| 1. |
- Clark, Andrew G., et al.
(författare)
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Evolution of genes and genomes on the Drosophila phylogeny
- 2007
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 450:7167, s. 203-218
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Tidskriftsartikel (refereegranskat)abstract
- Comparative analysis of multiple genomes in a phylogenetic framework dramatically improves the precision and sensitivity of evolutionary inference, producing more robust results than single-genome analyses can provide. The genomes of 12 Drosophila species, ten of which are presented here for the first time (sechellia, simulans, yakuba, erecta, ananassae, persimilis, willistoni, mojavensis, virilis and grimshawi), illustrate how rates and patterns of sequence divergence across taxa can illuminate evolutionary processes on a genomic scale. These genome sequences augment the formidable genetic tools that have made Drosophila melanogaster a pre-eminent model for animal genetics, and will further catalyse fundamental research on mechanisms of development, cell biology, genetics, disease, neurobiology, behaviour, physiology and evolution. Despite remarkable similarities among these Drosophila species, we identified many putatively non-neutral changes in protein-coding genes, non-coding RNA genes, and cis-regulatory regions. These may prove to underlie differences in the ecology and behaviour of these diverse species.
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| 2. |
- Haycock, Philip C., et al.
(författare)
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Association Between Telomere Length and Risk of Cancer and Non-Neoplastic Diseases A Mendelian Randomization Study
- 2017
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Ingår i: JAMA Oncology. - : American Medical Association. - 2374-2437 .- 2374-2445. ; 3:5, s. 636-651
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Tidskriftsartikel (refereegranskat)abstract
- IMPORTANCE: The causal direction and magnitude of the association between telomere length and incidence of cancer and non-neoplastic diseases is uncertain owing to the susceptibility of observational studies to confounding and reverse causation. OBJECTIVE: To conduct a Mendelian randomization study, using germline genetic variants as instrumental variables, to appraise the causal relevance of telomere length for risk of cancer and non-neoplastic diseases. DATA SOURCES: Genomewide association studies (GWAS) published up to January 15, 2015. STUDY SELECTION: GWAS of noncommunicable diseases that assayed germline genetic variation and did not select cohort or control participants on the basis of preexisting diseases. Of 163 GWAS of noncommunicable diseases identified, summary data from 103 were available. DATA EXTRACTION AND SYNTHESIS: Summary association statistics for single nucleotide polymorphisms (SNPs) that are strongly associated with telomere length in the general population. MAIN OUTCOMES AND MEASURES: Odds ratios (ORs) and 95% confidence intervals (CIs) for disease per standard deviation (SD) higher telomere length due to germline genetic variation. RESULTS: Summary data were available for 35 cancers and 48 non-neoplastic diseases, corresponding to 420 081 cases (median cases, 2526 per disease) and 1 093 105 controls (median, 6789 per disease). Increased telomere length due to germline genetic variation was generally associated with increased risk for site-specific cancers. The strongest associations (ORs [ 95% CIs] per 1-SD change in genetically increased telomere length) were observed for glioma, 5.27 (3.15-8.81); serous low-malignant-potential ovarian cancer, 4.35 (2.39-7.94); lung adenocarcinoma, 3.19 (2.40-4.22); neuroblastoma, 2.98 (1.92-4.62); bladder cancer, 2.19 (1.32-3.66); melanoma, 1.87 (1.55-2.26); testicular cancer, 1.76 (1.02-3.04); kidney cancer, 1.55 (1.08-2.23); and endometrial cancer, 1.31 (1.07-1.61). Associations were stronger for rarer cancers and at tissue sites with lower rates of stem cell division. There was generally little evidence of association between genetically increased telomere length and risk of psychiatric, autoimmune, inflammatory, diabetic, and other non-neoplastic diseases, except for coronary heart disease (OR, 0.78 [ 95% CI, 0.67-0.90]), abdominal aortic aneurysm (OR, 0.63 [ 95% CI, 0.49-0.81]), celiac disease (OR, 0.42 [ 95% CI, 0.28-0.61]) and interstitial lung disease (OR, 0.09 [ 95% CI, 0.05-0.15]). CONCLUSIONS AND RELEVANCE: It is likely that longer telomeres increase risk for several cancers but reduce risk for some non-neoplastic diseases, including cardiovascular diseases.
