scholarly journals A tail of plumage colouration: disentangling geographic, seasonal, and dietary effects on plumage colour in a migratory songbird

2021 ◽  
Author(s):  
Sean M Mahoney ◽  
Matthew W Reudink ◽  
Andrea Contina ◽  
Kelly A Roberts ◽  
Veronica T Schabert ◽  
...  
Keyword(s):  
Geographic Variation ◽  
Isotope Analysis ◽  
Extrinsic Factors ◽  
Signaling Systems ◽  
Plumage Colouration ◽  
Pigment Deposition ◽  
American Redstarts ◽  
Feather Colouration ◽  
Migratory Songbird ◽  
Δ15n And Δ13c

Plumage ornamentation in birds serves critical inter- and intra-sexual signaling functions. While carotenoid-based plumage colouration is often viewed as a classic condition-dependent sexually selected trait, plumage colouration can be influenced by a wide array of both intrinsic and extrinsic factors. Understanding the mechanisms underlying variation in colouration is especially important for species where the signaling function of ornamental traits is complex or the literature conflicting. Here, we examined variation in the yellow/orange tail feathers of American redstarts (Setophaga ruticilla) passing through two migratory stopover sites in eastern North America during both spring and fall migration to assess the role of geographic variation and seasonality in influencing feather colouration. In addition, we investigated whether diet during moult (inferred via stable isotope analysis of feather δ15N and δ13C) influenced plumage colouration. Our findings indicate that geographic variation, season, and diet all influence individual differences in American redstart colouration. However, the extent to which these factors influence colour expression is largely dependent on the colour metric under study, likely because different colour metrics reflect different attributes of the feather (e.g., structural components vs. pigment deposition). The effects of diet (δ15N) and season were pronounced for brightness, suggesting a strong effect of diet and feather wear/degradation on feather structure. Though hue, a metric that should strongly reflect pigment deposition, was also associated with a reduction in ornamentation from spring to fall, that effect was dependent on age, with only adults experiencing a reduction in ornamentation. Taken together, our results highlight the numerous sources of variation of plumage coloration and underscores the difficulty of unraveling complex visual signaling systems, such as those in American redstarts.

scholarly journals Tracing the Trophic Plasticity of the Coral–Dinoflagellate Symbiosis Using Amino Acid Compound-Specific Stable Isotope Analysis

2021 ◽  
Vol 9 (1) ◽  
pp. 182
Author(s):  
Christine Ferrier-Pagès ◽  
Stephane Martinez ◽  
Renaud Grover ◽  
Jonathan Cybulski ◽  
Eli Shemesh ◽  
...  
Keyword(s):  
Amino Acids ◽  
Essential Role ◽  
Isotope Analysis ◽  
Diagnostic Tools ◽  
Global Changes ◽  
Biosynthetic Pathways ◽  
Trophic Plasticity ◽  
Trophic Index ◽  
Δ15n And Δ13c ◽  
Acid Compound

The association between corals and photosynthetic dinoflagellates is one of the most well-known nutritional symbioses, but nowadays it is threatened by global changes. Nutritional exchanges are critical to understanding the performance of this symbiosis under stress conditions. Here, compound-specific δ15N and δ13C values of amino acids (δ15NAA and δ13CAA) were assessed in autotrophic, mixotrophic and heterotrophic holobionts as diagnostic tools to follow nutritional interactions between the partners. Contrary to what was expected, heterotrophy was mainly traced through the δ15N of the symbiont’s amino acids (AAs), suggesting that symbionts directly profit from host heterotrophy. The trophic index (TP) ranged from 1.1 to 2.3 from autotrophic to heterotrophic symbionts. In addition, changes in TP across conditions were more significant in the symbionts than in the host. The similar δ13C-AAs signatures of host and symbionts further suggests that symbiont-derived photosynthates are the main source of carbon for AAs synthesis. Symbionts, therefore, appear to be a key component in the AAs biosynthetic pathways, and might, via this obligatory function, play an essential role in the capacity of corals to withstand environmental stress. These novel findings highlight important aspects of the nutritional exchanges in the coral–dinoflagellates symbiosis. In addition, they feature δ15NAA as a useful tool for studies regarding the nutritional exchanges within the coral–symbiodiniaceae symbiosis.

