| 1. |
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| 2. |
- Arct, Aneta, et al.
(författare)
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Effects of elevated nest box temperature on incubation behaviour and offspring fitness-related traits in the Collared Flycatcher Ficedula albicollis
- 2022
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Ingår i: Journal of Ornithology. - : Springer Nature. - 2193-7192 .- 2193-7206. ; 163, s. 263-272
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Tidskriftsartikel (refereegranskat)abstract
- Ambient temperature experienced by an animal during development or subsequently as an adult can affect many aspects of its behaviour and life-history traits. In birds, egg incubation is a vital component of reproduction and parental care. Several studies have suggested that environmental factors (such as nest microclimate) can influence the ability of incubating parents to maintain suitable conditions for embryo development. Here, we manipulated the developmental conditions of embryos through a modification of nest box thermal microclimate to investigate female incubation behaviour and its impact on offspring fitness-related traits in a wild population of the Collared Flycatcher (Ficedula albicollis). The temperature in experimental nests was increased using a heat-pack placed under the roof of a nest box, resulting in an average temperature increase of 2.5 degrees C, which corresponds to projected climate change scenarios. We demonstrated that females from nests with elevated temperature spent less time in the nest box during egg incubation and had more off-bouts than females from control nests. Moreover, we found that offspring from the experimentally heated nests had larger body mass at fledging in comparison to the control ones. Our study indicates that nest microclimate during the incubation period affects female incubation behaviour and offspring quality, indicating that environmental variation in nest temperature early in ontogeny can have important and long-lasting fitness consequences.
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| 3. |
- Arct, Aneta, et al.
(författare)
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Parental genetic similarity and offspring performance in blue tits in relation to brood size manipulation
- 2019
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Ingår i: Ecology and Evolution. - : WILEY. - 2045-7758. ; 9:18, s. 10085-10091
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Tidskriftsartikel (refereegranskat)abstract
- In birds, as in many other taxa, higher genetic similarity of mates has long been known to reduce offspring fitness. To date, the majority of avian studies have focused on examination whether the genetic similarity of social mates predicts hatching success. Yet, increased genetic similarity of mates may also reduce offspring fitness during later life stages, including the nestling period and beyond. Here, we investigated whether parental genetic similarity influences offspring performance using data from free-living blue tits (Cyanistes caeruleus) collected across three breeding seasons. Additionally, we tested whether brood size manipulation affects the magnitude and direction of the relationship between genetic similarity of mates and offspring performance. Sixteen microsatellite markers were used to measure genetic similarity between biological parents. We found that the genetic similarity of parents negatively affects offspring immune response and this effect was independent of the experimental brood size manipulation.
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| 4. |
- Arct, Aneta, et al.
(författare)
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Temperature variability is associated with the occurrence of extrapair paternity in blue tits
- 2024
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Ingår i: Behavioral Ecology. - : Oxford University Press. - 1045-2249 .- 1465-7279. ; 35:1
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Tidskriftsartikel (refereegranskat)abstract
- In birds, extrapair paternity (EPP) constitutes an alternative mating strategy, with potentially important fitness consequences for both males and females and their offspring. Several factors have been identified that can influence the occurrence of EPP, but the role of environmental variability has so far received relatively little attention. Using long-term data set from a wild population of the blue tit (Cyanistes cearuleus), we assess the importance of ambient temperature in modulating the levels of extrapair paternity. Here, we showed that the variability of local thermal conditions affects the occurrence of EPP. Specifically, we found that the probability of EPP increased with rising variability in ambient temperature experienced by females prior to egg laying. This pattern is consistent with an idea of plastic female responses to unpredictable environments. Our results suggest that extrapair mating may represent an adaptive behavioral strategy to compensate for the potential negative effects of unstable environmental conditions.
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| 5. |
- Arct, Aneta, et al.