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| 3. |
- Hiron, Matthew, et al.
(författare)
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Crop damage by granivorous birds despite protection efforts by human bird scarers in a sorghum field in western Kenya
- 2014
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Ingår i: Ostrich: Journal of African Ornithology. - : National Inquiry Services Center (NISC). - 0030-6525. ; 85, s. 153-159
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Tidskriftsartikel (refereegranskat)abstract
- Cereal crop damage from granivorous birds poses a serious food security problem for subsistence farmers in sub-Saharan Africa. In this region, farmers may rely on human 'bird scarers' to limit crop damage. Here we report feeding behaviour and crop damage patterns caused by Village Weavers Ploceus cucullatus and African Mourning Doves Streptopelia decipiens during four days in a 0.12 ha sorghum field protected by two full-time bird scarers in western Kenya. Despite the scarers' efforts, almost 60% of the seed was lost before harvest. Bird abundance was largely determined by the presence of the bird scarers, with seed loss patterns being a function of distance from these people. Throughout the day, an average of 18 weavers (maximum 120) was present on the crop in any five-minute period. The number of mud projectiles thrown at the birds per 15 min showed only minor diurnal fluctuations, further suggesting that seed eaters attacked the crop throughout the day. Village Weaver individuals took an average 16 seeds per visit, whereas dove individuals took 32 seeds (maximum 105 and 455, respectively). Our study illustrates that avian crop pests can be extremely persistent and, even with consistent diurnal bird scaring activity, severely damage a small crop field. Bird scarers need to be active throughout daylight hours and patrol both the centres and edges of fields to create maximum disturbance to foraging seed eating birds. Further research is needed in order to investigate effects of local-and landscape-level land use patterns on the feeding behaviour of crop pests and the effectiveness of crop protection measures.
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| 4. |
- Josefsson, Jonas, et al.
(författare)
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Improving scientific rigour in conservation evaluations and a plea deal for transparency on potential biases
- 2020
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Ingår i: Conservation Letters. - : Wiley. - 1755-263X. ; 13:5
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Forskningsöversikt (refereegranskat)abstract
- The delivery of rigorous and unbiased evidence on the effects of interventions lay at the heart of the scientific method. Here we examine scientific papers evaluating agri-environment schemes, the principal instrument to mitigate farmland biodiversity declines worldwide. Despite previous warnings about rudimentary study designs in this field, we found that the majority of studies published between 2008 and 2017 still lack robust study designs to strictly evaluate intervention effects. Potential sources of bias that arise from the correlative nature are rarely mentioned, and results are still promoted by using a causal language. This lack of robust study designs likely results from poor integration of research and policy, while the erroneous use of causal language and an unwillingness to discuss bias may stem from publication pressures. We conclude that scientific reporting and discussion of study limitations in intervention research must improve and propose some practices toward this goal.
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| 5. |
- Klionsky, Daniel J., et al.
