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Johan Kjellberg Jensen Caroline Isaksson Cas Eikenaar Martin N. Andersson 《Ecology and evolution》2020,10(18):10196-10206
Birds have been observed to have dietary preferences for unsaturated fatty acids during migration. Polyunsaturated fatty acids (PUFAs) may increase the exercise performance of migrant birds; however, PUFAs are also peroxidation prone and might therefore incur increased costs in terms of enhanced oxidative damage in migratory individuals. To shed light on this potential constraint, we analyzed plasma fatty acid (FA) composition and estimated the unsaturation index as a proxy for susceptibility to lipid peroxidation of migrants and residents of the partially migratory common blackbird (Turdus merula) at a stopover site during autumn migration. As predicted, migrant birds had higher relative and absolute levels of PUFAs compared to resident birds. This included the strictly dietary ω‐3 PUFA α‐linolenic acid, suggesting a dietary and/or storage preference for these FAs in migrants. Interestingly, the FA unsaturation index did not differ between migrants and residents. These findings suggest a mechanism where birds alter their levels of metabolic substrate without simultaneously increasing the susceptibility of the substrate to lipid peroxidation. In summary, our results are in line with the hypothesis that increased exercise performance during migration might be constrained by oxidative stress, which is manifested in changes in the composition of key FAs to retain the unsaturation index constant despite the increased levels of peroxidizable PUFAs. 相似文献
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Mark C. Mainwaring D. Charles Deeming Chris I. Jones Ian R. Hartley 《Ecology and evolution》2014,4(6):851-861
Nest construction is taxonomically widespread, yet our understanding of adaptive intraspecific variation in nest design remains poor. Nest characteristics are expected to vary adaptively in response to predictable variation in spring temperatures over large spatial scales, yet such variation in nest design remains largely overlooked, particularly amongst open‐cup‐nesting birds. Here, we systematically examined the effects of latitudinal variation in spring temperatures and precipitation on the morphology, volume, composition, and insulatory properties of open‐cup‐nesting Common Blackbirds’ Turdus merula nests to test the hypothesis that birds living in cooler environments at more northerly latitudes would build better insulated nests than conspecifics living in warmer environments at more southerly latitudes. As spring temperatures increased with decreasing latitude, the external diameter of nests decreased. However, as nest wall thickness also decreased, there was no variation in the diameter of the internal nest cups. Only the mass of dry grasses within nests decreased with warmer temperatures at lower latitudes. The insulatory properties of nests declined with warmer temperatures at lower latitudes and nests containing greater amounts of dry grasses had higher insulatory properties. The insulatory properties of nests decreased with warmer temperatures at lower latitudes, via changes in morphology (wall thickness) and composition (dry grasses). Meanwhile, spring precipitation did not vary with latitude, and none of the nest characteristics varied with spring precipitation. This suggests that Common Blackbirds nesting at higher latitudes were building nests with thicker walls in order to counteract the cooler temperatures. We have provided evidence that the nest construction behavior of open‐cup‐nesting birds systematically varies in response to large‐scale spatial variation in spring temperatures. 相似文献
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Marina Jimnez‐Muoz Diana J. Cole Stephen N. Freeman Robert A. Robinson Stephen R. Baillie Eleni Matechou 《Ecology and evolution》2019,9(2):769-779
Bird ring‐recovery data have been widely used to estimate demographic parameters such as survival probabilities since the mid‐20th century. However, while the total number of birds ringed each year is usually known, historical information on age at ringing is often not available. A standard ring‐recovery model, for which information on age at ringing is required, cannot be used when historical data are incomplete. We develop a new model to estimate age‐dependent survival probabilities from such historical data when age at ringing is not recorded; we call this the historical data model. This new model provides an extension to the model of Robinson, 2010, Ibis, 152, 651–795 by estimating the proportion of the ringed birds marked as juveniles as an additional parameter. We conduct a simulation study to examine the performance of the historical data model and compare it with other models including the standard and conditional ring‐recovery models. Simulation studies show that the approach of Robinson, 2010, Ibis, 152, 651–795 can cause bias in parameter estimates. In contrast, the historical data model yields similar parameter estimates to the standard model. Parameter redundancy results show that the newly developed historical data model is comparable to the standard ring‐recovery model, in terms of which parameters can be estimated, and has fewer identifiability issues than the conditional model. We illustrate the new proposed model using Blackbird and Sandwich Tern data. The new historical data model allows us to make full use of historical data and estimate the same parameters as the standard model with incomplete data, and in doing so, detect potential changes in demographic parameters further back in time. 相似文献
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Austin Alleman Marah Stoldt Barbara Feldmeyer Susanne Foitzik 《Molecular ecology》2019,28(9):2342-2359
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Gregoire A Preault M Cezilly F Wood MJ Pradel R Faivre B 《Journal of evolutionary biology》2004,17(5):1152-1156
Natural selection is a central tenet of evolutionary theory, yet the estimation of the direction and intensity of selection remains problematic. Here, we assess the strength of selection on the early expression of a secondary sexual ornament, bill colour, in male European blackbirds (Turdus merula) using 5 years of capture-mark-recapture (CMR) data. The best-fitting model consisted of a quadratic relationship between survival rate and bill colour, indicating stabilizing natural selection on the early expression of a secondary sexual trait. There was no evidence for sexual selection acting on bill colour in the first year. We suggest that the consideration of early selection and the adoption of refined statistical methods may reveal patterns of selection in the wild that have, as yet, remained undetected. 相似文献
