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Abstract
Diet is a leading modifiable risk factor for chronic disease, but it remains difficult to measure accurately due to the error and bias inherent in self-reported methods of diet assessment. Consequently, there is a pressing need for more objective biomarkers of diet for use in health research. The stable isotope ratios of light elements are a promising set of candidate biomarkers because they vary naturally and reproducibly among foods, and those variations are captured in molecules and tissues with high fidelity. Recent studies have identified valid isotopic measures of short- and long-term sugar intake, meat intake, and fish intake in specific populations. These studies provide a strong foundation for validating stable isotopic biomarkers in the general US population. Approaches to improve specificity for specific foods are needed; for example, by modeling intake using multiple stable isotope ratios or by isolating and measuring specific molecules linked to foods of interest.
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Affiliation(s)
- Diane M O'Brien
- Center for Alaska Native Health Research, Institute of Arctic Biology and Department of Biology and Wildlife, University of Alaska, Fairbanks, Alaska 99775-7000;
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52
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deVries MS, del Rio CM, Tunstall TS, Dawson TE. Isotopic incorporation rates and discrimination factors in mantis shrimp crustaceans. PLoS One 2015; 10:e0122334. [PMID: 25835953 PMCID: PMC4383329 DOI: 10.1371/journal.pone.0122334] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2014] [Accepted: 02/10/2015] [Indexed: 11/19/2022] Open
Abstract
Stable isotope analysis has provided insights into the trophic ecology of a wide diversity of animals. Knowledge about isotopic incorporation rates and isotopic discrimination between the consumer and its diet for different tissue types is essential for interpreting stable isotope data, but these parameters remain understudied in many animal taxa and particularly in aquatic invertebrates. We performed a 292-day diet shift experiment on 92 individuals of the predatory mantis shrimp, Neogonodactylus bredini, to quantify carbon and nitrogen incorporation rates and isotope discrimination factors in muscle and hemolymph tissues. Average isotopic discrimination factors between mantis shrimp muscle and the new diet were 3.0 ± 0.6 ‰ and 0.9 ± 0.3 ‰ for carbon and nitrogen, respectively, which is contrary to what is seen in many other animals (e.g. C and N discrimination is generally 0–1 ‰ and 3–4 ‰, respectively). Surprisingly, the average residence time of nitrogen in hemolymph (28.9 ± 8.3 days) was over 8 times longer than that of carbon (3.4 ± 1.4 days). In muscle, the average residence times of carbon and nitrogen were of the same magnitude (89.3 ± 44.4 and 72.8 ± 18.8 days, respectively). We compared the mantis shrimps’ incorporation rates, along with rates from four other invertebrate taxa from the literature, to those predicted by an allometric equation relating carbon incorporation rate to body mass that was developed for teleost fishes and sharks. The rate of carbon incorporation into muscle was consistent with rates predicted by this equation. Our findings provide new insight into isotopic discrimination factors and incorporation rates in invertebrates with the former showing a different trend than what is commonly observed in other animals.