(författare)
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Guidelines for the use and interpretation of assays for monitoring autophagy
- 2012
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Ingår i: Autophagy. - : Informa UK Limited. - 1554-8635 .- 1554-8627. ; 8:4, s. 445-544
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Forskningsöversikt (refereegranskat)abstract
- In 2008 we published the first set of guidelines for standardizing research in autophagy. Since then, research on this topic has continued to accelerate, and many new scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Accordingly, it is important to update these guidelines for monitoring autophagy in different organisms. Various reviews have described the range of assays that have been used for this purpose. Nevertheless, there continues to be confusion regarding acceptable methods to measure autophagy, especially in multicellular eukaryotes. A key point that needs to be emphasized is that there is a difference between measurements that monitor the numbers or volume of autophagic elements (e.g., autophagosomes or autolysosomes) at any stage of the autophagic process vs. those that measure flux through the autophagy pathway (i.e., the complete process); thus, a block in macroautophagy that results in autophagosome accumulation needs to be differentiated from stimuli that result in increased autophagic activity, defined as increased autophagy induction coupled with increased delivery to, and degradation within, lysosomes (in most higher eukaryotes and some protists such as Dictyostelium) or the vacuole (in plants and fungi). In other words, it is especially important that investigators new to the field understand that the appearance of more autophagosomes does not necessarily equate with more autophagy. In fact, in many cases, autophagosomes accumulate because of a block in trafficking to lysosomes without a concomitant change in autophagosome biogenesis, whereas an increase in autolysosomes may reflect a reduction in degradative activity. Here, we present a set of guidelines for the selection and interpretation of methods for use by investigators who aim to examine macroautophagy and related processes, as well as for reviewers who need to provide realistic and reasonable critiques of papers that are focused on these processes. These guidelines are not meant to be a formulaic set of rules, because the appropriate assays depend in part on the question being asked and the system being used. In addition, we emphasize that no individual assay is guaranteed to be the most appropriate one in every situation, and we strongly recommend the use of multiple assays to monitor autophagy. In these guidelines, we consider these various methods of assessing autophagy and what information can, or cannot, be obtained from them. Finally, by discussing the merits and limits of particular autophagy assays, we hope to encourage technical innovation in the field.
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| 6. |
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| 7. |
- Rosin, Zuzanna, et al.
(författare)
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Village modernization may contribute more to farmland bird declines than agricultural intensification
- 2021
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Ingår i: Conservation Letters. - : Wiley. - 1755-263X. ; 14
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Tidskriftsartikel (refereegranskat)abstract
- The central tenet of European farmland ecology is that agricultural intensification during the 20th century was largely responsible for dramatic declines in species abundances. However, during this time, human rural settlements were also undergoing radical changes through modernization, with undocumented biodiversity impacts in this important wildlife habitat. We performed the first ever large-scale study to disentangle the impact of these simultaneous processes on farmland bird diversity in 104 Polish villages. We show that modernized villages and their surrounding agricultural fields had 50-60% fewer birds than those in and around comparable older villages. The relative contribution of modernization versus agricultural intensification to predicted bird declines was 88% versus 12% for bird communities in villages and 56% versus 44% in surrounding croplands, with considerable variation among ecological species subgroups. These results challenge our current understanding of agricultural ecosystem ecology and how best to implement conservation measures costing billions of euros annually.
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| 8. |
- Arlt, Debora, et al.
(författare)
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Effect of Geolocators on Migration and Subsequent Breeding Performance of a Long-Distance Passerine Migrant
- 2013
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Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 8
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Tidskriftsartikel (refereegranskat)abstract
- Geolocators are small light-weight data loggers used to track individual migratory routes, and their use has increasedexponentially in birds. However, the effects of geolocators on individual performance are still poorly known. Westudied geolocator effects on a long-distance migrating passerine bird, the northern wheatear (Oenanthe oenantheL.). We asked the general question of whether geolocators affect migratory behaviour and subsequent reproductiveperformance of small passerines by comparing arrival time, breeding time, breeding success and survival ofgeolocator versus control birds of known identity and breeding history. During two years geolocator birds (n=37)displayed a lower apparent survival (30%) as compared to controls (45%, n=164). Furthermore, returning geolocatorbirds (n=12) arrived on average 3.5 days later, started laying eggs 6.3 days later, and had lower nest success (25%)than control birds (78%). Our results suggest that geolocators affect migratory performance with carry-over effects tothe timing of breeding and reproductive success in the subsequent breeding season. We discuss the implications ofsuch geolocator effects for the study of migratory strategies of small passerines in general and suggest how toidentify and investigate such effects in the future.
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| 9. |
- Arlt, Debora, et al.
