| 1. |
- Griffith, Simon C., et al.
(författare)
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Variation in reproductive success across captive populations: Methodological differences, potential biases and opportunities
- 2017
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Ingår i: Ethology. - : Wiley. - 1439-0310 .- 0179-1613. ; 123:1, s. 1-29
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Tidskriftsartikel (refereegranskat)abstract
- Our understanding of fundamental organismal biology has been disproportionately influenced by studies of a relatively small number of ‘model’ species extensively studied in captivity. Laboratory populations of model species are commonly subject to a number of forms of past and current selection that may affect experimental outcomes. Here, we examine these processes and their outcomes in one of the most widely used vertebrate species in the laboratory – the zebra finch (Taeniopygia guttata). This important model species is used for research across a broad range of fields, partly due to the ease with which it can be bred in captivity. However despite this perceived amenability, we demonstrate extensive variation in the success with which different laboratories and studies bred their subjects, and overall only 64% of all females that were given the opportunity, bred successfully in the laboratory. We identify and review several environmental, husbandry, life-history and behavioural factors that potentially contribute to this variation. The variation in reproductive success across individuals could lead to biases in experimental outcomes and drive some of the heterogeneity in research outcomes across studies. The zebra finch remains an excellent captive animal system and our aim is to sharpen the insight that future studies of this species can provide, both to our understanding of this species and also with respect to the reproduction of captive animals more widely. We hope to improve systematic reporting methods and that further investigation of the issues we raise will lead both to advances in our fundamental understanding of avian reproduction as well as to improvements in future welfare and experimental efficiency.
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| 2. |
- Salmon, Pablo, et al.
(författare)
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Effects of the Urban Environment on Oxidative Stress in Early Life : Insights from a Cross-fostering Experiment
- 2018
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Ingår i: Integrative and Comparative Biology. - : Oxford University Press (OUP). - 1557-7023 .- 1540-7063. ; , s. 986-994
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Tidskriftsartikel (refereegranskat)abstract
- As urban areas expand rapidly worldwide, wildlife is exposed to a wide range of novel environmental stressors, such as increased air pollution and artificial light at night. Birds in highly polluted and/or urbanized habitats have been found to have increased antioxidant protection, which is likely important to avoid accumulation of oxidative damage, which can have negative fitness consequences. Yet, the current knowledge about the ontogeny of antioxidant protection in urban areas is limited; i.e., is the capacity to up-regulate the antioxidant defences already established during pre-natal development, or does it manifest itself during post-natal development? We cross-fostered great tit (Parus major) nestlings within and between urban and rural habitats, to determine if oxidative stress (measured as non-enzymatic total antioxidant capacity, superoxide dismutase (SOD), and plasma lipid peroxidation) is affected by habitat of origin and/or by habitat of rearing. The results demonstrate that being reared in the urban environment triggers an increase in SOD (an intracellular, enzymatic antioxidant) independent of natal habitat. Oxidative damage increased with hatching date in urban-reared nestlings, but there was little seasonal change in rural-reared nestlings. Total antioxidant capacity was neither affected by habitat of rearing or habitat of origin, but we observed a decline with hatching date in both rearing habitats. Taken together, our results support the growing evidence that the urban environment induces a direct plastic adjustment in antioxidant protection, but that up-regulation is not sufficient to avoid increased oxidative damage in late-hatched broods. Future studies should explore the underlying causes for this effect in late-hatched broods and whether it has any negative long-term implications, both at the individual- and the population level.
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| 3. |
- García-Díaz, Carmen C., et al.