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Affiliation(s)
- Maya S. deVries
- Department of Integrative Biology, University of California, Berkeley, California, United States of America
- * E-mail:
| | - Carlos Martínez del Rio
- Department of Zoology and Physiology, University of Wyoming, Laramie, Wyoming, United States of America
| | - Tate S. Tunstall
- Department of Integrative Biology, University of California, Berkeley, California, United States of America
| | - Todd E. Dawson
- Department of Integrative Biology, University of California, Berkeley, California, United States of America
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53
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Vander Zanden MJ, Clayton MK, Moody EK, Solomon CT, Weidel BC. Stable isotope turnover and half-life in animal tissues: a literature synthesis. PLoS One 2015; 10:e0116182. [PMID: 25635686 PMCID: PMC4321325 DOI: 10.1371/journal.pone.0116182] [Citation(s) in RCA: 208] [Impact Index Per Article: 23.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2014] [Accepted: 12/04/2014] [Indexed: 11/27/2022] Open
Abstract
Stable isotopes of carbon, nitrogen, and sulfur are used as ecological tracers for a variety of applications, such as studies of animal migrations, energy sources, and food web pathways. Yet uncertainty relating to the time period integrated by isotopic measurement of animal tissues can confound the interpretation of isotopic data. There have been a large number of experimental isotopic diet shift studies aimed at quantifying animal tissue isotopic turnover rate λ (%·day(-1), often expressed as isotopic half-life, ln(2)/λ, days). Yet no studies have evaluated or summarized the many individual half-life estimates in an effort to both seek broad-scale patterns and characterize the degree of variability. Here, we collect previously published half-life estimates, examine how half-life is related to body size, and test for tissue- and taxa-varying allometric relationships. Half-life generally increases with animal body mass, and is longer in muscle and blood compared to plasma and internal organs. Half-life was longest in ecotherms, followed by mammals, and finally birds. For ectotherms, different taxa-tissue combinations had similar allometric slopes that generally matched predictions of metabolic theory. Half-life for ectotherms can be approximated as: ln (half-life) = 0.22*ln (body mass) + group-specific intercept; n = 261, p<0.0001, r2 = 0.63. For endothermic groups, relationships with body mass were weak and model slopes and intercepts were heterogeneous. While isotopic half-life can be approximated using simple allometric relationships for some taxa and tissue types, there is also a high degree of unexplained variation in our models. Our study highlights several strong and general patterns, though accurate prediction of isotopic half-life from readily available variables such as animal body mass remains elusive.
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Affiliation(s)
- M. Jake Vander Zanden
- Center for Limnology, University of Wisconsin—Madison, Madison,
Wisconsin, United States of America
| | - Murray K. Clayton
- Department of Statistics, University of Wisconsin—Madison, Madison,
Wisconsin, United States of America
| | - Eric K. Moody
- Center for Limnology, University of Wisconsin—Madison, Madison,
Wisconsin, United States of America
- School of Life Sciences, Arizona State University, Tempe, Arizona, United
States of America
| | - Christopher T. Solomon
- Department of Natural Resource Sciences, McGill University, Ste. Anne de
Bellevue, Quebec, Canada
| | - Brian C. Weidel
- Lake Ontario Biological Station, USGS, Oswego, New York, United States of
America
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54
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Thomas SM, Crowther TW. Predicting rates of isotopic turnover across the animal kingdom: a synthesis of existing data. J Anim Ecol 2015; 84:861-870. [DOI: 10.1111/1365-2656.12326] [Citation(s) in RCA: 121] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2014] [Accepted: 11/29/2014] [Indexed: 11/29/2022]
Affiliation(s)
- Stephen M. Thomas
- Department of Environmental Sciences; University of Helsinki; P.O. Box 65 Helsinki FI-00014 Finland
| | - Thomas W. Crowther
- Yale School of Forestry and Environmental Studies; Yale University; 370 Prospect St New Haven CT USA
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55
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Lavoie RA, Baird CJ, King LE, Kyser TK, Friesen VL, Campbell LM. Contamination of mercury during the wintering period influences concentrations at breeding sites in two migratory piscivorous birds. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2014; 48:13694-13702. [PMID: 25380025 DOI: 10.1021/es502746z] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Many aquatic fish-eating birds migrate long distances and are exposed to different mercury concentrations ([Hg]) during their annual cycle. Here we examined the importance of migration on [Hg] in two colonial migratory fish-eating bird species. We determined temporal trends of [Hg] and stable isotopes of carbon (δ(13)C) and nitrogen (δ(15)N) during the annual cycle in Double-crested Cormorants (Phalacrocorax auritus) and Caspian Terns (Hydroprogne caspia) breeding in Lake Ontario by a repeated sampling of breast feathers and blood from recaptured individuals. We found an effect of previous winter [Hg], species, sex, and location to explain variations of Hg at breeding sites. This suggests Hg carryover from winter to summer periods and that variations of [Hg] in the summer are partially explained by [Hg] in the winter. Carryover of Hg among seasons and slow changes in [Hg] over time were found especially for individuals in high winter exposure groups, suggesting a slow depuration rate and a fast uptake rate for both species. In contrast, stable isotope values rapidly switched to reach equilibrium at a similar midpoint regardless of winter habitat or diet suggesting minimal carryover of isotopic signatures. The potential of Hg carryover from wintering sites indicates that Hg concentrations in birds at a given time may be influenced by previous exposure from distant locations.