(författare)
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Prolonged stopover duration characterises migration strategy and constraints of a long-distance migrant songbird
- 2015
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Ingår i: Animal Migration. - : Walter de Gruyter GmbH. - 2084-8838. ; 2, s. 47-62
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Tidskriftsartikel (refereegranskat)abstract
- Stopover behaviour is a central element ofmigration strategies. But in recent geolocator studies,despite now being able to track individual songbirdsduring their entire migration, their stopover behaviourhas received little attention. We used light-sensitivegeolocators to identify the migratory routes and schedulesof 12 northern wheatears (Oenanthe oenanthe) breedingin Sweden. Three geolocators collected temperature datacomplementing inferences from light data by providingadditional information on behaviour during migration.The wheatears performed a slow migration withconsiderable stopover time (84%/76% of autumn/springmigration), with short stops while traveling throughEurope, and a prolonged stopover period in both autumnand spring in the Mediterranean region. Spring migrationwas faster than autumn migration, mainly because ofdecreased stopover time. Migration routes and timeschedules were similar to those from a German breedingpopulation. Compared to wheatears breeding in Alaskawith a three-fold migration distance, Swedish wheatearsspent more time during stopovers during autumn andspring migration, suggesting less time constraints andpotential flexibility in migration schedules. The findingof prolonged stopovers, similar to other recent geolocatorstudies, shows that temporary residency periods maybe common. This changes our current view on stopoverecology to one where temporary residency periods arepart of spatio-temporal strategies optimising resource useduring the entire annual cycle.
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| 10. |
- Aronsson, Malin, et al.
(författare)
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Intensity of space use reveals conditional sex-specific effects of prey and conspecific density on home range size
- 2016
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Ingår i: Ecology and Evolution. - : Wiley. - 2045-7758. ; 6, s. 2957-2967
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Tidskriftsartikel (refereegranskat)abstract
- Home range (HR) size variation is often linked to resource abundance, with sex differences expected to relate to sex-specific fitness consequences. However, studies generally fail to disentangle the effects of the two main drivers of HR size variation, food and conspecific density, and rarely consider how their relative influence change over spatiotemporal scales. We used location data from 77 Eurasian lynx (Lynx lynx) from a 16-year Scandinavian study to examine HR sizes variation relative to prey and conspecific density at different spatiotemporal scales. By varying the isopleth parameter (intensity of use) defining the HR, we show that sex-specific effects were conditional on the spatial scale considered. Males had larger HRs than females in all seasons. Females' total HR size declined as prey and conspecific density increased, whereas males' total HR was only affected by conspecific density. However, as the intensity of use within the HR increased (from 90% to 50% isopleth), the relationship between prey density and area showed opposing patterns for females and males; for females, the prey density effect was reduced, while for males, prey became increasingly important. Thus, prey influenced the size of key regions within male HRs, despite total HR size being independent of prey density. Males reduced their HR size during the mating season, likely to remain close to individual females in estrous. Females reduced their HR size postreproduction probably because of movement constrains imposed by dependent young. Our findings highlight the importance of simultaneously considering resources and intraspecific interactions as HR size determinants. We show that sex-specific demands influence the importance of prey and conspecific density on space use at different spatiotemporal scales. Thus, unless a gradient of space use intensity is examined, factors not related to total HR size might be disregarded despite their importance in determining size of key regions within the HR.
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| 11. |
- Aronsson, Malin, et al.
(författare)
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Resource dispersion and relatedness interact to explain space use in a solitary predator
- 2020
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Ingår i: Oikos. - : Wiley. - 0030-1299 .- 1600-0706. ; 129, s. 1174-1184
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Tidskriftsartikel (refereegranskat)abstract
- Resource dispersion or kin selection are commonly used to explain animal spatial and social organization. Despite this, studies examining how these factors interact in wild populations of solitary animals are rare. We used 16 years of individual-level spatial and genetic data to disentangle how resources and relatedness influence spatial organization of a solitary predator, the Eurasian lynx Lynx lynx. As expected, space-use overlap between neighbouring individuals increased when food resources were heterogeneous and unpredictably distributed (as predicted from resource dispersion) or when neighbours were closely related (as predicted from kin selection). However, these patterns were highly dependent on each other. Increased spatial overlap was restricted to mother-daughter dyads, with this effect only occurring in areas and during seasons when prey was clumped and irregularly distributed in the landscape. Additionally, full-siblings with similar levels of genetic relatedness did not show these patterns, suggesting that kin selection is mediated through mother-daughter recognition, and is only beneficial under specific resource dispersion circumstances. Our results provide key insights into the flexibility of spatial organization of solitary animals, and clearly show the importance of considering the interaction between resources and kinship when assessing animal space use patterns.
