| 1. |
- Ekström, Magnus, et al.
(författare)
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Oral corticosteroid use, morbidity and mortality in asthma: A nationwide prospective cohort study in Sweden
- 2019
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Ingår i: Allergy: European Journal of Allergy and Clinical Immunology. - : Wiley. - 0105-4538 .- 1398-9995. ; 74:11, s. 2181-2190
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Tidskriftsartikel (refereegranskat)abstract
- Background: Patterns and determinants of long-term oral corticosteroid (OCS) use in asthma and related morbidity and mortality are not well-described. In a nationwide asthma cohort in Sweden, we evaluated the patterns and determinants of OCS use and risks of OCS-related morbidities and mortality. Methods: Data for 217993 asthma patients (aged≥6years) in secondary care were identified between 2007 and 2014 using Swedish national health registries. OCS use at baseline was categorized: regular users (≥5mg/d/y; n=3299; 1.5%); periodic users (>0 but <5mg/d/y; n=49930; 22.9%); and nonusers (0mg/d/y; n=164765; 75.6%). Relative risks of becoming a regular OCS user and for morbidity and mortality were analysed using multivariable Cox regression. Results: At baseline, 24% of asthma patients had used OCS during the last year and 1.5% were regular users. Of those not using OCS at baseline, 26% collected at least one OCS prescription and 1.3% became regular OCS users for at least 1year during the median follow-up of 5.3years. Age at asthma diagnosis, increasing GINA severity and Charlson Comorbidity Index were associated with regular OCS use. Compared to periodic and non-OCS use, regular use was associated with increased incidence of OCS-related morbidities and greater all-cause mortality, adjusted HR 1.34 (95% CI 1.24-1.45). Conclusions: Oral corticosteroids use is frequent for asthma patients, and many are regular users. Regular OCS use is associated with increased risk of morbidity and mortality. These findings indicate that there is a need of other treatment options for patients with severe asthma who are using regular OCS. © 2019 The Authors Allergy Published by John Wiley & Sons Ltd
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| 2. |
- Fogelström, Elsa, et al.
(författare)
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Plant-herbivore synchrony and selection on plant flowering phenology
- 2017
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Ingår i: Ecology. - : Wiley. - 0012-9658 .- 1939-9170. ; 98:3, s. 703-711
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Tidskriftsartikel (refereegranskat)abstract
- Temporal variation in natural selection has profound effects on the evolutionary trajectories of populations. One potential source of variation in selection is that differences in thermal reaction norms and temperature influence the relative phenology of interacting species. We manipulated the phenology of the butterfly herbivore Anthocharis cardamines relative to genetically identical populations of its host plant, Cardamine pratensis, and examined the effects on butterfly preferences and selection acting on the host plant. We found that butterflies preferred plants at an intermediate flowering stage, regardless of the timing of butterfly flight relative to flowering onset of the population. Consequently, the probability that plant genotypes differing in timing of flowering should experience a butterfly attack depended strongly on relative phenology. These results suggest that differences in spring temperature influence the direction of herbivore-mediated selection on flowering phenology, and that climatic conditions can influence natural selection also when phenotypic preferences remain constant.
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| 3. |
- Friberg, Magne, et al.