(författare)
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The interactive effect of ambient temperature and brood size manipulation on nestling body mass in blue tits : an exploratory analysis of a long-term study
- 2022
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Ingår i: Frontiers in Zoology. - : BioMed Central (BMC). - 1742-9994. ; 19:1
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Tidskriftsartikel (refereegranskat)abstract
- Background Relatively few studies have examined the interactive effects of ecological factors on physiological responses in wild animals. Nearly all of them have been short-term investigations that did not include experimental manipulations, limiting our ability to understand how climate change will affect natural populations. Using a 10-year brood size manipulation experiment in wild blue tits (Cyanistes caeruleus), we quantified the impact of weather conditions and brood competition on the body mass and structural size (tarsus length) of nestlings just prior to leaving the nest. Results We found that variation in nestling body mass on day 14 after hatching was explained by an interactive effect between average ambient temperature experienced during nestling period and brood size treatment. Specifically, in control broods nestling body mass was correlated with temperature in a non-linear manner (concave) with the vertex point (maximum body mass) at ca. 13 degrees C. In contrast, in enlarged broods nestling body mass permanently increased (also non-linearly) as temperature advanced. Conclusions Our results highlight the importance of considering the effects of brood rearing conditions alongside other environmental factors experienced during growth while investigating early-life environmental effects on body condition.
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| 6. |
- Bonnet, Timothee, et al.
(författare)
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Genetic variance in fitness indicates rapid contemporary adaptive evolution in wild animals
- 2022
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 376:6596, s. 1012-1016
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Tidskriftsartikel (refereegranskat)abstract
- The rate of adaptive evolution, the contribution of selection to genetic changes that increase mean fitness, is determined by the additive genetic variance in individual relative fitness. To date, there are few robust estimates of this parameter for natural populations, and it is therefore unclear whether adaptive evolution can play a meaningful role in short-term population dynamics. We developed and applied quantitative genetic methods to long-term datasets from 19 wild bird and mammal populations and found that, while estimates vary between populations, additive genetic variance in relative fitness is often substantial and, on average, twice that of previous estimates. We show that these rates of contemporary adaptive evolution can affect population dynamics and hence that natural selection has the potential to partly mitigate effects of current environmental change.
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| 7. |
- Briedis, Martins, et al.
(författare)
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A full annual perspective on sex-biased migration timing in long-distance migratory birds
- 2019
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Ingår i: Proceedings of the Royal Society of London. Biological Sciences. - : The Royal Society. - 0962-8452 .- 1471-2954. ; 286:1897
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Tidskriftsartikel (refereegranskat)abstract
- In many taxa, the most common form of sex-biased migration timing is protandry – the earlier arrival of males at breeding areas. Here we test this concept across the annual cycle of long-distance migratory birds. Using more than 350 migration tracks of small-bodied trans-Saharan migrants, we quantify differences in male and female migration schedules and test for proximate determinants of sex-specific timing. In autumn, males started migration about 2 days earlier, but this difference did not carry over to arrival at the non-breeding sites. In spring, males on average departed from the African non-breeding sites about 3 days earlier and reached breeding sites ca 4 days ahead of females. A cross-species comparison revealed large variation in the level of protandry and protogyny across the annual cycle. While we found tight links between individual timing of departure and arrival within each migration season, only for males the timing of spring migration was linked to the timing of previous autumn migration. In conclusion, our results demonstrate that protandry is not exclusively a reproductive strategy but rather occurs year-round and the two main proximate determinants for the magnitude of sex-biased arrival times in autumn and spring are sex-specific differences in departure timing and migration duration.
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| 8. |
- Briedis, Martins, et al.
(författare)
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Broad-scale patterns of the Afro-Palaearctic landbird migration
- 2020
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Ingår i: Global Ecology and Biogeography. - : WILEY. - 1466-822X .- 1466-8238. ; 29:4, s. 722-735
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Tidskriftsartikel (refereegranskat)abstract
- Aim: Knowledge of broad-scale biogeographical patterns of animal migration is important for understanding ecological drivers of migratory behaviours. Here, we present a flyway-scale assessment of the spatial structure and seasonal dynamics of the Afro-Palaearctic bird migration system and explore how phenology of the environment guides long-distance migration.Location: Europe and Africa.Time period: 2009-2017.Major taxa studied: Birds.Methods: We compiled an individual-based dataset comprising 23 passerine and near-passerine species of 55 European breeding populations, in which a total of 564 individuals were tracked during migration between Europe and sub-Saharan Africa. In addition, we used remotely sensed primary productivity data (the normalized difference vegetation index) to estimate the timing of vegetation green-up in spring and senescence in autumn across Europe. First, we described how individual breeding and non-breeding sites and the migratory flyways link geographically. Second, we examined how the timing of migration along the two major Afro-Palaearctic flyways is tuned with vegetation phenology at the breeding sites.Results: We found the longitudes of individual breeding and non-breeding sites to be related in a strongly positive manner, whereas the latitudes of breeding and non-breeding sites were related negatively. In autumn, migration commenced ahead of vegetation senescence, and the timing of migration was 5-7 days earlier along the Western flyway compared with the Eastern flyway. In spring, the time of arrival at breeding sites was c. 1.5 days later for each degree northwards and 6-7 days later along the Eastern compared with the Western flyway, reflecting the later spring green-up at higher latitudes and more eastern longitudes.Main conclusions: Migration of the Afro-Palaearctic landbirds follows a longitudinally parallel leapfrog migration pattern, whereby migrants track vegetation green-up in spring but depart before vegetation senescence in autumn. The degree of continentality along migration routes and at the breeding sites of the birds influences the timing of migration on a broad scale.