scholarly journals Stable Isotope Enrichment (Δ15N) in the Predatory Flower Bug (Orius majusculus) Predicts Fitness-Related Differences between Diets

Insects ◽  
2020 ◽  
Vol 11 (4) ◽  
pp. 255
Author(s):  
Marta Montoro ◽  
Per M. Jensen ◽  
Lene Sigsgaard
Keyword(s):  
Diet Quality ◽  
Isotopic Ratio ◽  
Isotope Analysis ◽  
Mass Rearing ◽  
Isotope Enrichment ◽  
Orius Majusculus ◽  
Food And Feed ◽  
The Difference ◽  
Biochemical Analyses ◽  
Δ15n And Δ13c

Mass rearing of insects, used both as biological control agents and for food and feed, is receiving increasing attention. Efforts are being made to improve diets that are currently in use, and to identify alternative diets, as is the case with the predatory flower bug (Orius majusculus) and other heteropteran predators, due to the high costs of their current diet, the eggs of the Mediterranean flour moth (E. kuehniella). The assessment of alternative diets may include measurements of the predator’s fitness-related traits (development time, weight, etc.), and biochemical analyses such as lipid and protein content in the diet and the insects. However, assessing diet quality via the predator’s fitness-related traits is laborious, and biochemical composition is often difficult to relate to the measured traits. Isotope analysis, previously used for diet reconstruction studies, can also serve as a tool for the assessment of diet quality. Here, the variation in discrimination factors or isotope enrichment (Δ15N and Δ13C) indicates the difference in isotopic ratio between the insect and its diet. In this study, we investigated the link between Δ15N and diet quality in the predatory bug Orius majusculus. Three groups of bugs were fed different diets: Ephestia kuehniella eggs, protein-rich Drosophila melanogaster and lipid-rich D. melanogaster. The isotopic enrichment and fitness-related measurements were assessed for each group. Results show a relation between Δ15N and fitness-related measurements, which conform to the idea that lower Δ15N indicates a higher diet quality.

Trophodynamic effects of trawling on the feeding ecology of pandora, Pagellus erythrinus, off the northern Sicily coast (Mediterranean Sea)

2010 ◽  
Vol 61 (4) ◽  
pp. 408 ◽  
Author(s):  
E. Fanelli ◽  
F. Badalamenti ◽  
G. D'Anna ◽  
C. Pipitone ◽  
C. Romano
Keyword(s):  
Stable Isotope ◽  
Feeding Habits ◽  
Isotope Analysis ◽  
Stomach Contents ◽  
Central Mediterranean ◽  
Clear Trend ◽  
Brachyuran Crab ◽  
Pagellus Erythrinus ◽  
Indirect Indicator ◽  
Δ15n And Δ13c

Because trawling disturbs benthic organisms, it could affect the diet of benthic-feeding fish with implications for food-web dynamics. The present study assessed the effects of commercial trawling on the trophodynamics and diet of pandora, Pagellus erythrinus, by comparing its stomach contents and stable-isotope (δ15N and δ13C) composition in two trawled and two untrawled gulfs in northern Sicily (central Mediterranean). Fish were collected on muddy bottoms at 50–100-m depth. Higher abundance and biomass and a slightly larger mean body length were found in the untrawled gulfs. The feeding habits were similar although more selective in the untrawled gulfs. The diet was mainly composed of decapod crustaceans (especially the brachyuran crab Goneplax rhomboides) and of polychaetes. The trophic level of pandora, estimated by its δ15N values, was higher in the untrawled gulfs. No clear trend between trawled and untrawled gulfs was found for the source of carbon in the diet (δ13C). The diet of a benthic feeder such as pandora may be used as an indirect indicator of trawling disturbance, as long as stomach contents and stable-isotope analysis are used jointly to assess the diet and trophodynamics of a species.