(författare)
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Butterflies and plants : preference/performance studies in relation to plant size and the use of intact plants vs. cuttings
- 2016
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Ingår i: Entomologia Experimentalis et Applicata. - : Wiley. - 0013-8703 .- 1570-7458. ; 160:3, s. 201-208
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Tidskriftsartikel (refereegranskat)abstract
- Plants have evolved a number of defences to ameliorate herbivore attacks including chemicals induced by mechanical wounding. Such changes in plant chemical composition are potential confounding factors in experiments on plant-insect interactions, which often present cuttings of potential host plants to phytophagous insects. In particular, this could affect studies of female egg-laying preference and larval performance, because the same plant chemicals that deter certain generalist insects can elevate attacks from more specialized insects. Furthermore, plant cuttings are by definition smaller than intact plants, and any female host size preference could thus affect experiments using plant cuttings. We first assessed female preference and larval performance of a specialist herbivore, Pieris napi (L.) (Lepidoptera: Pieridae, Pierini), confronted with either intact plants or leaf-cuttings of four Brassicaceae host plants, Alliaria petiolata (Bieb.) Cavara & Grande, Barbarea vulgaris (L.) WT Aiton, Berteroa incana (L.) DC., and Brassica napus (L.). Egg and larval survival did not differ between intact plants and leaf-cuttings, whereas larval growth was slightly, but significantly, faster on leaf-cuttings. Females, however, significantly preferred to lay eggs on intact plants of all four hosts, although the preference hierarchy for the intact plants was largely mirrored by that for leaf-cuttings. We then tested the female preference for different size-classes of intact B. napus plants. Small individuals received more eggs than larger individuals, and follow-up experiments showed that this difference was largely generated by a strong female preference for cotyledon leaves; there was no significant difference in female preference for large and small individuals when both carried cotyledons, and females landing on cotyledons were more likely to oviposit compared to when landing on a true leaf. Our study concludes that plant cuttings can serve as adequate proxies for live plants for preference/performance studies, but that experimentalists should be aware of the variation imposed both by plant handling and plant phenology for female oviposition preference.
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| 4. |
- Friberg, Magne, et al.
(författare)
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Decoupling of female host plant preference and offspring performance in relative specialist and generalist butterflies
- 2015
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Ingår i: Oecologia. - : Springer Science and Business Media LLC. - 0029-8549 .- 1432-1939. ; 178:4, s. 1181-1192
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Tidskriftsartikel (refereegranskat)abstract
- The preference-performance hypothesis posits that the host plant range of plant-feeding insects is ultimately limited by larval costs associated with feeding on multiple resources, and that female egg-laying preferences evolve in response to these costs. The trade-off of either using few host plant species and being a strong competitor on them due to effective utilization or using a wide host plant range but being a poor competitor is further predicted to result in host plant specialization. This follows under the hypothesis that both females and offspring are ultimately favoured by utilizing only the most suitable host(s). We develop an experimental approach to identify such trade-offs, i.e. larval costs associated with being a host generalist, and apply a suite of experiments to two sympatric and syntopic populations of the closely related butterflies Pieris napi and Pieris rapae. These butterflies show variation in their level of host specialization, which allowed comparisons between more and less specialized species and between families within species. Our results show that, first, the link between female host preference and offspring performance was not significantly stronger in the specialist compared to the generalist species. Second, the offspring of the host plant specialist did not outperform the offspring of the generalist on the former's most preferred host plant species. Finally, the more generalized species, or families within species, did not show higher survival or consistently higher growth rates than the specialists on the less preferred plants. Thus, the preference and performance traits appear to evolve as largely separated units.
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| 5. |
- Friberg, Magne, et al.
(författare)
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Host preference variation cannot explain microhabitat differentiation among sympatric Pieris napi and Pieris rapae butterflies
- 2019
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Ingår i: Ecological Entomology. - : Wiley. - 0307-6946 .- 1365-2311. ; 44:4, s. 571-576
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Tidskriftsartikel (refereegranskat)abstract
- 1. Often, closely related insect species feed on different host plant species, and the tremendous diversity of phytophagous insects is therefore attributed to host plant-driven speciation. However, for most taxa, host use information comes from field observations of egg-laying females or feeding caterpillars, which means that the underlying reason for a particular host-affiliation is not easily determined. 2. Therefore, it is often unclear whether an insect feeds on a certain host because it prefers that plant to alternative hosts, or because the host distribution overlaps with the habitat requirements of the insect. 3. We ask to what extent a divergent host use in the field mirrors the host plant preferences of two closely related butterflies, Pieris napi and Pieris rapae (Pieridae). In nature, P. napi typically occurs in moister habitats than P. rapae. 4. We scanned several microhabitats at a field site in Southern Sweden during multiple years, and collected Pieris eggs from three different plants, Cardamine pratensis (wet meadows), Barbarea vulgaris (drier micro-habitats) and Alliaria petiolata (intermediate areas). 5. As predicted, P. rapae eggs were more common than P. napi eggs on B. vulgaris, whereas all of the 358 individuals collected from C. pratensis were P. napi, indicating a divergence in host use between the Pieris species. However, under controlled laboratory conditions, both species had virtually identical oviposition preferences, laying eggs on all three plants, notably P. rapae also laying eggs on C. pratensis, indicating that habitat use, not plant preference, drives host plant use in nature.