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Affiliation(s)
- Raphael A Lavoie
- Biology Department, Queen's University , 116 Barrie Street, Kingston, Ontario, Canada K7L3N6
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56
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Hobson KA, Quirk TW. Effect of age and ration on diet-tissue isotopic (Δ13C, Δ15N) discrimination in striped skunks (Mephitis mephitis). ISOTOPES IN ENVIRONMENTAL AND HEALTH STUDIES 2014; 50:300-306. [PMID: 24506487 DOI: 10.1080/10256016.2014.867852] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
An important prerequisite for the effective use of stable isotopes in animal ecology is the accurate assessment of isotopic discrimination factors linking animals to their diets for a multitude of tissue types. Surprisingly, these values are poorly known in general and especially for mammalian carnivores and omnivores in particular. Also largely unknown are the factors that influence diet-tissue isotopic discrimination such as nutritional quality and age. We raised adult and juvenile striped skunks (Mephitis mephitis) in captivity on a constant omnivore diet (Mazuri Omnivore A 5635). Adults (n=6) and juveniles (n=3) were kept for 7 months and young (n=7) to the age of 50 days. We then examined individuals for stable carbon (δ(13)C) and nitrogen (δ(15)N) isotope values of hair, nails, lipid, liver, muscle, bone collagen and the plasma, and cellular fractions of blood. Discrimination values differed among age groups and were significantly higher for young compared with their mothers, likely due to the effects of weaning. Δ(15)N isotopic discrimination factors ranged from 3.14 (nails) to 5.6‰ (plasma) in adults and 4.3 (nails) to 5.8‰ (liver) for young. For Δ(13)C, values ranged from-3.3 (fat) to 3.0‰ (collagen) in adults and from-3.3 (fat) to 2.0‰ (collagen) in young. Our data provide an important tool for predicting diets and source of feeding for medium-sized mammalian omnivorous adults integrated over short (e.g. liver, plasma) through long (e.g. collagen) periods and underline the potential effects of age on isotopic values in omnivore diets.
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57
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Braun A, Auerswald K, Vikari A, Schnyder H. Dietary protein content affects isotopic carbon and nitrogen turnover. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2013; 27:2676-2684. [PMID: 24591029 DOI: 10.1002/rcm.6737] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2013] [Revised: 08/21/2013] [Accepted: 09/12/2013] [Indexed: 06/03/2023]
Abstract
RATIONALE Isotopic turnover quantifies the metabolic renewal process of elements in organs and excreta. Knowledge of the isotopic turnover of animal organs and excreta is necessary for diet reconstruction via stable isotope analysis, as used in animal ecology, palaeontology and food authentication. Effects of dietary protein content on the isotopic carbon and nitrogen turnover (i.e. delay, representing the time between ingestion and start of renewal, and half-life) are unknown for most mammalian organs and excreta. METHODS To examine the effect of dietary protein content on turnover (delay and turnover rate), we fed 18 rats either a diet at protein maintenance or above protein maintenance, and quantified their isotopic carbon and nitrogen turnover in ten organs and excreta. These included the excreta faeces and urine, the visceral organs blood plasma, liver, kidney, lung and spleen, the cerebral tissue brain, and the muscular tissues heart and muscle. For data analysis, we used piecewise linear/non-linear exponential modelling that allows quantifying delay and turnover rate simultaneously. RESULTS Delays were ~0.5 days for carbon and nitrogen turnover and were not affected by dietary protein content. Half-lives during the following reaction progress were in the range of 1 to 45 days, increasing from excreta to visceral organs to muscular and cerebral organs. Rats fed the higher protein amount had 30% shorter nitrogen half-lives, and 20% shorter carbon half-lives. CONCLUSIONS The renewal times of organs and excreta depend on the dietary protein content. Hence, isotopic diet reconstruction is confronted with variation in half-lives within the same organ or excrement, altering the time window through which information can be perceived.