Relationships between carotenoid-based female plumage and age, reproduction, and mate colour in the American Redstart (Setophaga ruticilla)

2013 ◽  
Vol 91 (8) ◽  
pp. 589-595 ◽  
Author(s):  
Matthew M. Osmond ◽  
Matthew W. Reudink ◽  
Ryan R. Germain ◽  
Peter P. Marra ◽  
Joseph J. Nocera ◽  
...  
Keyword(s):  
Parental Care ◽  
First Year ◽  
Plumage Colour ◽  
Setophaga Ruticilla ◽  
Reflectance Spectrometry ◽  
American Redstart ◽  
Plumage Colouration ◽  
Adult Females ◽  
American Redstarts ◽  
Second Year

Most studies investigating the function and evolution of ornaments have focused on males. Variation in ornaments may also reflect individual quality and convey information in females. We examined correlations between female plumage colour and reproductive variables in the sexually dichromatic songbird, the American Redstart (Setophaga ruticilla (L., 1758)). Female American Redstarts display yellow, carotenoid-based plumage patches on their tails, wings, and flanks. Using reflectance spectrometry, we quantified brightness (feather structure) and “yellowness” (hue and chroma) of tail and flank feathers to examine whether female plumage colour varies with age, reproductive success, parental care, and the plumage colour of mates. Female plumage varied with age, with adult (after-second-year) females having brighter tail feathers than first-year females. We failed to find a relationship between female plumage colour and pairing or first-egg dates. However, adult females with brighter tails visited their nests less frequently and first-year females with brighter tails fledged fewer offspring. Adult females with brighter tails also mated with males who provided less care. In addition, adult females with yellower flanks paired with males with brighter flanks and with males who provided less parental care. We suggest that plumage colouration in female American Redstarts can act as a signal of individual age and quality.

scholarly journals A tail of plumage colouration: disentangling geographic, seasonal and dietary effects on plumage colour in a migratory songbird

2022 ◽  
Author(s):  
Sean M. Mahoney ◽  
Matthew W. Reudink ◽  
Andrea Contina ◽  
Kelly A. Roberts ◽  
Veronica T. Schabert ◽  
...  
Keyword(s):  
Plumage Colour ◽  
Dietary Effects ◽  
Plumage Colouration ◽  
Migratory Songbird

scholarly journals Cross-hemisphere migration of a 25 g songbird

2012 ◽  
Vol 8 (4) ◽  
pp. 505-507 ◽  
Author(s):  
Franz Bairlein ◽  
D. Ryan Norris ◽  
Rolf Nagel ◽  
Marc Bulte ◽  
Christian C. Voigt ◽  
...  
Keyword(s):  
New World ◽  
Isotope Analysis ◽  
Canadian Arctic ◽  
Light Level ◽  
Western Hemisphere ◽  
Eastern Africa ◽  
Western Africa ◽  
The North ◽  
Migratory Songbird ◽  
Eastern Canadian Arctic

The northern wheatear ( Oenanthe oenanthe ) is a small (approx. 25 g), insectivorous migrant with one of the largest ranges of any songbird in the world, breeding from the eastern Canadian Arctic across Greenland, Eurasia and into Alaska (AK). However, there is no evidence that breeding populations in the New World have established overwintering sites in the Western Hemisphere. Using light-level geolocators, we demonstrate that individuals from these New World regions overwinter in northern sub-Sahara Africa, with Alaskan birds travelling approximately 14 500 km each way and an eastern Canadian Arctic bird crossing a wide stretch of the North Atlantic (approx. 3500 km). These remarkable journeys, particularly for a bird of this size, last between one to three months depending on breeding location and season (autumn/spring) and result in mean overall migration speeds of up to 290 km d −1 . Stable-hydrogen isotope analysis of winter-grown feathers sampled from breeding birds generally support the notion that Alaskan birds overwinter primarily in eastern Africa and eastern Canadian Arctic birds overwinter mainly in western Africa. Our results provide the first evidence of a migratory songbird capable of linking African ecosystems of the Old World with Arctic regions of the New World.

