Integrated plumage colour variation in relation to body condition, reproductive investment and laying date in the collared flycatcher

AbstractGlucocorticoid hormones may mediate trade-offs between current and future reproduction. However, understanding their role is complicated by predation risk, which simultaneously affects the value of the current reproductive investment and elevates glucocorticoid levels. Here, we shed light on these issues in long-lived female Eiders (Somateria mollissima) by investigating how current reproductive investment (clutch size) and hatching success relate to faecal glucocorticoid metabolite [fGCM] level and residual reproductive value (minimum years of breeding experience, body condition, relative telomere length) under spatially variable predation risk. Our results showed a positive relationship between colony-specific predation risk and mean colony-specific fGCM levels. Clutch size and female fGCM were negatively correlated only under high nest predation and in females in good body condition, previously shown to have a longer life expectancy. We also found that younger females with longer telomeres had smaller clutches. The drop in hatching success with increasing fGCM levels was least pronounced under high nest predation risk, suggesting that elevated fGCM levels may allow females to ensure some reproductive success under such conditions. Hatching success was positively associated with female body condition, with relative telomere length, particularly in younger females, and with female minimum age, particularly under low predation risk, showing the utility of these metrics as indicators of individual quality. In line with a trade-off between current and future reproduction, our results show that high potential for future breeding prospects and increased predation risk shift the balance toward investment in future reproduction, with glucocorticoids playing a role in the resolution of this trade-off.

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Enzymatic antioxidants but not baseline glucocorticoids mediate the reproduction–survival trade-off in a wild bird

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2018.2141 ◽

2018 ◽

Vol 285 (1892) ◽

pp. 20182141 ◽

Cited By ~ 7

Author(s):

Stefania Casagrande ◽

Michaela Hau

Keyword(s):

Life History ◽

Body Condition ◽

Redox State ◽

Reproductive Investment ◽

Redox System ◽

Reactive Oxygen Metabolites ◽

Enzymatic Antioxidants ◽

Trade Off ◽

Trade Offs ◽

Nest Provisioning

The trade-off between reproductive investment and survival is central to life-history theory, but the relative importance and the complex interactions among the physiological mechanisms mediating it are still debated. Here we experimentally tested whether baseline glucocorticoid hormones, the redox system or their interaction mediate reproductive investment–survival trade-offs in wild great tits ( Parus major ). We increased the workload of parental males by clipping three feathers on each wing, and 5 days later determined effects on baseline corticosterone concentrations (Cort), redox state (reactive oxygen metabolites, protein carbonyls, glutathione peroxidase [GPx], total non-enzymatic antioxidants), body mass, body condition, reproductive success and survival. Feather-clipping did not affect fledgling numbers, chick body condition, nest provisioning rates or survival compared with controls. However, feather-clipped males lost mass and increased both Cort and GPx concentrations. Within feather-clipped individuals, GPx increases were positively associated with reproductive investment (i.e. male nest provisioning). Furthermore, within all individuals, males that increased GPx suffered reduced survival rates. Baseline Cort increases were related to mass loss but not to redox state, nest provisioning or male survival. Our findings provide experimental evidence that changes in the redox system are associated with the trade-off between reproductive investment and survival, while baseline Cort may support this trade-off indirectly through a link with body condition. These results also emphasize that plastic changes in individuals, rather than static levels of physiological signals, may mediate life-history trade-offs.

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Effects of Environmental Conditions and Parental Quality on Inter- and Intraclutch Egg-Size Variation in the Collared Flycatcher (Ficedula Albicollis)

The Auk ◽

10.1093/auk/122.2.509 ◽

2005 ◽

Vol 122 (2) ◽

pp. 509-522 ◽

Cited By ~ 2

Author(s):

Rita Hargitai ◽

János Török ◽

László Tóth ◽

Gergely Hegyi ◽

Balázs Rosivall ◽

...

Keyword(s):

Egg Size ◽

Size Variation ◽

Laying Date ◽

Life History Trait ◽

Ficedula Albicollis ◽

Collared Flycatcher ◽

Egg Formation ◽

Adaptive Explanation ◽

Breeding Condition

AbstractEgg size is a particularly important life-history trait mediating maternal influences on offspring phenotype. Females can vary their egg-size investment in relation to environmental circumstances, their own breeding condition, and the quality of their mate. Here we analyzed inter- and intraclutch variation in egg size in the Collared Flycatcher (Ficedula albicollis) on the basis of eight years of data. According to our results, mean egg size increased with female condition, but did not differ among young, middle-aged, and old females. The male’s age, body size, and forehead patch size did not influence egg size; thus, we found no evidence for differential investment in egg size in relation to male quality. We found no effect of laying date on egg size when controlling for ambient temperature during the egg formation period, yet temperature had a significant effect on egg size. That result indicates proximate constraints on egg formation. Furthermore, we report on annual differences in intraclutch egg-size variation. Egg size increased within clutches in years with a warm prelaying period; whereas in years when the weather during that period was cold, there was no significant intraclutch trend. Proximate considerations seem to explain the observed patterns of intraclutch egg-size variation; however, we cannot reject the adaptive explanation. Mean egg size and intraclutch egg-size variation were unrelated to clutch size. Therefore, we found no evidence for a trade-off between size and number of eggs within a clutch.