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Affiliation(s)
- Alexander Braun
- Lehrstuhl für Grünlandlehre, Department of Plant Science, Technische Universität München, D-85350, Freising, Germany
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58
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Hofmeister NR, Welk M, Freedberg S. Elevated levels of δ15N in riverine Painted Turtles (Chrysemys picta): trophic enrichment or anthropogenic input? CAN J ZOOL 2013. [DOI: 10.1139/cjz-2013-0121] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The natural abundance of stable isotopes of elements in animal tissue is influenced by both biotic and abiotic factors. Biotically, animals feeding at higher trophic levels are enriched in the ratio of 15N:14N (δ15N) relative to their food resources owing to the preferential excretion of 14N. Abiotically, increases in δ15N may also reflect different sources of biologically available nitrogen, including nitrogen resulting from denitrification of inorganic fertilizer. We studied variation in δ15N among freshwater turtle populations to assess spatial variation in δ15N and to determine whether this variation can be attributed to differences in nitrogen source or trophic enrichment. We examined nitrogen and carbon stable isotope ratios in duckweed (genus Lemna L.) and in Painted Turtles (Chrysemys picta (Schneider, 1783)) in aquatic ecosystems expected to be differentially affected by agricultural activity and denitrification of inorganic fertilizer. Across sites, C. picta δ15N was strongly correlated with Lemna δ15N and was elevated in sites influenced by agricultural activity. Furthermore, trophic position of turtles was not associated with δ15N but was consistent with expected values for primary consumers in freshwater systems, indicating that differences in tissue δ15N could be attributed to differences in initial sources of nitrogen in each ecosystem. Our results suggest that care must be taken when attributing differences in isotopic values of animal populations to trophic factors.
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Affiliation(s)
- Natalie R. Hofmeister
- Department of Ecology, Evolution and Environmental Biology, Columbia University, 1200 Amsterdam Avenue, New York, NY 10027, USA
| | - Megan Welk
- College of Menominee Nation, Keshena, WI 54135, USA
| | - Steven Freedberg
- Department of Biology, St. Olaf College, 1520 St. Olaf Avenue, Northfield, MN 55057, USA
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59
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Chen CCW, Welch KC. Hummingbirds can fuel expensive hovering flight completely with either exogenous glucose or fructose. Funct Ecol 2013. [DOI: 10.1111/1365-2435.12202] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Chris Chin Wah Chen
- Department of Biological Sciences University of Toronto Scarborough 1265 Military TrailToronto Ontario M1C 1A4 Canada
- Department of Cell & Systems Biology University of Toronto 25 Harbord StreetToronto Ontario M5S 3G5 Canada
| | - Kenneth Collins Welch
- Department of Biological Sciences University of Toronto Scarborough 1265 Military TrailToronto Ontario M1C 1A4 Canada
- Department of Cell & Systems Biology University of Toronto 25 Harbord StreetToronto Ontario M5S 3G5 Canada
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60
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Blanco-Fontao B, Sandercock BK, Obeso JR, McNew LB, Quevedo M. Effects of sexual dimorphism and landscape composition on the trophic behavior of Greater Prairie-Chicken. PLoS One 2013; 8:e79986. [PMID: 24244588 PMCID: PMC3823567 DOI: 10.1371/journal.pone.0079986] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2013] [Accepted: 10/07/2013] [Indexed: 11/20/2022] Open
Abstract
Partitioning of ecological niche is expected in lekking species that show marked sexual size dimorphism as a consequence of sex-specific ecological constraints. However, niche partitioning is uncertain in species with moderate sexual dimorphism. In addition, the ecological niche of a species may also be affected by landscape composition; particularly, agricultural fragmentation may greatly influence the trophic behavior of herbivores. We studied trophic niche variation in Greater Prairie-Chickens (Tympanuchus cupido), a grouse species that shows moderate sex-dimorphism. Greater Prairie-Chickens are native to tallgrass prairies of North America, although populations persist in less natural mosaics of cropland and native habitats. We used stable isotope analysis of carbon and nitrogen in blood, claws and feathers to assess seasonal differences in trophic niche breadth and individual specialization between male and female Greater Prairie-Chickens, and between birds living in continuous and fragmented landscapes. We found that females showed broader niches and higher individual specialization than males, especially in winter and autumn. However, differences between females and males were smaller in spring when birds converge at leks, suggesting that females and males may exhibit similar feeding behaviors during the lekking period. In addition, we found that birds living in native prairies showed greater annual trophic variability than conspecifics in agricultural mosaic landscapes. Native habitats may provide greater dietary diversity, resulting in greater diversity of feeding strategies.