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| 6. |
- Gustavsson, Sandra, et al.
(författare)
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Can echocardiography and ECG discriminate hereditary transthyretin V30M amyloidosis from hypertrophic cardiomyopathy?
- 2015
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Ingår i: Amyloid. - : Informa UK Limited. - 1350-6129 .- 1744-2818. ; 22:3, s. 163-170
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Tidskriftsartikel (refereegranskat)abstract
- Objective: Hereditary transthyretin (ATTR) amyloidosis with increased left ventricular wall thickness could easily be misdiagnosed by echocardiography as hypertrophic cardiomyopathy (HCM). Our aim was to create a diagnostic tool based on echocardiography and ECG that could optimise identification of ATTR amyloidosis. Methods: Data were analysed from 33 patients with biopsy proven ATTR amyloidosis and 30 patients with diagnosed HCM. Conventional features from ECG were acquired as well as two dimensional and Doppler echocardiography, speckle tracking derived strain and tissue characterisation analysis. Classification trees were used to select the most important variables for differentiation between ATTR amyloidosis and HCM. Results: The best classification was obtained using both ECG and echocardiographic features, where a QRS voltage >30 mm was diagnostic for HCM, whereas in patients with QRS voltage <30 mm, an interventricular septal/posterior wall thickness ratio (IVSt/PWt) >1.6 was consistent with HCM and a ratio <1.6 supported the diagnosis of ATTR amyloidosis. This classification presented both high sensitivity (0.939) and specificity (0.833). Conclusion: Our study proposes an easily interpretable classification method for the differentiation between HCM and increased left ventricular myocardial thickness due to ATTR amyloidosis. Our combined echocardiographic and ECG model could increase the ability to identify ATTR cardiac amyloidosis in clinical practice.
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| 7. |
- Hill, Jason, et al.
(författare)
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Unprecedented reorganization of holocentric chromosomes provides insights into the enigma of lepidopteran chromosome evolution
- 2019
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Ingår i: Science Advances. - : American Association for the Advancement of Science (AAAS). - 2375-2548. ; 5:6
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Tidskriftsartikel (refereegranskat)abstract
- Chromosome evolution presents an enigma in the mega-diverse Lepidoptera. Most species exhibit constrained chromosome evolution with nearly identical haploid chromosome counts and chromosome-level gene collinearity among species more than 140 million years divergent. However, a few species possess radically inflated chromosomal counts due to extensive fission and fusion events. To address this enigma of constraint in the face of an exceptional ability to change, we investigated an unprecedented reorganization of the standard lepidopteran chromosome structure in the green-veined white butterfly (Pieris napi). We find that gene content in P. napi has been extensively rearranged in large collinear blocks, which until now have been masked by a haploid chromosome number close to the lepidopteran average. We observe that ancient chromosome ends have been maintained and collinear blocks are enriched for functionally related genes suggesting both a mechanism and a possible role for selection in determining the boundaries of these genome-wide rearrangements.
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| 8. |
- Kazemi, Baharan, et al.
