stress reactivity as compared to low-predation populations. We suggest that this dampened stress reactivity has evolved to reduce energy expenditure in environments with frequent and intense stressors, such as piscivorous fish. Importantly, the magnitude of stress responses exhibited by fish from high-predation sites in the wild changed very little after two generations of laboratory rearing in the absence of predators. By comparison, low-predation populations exhibited greater among-population variation and larger changes subsequent to laboratory rearing. These low-predation populations appear to have evolved more dampened stress responses in blue holes with lower food availability. Moreover, females showed a lower ventilation frequency, and this sexual dimorphism was stronger in high-predation populations. This may reflect a greater premium placed on energy efficiency in live-bearing females, especially under high-predation risk where females show higher fecundities. Altogether, by demonstrating parallel adaptive divergence in stress reactivity, we highlight how energetic trade-offs may mould the evolution of the vertebrate stress response under varying predation risk and resource availability.
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| 16. |
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| 17. |
- Vinterstare, Jerker, et al.
(författare)
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Sex matters : predator presence induces sexual dimorphism in a monomorphic prey, from stress genes to morphological defences
- 2023
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Ingår i: Evolution; international journal of organic evolution. - : Oxford University Press (OUP). - 1558-5646. ; 77:1, s. 304-317
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Tidskriftsartikel (refereegranskat)abstract
- Inducible defences allow prey to increase survival chances when predators are present while avoiding unnecessary costs in their absence. Many studies report considerable inter-individual variation in inducible defence expression, yet what underlies this variation is poorly understood. A classic vertebrate example of a predator-induced morphological defence is the increased body depth in crucian carp (Carassius carassius), which reduces the risk of predation from gape-size limited predators. Here, we report that among-individual variation in morphological defence expression can be linked to sex. We documented sexual dimorphism in lakes in which crucian carp coexisted with predators, where females showed shallower relative body depths than males, but not in a predator-free lake. When exposing crucian carp from a population without predators to perceived predation risk in a laboratory environment (presence/absence of pike, Esox lucius), we found that males expressed significantly greater morphological defence than females, causing sexual dimorphism only in the presence of predators. We uncovered a correlative link between the sex-specific inducible phenotypic response and gene expression patterns in major stress-related genes (POMC, MC3R, and MC4R). Together, our results highlight that sex-specific responses may be an important, yet underappreciated, component underlying inter-individual differences in the expression of inducible defences, even in species without pronounced sexual dimorphism.
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| 18. |
- Vinterstare, Jerker
(författare)
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Åtgärdsprogram för mal : (Siluris glanis)
- 2017
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Åtgärdsprogrammet syftar till att förbättra malens (Siluris glanis) överlevnad i landet. Det är ett vägledande, men ej legalt bindande, aktionsprogram. Malen är Sveriges största sötvattensfisk. Den största mal som fångats i Sverige var 3,6 meter lång och vägde uppskattningsvis 180 kg. Malen vandrade in till Sverige under Ancylus-perioden, när Östersjön var ett varmt och sött innanhav. Malen lever i sjöar och flodmiljöer. Den är allätare och kan utöver fisk även äta groddjur, gnagare, fåglar, kräftor, insekter, maskar och blötdjur. Malen är revirhävdande, framför allt under lektiden. För sin reproduktion är den beroende av varmt vatten samt vattenväxter och strandnära vegetation. Hanen bygger ett bo bland vegetation och rötter dit honan lockas för lek. Hanen vaktar sedan äggen tills de kläckts. Ungarna växer upp i skydd av vegetationen. I Sverige var arten mer spridd förr, men förändringar i markanvändningen från 1800-talets mitt, med exempelvis sjösänkningar och anläggande av vattenkraftverk, har minskat förekomsten. Idag finns malen endast kvar i fyra ursprungliga områden: Båvenområdet, Emån, övre delen av Helge å och nedre delen av Helge å. Utöver dessa är mal känd från ett fåtal andra sjöar, varav de flesta är illegala utsättningar. Hotbilden är idag fragmentering och isolerade bestånd då många vattendrag och sjösystem är påverkade av vattenkraft och andra dämmen, vilka hindrar malen från att sprida sig till fler och större områden. Sjösänkningar, rensningar av vattendrag och annan verksamhet har inneburit och innebär än idag att lämpliga lekmiljöer och uppväxtområden försvunnit. Genetiska undersökningar visar att malpopulationerna i Sverige har låg genetisk variation och att det troligtvis är få individer som deltar i leken, vilket talar för att antalet lekhabitat är en begränsande faktor idag. I den svenska rödlistan från 2015 klassas malen som Sårbar (VU). Malen är fredad från fiske enligt 2 kap. 5 § i förordningen (1994:1716) om fisket, vattenbruket och fiskenäringen. Målet med programmet är att förstärka bestånden genom åtgärdande av vandringshinder samt översyn och anpassning av reglering. Andra viktiga åtgärder är olika biotopförbättrande åtgärder, exempelvis gynnade av strandnära vegetation och test av konstgjorda leknästen. Utöver detta finns ett stort fokus på förbättrat kunskapsunderlag och informationsspridning. De åtgärder som förutsätts finansieras av Havs- och vattenmyndighetens medel för genomförande av åtgärdsprogram för hotade arter beräknas totalt uppgå till 5 875 000kr under programmets giltighetsperiod 2017– 2021.
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