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Affiliation(s)
- Beatriz Blanco-Fontao
- Research Unit of Biodiversity, (UO/CSIC/PA), Asturias, Spain
- Dpt. Biología de Organismos y Sistemas, Área de Ecología, Universidad de Oviedo, Asturias, Spain
- * E-mail:
| | - Brett K. Sandercock
- Division of Biology, Kansas State University, Manhattan, Kansas, United States of America
| | - José Ramón Obeso
- Research Unit of Biodiversity, (UO/CSIC/PA), Asturias, Spain
- Dpt. Biología de Organismos y Sistemas, Área de Ecología, Universidad de Oviedo, Asturias, Spain
| | - Lance B. McNew
- Division of Biology, Kansas State University, Manhattan, Kansas, United States of America
| | - Mario Quevedo
- Research Unit of Biodiversity, (UO/CSIC/PA), Asturias, Spain
- Dpt. Biología de Organismos y Sistemas, Área de Ecología, Universidad de Oviedo, Asturias, Spain
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61
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Linnebjerg JF, Fort J, Guilford T, Reuleaux A, Mosbech A, Frederiksen M. Sympatric breeding auks shift between dietary and spatial resource partitioning across the annual cycle. PLoS One 2013; 8:e72987. [PMID: 24023663 PMCID: PMC3758292 DOI: 10.1371/journal.pone.0072987] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2013] [Accepted: 07/23/2013] [Indexed: 11/21/2022] Open
Abstract
When species competing for the same resources coexist, some segregation in the way they utilize those resources is expected. However, little is known about how closely related sympatric breeding species segregate outside the breeding season. We investigated the annual segregation of three closely related seabirds (razorbill Alcatorda, common guillemot Uriaaalge and Brünnich's guillemot U. lomvia) breeding at the same colony in Southwest Greenland. By combining GPS and geolocation (GLS) tracking with dive depth and stable isotope analyses, we compared spatial and dietary resource partitioning. During the breeding season, we found the three species to segregate in diet and/or dive depth, but less in foraging area. During both the post-breeding and pre-breeding periods, the three species had an increased overlap in diet, but were dispersed over a larger spatial scale. Dive depths were similar across the annual cycle, suggesting morphological adaptations fixed by evolution. Prey choice, on the other hand, seemed much more flexible and therefore more likely to be affected by the immediate presence of potential competitors.
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Affiliation(s)
| | - Jérôme Fort
- Department of Bioscience, Aarhus University, Roskilde, Denmark
| | - Tim Guilford
- Department of Zoology, University of Oxford, Oxford, Oxfordshire, United Kingdom
| | - Anna Reuleaux
- Department of Bioscience, Aarhus University, Roskilde, Denmark
| | - Anders Mosbech
- Department of Bioscience, Aarhus University, Roskilde, Denmark
- Arctic Research Centre (ARC), Aarhus University, Aarhus, Denmark
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62
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Dietz MW, Piersma T, Dekinga A, Korthals H, Klaassen M. Unusual patterns in ¹⁵N blood values after a diet switch in red knot shorebirds. ISOTOPES IN ENVIRONMENTAL AND HEALTH STUDIES 2013; 49:283-292. [PMID: 23656233 DOI: 10.1080/10256016.2013.776045] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
When a diet switch results in a change in dietary isotopic values, isotope ratios of the consumer's tissues will change until a new equilibrium is reached. This change is generally best described by an exponential decay curve. Indeed, after a diet switch in captive red knot shorebirds (Calidris canutus islandica), the depletion of (13)C in both blood cells and plasma followed an exponential decay curve. Surprisingly, the diet switch with a dietary (15)N/(14)N ratio (δ(15)N) change from 11.4 to 8.8 ‰ had little effect on δ(15)N in the same tissues. The diet-plasma and diet-cellular discrimination factors of (15)N with the initial diet were very low (0.5 and 0.2 ‰, respectively). δ(15)N in blood cells and plasma decreased linearly with increasing body mass, explaining about 40 % of the variation in δ(15)N. δ(15)N in plasma also decreased with increasing body-mass change (r (2)=.07). This suggests that the unusual variation in δ(15)N with time after the diet switch was due to interferences with simultaneous changes in body-protein turnover.