(författare)
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Plasticity of mitochondrial function safeguards phosphorylating respiration during in vitro simulation of rest-phase hypothermia
- 2023
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Ingår i: FASEB Journal. - 1530-6860. ; 37:4
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Tidskriftsartikel (refereegranskat)abstract
- Many animals downregulate body temperature to save energy when resting (rest-phase hypothermia). Small birds that winter at high latitudes have comparatively limited capacity for hypothermia and so pay large energy costs for thermoregulation during cold nights. Available evidence suggests this process is fueled by adenosine triphosphate (ATP)-dependent mechanisms. Most ATP is produced by oxidative phosphorylation in the mitochondria, but mitochondrial respiration may be lower during hypothermia because of the temperature dependence of biological processes. This can create conflict between increased organismal ATP demand and a lower mitochondrial capacity to provide it. We studied this in blood cell mitochondria of wild great tits (Parus major) by simulating rest-phase hypothermia via a 6°C reduction in assay temperature in vitro. The birds had spent the night preceding the experiment in thermoneutrality or in temperatures representing mild or very cold winter nights, but night temperatures never affected mitochondrial respiration. However, across temperature groups, endogenous respiration was 14% lower in hypothermia. This did not reflect general thermal suppression of mitochondrial function because phosphorylating respiration was unaffected by thermal state. Instead, hypothermia was associated with a threefold reduction of leak respiration, from 17% in normothermia to 4% in hypothermia. Thus, the coupling of total respiration to ATP production was 96% in hypothermia, compared to 83% in normothermia. Our study shows that the thermal insensitivity of phosphorylation combined with short-term plasticity of leak respiration may safeguard ATP production when endogenous respiration is suppressed. This casts new light on the process by which small birds endure harsh winter cold and warrants future tests across tissues in vivo.
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| 4. |
- Nord, Andreas
(författare)
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De första svenska fynden av parköronvivel Otiorhynchus crataegi Germar, 1824 (Coleoptera: Curculionidae)
- 2022
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Ingår i: Fazett. - 1100-2425. ; 35:1, s. 31-37
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- crataegi Germar, 1824. The first specimen was found in the city of Malmö in the southernmost province of Sweden in the beginning of October 2020, where one individual had taken shelter from a heavy morning rain on a house wall, together with several other beetle species. The species was subsequently sought after during late autumn and winter by sifting litter beneath putative host plants, but it could not be relocated until May 2021 when a large, but local, population was found in a scarlet firethorn (Pyracantha coccinea) hedge some hundred metres from the original location. The species has since then been observed in the same hedge on numerous occasions, suggesting that O. crataegi might be established in southernmost Sweden. Its sudden appearance in Sweden seems to be the result of an unintentional introduction with ornamental hedging plants from continental Europe rather than of a natural range expansion from nearby Denmark.
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| 5. |
- Andreasson, Fredrik, et al.
(författare)
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Experimentally increased nest temperature affects body temperature, growth and apparent survival in blue tit nestlings
- 2018
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Ingår i: Journal of Avian Biology. - : Wiley. - 0908-8857. ; 49:2
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Tidskriftsartikel (refereegranskat)abstract
- The thermal environment experienced by birds during early postembryonic development may be an important factor shaping growth and survival. However, few studies have directly manipulated nest temperature (T n) during the nestling phase, and none have measured the consequences of experimental heat stress on nestlings’ body temperature (T b). It is therefore not known to what extent any fitness consequences of development in a thermally challenging environment arise as a direct, or indirect, effect of heat stress. We, therefore, studied how experimentally increased T n affected T b in 8–12 d old blue tit Cyanistes caeruleus nestlings, to investigate if increased thermoregulatory demands to maintain normothermic T b influenced nestling growth and apparent long-term survival. Nestlings in heated nest-boxes had significantly higher T b compared to unheated nestlings during most of the experimental period. Yet, despite facing T n 50°C (as measured in the bottom of the nest cup below the nestlings), the highest nestling T b recorded was 43.8°C with nestlings showing evidence of controlled facultative hyperthermia without any increased nestling mortality in heated nests. However, body mass gain was lower in these nestlings compared to nestlings from control nest-boxes. Contrary to our prediction, a larger proportion of nestlings from heated nest-boxes were recaptured during their first winter, or subsequently recruited into the breeding population as first- or second-year breeders. This result should, however, be treated with caution because of low recapture rates. This study highlights the importance of the thermal environment during nestling development, and its role in shaping both growth patterns and possibly also apparent survival.