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| 12. |
- Ball, Elisabeth, et al.
(författare)
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Repeatability of radiographic assessments for feline hip dysplasia suggest consensus scores in radiology are more uncertain than commonly assumed
- 2022
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 12
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Tidskriftsartikel (refereegranskat)abstract
- Variation in the diagnostic interpretation of radiographs is a well-recognised problem in human and veterinary medicine. One common solution is to create a 'consensus' score based on a majority or unanimous decision from multiple observers. While consensus approaches are generally assumed to improve diagnostic repeatability, the extent to which consensus scores are themselves repeatable has rarely been examined. Here we use repeated assessments by three radiologists of 196 hip radiographs from 98 cats within a health-screening programme to examine intra-observer, interobserver, majority-consensus and unanimous-consensus repeatability scores for feline hip dysplasia. In line with other studies, intra-observer and inter-observer repeatability was moderate (63-71%), and related to the reference assessment and time taken to reach a decision. Consensus scores did show reduced variation between assessments compared to individuals, but consensus repeatability was far from perfect. Only 75% of majority consensus scores were in agreement between assessments, and based on Bayesian multinomial modelling we estimate that unanimous consensus scores can have repeatabilities as low as 83%. These results clearly show that consensus scores in radiology can have large uncertainties, and that future studies in both human and veterinary medicine need to include consensus-uncertainty estimates if we are to properly interpret radiological diagnoses and the extent to which consensus scores improve diagnostic accuracy.
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| 13. |
- Berggren, Åsa, et al.
(författare)
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Approaching Ecological Sustainability in the Emerging Insects-as-Food Industry
- 2019
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Ingår i: Trends in ecology & evolution. - : Elsevier BV. - 0169-5347 .- 1872-8383. ; 34, s. 132-138
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Forskningsöversikt (refereegranskat)abstract
- The emerging insects-as-food industry is increasingly promoted as a sustainable alternative to other animal protein production systems. However, the exact nature of its environmental benefits are uncertain because of the overwhelming lack of knowledge concerning almost every aspect of production: from suitable species, their housing and feed requirements, and potential for accidental release. If ecological sustainability is to be a hallmark of mass insect rearing for consumption, ecologists need to engage in research related to sustainability criteria that are directly linked to key elements of the development of the industry. There is more to this subject than simply comparing feed-conversion ratios (FCRs) of insects to traditional livestock production, and we highlight areas where research needs to be immediately focused.
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| 14. |
- Berggren, Åsa, et al.
(författare)
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The Relationship Between Morphological Symmetry and Immune Response in Wild-Caught Adult Bush-Crickets
- 2009
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Ingår i: Symmetry. - : MDPI AG. - 2073-8994. ; 1, s. 106-114
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Tidskriftsartikel (refereegranskat)abstract
- Despite interest in the relationship between fluctuating asymmetry (FA), immune response and ecological factors in insects, little data are available from wild populations. In this study we measured FA and immune response in 370 wild-caught male bush-crickets, Metrioptera roeseli, from 20 experimentally introduced populations in southern-central Sweden. Individuals with more-symmetric wings had a higher immune response as measured by the cellular encapsulation of a surgically-implanted nylon monofilament. However, we found no relationship between measures of FA in other organs (i.e. tibia and maxillary palp) and immune response, suggesting that this pattern may reflect differing selection pressures
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| 15. |
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| 16. |
- Berggren, Åsa, et al.