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Affiliation(s)
- Maurine W Dietz
- Animal Ecology Group, Centre for Ecological and Evolutionary Studies, University of Groningen, Groningen, The Netherlands.
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63
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Caut S. Isotope incorporation in broad-snouted caimans (crocodilians). Biol Open 2013; 2:629-34. [PMID: 23789113 PMCID: PMC3683165 DOI: 10.1242/bio.20134945] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2013] [Accepted: 04/23/2013] [Indexed: 11/22/2022] Open
Abstract
The trophic ecology and migration of vertebrate species have been increasingly studied using stable isotope analysis. However, this approach requires knowledge on how dietary isotopic values are reflected in consumers' tissues. To date, this information has only been obtained for a handful of ectotherms; in particular, little is known about crocodilians. In this study, diet-tissue discrimination factors (DTDFs) and carbon and nitrogen stable isotope turnover rates were estimated for plasma, red blood cells (RBCs), and muscle obtained from broad-snouted caimans (Caiman latirostris). Individuals were fed two different control diets for 189 days. DTDFs for δ15N (Δ15N) and δ13C (Δ13C) ranged from −2.24‰ to 0.39‰ and from −0.52‰ to 1.06‰, respectively. Isotope turnover rates in tissues, expressed as half-lives, ranged from 11 to 71 days, with plasma<muscle<RBCs. Δ15N was found to be particularly small, even when compared to values found for other ectotherms, a result that may be linked to the unique excretion physiology of crocodilians. These stable isotope incorporation data should help inform future interpretations of isotopic values obtained in the field for this taxon.
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Affiliation(s)
- Stephane Caut
- Estación Biológica de Doñana, Consejo Superior de Investigaciones Científicas (CSIC) , Apartado 1056, E-41080 Sevilla , Spain
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64
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Herrera Montalvo LG, Rodríguez Galindo M, Ibarra López MP. Asymmetric Contribution of Isotopically Contrasting Food Sources to Vertebrate Consumers in a Subtropical Semi-arid Ecosystem. Biotropica 2013. [DOI: 10.1111/btp.12018] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- L. Gerardo Herrera Montalvo
- Estación de Biología de Chamela; Instituto de Biología; Universidad Nacional Autónoma de México; Apartado Postal 21; San Patricio; Jalisco; 48980; Mexico
| | - Malinalli Rodríguez Galindo
- Posgrado en Ciencias Biológicas; Instituto de Biología; Universidad Nacional Autónoma de México; México D.F; 04510; Mexico
| | - M. Pilar Ibarra López
- Departamento de Ecología y Recursos; Naturales Centro Universitario de la Costa Sur, Universidad de Guadalajara Av.; Independencia Nacional 151; Autlán; Jalisco; 48900; Mexico
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65
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Hipfner J, Addison B, Charette M. Dietary segregation between two cohabiting species of sparrows revealed with stable isotope analysis. CAN J ZOOL 2013. [DOI: 10.1139/cjz-2012-0103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Fox Sparrows (Passerella iliaca (Merrem, 1786)) and Song Sparrows (Melospiza melodia (A. Wilson, 1810)) cohabit on many islands along the Pacific coast of North America, and previous studies suggest that they rely on similar prey types. We used δ13C and δ15N stable isotope analysis on blood collected from breeding adults of both species in each of two habitats on Triangle Island, British Columbia, Canada, to test the hypothesis that the two species exhibit a consistent pattern (direction) of dietary segregation in different habitat types. Both δ13C and especially δ15N values differed between habitats, indicating that the two habitats were isotopically distinct. As predicted, δ15N values differed consistently between the two species in the two habitats, averaging ∼1.5‰ higher in the smaller Song Sparrow than in the larger Fox Sparrow in both. We infer that Song Sparrows included more animal matter and less plant matter in their diets than Fox Sparrows, and suggest that fixed traits related to body size might underlie the dietary (trophic) differences. In contrast, δ13C values did not differ between species. We conclude that dietary segregation could help to facilitate the widespread cohabitation of these two species of sparrows.