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| 6. |
- Lewden, Agnès, et al.
(författare)
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Body temperature responses to handling stress in wintering Black-capped Chickadees (Poecile atricapillus L.)
- 2017
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Ingår i: Physiology & Behavior. - : Elsevier BV. - 1873-507X .- 0031-9384. ; 179, s. 49-54
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Tidskriftsartikel (refereegranskat)abstract
- Body temperature variation in response to acute stress is typically characterized by peripheral vasoconstriction and a concomitant increase in core body temperature (stress-induced hyperthermia). It is poorly understood how this response differs between species and within individuals of the same species, and how it is affected by the environment. We therefore investigated stress-induced body temperature changes in a non-model species, the Black-capped Chickadee, in two environmental conditions: outdoors in low ambient temperature (mean: − 6.6 °C), and indoors, in milder ambient temperature close to thermoneutrality (mean: 18.7 °C). Our results show that the change in body temperature in response to the same handling stressor differs in these conditions. In cold environments, we noted a significant decrease in core body temperature (− 2.9 °C), whereas the response in mild indoor conditions was weak and non-significant (− 0.6 °C). Heat loss in outdoor birds was exacerbated when birds were handled for longer time. This may highlight the role of behavioral thermoregulation and heat substitution from activity to body temperature maintenance in harsh condition. Importantly, our work also indicates that changes in the physical properties of the bird during handling (conductive cooling from cold hands, decreased insulation from compression of plumage and prevention of ptiloerection) may have large consequences for thermoregulation. This might explain why females, the smaller sex, lost more heat than males in the experiment. Because physiological and physical changes during handling may carry over to affect predation risk and maintenance of energy balance during short winter days, we advice caution when designing experimental protocols entailing prolonged handling of small birds in cold conditions.
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| 7. |
- Nilsson, Jan-Åke, et al.
(författare)
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Testing the heat dissipation limit theory in a breeding passerine
- 2018
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Ingår i: Proceedings of the Royal Society B: Biological Sciences. - : The Royal Society. - 1471-2954 .- 0962-8452. ; 285:1878
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Tidskriftsartikel (refereegranskat)abstract
- The maximum work rate of animals has recently been suggested to be determined by the rate at which excess metabolic heat generated during work can be dissipated (heat dissipation limitation (HDL) theory). As a first step towards testing this theory in wild animals, we experimentally manipulated brood size in breeding marsh tits (Poecile palustris) to change their work rate. Parents feeding nestlings generally operated at above-normal body temperatures. Body temperature in both males and females increased with maximum ambient temperature and with manipulated work rate, sometimes even exceeding 45°C, which is close to suggested lethal levels for birds. Such high body temperatures have previously only been described for birds living in hot and arid regions. Thus, reproductive effort in marsh tits may potentially be limited by the rate of heat dissipation. Females had lower body temperatures, a possible consequence of their brood patch serving as a thermal window facilitating heat dissipation. Because increasing body temperatures are connected to somatic costs, we suggest that the HDL theory may constitute a possible mediator of the trade-off between current and future reproduction. It follows that globally increasing, more stochastic, ambient temperatures may restrict the capacity for sustained work of animals in the future.
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| 8. |
- Nilsson, Jan-Åke, et al.