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| 9. |
- Drobniak, Szymon M., et al.
(författare)
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Differential effects of steroid hormones on levels of broad-sense heritability in a wild bird : possible mechanism of environment x genetic variance interaction?
- 2022
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Ingår i: Heredity. - : Springer Nature. - 0018-067X .- 1365-2540. ; 128:1, s. 63-76
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Tidskriftsartikel (refereegranskat)abstract
- Genetic variation is one of the key concepts in evolutionary biology and an important prerequisite of evolutionary change. However, we know very little about processes that modulate its levels in wild populations. In particular, we still are to understand why genetic variances often depend on environmental conditions. One of possible environment-sensitive modulators of observed levels of genetic variance are maternal effects. In this study we attempt to experimentally test the hypothesis that maternally transmitted agents (e.g. hormones) may influence the expression of genetic variance in quantitative traits in the offspring. We manipulated the levels of steroid hormones (testosterone and corticosterone) in eggs laid by blue tits in a wild population. Our experimental setup allowed for full crossing of genetic and rearing effects with the experimental manipulation. We observed that birds treated with corticosterone exhibited a significant decrease in broad-sense genetic variance of tarsus length, and an increase in this component in body mass on the 2nd day post-hatching. Our study indicates, that maternally transmitted substances such as hormones may have measurable impact on the levels of genetic variance and hence, on the evolutionary potential of quantitative traits.
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| 10. |
- Drobniak, Szymon M., et al.
(författare)
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Habitat shapes diversity of gut microbiomes in a wild population of blue tits Cyanistes caeruleus
- 2022
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Ingår i: Journal of Avian Biology. - : John Wiley & Sons. - 0908-8857 .- 1600-048X. ; 2022:2
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Tidskriftsartikel (refereegranskat)abstract
- Microbiome constitutes an important axis of individual variation that, together with genes and the environment, influences an individual's physiology and fitness. Microbiomes are dependent not only on an individual's body condition but also on external factors, such as diet or stress levels, and as such can be involved into feedbacks between the external ecological factors and internal physiology. In our study, we used a wild population of blue tits Cyanistes caeruleus to investigate the impact of external habitat composition on the microbiome of adult birds. We hypothesized that - through differences in plant composition, potentially affecting diet complexity - habitat type may impact the diversity and structure of the gut microbiome. Blue tits breeding in dense deciduous forests tended to have more diverse microbiomes and be significantly different in terms of microbiome composition from birds breeding in open, sparsely forested hay meadows. Distinct study plots also tended to differ in a number of parameters describing microbiome diversity. We observed no microbiome differentiation according to individual characteristics such as sex or age. The study emphasizes that external environment is one of the important modulators of microbiome diversity and calls for more such studies in wild animal populations.
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| 11. |
- Fletcher, Kevin, et al.
(författare)
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Glucocorticoid response to both predictable and unpredictable challenges detected as corticosterone metabolites in collared flycatcher droppings
- 2018
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Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 13:12
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Tidskriftsartikel (refereegranskat)abstract
- In most vertebrate animals, glucocorticoid hormones are the chief mediators of homeostasis in response to ecological conditions and as they progress through their lifecycle. In addition, glucocorticoids are a major part of the stress response and stress induced elevations of the hormone can make it difficult to assess glucocorticoid secretion in response to changes in life-stage and current environmental conditions in wild animals. Particularly when quantifying circulating levels of glucocorticoids in the blood which fluctuate rapidly in response to stress. An alternative method of quantifying glucocorticoids is as hormone metabolites in faeces or urine giving a historical sample related to the gut passage time and urinary tract that is less sensitive to stressful events which cause spikes in the circulating hormone level. Although the concentration of glucocorticoid metabolites are influenced by faecal mass thereby potentially affecting any differences in hormone metabolites detected amongst samples. In the present study, we aimed to detect changes in levels of corticosterone, the primary bird glucocorticoid, in relation to the phase of reproduction, in a breeding population of collared flycatchers by sampling corticosterone metabolites in droppings. We also tested how corticosterone metabolite concentrations were affected by ambient temperature and related to body condition in adult birds. Our results indicate that the upregulation of corticosterone between incubation and nestling feeding in female birds is crucial for successful reproduction in this species. Also, females appear to downregulate corticosterone during incubation in response to lower ambient temperature and poorer body condition. Our results did not indicate a relationship between dropping mass and corticosterone metabolite concentrations, which suggests that our findings were linked to the regulation of corticosterone in response to predictable and unpredictable challenges.