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Affiliation(s)
- J.M. Hipfner
- Centre for Wildlife Ecology, Simon Fraser University and Environment Canada, RR#1, 5421 Robertson Road, Delta, BC V4K 3N2, Canada
| | - B. Addison
- Lund University, Ecology Building, Sölvegatan 37, SE 223 62 Lund, Sweden
| | - M.R. Charette
- Ecorana Environmental limited. 3601 Hilcrest Avenue, North Vancouver, BC V7R 4B7, Canada
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66
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Authier M, Dragon AC, Cherel Y, Guinet C. How large is large: estimating ecologically meaningful isotopic differences in observational studies of wild animals. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2012; 26:2657-2664. [PMID: 23124655 DOI: 10.1002/rcm.6389] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
RATIONALE In ecological studies of wildlife movements and foraging, bio-logging and isotopic data are routinely collected and increasingly analyzed in tandem. Such analyses have two shortcomings: (1) small sample size linked with the number of telemetric tags that can be deployed, and (2) the observational nature of isotopic gradients. Wildlife ecologists are thus put in a statistical conundrum known as the small n, large p problem. METHODS Using shrinkage regression, which directly addresses the issue of accurately estimating effects from sparse data, we studied what counts as a biologically meaningful isotopic difference (a prerequisite to delineate isoscapes) in the southern elephant seal (Mirounga leonina), a large and elusive marine predator. RESULTS Seals foraging in Antarctic waters had a lower carbon isotopic value (by ≈ 2‰) than seals foraging either in the interfrontal zone or on the Kerguelen Plateau. The latter two foraging strategies were indistinguishable on the sole basis of δ(13) C values with our data. CONCLUSIONS Shrinkage regression is a conservative statistical technique that has wide applicability in isotopic ecology to help separate robust biological signals from noise.
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Affiliation(s)
- Matthieu Authier
- Centre d'Études Biologiques de Chizé, UPR 1934 du CNRS, 79 360, Villiers-en-Bois, France.
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67
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Tissue turnover rates and isotopic trophic discrimination factors in the endothermic teleost, pacific bluefin tuna (Thunnus orientalis). PLoS One 2012; 7:e49220. [PMID: 23145128 PMCID: PMC3492276 DOI: 10.1371/journal.pone.0049220] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2012] [Accepted: 10/08/2012] [Indexed: 11/29/2022] Open
Abstract
Stable isotope analysis (SIA) of highly migratory marine pelagic animals can improve understanding of their migratory patterns and trophic ecology. However, accurate interpretation of isotopic analyses relies on knowledge of isotope turnover rates and tissue-diet isotope discrimination factors. Laboratory-derived turnover rates and discrimination factors have been difficult to obtain due to the challenges of maintaining these species in captivity. We conducted a study to determine tissue- (white muscle and liver) and isotope- (nitrogen and carbon) specific turnover rates and trophic discrimination factors (TDFs) using archived tissues from captive Pacific bluefin tuna (PBFT), Thunnus orientalis, 1–2914 days after a diet shift in captivity. Half-life values for 15N turnover in white muscle and liver were 167 and 86 days, and for 13C were 255 and 162 days, respectively. TDFs for white muscle and liver were 1.9 and 1.1‰ for δ15N and 1.8 and 1.2‰ for δ13C, respectively. Our results demonstrate that turnover of 15N and 13C in bluefin tuna tissues is well described by a single compartment first-order kinetics model. We report variability in turnover rates between tissue types and their isotope dynamics, and hypothesize that metabolic processes play a large role in turnover of nitrogen and carbon in PBFT white muscle and liver tissues. 15N in white muscle tissue showed the most predictable change with diet over time, suggesting that white muscle δ15N data may provide the most reliable inferences for diet and migration studies using stable isotopes in wild fish. These results allow more accurate interpretation of field data and dramatically improve our ability to use stable isotope data from wild tunas to better understand their migration patterns and trophic ecology.