(författare)
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Using current systems to inform rearing facility design in the insect-as-food industry
- 2018
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Ingår i: Journal of insects as food and feed. - 2352-4588. ; 4, s. 167-170
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Tidskriftsartikel (refereegranskat)abstract
- As wild harvesting of insects gives way to mass rearing, there is an urgent need to develop expertise and methods in insect animal husbandry and facility design. In order to advance the science of animal husbandry and production in this field, comparisons and contrasts of different insect rearing facilities currently in production are likely to be beneficial. Here we initiate this discussion by suggesting a focus on insect rearing facilities at the two ends of the production scale spectrum (small-scale rearing and mass rearing) that have different end products (insects-as-food and insects for other purposes). We suggest that organisations with a philosophy of information sharing (e.g. universities) need to play an active role in this developing production system, by bridging gaps between academia, industry and traditional knowledge to ensure a rapid and societally acceptable development of wide-scale entomophagy.
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| 17. |
- Eggers, Sönke, et al.
(författare)
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Differential demographic responses of sympatric Parids to vegetation management in boreal forest
- 2014
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Ingår i: Forest Ecology and Management. - : Elsevier BV. - 0378-1127 .- 1872-7042. ; 319, s. 169-175
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Tidskriftsartikel (refereegranskat)abstract
- Large-scale removal of small-diameter trees (i.e. thinning from below) in boreal forest can diminish niche diversity for birds that rely on a well-developed understory for nesting and foraging. Yet, few studies have examined how reduced niche diversity in managed forests affects fitness measures in closely-related species and the ability of competing species to co-exist. We related forest thinning to population trends of the willow tit Poecile montana (declining) and its dominant competitor the crested tit Lophophanes cristatus (stable), and conducted a 3-year comparative study to determine how variation in understory spruce density differentially influences survival and reproduction in these species. In line with our prediction that crested tits would gain resource priority under conditions of reduced forest understory complexity, willow tits and their nestlings suffered a disproportionate decline in both nest and adult survival prospects relative to crested tits as understoiy spruce density declined. Willow tits also had increased numbers of tail feather fault bars with decreasing understory complexity, further supporting the idea that willow tits suffer from food shortage and increased predation risk in areas of reduced understory. The long-term population declines of willow tits in boreal forest appears linked to large scale harvest of small-diameter spruce trees that provide important understory vegetation. A patchy arrangement of different thinning treatments through 'Understory Retention Thinning' (URT) may provide a cost-effective way to restore long-term structural complexity and biodiversity in densely stocked conifer stands. (C) 2014 Elsevier B.V. All rights reserved.
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| 18. |
- Feckler, Alexander, et al.
(författare)
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When significance becomes insignificant: Effect sizes and their uncertainties in Bayesian and frequentist frameworks as an alternative approach when analyzing ecotoxicological data
- 2018
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Ingår i: Environmental Toxicology and Chemistry. - : Wiley. - 0730-7268 .- 1552-8618. ; 37, s. 1949-1955
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Tidskriftsartikel (refereegranskat)abstract
- Bayesian methods and frequentist confidence intervals are proposed as an alternative approach in ecotoxicology, emphasizing effect sizes and associated (un)certainties to judge the biological relevance of effects instead of basing decisions on p values. These approaches show advantages over null hypothesis significance testing. In particular, Bayesian methods revealed more potential than frequentist counterparts, as the posterior distribution and its credible intervals can be directly interpreted as the probability of effect sizes. Environ Toxicol Chem 2018;37:1949-1955. (c) 2018 SETAC
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| 19. |
- Hopkins, Richard, et al.
(författare)
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Tropiska ekologer i Kenya
- 2011
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Ingår i: Resurs (Uppsala). - 1653-2058. ; , s. 3-3
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Tidskriftsartikel (populärvet., debatt m.m.)
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| 20. |
- Johansson, Örjan, et al.
