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 Integrating multiple chemical tracers to elucidate the diet and habitat of Cookiecutter Sharks

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Aaron B. Carlisle ◽  
Elizabeth Andruszkiewicz Allan ◽  
Sora L. Kim ◽  
Lauren Meyer ◽  
Jesse Port ◽  
...  
Keyword(s):  
Trophic Ecology ◽  
Foraging Ecology ◽  
Isotope Analysis ◽  
Environmental Dna ◽  
Small Sample ◽  
Apex Predators ◽  
Central Pacific ◽  
Chemical Tracers ◽  
Important Prey ◽  
Tracer Techniques

AbstractThe Cookiecutter shark (Isistius brasiliensis) is an ectoparasitic, mesopelagic shark that is known for removing plugs of tissue from larger prey, including teleosts, chondrichthyans, cephalopods, and marine mammals. Although this species is widely distributed throughout the world’s tropical and subtropical oceanic waters, like many deep-water species, it remains very poorly understood due to its mesopelagic distribution. We used a suite of biochemical tracers, including stable isotope analysis (SIA), fatty acid analysis (FAA), and environmental DNA (eDNA), to investigate the trophic ecology of this species in the Central Pacific around Hawaii. We found that large epipelagic prey constituted a relatively minor part of the overall diet. Surprisingly, small micronektonic and forage species (meso- and epipelagic) are the most important prey group for Cookiecutter sharks across the studied size range (17–43 cm total length), with larger mesopelagic species or species that exhibit diel vertical migration also being important prey. These results were consistent across all the tracer techniques employed. Our results indicate that Cookiecutter sharks play a unique role in pelagic food webs, feeding on prey ranging from the largest apex predators to small, low trophic level species, in particular those that overlap with the depth distribution of the sharks throughout the diel cycle. We also found evidence of a potential shift in diet and/or habitat with size and season. Environmental DNA metabarcoding revealed new prey items for Cookiecutter sharks while also demonstrating that eDNA can be used to identify recent prey in stomachs frozen for extended periods. Integrating across chemical tracers is a powerful tool for investigating the ecology of elusive and difficult to study species, such as meso- and bathypelagic chondrichthyans, and can increase the amount of information gained from small sample sizes. Better resolving the foraging ecology of these mesopelagic predators is critical for effective conservation and management of these taxa and ecosystems, which are intrinsically vulnerable to overfishing and exploitation.

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 Subcolony Variation in Breeding Success in the Tufted Puffin (Fratercula Cirrhata): Association With Foraging Ecology and Implications

The Auk ◽  
2007 ◽  
Vol 124 (4) ◽  
pp. 1149-1157
Author(s):  
J. Mark Hipfner ◽  
Mathieu R. Charette ◽  
Gwylim S. Blackburn
Keyword(s):  
Stable Isotope ◽  
Breeding Success ◽  
Large Scale ◽  
Foraging Ecology ◽  
Isotope Analysis ◽  
Egg Yolk ◽  
Foraging Strategies ◽  
Small Scale ◽  
Carbon And Nitrogen ◽  
Tufted Puffin

Abstract Large-scale oceanographic processes are the main drivers of seabird breeding success, but small-scale processes, though not as well understood, can also be important. We compared the success of Tufted Puffins (Fratercula cirrhata) breeding at two subcolonies only 1.5 km apart on Triangle Island, British Columbia, Canada, 2002–2005. In addition, we used stable-isotope analysis to test the hypothesis that parental foraging strategies differed between the two subcolonies, potentially underlying the variation in breeding success. Success was concordant across years at the two sites but, overall, Tufted Puffins bred more successfully at Strata Rock than at Puffin Rock. They raised chicks in all four years at Strata Rock, but in only three years at Puffin Rock; in two of those three years, Strata Rock chicks were, on average, 60 g and 100 g heavier than Puffin Rock chicks just before fledging. Discriminant analysis of carbon and nitrogen stable-isotope ratios in egg yolk and chick blood in 2004 and 2005 indicated that parental foraging differed between the two subcolonies, with both spatial (δ13C) and trophic-level (δ15N) differences involved. Thus, our study demonstrates the existence of foraging asymmetries in a pelagic seabird at a small spatial scale (between subcolonies), complementing patterns found at larger scales (between colonies). Moreover, the foraging asymmetries were associated with inequalities in fitness measures. We conclude that small-scale processes—in this case, systematic differences in the foraging ecology of local groups—can interact with large-scale oceanographic processes to determine seabird breeding success. Variation sous-coloniale du succès de reproduction de Fratercula cirrhata: Association avec l'écologie de la quête alimentaire et implications