(författare)
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Learning of salient prey traits explains Batesian mimicry evolution
- 2018
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Ingår i: Evolution. - : Wiley. - 0014-3820 .- 1558-5646. ; 72:3, s. 531-539
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Tidskriftsartikel (refereegranskat)abstract
- Batesian mimicry evolution involves an initial major mutation that produces a rough resemblance to the model, followed by smaller improving changes. To examine the learning psychology of this process, we applied established ideas about mimicry in Papilio polyxenes asterius of the model Battus philenor. We performed experiments with wild birds as predators and butterfly wings as semiartificial prey. Wings of hybrids of P. p. asterius and Papilio machaon were used to approximate the first mutant, with melanism as the hypothesized first mimetic trait. Based on previous results about learning psychology and imperfect mimicry, we predicted that: melanism should have high salience (i.e., being noticeable and prominent), meaning that predators readily discriminate a melanistic mutant from appearances similar to P. machaon; the difference between the first mutant and the model should have intermediate salience to allow further improvement of mimicry; and the final difference in appearance between P. p. asterius and B. philenor should have very low salience, causing improvement to level off. Our results supported both the traditional hypothesis and all our predictions about relative salience. We conclude that there is good agreement between long-held ideas about how Batesian mimicry evolves and recent insights from learning psychology about the role of salience in mimicry evolution.
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| 9. |
- Kivelä, Sami M., et al.
(författare)
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Adaptive developmental plasticity in a butterfly : mechanisms for size and time at pupation differ between diapause and direct development
- 2017
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Ingår i: Biological Journal of the Linnean Society. - : Oxford University Press (OUP). - 0024-4066 .- 1095-8312. ; 122:1, s. 46-57
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Tidskriftsartikel (refereegranskat)abstract
- Diapause (overwintering) and direct development are alternative developmental pathways in temperate insects. Diapause necessitates physiological preparations for dormancy, while direct development is associated with strong time constraints, resulting in selection for fast development under the direct development pathway. Physiological and behavioural preparations for pupation contribute to development time, so divergent selection in them is expected between the alternative developmental pathways. Critical mass for pupation induction is a central physiological parameter for the pupation process. Here, we compare the critical masses and the characteristics of the wandering stage - wandering taking place after the cessation of growth and before pupation - between diapausing and directly developing larvae in the butterfly Pieris napi. Critical mass estimation succeeded only for diapausing individuals, among which it was lower in females than in males, indicating an inter-pathway difference in the physiology of critical mass. Directly developing individuals wandered for a shorter time and distance and lost less mass before pupation than diapausing individuals. These physiological and behavioural differences represent adaptive phenotypic plasticity and contribute to fast development under direct development. Thus, the observed developmental plasticity in physiology offers a mechanistic explanation for adaptive life-history variation between alternative developmental pathways and sexual dimorphism.
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| 10. |
- Kivelä, Sami M., et al.
(författare)
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Towards a mechanistic understanding of insect life history evolution : oxygen-dependent induction of moulting explains moulting sizes
- 2016
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Ingår i: Biological Journal of the Linnean Society. - : Oxford University Press (OUP). - 0024-4066 .- 1095-8312. ; 117:3, s. 586-600
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Tidskriftsartikel (refereegranskat)abstract
- Moults characterise insect growth trajectories, typically following a consistent pattern known as Dyar's rule; proportional size increments remain constant across inter-instar moults. Empirical work suggests that oxygen limitation triggers moulting. The insect respiratory system, and its oxygen supply capacity, grows primarily at moults. It is hypothesized that the oxygen demand increases with increasing body mass, eventually meeting the oxygen supply capacity at an instar-specific critical mass where moulting is triggered. Deriving from this hypothesis, we develop a novel mathematical model for moulting and growth in insect larvae. Our mechanistic model has great success in predicting moulting sizes in four butterfly species, indirectly supporting a size-dependent mechanism underlying moulting. The results demonstrate that an oxygen-dependent induction of moulting mechanism would be sufficient to explain moulting sizes in the study species. Model predictions deviated slightly from Dyar's rule, the deviations being typically negligible within the present data range. The developmental decisions (e.g. moulting) made by growing larvae significantly affect age and size at maturity, which has important life history implications. The successful modelling of moulting presented here provides a novel framework for the development of realistic insect growth models, which are required for a better understanding of life history evolution.
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