(författare)
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The use of the nest for parental roosting and thermal consequences of the nest for nestlings and parents
- 2017
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Ingår i: Behavioral Ecology and Sociobiology. - : Springer Science and Business Media LLC. - 1432-0762 .- 0340-5443. ; 71
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Tidskriftsartikel (refereegranskat)abstract
- At temperate latitudes, altricial birds and their nestlings need to handle night temperatures well below thermoneutrality during the breeding season. Thus, energy costs of thermoregulation might constrain nestling growth, and low nocturnal temperatures might require resources that parents could otherwise have invested into nestlings during the day. To manipulate parental work rate, we performed brood size manipulations in breeding marsh tits (Poecile palustris). Nest box temperatures were always well above ambient temperature and increased with increasing brood size. In line with predictions, a large majority of females (but no males) made use of this benign environment for roosting. Furthermore, females tending enlarged broods, thereby having to work harder during the day, reduced their body temperature at night. This might have reduced nocturnal energy expenditure. Our finding that a higher proportion of enlarged, as compared to control, females continued to use the nest box as roosting sites even after a simulated predation event despite increased vulnerability to predation, further highlighting the need for energy conservation in this group. High nest box attendance and reduced body temperature in brood-reduced females may indicate that these females prioritised self-maintenance by initiating other costly physiological adjustments, e.g. moult, when relieved from parental work. We suggest that the energy demand for defending homeothermy is an element of the general trade-off between current and future reproduction, i.e. between daytime investment in food provisioning and the potential short- and long-term costs of a reduction in body temperature and increased predation risk.
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| 9. |
- Nord, Andreas, et al.
(författare)
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Reduced immune responsiveness contributes to winter energy conservation in an Arctic bird
- 2020
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Ingår i: Journal of Experimental Biology. - : The Company of Biologists. - 1477-9145 .- 0022-0949. ; 223:8
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Tidskriftsartikel (refereegranskat)abstract
- Animals in seasonal environments must prudently manage energyexpenditure to survive the winter. This may be achieved throughreductions in the allocation of energy for various purposes (e.g.thermoregulation, locomotion, etc.). We studied whether such tradeoffsalso include suppression of the innate immune response, bysubjecting captive male Svalbard ptarmigan (Lagopus mutahyperborea) to bacterial lipopolysaccharide (LPS) during exposureto either mild temperature (0°C) or cold snaps (acute exposure to−20°C), in constant winter darkness when birds were in energyconservingmode, and in constant daylight in spring. The innateimmune response was mostly unaffected by temperature. However,energy expenditure was below baseline when birds were immunechallenged in winter, but significantly above baseline in spring. Thissuggests that the energetic component of the innate immuneresponse was reduced in winter, possibly contributing to energyconservation. Immunological parameters decreased (agglutination,lysis, bacteriostatic capacity) or did not change (haptoglobin/PIT54)after the challenge, and behavioural modifications (anorexia, massloss) were lengthy (9 days). While we did not study the mechanismsexplaining these weak, or slow, responses, it is tempting to speculatethey may reflect the consequences of having evolved in anenvironment where pathogen transmission rate is presumably lowfor most of the year. This is an important consideration if climatechange and increased exploitation of the Arctic would alter pathogencommunities at a pace outwith counter-adaption in wildlife.
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| 10. |
- Pap, Peter L., et al.
(författare)
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Vane macrostructure of primary feathers and its adaptations to flight in birds
- 2019
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Ingår i: Biological Journal of the Linnean Society. - : Oxford University Press (OUP). - 0024-4066 .- 1095-8312. ; 126:2, s. 256-267
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Tidskriftsartikel (refereegranskat)abstract
- The selection pressures that drive flight feather morphology are poorly understood. Using a phylogenetic comparative approach and data from 178 species of birds, we investigated whether both position along the wing length and flight feather length affected vane structure. We found that barb density was lower on distal primaries than on proximal primaries of the leading feather vane. In contrast, on the trailing vane only mid-point barb density differed and, here, it showed denser barbs on the distal primaries. This difference was greater at the feather base than at the tip. Barb angle was higher along the full length of the leading edge vane on the proximal primaries than on the distal primaries. Overall, barb density decreased from base to tip on both trailing and leading vanes on both the proximal and the distal primaries. In general, barb angle was less acute at the feather base than at the tip. Barbs were in general denser in continuous flapping fliers than in soarers and the angle of barbs on both the proximal and the distal primaries was affected by flight type. However, we did not identify consistent differences in the pattern of barb angle change among flight style groups. These findings add new perspectives to our understanding of the functional morphology of the flight feather vane, although we still have limited knowledge on how aerodynamic forces, particularly during take-off and landing, affect the morphology of the feather vane.
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