scholarly journals Tracking data and retrospective analyses of diet reveal the consequences of loss of marine subsidies for an obligate scavenger, the Andean condor

2018 ◽  
Vol 285 (1879) ◽  
pp. 20180550 ◽  
Author(s):  
Sergio A. Lambertucci ◽  
Joan Navarro ◽  
José A. Sanchez Zapata ◽  
Keith A. Hobson ◽  
Pablo A. E. Alarcón ◽  
...  
Keyword(s):  
Marine Mammals ◽  
Foraging Ecology ◽  
Average Distance ◽  
Isotope Analysis ◽  
Terrestrial Ecosystems ◽  
Mountain Range ◽  
Marine Subsidies ◽  
Nesting Sites ◽  
Foraging Pattern ◽  
Andean Condor

Over the last century, marine mammals have been dramatically reduced in the world's oceans. We examined evidence that this change caused dietary and foraging pattern shifts of the Andean condor ( Vultur gryphus ) in Patagonia. We hypothesized that, after the decrease in marine mammals and the increase in human use of coastlines, condor diet changed to a more terrestrial diet, which in turn influenced their foraging patterns. We evaluated the diet by means of stable isotope analysis ( δ 13 C, δ 15 N and δ 34 S) of current (last decade) and historical (1841–1933) feathers. We further evaluated the movement patterns of 23 condors using satellite tracking of individuals. Condors reduced their use of marine-derived prey in recent compared with historical times from 33 ± 13% to less than 8 ± 3% respectively; however, they still breed close to the coast. The average distance between the coast and nests was 62.5 km, but some nests were located close to the sea (less than 5 km). Therefore, some birds must travel up to 86 km from nesting sites, crossing over the mountain range to find food. The worldwide reduction in marine mammal carcasses, especially whales, may have major consequences on the foraging ecology of scavengers, as well as on the flux of marine inputs within terrestrial ecosystems.

Endogenous biomarkers reveal diet partitioning among three sympatric species of swallows

The Auk ◽  
2021 ◽  
Author(s):  
Kaelyn H Bumelis ◽  
Michael D Cadman ◽  
Keith A Hobson
Keyword(s):  
Isotope Analysis ◽  
Sympatric Species ◽  
Tree Swallow ◽  
Population Declines ◽  
Interspecific Differences ◽  
Cliff Swallow ◽  
Aerial Insectivores ◽  
Breeding Grounds ◽  
Potential Factors ◽  
Δ 15N

Abstract Since the early 1990s, aerial insectivorous birds have shown serious population declines in North America, but it is not clear if factors common to all species within this guild account for these declines. Among sympatric swallows, population trends differ, and this may be due to differences in ecology operating throughout the annual cycle. Although these species all feed on aerial insects, prey taxa can differ tremendously in their “aeroecology” and use by swallows. We examined the potential for dietary differences among three species of swallows, Barn Swallow (Hirundo rustica), Cliff Swallow (Petrochelidon pyrrhonota), and Tree Swallow (Tachycineta bicolor), breeding sympatrically in southern Ontario, Canada. Potential interspecific differences in nestling diet were examined using two endogenous biomarkers, DNA barcoding of nestling feces and stable isotope analysis (δ 2H, δ 13C, δ 15N) of nestling feathers. We found evidence for differences in dietary sources of provisioned young where Barn Swallows provisioned more terrestrial-based prey, Cliff Swallows provisioned an intermediate diet, and Tree Swallows the most aquatic-emergent insect diet. We suggest this information may help to identify potential factors contributing to differential declines of aerial insectivores operating on the breeding grounds, including diet quality.

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.