(författare)
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Identification errors in camera-trap studies result in systematic population overestimation
- 2020
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 10
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Tidskriftsartikel (refereegranskat)abstract
- Reliable assessments of animal abundance are key for successful conservation of endangered species. For elusive animals with individually-unique markings, camera-trap surveys are a benchmark standard for estimating local and global population abundance. Central to the reliability of resulting abundance estimates is the assumption that individuals are accurately identified from photographic captures. To quantify the risk of individual misidentification and its impact on population abundance estimates we performed an experiment under controlled conditions in which 16 captive snow leopards (Panthera uncia) were camera-trapped on 40 occasions and eight observers independently identified individuals and recaptures. Observers misclassified 12.5% of all capture occasions, resulting in systematically inflated population abundance estimates on average by one third (mean +/- SD = 35 +/- 21%). Our results show that identifying individually-unique individuals from camera-trap photos may not be as reliable as previously believed, implying that elusive and endangered species could be less abundant than current estimates indicate.
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| 21. |
- Johansson, Örjan, et al.
(författare)
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Seasonal variation in daily activity patterns of snow leopards and their prey
- 2022
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 12
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Tidskriftsartikel (refereegranskat)abstract
- The daily and seasonal activity patterns of snow leopards (Panthera uncia) are poorly understood, limiting our ecological understanding and hampering our ability to mitigate threats such as climate change and retaliatory killing in response to livestock predation. We fitted GPS-collars with activity loggers to snow leopards, Siberian ibex (Capra sibirica: their main prey), and domestic goats (Capra hircus: common livestock prey) in Mongolia between 2009 and 2020. Snow leopards were facultatively nocturnal with season-specific crepuscular activity peaks: seasonal activity shifted towards night-sunrise during summer, and day-sunset in winter. Snow leopard activity was in contrast to their prey, which were consistently diurnal. We interpret these results in relation to: (1) darkness as concealment for snow leopards when stalking in an open landscape (nocturnal activity), (2) low-intermediate light preferred for predatory ambush in steep rocky terrain (dawn and dusk activity), and (3) seasonal activity adjustments to facilitate thermoregulation in an extreme environment. These patterns suggest that to minimise human-wildlife conflict, livestock should be corralled at night and dawn in summer, and dusk in winter. It is likely that climate change will intensify seasonal effects on the snow leopard's daily temporal niche for thermoregulation in the future.
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| 22. |
- Johansson, Örjan, et al.
(författare)
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Sex-specific seasonal variation in puma and snow leopard home range utilization
- 2018
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Ingår i: Ecosphere. - : Wiley. - 2150-8925. ; 9
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Tidskriftsartikel (refereegranskat)abstract
- Territory size is often larger for males than for females in species without biparental care. For large solitary carnivores, this is explained by males encompassing a set of female territories to monopolize their reproduction during mating (area maximization). However, males are expected to behave more like females outside of breeding, with their area utilization being dependent on the range required to secure food resources (area minimization). To examine how male and female solitary carnivores adjust their spatial organization during the year as key resources (mates and prey) change, we radio-collared 17 pumas (Puma concolor; nine males and eight females) and 14 snow leopards (Panthera uncia; seven males and seven females) and estimated home range size and overlap on two temporal scales (annual vs. monthly). Contrary to expectation, we found no evidence that males monopolized females (the mean territory overlap between females and the focal male during the mating season was 0.28 and 0.64 in pumas and snow leopards, respectively). Although male-male overlap of annual home ranges was comparatively high (snow leopards [0.21] vs. pumas [0.11]), monthly home range overlaps were small (snow leopards [0.02] vs. pumas [0.08]) suggesting strong territoriality. In pumas, both males and females reduced their monthly home ranges in winter, and at the same time, prey distribution was clumped and mating activity increased. In snow leopards, females showed little variation in seasonal home range size, following the seasonal stability in their primary prey. However, male snow leopards reduced their monthly home range utilization in the mating season. In line with other studies, our results suggest that female seasonal home range variation is largely explained by changes in food resource distribution. However, contrary to expectations, male territories did not generally encompass those of females, and males reduced their home ranges during mating. Our results show that male and female territorial boundaries tend to intersect in these species, and hint at the operation of female choice and male mate guarding within these mating systems.
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| 23. |
- Johansson, Örjan, et al.