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| 12. |
- Fletcher, Kevin, et al.
(författare)
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Importance of infection of haemosporidia blood parasites during different life history stages for long-term reproductive fitness of collared flycatchers
- 2019
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Ingår i: Journal of Avian Biology. - : John Wiley & Sons. - 0908-8857 .- 1600-048X. ; 50:8
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Tidskriftsartikel (refereegranskat)abstract
- The interaction between birds and haemosporidia blood parasites is a well-used system in the study of parasite biology. However, where, when and how parasites are transmitted is often unclear and defining parasite transmission dynamics is essential because of how they influence parasite-mediated costs to the host. In this study, we used cross-sectional and longitudinal data taken from a collared flycatcher Ficedula albicollis population to investigate the temporal dynamics of haemosporidia parasite infection and parasite-mediated costs to host fitness. We investigated host-parasite interactions starting at the nestling stage of the bird's life-cycle and then followed their progress over three breeding attempts to quantify their fitness - measured as the number of offspring they produced that recruited back into the breeding population. We found that the majority of haemosporidia blood parasite infections occurred within the first year of life and that the most common parasite lineages that infected the breeding population also infected juvenile birds in the natal environment. Moreover, our findings suggest that collared flycatcher nestlings in poorer condition could be at a higher risk of haemosporidia blood parasite infection. In this study, only female and not male bird fitness was adversely affected by parasite infection and the cost of infection on female fitness depended on the timing of transmission. In conclusion, our study indicates that in collared flycatchers, early-life is potentially important for many of the interactions with haemosporidia parasite lineages, and evidence of parasite-mediated costs to fitness suggest that these parasites may have influenced the host population dynamics.
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| 13. |
- Holmlund, Anders, 1953-
(författare)
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Oral health and cardiovascular disease
- 2008
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In the past two decades studies have indicated that oral health might be associated with the prevalence for cardiovascular disease (CVD), although the biological link still remains unknown. Bacteria and inflammatory mediators causing periodontal disease have also been suggested to influence the progression of atherosclerosis.The aims of this thesis were to study oral inflammation and associations between different oral health parameters and CVD. Inflammatory mediators such as interleukin-1 (IL-1) as well as bone resorption activity (BRA) were significantly higher in gingival crevicular fluid (GCF) from sites with periodontal disease compared to healthy sites. Treatment resulted in a reduction of BRA as well as the levels of IL-1 for most of the diseased pockets. The levels of IL-1 were not correlated to the amount of BRA.Number of teeth (NT) was consistently associated to CVD and was the only oral health parameter that related to all-cause mortality and mortality in CVD in a dose-dependent manner. Subjects with <10 teeth had a 7-fold increase risk for mortality in coronary heart disease compared to those with >25 teeth. Furthermore, NT was also significantly associated to the levels of leukocytes and to the metabolic syndrome, which consists of a combination of cardiovascular risk factors.Other investigated oral health parameters, such as severity of periodontal disease, number of deepened pockets, and bleeding on probing, were not related to CVD in a consistent way. Oral health parameters as well as myocardial infarction (MI) were related to serum antibody levels against Porphyromonas gingivalis (Pg), indicating that Pg might be a link between oral health and MI.In conclusion, treatment reduced the increased levels of IL-1 and BRA in GCF from sites with periodontal disease. Oral health was associated to CVD with number of teeth being the only oral health parameter that consistently was associated to CVD. Serum antibody levels against P. gingivalis were related to myocardial infarction (MI) as well as to oral health parameters, suggesting that this bacteria could be a link between oral health and CVD.