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Qian Zhao Jianzhong Wu Liyan Zhang Lizhen Xu Chao Yan Zhenping Gong 《Journal of Phytopathology》2019,167(1):41-55
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Shiny Cowbirds Molothrus bonariensis and Screaming Cowbirds Molothrus rufoaxillaris are closely related brood parasites but the former is socially polygynous or promiscuous and an extreme host generalist, whereas the latter is socially monogamous and parasitizes almost exclusively one host. Females of both species lay in relative darkness, before dawn, relying for host nest location on previous days’ prospecting activity, or possibly on following better‐informed roost associates. We studied the temporal and spatial patterns of roosting behaviour in these species to test the hypothesis that roosting behaviour of cowbirds is related to their breeding strategy (brood parasitism) and reflects differences in strategies between species. We recorded fidelity to a roost, location fidelity within a roost, inter‐individual spatial associations and timing of roost departures and parasitic events, using tagged individuals. Female Shiny Cowbirds and both sexes of Screaming Cowbirds showed marked fidelity in roosting location, and roost departures occurred both during and after the known time window for parasitism, with earlier departures probably corresponding to laying days. Screaming Cowbird females and males that were trapped together and showed high levels of association during the day, also showed high levels of association in the roost. We describe the spatial and temporal patterns of a relatively poorly known aspect of avian ecology in general and the behaviour of brood parasites in particular. 相似文献
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W.‐M. Xiao M.‐C. Zhao M. Zou Y.‐D. Tan X.‐G. Zhang 《Plant biology (Stuttgart, Germany)》2014,16(3):539-549
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Manuel Hiss Rasa M. Meskauskiene Muhammad A. Arif Eva L. Decker Anika Erxleben Wolfgang Frank Sebastian T. Hanke Daniel Lang Anja Martin Christina Neu Ralf Reski Sandra Richardt Mareike Schallenberg‐Rüdinger Peter Szövényi Theodhor Tiko Gertrud Wiedemann Luise Wolf Philip Zimmermann Stefan A. Rensing 《The Plant journal : for cell and molecular biology》2014,79(3):530-539
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Kwanho Jeong Abdul Baten Daniel L. E. Waters Omar Pantoja Cecile C. Julia Matthias Wissuwa Sigrid Heuer Tobias Kretzschmar Terry J. Rose 《Plant biotechnology journal》2017,15(1):15-26
The physiology and molecular regulation of phosphorus (P) remobilization from vegetative tissues to grains during grain filling is poorly understood, despite the pivotal role it plays in the global P cycle. To test the hypothesis that a subset of genes involved in the P starvation response are involved in remobilization of P from flag leaves to developing grains, we conducted an RNA‐seq analysis of rice flag leaves during the preremobilization phase (6 DAA) and when the leaves were acting as a P source (15 DAA). Several genes that respond to phosphate starvation, including three purple acid phosphatases (OsPAP3, OsPAP9b and OsPAP10a), were significantly up‐regulated at 15 DAA, consistent with a role in remobilization of P from flag leaves during grain filling. A number of genes that have not been implicated in the phosphate starvation response, OsPAP26, SPX‐MFS1 (a putative P transporter) and SPX‐MFS2, also showed expression profiles consistent with involvement in P remobilization from senescing flag leaves. Metabolic pathway analysis using the KEGG system suggested plastid membrane lipid synthesis is a critical process during the P remobilization phase. In particular, the up‐regulation of OsPLDz2 and OsSQD2 at 15 DAA suggested phospholipids were being degraded and replaced by other lipids to enable continued cellular function while liberating P for export to developing grains. Three genes associated with RNA degradation that have not previously been implicated in the P starvation response also showed expression profiles consistent with a role in P mobilization from senescing flag leaves. 相似文献
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- Drought is one of the most serious environmental factors limiting production of sugarcane worldwide. In order to assess the influence of gibberellins (GA3) on drought and plant growth, along with associated physio‐biochemical attributes, expression of eight drought‐responsive genes were quantified and analysed.
- At grand growth stage (120 DAP) two sugarcane varieties (CoLk94184, CoPK05191) were exposed to drought by withholding irrigation. GA3 (35 ppm) was applied using battery‐operated uniform controlled dispensing sprayer twice at 1‐week intervals on 2‐week drought‐stressed plants. Physio‐biochemical attributes including antioxidant enzyme activities were estimated following standard protocols. RT‐PCR was performed to visualise the drought‐associated gene expression patterns.
- Drought triggered a reduction in RWC and chlorophyll content but these recovered when droughted plants were exposed to GA3. Proline content increased many fold in both varieties under stress, but decreased under the influence of GA3. There was a mixed response of antioxidant enzyme activity, which distinctly declined after GA3 exposure, together with a lesser reduction in dry matter content over that of control plants. With increasing stress, expression of pyrroline‐5‐carboxylase synthetase (P5CS) and betaine‐aldehyde dehydrogenase genes was observed, selectively up‐regulated in CoPK05191. Expression of proline oxidase/transporter was high in CoPK05191 but diminished along with proline content after exposure to GA3. CoLk94184 showed no significant difference in P5CS gene expression under stress condition, whereas expression of betaine‐aldehyde dehydrogenase gene was unchanged in response to stress.
- Results demonstrated that exposure of droughted plants to GA3 not only led to recovery of activity of drought‐associated physio‐biochemical attributes, but also minimised impact on cane dry weight and quality. Further, GA3 application caused differential gene expression that possibly triggers increased responsiveness towards drought tolerance in sugarcane.