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Multiple components of feather microstructure contribute to structural plumage colour diversity in fairy-wrens

Biological Journal of the Linnean Society ◽

10.1093/biolinnean/blz114 ◽

2019 ◽

Vol 128 (3) ◽

pp. 550-568 ◽

Cited By ~ 7

Author(s):

Marie Fan ◽

Liliana D’alba ◽

Matthew D Shawkey ◽

Anne Peters ◽

Kaspar Delhey

Keyword(s):

Plumage Colour ◽

Structural Elements ◽

Closely Related Species ◽

Microscopic Scale ◽

Colour Variation ◽

Multiple Components ◽

Spongy Layer ◽

Evolutionary Changes ◽

Genetic And Environmental Factors ◽

Feather Microstructure

AbstractClosely related species often differ in coloration. Understanding the mechanistic bases of such differences can reveal whether evolutionary changes in colour are driven by single key mechanisms or changes in multiple pathways. Non-iridescent structural plumage colours in birds are a good model in which to test these questions. These colours result from light absorption by pigments, light scattering by the medullary spongy layer (a nanostructure found within barbs) and contributions from other structural elements. Fairy-wrens (Malurus spp.) are a small clade of closely related birds that display a large diversity of ornamental structural colours. Using spectrometry, electron microscopy and Fourier analysis, we show that 30 structural colours, varying from ultraviolet to blue and purple, share a similar barb morphology. Despite this similarity, we find that at the microscopic scale, variation across multiple structural elements, including the size and density of the keratin cortex, spongy layer and melanin, explains colour diversity. These independent axes of morphological variation together account for sizeable amounts of structural colour variability (R2 = 0.21–0.65). The coexistence of many independent, evolutionarily labile mechanisms that generate colour variation suggests that the diversity of structural colours in this clade could be mediated by many independent genetic and environmental factors.

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A simple index to quantify and compare the magnitude of intraspecific geographic plumage colour variation in typical antbirds (Aves: Passeriformes: Thamnophilidae)

Biological Journal of the Linnean Society ◽

10.1093/biolinnean/blaa041 ◽

2020 ◽

Vol 130 (2) ◽

pp. 239-246

Author(s):

Rafael S Marcondes ◽

Robb T Brumfield

Keyword(s):

Geographic Variation ◽

Phenotypic Variation ◽

Evolutionary Biology ◽

Phylogeographic Structure ◽

Plumage Colour ◽

Colour Space ◽

Colour Variation ◽

Simple Index ◽

High Prevalence ◽

Variable Species

Abstract Intraspecific geographic phenotypic variation is a crucial theme in evolutionary biology. Comparing its magnitude across species can provide insights into its ecological and genetic correlates. Here, we developed an index, which we dub the V index, to quantify intraspecific plumage colour variation in typical antbirds (Thamnophilidae), a family which has long interested ornithologists due to a high prevalence of intraspecific variation. The V index is based on a bivariate colour space defined by brightness and redness. Its value for each species equals the mean area occupied by each of its subspecies in that colour space, divided by the area of the species. Lower values indicate greater intraspecific geographic variation. Based on this index, Thamnophilus caerulescens (Variable Antshrike) was exceptionally geographically variable compared to other thamnophilids, as previously suggested based on qualitative evidence. In general, we found that the most variable species had disjunct distributions and deep phylogeographic structure, suggesting an effect of historical population dynamics in producing geographic variation. The V index can be adapted for use with other taxa, traits, and taxonomic levels, and we expect it will instigate novel ways of thinking about phenotypic variation in birds and other animals.

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Winter corticosterone and body condition predict breeding investment in a nonmigratory bird

Behavioral Ecology ◽

10.1093/beheco/arz129 ◽

2019 ◽

Vol 30 (6) ◽

pp. 1642-1652 ◽

Cited By ~ 2

Author(s):

Chloé Montreuil-Spencer ◽

Kelsey Schoenemann ◽

Ádám Z Lendvai ◽

Frances Bonier

Keyword(s):

Life History ◽

Breeding Season ◽

Body Condition ◽

Reproductive Investment ◽

Phenotypic Traits ◽

Residual Body ◽

Life History Stage ◽

Nonbreeding Season ◽

Fat Reserves ◽

Fat Score

Abstract Reproduction is an energetically demanding life history stage that requires costly physiological and behavioral changes, yet some individuals will invest more into reproduction and breed more successfully than others. To understand variation in reproductive investment, previous studies have evaluated factors during breeding, but conditions outside of this life history stage may also play a role. Using a free-ranging population of black-capped chickadees (Poecile atricapillus), we assessed the repeatability of plastic traits relating to energetic condition (circulating initial corticosterone concentrations and body condition) during the nonbreeding season and evaluated whether these traits predicted reproductive investment in the subsequent breeding season. We found that initial corticosterone concentrations and an index of body condition, but not fat score, were moderately repeatable over a 1-week period in winter. This trait repeatability supports the interpretation that among-individual variation in these phenotypic traits could reflect an intrinsic strategy to cope with challenging conditions across life history stages. We found that females with larger fat reserves during winter laid eggs sooner and tended to spend more time incubating their eggs and feeding their offspring. In contrast, we found that females with higher residual body mass delayed breeding, after controlling for the relationship between fat score and timing of breeding. Additionally, females with higher initial corticosterone in winter laid lighter eggs. Our findings suggest that conditions experienced outside of the breeding season may be important factors explaining variation in reproductive investment.

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