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| 14. |
- Hsu, Bin-Yan, et al.
(författare)
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Transient growth-enhancing effects of elevated maternal thyroid hormones at no apparent oxidative cost during early postnatal period
- 2019
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Ingår i: Journal of Avian Biology. - : Wiley. - 0908-8857 .- 1600-048X. ; 50:1
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Tidskriftsartikel (refereegranskat)abstract
- Maternal thyroid hormones (THs) have been proven crucial for embryonic development in humans, but their influence within the natural variation on wild animals remains unknown. So far the only two studies that experimentally investigated the potential fitness consequences of maternal THs in birds found inconsistent results. More studies are thus required to assess the general effects of maternal THs and their influences on more behavioral and physiological parameters. In this study, we experimentally elevated yolk TH content in a wild migratory passerine species, the collared flycatcher Ficedula albicollis, to investigate the effects on hatching success, nestling growth and oxidative stress. We found that TH‐injected eggs had a higher hatching success, and the nestlings hatched from TH‐injected eggs were heavier and larger than control nestlings, but only during the early postnatal period. These differences vanished by fledging. Nestlings from TH‐injected eggs exhibited lower activity of the glutathione‐s‐transferase, a major antioxidant enzyme, than control nestlings at day 12, a few days before fledging, but they did not differ in oxidative damage and overall intracellular oxidative state. These results suggest that the early growth‐enhancing effects incurred no observable oxidative stress. We hypothesize that such a transient growth‐enhancing effect might be adaptive in advancing the development and maturation of the offspring so they are well‐prepared in time for the upcoming migration. Further studies investigating whether such advancing effects can influence long‐term fitness, will be more than valuable.
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| 15. |
- Janas, Katarzyna, et al.
(författare)
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Carotenoid-based coloration correlates with the hatching date of Blue TitCyanistes caeruleusnestlings
- 2020
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Ingår i: Ibis. - : WILEY. - 0019-1019 .- 1474-919X. ; 162:3, s. 645-654
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Tidskriftsartikel (refereegranskat)abstract
- Carotenoid-based coloration occurs predominantly in adult birds, yet in some species from the family Paridae, this trait is also present at the nestling stage. One of the factors proposed to affect the expression of this trait in immature birds is hatching date. Here, using the avian tetrahedral colour space model, we examined the influence of hatching date on the breast carotenoid-based plumage coloration of the Blue TitCyanistes caeruleusnestlings. Because Blue Tits are sexually dichromatic, we also investigated the potential interaction between hatching date and sex that could arise from differences in condition dependence of this trait between males and females. We found a positive relationship betweenUVchroma of breast feathers and hatching date. The amount ofUVreflectance is thought to be negatively related to carotenoid content in feathers. The observed increase ofUVchroma through the breeding season might therefore be caused by a seasonal decline in the availability and quality of Lepidoptera larvae - the main source of carotenoids in food of the Tits. We also observed a sex difference in the relationship between brightness of breast feathers (achromatic, structural component) and hatching date, which in males was negative and in females not significant. Our study provides further evidence that the timing of breeding is related to the expression of nestling carotenoid-based coloration, a potentially meaningful element of offspring-parent communication, and suggests a sex-specific effect of hatching date on its structural component.
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| 16. |
- Janas, Katarzyna, et al.
(författare)
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Differential effects of early growth conditions on colour-producing nanostructures revealed through small angle X-ray scattering and electron microscopy
- 2020
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Ingår i: Journal of Experimental Biology. - : COMPANY BIOLOGISTS LTD. - 0022-0949 .- 1477-9145. ; 223:18
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Tidskriftsartikel (refereegranskat)abstract
- The costs associated with the production and maintenance of colour patches is thought to maintain their honesty. Although considerable research on sexual selection has focused on structurally coloured plumage ornaments, the proximate mechanisms of their potential condition dependence, and thus their honesty, is rarely addressed, particularly in an experimental context. Blue tit (Cyanistes caeruleus) nestlings have ultraviolet (UV)-blue structurally coloured tail feathers, providing a unique opportunity for investigation of the causes of variation in their colour. Here, we examined the influence of early growing conditions on the reflectance and structural properties of UV-blue-coloured tail feathers of blue tit nestlings. We applied a two-stage brood size manipulation to determine which stage of development more strongly impacts the quality of tail feather colouration and microstructure. We used small-angle X-ray scattering (SAXS) and electron microscopy to characterise the nanoscale and microscale structure of tail feather barbs. Nestlings from the broods enlarged at a later stage of growth showed a sex-specific rectrix development delay, with males being more sensitive to this manipulation. Contrary to predictions, treatment affected neither the quality of the barbs' nanostructures nor the brightness and UV chroma of feathers. However. at the microscale. barbs' keratin characteristics were impaired in late-enlarged broods. Our results suggest that nanostructure quality, which determines the UV-blue colour in tail feathers, is not sensitive to early rearing conditions. Furthermore, availability of resources during feather growth seems to impact the quality of feather microstructure more than body condition, which is likely to be determined at an earlier stage of nestling growth.