(författare)
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The timing of breeding and independence for snow leopard females and their cubs
- 2021
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Ingår i: Mammalian Biology. - : Springer Science and Business Media LLC. - 1616-5047 .- 1618-1476. ; 101, s. 173-180
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Tidskriftsartikel (refereegranskat)abstract
- Significant knowledge gaps persist on snow leopard demography and reproductive behavior. From a GPS-collared population in Mongolia, we estimated the timing of mating, parturition and independence. Based on three mother-cub pairs, we describe the separation phase of the cub from its mother as it gains independence. Snow leopards mated from January-March and gave birth from April-June. Cubs remained with their mother until their second winter (20-22 months of age) when cubs started showing movements away from their mother for days at a time. This initiation of independence appeared to coincide with their mother mating with the territorial male. Two female cubs remained in their mothers' territory for several months after initial separation, whereas the male cub quickly dispersed. By comparing the relationship between body size and age of independence across 11 solitary, medium-to-large felid species, it was clear that snow leopards have a delayed timing of separation compared to other species. We suggest this may be related to their mating behavior and the difficulty of the habitat and prey capture for juvenile snow leopards. Our results, while limited, provide empirical estimates for understanding snow leopard ecology and for parameterizing population models.
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| 24. |
- Kanuch, Peter, et al.
(författare)
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Gene flow relates to evolutionary divergence among populations at the range margin
- 2020
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Ingår i: PeerJ. - : PeerJ. - 2167-8359. ; 8
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Tidskriftsartikel (refereegranskat)abstract
- Background: Morphological differentiation between populations resulting from local adaptations to environmental conditions is likely to be more pronounced in populations with increasing genetic isolation. In a previous study a positive clinal variation in body size was observed in isolated Roesel's bush-cricket, Metrioptera roeselii, populations, but were absent from populations within a continuous distribution at the same latitudinal range. This observational study inferred that there was a phenotypic effect of gene flow on climate-induced selection in this species. Methods: To disentangle genetic versus environmental drivers of population differences in morphology, we measured the size of four different body traits in wild-caught individuals from the two most distinct latitudinally-matched pairs of populations occurring at about 60 degrees N latitude in northern Europe, characterised by either restricted or continuous gene flow, and corresponding individuals raised under laboratory conditions. Results: Individuals that originated from the genetically isolated populations were always bigger (femur, pronotum and genital appendages) when compared to individuals from latitudinally-matched areas characterised by continuous gene flow between populations. The magnitude of this effect was similar for wild-caught and laboratory-reared individuals. We found that previously observed size cline variation in both male and female crickets was likely to be the result of local genetic adaptation rather than phenotypic plasticity. Conclusions: This strongly suggests that restricted gene flow is of major importance for frequencies of alleles that participate in climate-induced selection acting to favour larger phenotypes in isolated populations towards colder latitudes.
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- Kanuch, Peter, et al.
(författare)
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On variation of polyandry in a bush-cricket, Metrioptera roeselii, in northern Europe
- 2013
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Ingår i: Journal of Insect Science. - : Oxford University Press (OUP). - 1536-2442 .- 0970-3837. ; 13, s. 1-10
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Tidskriftsartikel (refereegranskat)abstract
- Patterns of polyandry in nuptial-gift-giving insects are often explained in terms of sexually antagonistic coevolution. However, the potential influence of environmental constraints and life- history traits on polyandry in these species is still largely unexplored. As an initial step in examining the role of these factors, this study measured the number of matings (spermatodoses per female) of female Roesel’s bush-crickets, Metrioptera roeselii Hagenbach (Orthoptera: Tettigoniidae), along a latitudinal gradient in northern Europe (16 sites, 53.89–60.47° N). Females contained between 0 and 5 spermatodoses (mean ± SE: 1.7 ± 0.08; N = 114), with the degree of polyandry generally increasing at higher latitudes (approximately 0.12–0.3 matings per degree of latitude). As expected, female body size also had an influence on polyandry; the number of matings increased from small to moderately large individuals before declining. The field-based results suggested that there were potentially interesting interactions between environment, life-history traits, and patterns of polyandry in nuptial-gift-giving insect species, and these potentially interesting interactions are used to outline future research directions.
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