Stable Isotope Analysis Enhances Our Understanding of Diamondback Terrapin (Malaclemys terrapin) Foraging Ecology

2018 ◽  
Vol 42 (2) ◽  
pp. 596-611 ◽  
Author(s):  
Mathew J. Denton ◽  
Amanda W. J. Demopoulos ◽  
John D. Baldwin ◽  
Brian J. Smith ◽  
Kristen M. Hart
Keyword(s):  
Stable Isotope ◽  
Stable Isotope Analysis ◽  
Foraging Ecology ◽  
Isotope Analysis ◽  
Diamondback Terrapin ◽  
Malaclemys Terrapin

scholarly journals Absence of Population Genetic Structure Among Breeding Colonies of the Waved Albatross

The Condor ◽  
2006 ◽  
Vol 108 (2) ◽  
pp. 440-445 ◽  
Author(s):  
Kathryn P. Huyvaert ◽  
Patricia G. Parker
Keyword(s):  
Genetic Variation ◽  
Gene Flow ◽  
Genetic Structure ◽  
Population Genetic Structure ◽  
Population Genetic ◽  
Breeding Population ◽  
Genetic Structuring ◽  
Galapagos Archipelago ◽  
Phoebastria Irrorata ◽  
Waved Albatrosses

Abstract We used four variable microsatellite loci to examine the distribution of genetic variation and degree of genetic structuring among three subcolonies of Waved Albatrosses (Phoebastria irrorata). The breeding population of this species is almost entirely limited to the island of Española in the Galápagos Archipelago. Such strong philopatry could lead to population genetic structure among subcolonies on the island. Pairwise values of the FST analog, θ, calculated from microsatellite genotypes, were all less than 0.012, indicating little genetic differentiation and the presence of gene flow throughout the population.

FEMALE-BIASED SEX RATIO ARISES AFTER PARENTAL CARE IN THE SEXUALLY DIMORPHIC WAVED ALBATROSS (PHOEBASTRIA IRRORATA)

The Auk ◽  
2007 ◽  
Vol 124 (4) ◽  
pp. 1336 ◽  
Author(s):  
Jill A. Awkerman ◽  
Mark A. Westbrock ◽  
Kathryn P. Huyvaert ◽  
David J. Anderson
Keyword(s):  
Sex Ratio ◽  
Parental Care ◽  
Sexually Dimorphic ◽  
Biased Sex Ratio ◽  
Phoebastria Irrorata

Indicator species analysis as a test of non-random distribution of species in the context of marine protected areas

2002 ◽  
Vol 29 (3) ◽  
pp. 385-390 ◽  
Author(s):  
David Mouillot ◽  
Jean-Michel Culioli ◽  
Thang Do Chi
Keyword(s):  
Indicator Species ◽  
Marine Reserve ◽  
Randomization Test ◽  
Conservation Area ◽  
Data Set ◽  
New Approach ◽  
Indicator Value ◽  
Mass Capture ◽  
Species Analysis ◽  
Species Being

Species are identified as bioindicators when their presence or abundance within sites of a particular habitat or a conservation area are high. Dufrêne and Legendre (1997), Ecological Monographs 67: 345–366, proposed the use of a flexible asymmetrical approach to detect indicator species and species assemblages characterizing groups of sites, the indicator value for each species being subsequently tested by randomization. Although the advantages of these methods in comparison to other multivariate or two-way indicator species analyses have been demonstrated, relatively few ecological studies have made use of them. The aim of the present study was to demonstrate the advantages of the indicator species test using a data set generated by traditional fisheries activities at four areas in the Bonifacio Strait Marine Reserve, Corsica, France. ANOVA, Kruskal-Wallis and another randomization test were also performed on the same data set. Of the 54 species caught in the fishing nets, the indicator species analyses identified 19 species for which the indicator value was significant for a given area, whereas the a posteriori Tukey test for ANOVA detected only 12 species for which the mass capture per unit effort was significantly greater for a given area. The efficiency of this new approach within the framework of conservation and marine reserve studies is demonstrated by focusing on three species (Sciaena umbra, Palinurus elephas and Maja verrucosa).

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