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| 17. |
- Janas, Katarzyna, et al.
(författare)
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Sexual dichromatism, size dimorphism, and microscale anatomy of white wing stripe in blue tits
- 2021
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Ingår i: Current Zoology. - : Oxford University Press. - 1674-5507 .- 2396-9814. ; 67:6, s. 585-596
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Tidskriftsartikel (refereegranskat)abstract
- Achromatic patches are a common element of plumage patterns in many bird species and there is growing body of evidence that in many avian taxa they can play a signaling role in mate choice. Although the blue tit Cyanistes caeruleus is a well-established model species in the studies on coloration, its white wing patch has never been examined in the context of sex-specific trait expression. In this exploratory study, we examined sexual size dimorphism and dichromatism of greater covert's dots creating white wing patch and analyzed its correlations with current body condition and crown coloration-a trait with established role in sexual selection. Further, we qualitatively analyzed microstructural barb morphology underlying covert's coloration. We found significant sexual dimorphism in the dot size independent of covert size and sexual dichromatism in both white dot and blue outer covert's vane spectral characteristics. Internal structure of covert barbs within the white dot was similar to the one found in barbs from the blue part that is, with a medullary area consisting of dead keratinocytes containing channel-type beta-keratin spongy nanostructure and centrally located air cavities. However, it lacked melanosomes which was the main observed difference. Importantly, UV chroma of covert's blue vane was positively correlated with crown UV chroma and current condition (the latter only in males), which should be a premise for further research on the signal function of the wing stripe.
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| 18. |
- Martyka, Rafal, et al.
(författare)
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Age- and trait-dependent breeding responses to environmental variation in a short-lived songbird
- 2023
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Ingår i: Scientific Reports. - : Springer Nature. - 2045-2322. ; 13:1
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Tidskriftsartikel (refereegranskat)abstract
- Breeding responses of organisms to environmental changes may profoundly depend on an individual's age, as an age-environment interaction may be expected to affect the expression of reproductive traits. However, little is known about how this interaction affects short-lived species that experience various environmental conditions in adulthood. Here, we used a 32-year dataset from the collared flycatcher, Ficedula albicollis, population to test whether and how the environment interacts with age to shape female age-specific reproduction. To characterise environmental variation, we applied the remotely sensed normalised difference vegetation index (NDVI), estimating vegetation productivity, and used it as a surrogate for habitat quality. Then, we analysed how within-individual age and NDVI determine patterns in laying date, clutch size, offspring production, and recruitment. We found that young and old females, but not middle-aged females, breeding under low NDVI started to lay eggs later and produced smaller clutches than females of the same age breeding under higher NDVI. No such effects were observed for offspring production or recruitment. Our study provides evidence that both an individual's age and the environmental variation experienced during adulthood may be crucial for shaping reproductive patterns in short-lived avian species, as has been found in long-lived birds.
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| 19. |
- Nadachowska-Brzyska, Krystyna, et al.
(författare)
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Genomic inference of contemporary effective population size in a large island population of collared flycatchers (Ficedula albicollis)
- 2021
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Ingår i: Molecular Ecology. - : John Wiley & Sons. - 0962-1083 .- 1365-294X. ; 30:16, s. 3965-3973
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Tidskriftsartikel (refereegranskat)abstract
- Due to its central importance to many aspects of evolutionary biology and population genetics, the long-term effective population size (N-e) has been estimated for numerous species and populations. However, estimating contemporary N-e is difficult and in practice this parameter is often unknown. In principle, contemporary N-e can be estimated using either analyses of temporal changes in allele frequencies, or the extent of linkage disequilibrium (LD) between unlinked markers. We applied these approaches to estimate contemporary N-e of a relatively recently founded island population of collared flycatchers (Ficedula albicollis). We sequenced the genomes of 85 birds sampled in 1993 and 2015, and applied several temporal methods to estimate N-e at a few thousand (4000-7000). The approach based on LD provided higher estimates of N-e (20,000-32,000) and was associated with high variance, often resulting in infinite N-e. We conclude that whole-genome sequencing data offers new possibilities to estimate high (>1000) contemporary N-e, but also note that such estimates remain challenging, in particular for LD-based methods for contemporary N-e estimation.