Isotopic (δ15N and δ13C) evidence for intersexual foraging differences and temporal variation in habitat use in waved albatrosses

2007 ◽  
Vol 85 (2) ◽  
pp. 273-279 ◽  
Author(s):  
Jill A. Awkerman ◽  
Keith A. Hobson ◽  
David J. Anderson
Keyword(s):  
Foraging Ecology ◽  
Marine Reserve ◽  
Isotope Analysis ◽  
Sexually Dimorphic ◽  
Eastern Equatorial Pacific ◽  
Species Analysis ◽  
Breeding Grounds ◽  
Phoebastria Irrorata ◽  
Waved Albatrosses ◽  
Δ15n And Δ13c

Waved albatrosses ( Phoebastria irrorata Salvin, 1883) forage close to their breeding grounds on Isla Española, Galápagos, during the short chick-brooding stage and make long trips to the Peruvian upwelling during incubation and chick rearing. Previous studies have suggested foraging segregation by sex: females spend more time searching than males do while foraging in the Galápagos Marine Reserve (GMR), and band recoveries suggest higher bycatch vulnerability of males in the Peruvian upwelling. We used stable isotope analysis (δ15N and δ13C) of whole blood of adult male and female albatrosses to test for intraspecific foraging segregation in this sexually dimorphic species. Analysis of serial blood samples revealed higher δ15N values in males, suggesting consumption of prey items of higher trophic level. We also detected seasonal variation in foraging ecology, with higher δ15N values at the beginning of the breeding season. Sex and regional differences in δ13C values were not significant, reflecting primarily pelagic foraging sites of both sexes, both in the GMR and the Peruvian upwelling. Our results provide evidence of trophic segregation, suggestive of competitive exclusion, and novel information on marine isoscape values in the Eastern Equatorial Pacific.

scholarly journals Trophic interactions between gall-forming molluscs Stilifer spp. (Gastropoda, Eulimidae) and their hosts (Echinodermata)

2020 ◽  
Vol 30 (4) ◽  
pp. 195-202
Author(s):  
E. S. Mekhova ◽  
P. Yu. Dgebuadze
Keyword(s):  
Digestive System ◽  
Isotope Analysis ◽  
Trophic Relationships ◽  
Symbiotic Association ◽  
Δ13c Values ◽  
Isotopic Signatures ◽  
Δ15n And Δ13c ◽  
Linckia Laevigata ◽  
Digestive Glands ◽  
Tube Feet

The trophic relationships between two species of symbiotic gall-forming molluscs from the genus Stilifer (family Eulimidae) and two of their hosts-asteroid species, Linckia laevigata and Culcita noveaguineae, were investigated using the stable isotope analysis of carbon and nitrogen. The aim of present study was to identify the most preferable host tissue in the symbionts’ diet. We analyzed δ15N and δ13C values in tube-feet, gonads and digestive glands of the hosts-starfishes and in muscles of the molluscs. Both symbiont species did not differ to each other both in δ15N and δ13C values. The average δ15N and δ13C values of Stilifer variabilis were significantly different from the digestive glands and gonads of their host Culcita novaeguineae and did not show differences from the tube-feet of starfishes. A similar pattern was found in the symbiotic association of Stilifer utinomi and Linckia laevigata. The tube-feet of analyzed starfishes had significantly higher average δ15N and δ13C values than the digestive glands and gonads. Obtained isotopic signatures indicate that symbionts do not feed on the host's tissues, but take nutrients from their digestive system. It seems that the proboscis of Stilifer spp. absorbs the nutrients from the digestive system of the host-starfish thereby not disturbing significantly the host's immune system.

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