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| 20. |
- Pape Møller, Anders, et al.
(författare)
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Interaction of climate change with effects of conspecific and heterospecific density on reproduction
- 2020
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Ingår i: Oikos. - : Wiley. - 0030-1299 .- 1600-0706. ; 129:12, s. 1807-1819
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Tidskriftsartikel (refereegranskat)abstract
- We studied the relationship between temperature and the coexistence of great tit Parus major and blue tit Cyanistes caeruleus, breeding in 75 study plots across Europe and North Africa. We expected an advance in laying date and a reduction in clutch size during warmer springs as a general response to climate warming and a delay in laying date and a reduction in clutch size during warmer winters due to density‐dependent effects. As expected, as spring temperature increases laying date advances and as winter temperature increases clutch size is reduced in both species. Density of great tit affected the relationship between winter temperature and laying date in great and blue tit. Specifically, as density of great tit increased and temperature in winter increased both species started to reproduce later. Density of blue tit affected the relationship between spring temperature and blue and great tit laying date. Thus, both species start to reproduce earlier with increasing spring temperature as density of blue tit increases, which was not an expected outcome, since we expected that increasing spring temperature should advance laying date, while increasing density should delay it cancelling each other out. Climate warming and its interaction with density affects clutch size of great tits but not of blue tits. As predicted, great tit clutch size is reduced more with density of blue tits as temperature in winter increases. The relationship between spring temperature and density on clutch size of great tits depends on whether the increase is in density of great tit or blue tit. Therefore, an increase in temperature negatively affected the coexistence of blue and great tits differently in both species. Thus, blue tit clutch size was unaffected by the interaction effect of density with temperature, while great tit clutch size was affected in multiple ways by these interactions terms.
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| 21. |
- Saether, Bernt-Erik, et al.
(författare)
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Density-Dependent Adaptive Topography in a Small Passerine Bird, the Collared Flycatcher
- 2021
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Ingår i: American Naturalist. - : University of Chicago Press. - 0003-0147 .- 1537-5323. ; 197:1, s. 93-110
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Tidskriftsartikel (refereegranskat)abstract
- Adaptive topography is a central concept in evolutionary biology, describing how the mean fitness of a population changes with gene frequencies or mean phenotypes. We use expected population size as a quantity to be maximized by natural selection to show that selection on pairwise combinations of reproductive traits of collared flycatchers caused by fluctuations in population size generated an adaptive topography with distinct peaks often located at intermediate phenotypes. This occurred because r- and K-selection made phenotypes favored at small densities different from those with higher fitness at population sizes close to the carrying capacity K. Fitness decreased rapidly with a delay in the timing of egg laying, with a density-dependent effect especially occurring among early-laying females. The number of fledglings maximizing fitness was larger at small population sizes than when close to K. Finally, there was directional selection for large fledglings independent of population size. We suggest that these patterns can be explained by increased competition for some limiting resources or access to favorable nest sites at high population densities. Thus, r- and K-selection based on expected population size as an evolutionary maximization criterion may influence life-history evolution and constrain the selective responses to changes in the environment.
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| 22. |
- Spagopoulou, Foteini, et al.
(författare)
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Silver-spoon upbringing improves early-life fitness but promotes reproductive ageing in a wild bird
- 2020
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Ingår i: Ecology Letters. - : Wiley. - 1461-023X .- 1461-0248. ; 23:6, s. 994-1002
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Tidskriftsartikel (refereegranskat)abstract
- Early-life conditions can have long-lasting effects and organisms that experience a poor start in life are often expected to age at a faster rate. Alternatively, individuals raised in high-quality environments can overinvest in early-reproduction resulting in rapid ageing. Here we use a long-term experimental manipulation of early-life conditions in a natural population of collared flycatchers (Ficedula albicollis), to show that females raised in a low-competition environment (artificially reduced broods) have higher early-life reproduction but lower late-life reproduction than females raised in high-competition environment (artificially increased broods). Reproductive success of high-competition females peaked in late-life, when low-competition females were already in steep reproductive decline and suffered from a higher mortality rate. Our results demonstrate that 'silver-spoon' natal conditions increase female early-life performance at the cost of faster reproductive ageing and increased late-life mortality. These findings demonstrate experimentally that natal environment shapes individual variation in reproductive and actuarial ageing in nature.
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| 23. |
- Stier, Antoine, et al.
(författare)
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Born to be young? : Prenatal thyroid hormones increase early-life telomere length in wild collared flycatchers
- 2020
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Ingår i: Biology Letters. - : ROYAL SOC. - 1744-9561 .- 1744-957X. ; 16:11
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Tidskriftsartikel (refereegranskat)abstract
- The underlying mechanisms of the lifelong consequences of prenatal environmental condition on health and ageing remain little understood. Thyroid hormones (THs) are important regulators of embryogenesis, transferred from the mother to the embryo. Since prenatal THs can accelerate early-life development, we hypothesized that this might occur at the expense of resource allocation in somatic maintenance processes, leading to premature ageing. Therefore, we investigated the consequences of prenatal TH supplementation on potential hallmarks of ageing in a free-living avian model in which we previously demonstrated that experimentally elevated prenatal TH exposure accelerates early-life growth. Using cross-sectional sampling, we first report that mitochondrial DNA (mtDNA) copy number and telomere length significantly decrease from early-life to late adulthood, thus suggesting that these two molecular markers could be hallmarks of ageing in our wild bird model. Elevated prenatal THs had no effect on mtDNA copy number but counterintuitively increased telomere length both soon after birth and at the end of the growth period (equivalent to offsetting ca 4 years of post-growth telomere shortening). These findings suggest that prenatal THs might have a role in setting the 'biological' age at birth, but raise questions about the nature of the evolutionary costs of prenatal exposure to high TH levels.
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| 24. |
- Sudyka, Joanna, et al.
(författare)
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Birds with high lifetime reproductive success experience increased telomere loss
- 2019
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Ingår i: Biology Letters. - : ROYAL SOC. - 1744-9561 .- 1744-957X. ; 15:1
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Tidskriftsartikel (refereegranskat)abstract
- Lifetime reproductive success (LRS) is what counts in terms of evolution, but investments in reproduction entail costs for an organism. The idea that telomere dynamics may be shaped in response to such costs is already established; however, we still lack information on whether this relation translates to overall fitness. Here, we quantified LRS (number of fledged young) and longitudinal telomere dynamics of small passerine birds-the blue tits (Cyanistes caeruleus). We found that individual telomere erosion rate was positively associated with lifetime fledgling number. Birds with more fledged young experienced increased telomere attrition. We show that telomere attrition rate, but not telomere length, is related to individual fitness and suggest that telomere dynamics may underlie reproductive costs experienced by animals as a consequence of prioritizing their lifetime fitness. This is the first study, to our knowledge, to provide evidence that more pronounced telomere erosion is associated with higher fitness gain.
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| 25. |
- Sudyka, Joanna, et al.
(författare)
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Sex-specific effects of parasites on telomere dynamics in a short-lived passerinethe blue tit
- 2019
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Ingår i: The Science of Nature. - : SPRINGER HEIDELBERG. - 0028-1042 .- 1432-1904. ; 106:1-2
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Tidskriftsartikel (refereegranskat)abstract
- Parasitic infections potentially drive host's life-histories since they can have detrimental effects on host's fitness. Telomere dynamics is a candidate mechanism to underlie life-history trade-offs and as such may correlate with observed fitness reduction in infected animals. We examined the relationship of chronic infection with two genera of haemosporidians causing avian malaria and malaria-like disease with host's telomere length (TL) in a longitudinal study of free-ranging blue tits. The observed overall infection prevalence was 80% and increased with age, constituting a potentially serious selective pressure in our population. We found longer telomeres in individuals infected with a parasite causing lesser blood pathologies i.e. Haemoproteus compared to Plasmodium genus, but this only held true among males. Female TL was independent of the infection type. Our results indicate that parasitic infections could bring about other types of costs to females than to males with respect to TL. Additionally, we detected linear telomere loss with age, however a random regression analysis did not confirm significant heterogeneity in TL of first breeders and telomere shortening rates in further life.
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