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68
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Kim SL, del Rio CM, Casper D, Koch PL. Isotopic incorporation rates for shark tissues from a long-term captive feeding study. ACTA ACUST UNITED AC 2012; 215:2495-500. [PMID: 22723489 DOI: 10.1242/jeb.070656] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Stable isotope analysis has provided insight into the dietary and habitat patterns of many birds, mammals and teleost fish. A crucial biological parameter to interpret field stable isotope data is tissue incorporation rate, which has not been well studied in large ectotherms. We report the incorporation of carbon and nitrogen into the tissues of leopard sharks (Triakis semifasciata). Because sharks have relatively slow metabolic rates and are difficult to maintain in captivity, no long-term feeding study has been conducted until the point of isotopic steady state with a diet. We kept six leopard sharks in captivity for 1250 days, measured their growth, and serially sampled plasma, red blood cells and muscle for stable carbon and nitrogen isotope analysis. A single-compartment model with first-order kinetics adequately described the incorporation patterns of carbon and nitrogen isotopes for these three tissues. Both carbon and nitrogen were incorporated faster in plasma than in muscle and red blood cells. The rate of incorporation of carbon into muscle was similar to that predicted by an allometric equation relating isotopic incorporation rate to body mass that was developed previously for teleosts. In spite of their large size and unusual physiology, the rates of isotopic incorporation in sharks seem to follow the same patterns found in other aquatic ectotherms.
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Affiliation(s)
- Sora Lee Kim
- Department of Earth and Planetary Sciences, University of California, Santa Cruz, 1156 High Street, Santa Cruz, CA 95064, USA.
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69
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Pajuelo M, Bjorndal KA, Reich KJ, Vander Zanden HB, Hawkes LA, Bolten AB. Assignment of nesting loggerhead turtles to their foraging areas in the Northwest Atlantic using stable isotopes. Ecosphere 2012. [DOI: 10.1890/es12-00220.1] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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70
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The isotopic composition and insect content of diet predict tissue isotopic values in a South American passerine assemblage. J Comp Physiol B 2012; 183:419-30. [PMID: 23014885 DOI: 10.1007/s00360-012-0711-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2012] [Revised: 08/30/2012] [Accepted: 08/31/2012] [Indexed: 10/27/2022]
Abstract
We analyzed the carbon and nitrogen isotopic values of the muscle, liver, and crop contents ("diet") of 132 individuals of 16 species of Chilean birds. The nitrogen content of diet was tightly correlated with the fraction of gut contents represented by insects relative to plant material. The carbon and nitrogen isotopic values of diet, liver, and muscle were all linearly correlated, implying high temporal consistency in the isotopic value of the diet of these birds. However, δ(15)N was not significantly related with the percentage of insects in diet. These results cast doubt on the applicability of the use of (15)N enrichment to diagnose trophic level in, at least some, terrestrial ecosystems. However, the residuals of the relationship relating the isotopic value of bird tissues with those of their diet were weakly negatively correlated with insect intake. We hypothesize that this negative correlation stems from the higher quality of protein found in insects relative to that of plant materials. Finally, our data corroborated a perplexing and controversial negative relationship between tissue to diet isotopic discrimination and the isotopic value of diet. We suggest that this relationship is an example of the commonly observed regression to the mean effect that plagues many scientific studies.
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71
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MacAvoy S, Lazaroff S, Kraeer K, Arneson L. Sex and strain differences in isotope turnover rates and metabolism in house mice (Mus musculus). CAN J ZOOL 2012. [DOI: 10.1139/z2012-066] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The rate of nutrient incorporation into most organisms is an unknown but important factor in temporally variable systems. We investigate within-species variation in tissue turnover and metabolic rate among house mice ( Mus musculus L., 1758). By establishing a predictive relationship between tissue turnover rate and metabolic rate, field-based studies could more easily estimate tissue turnover rates using metabolic rate as a surrogate. Here, a diet change was administered using male and female mice of two strains (BALB/c and CBA/J) to test whether a predictive relationship was detectable within a species. Resting metabolic rate (mean values of 1.50–3.64 mL O2·h–1·g–1) and metabolic tissue turnover m (0.02–0.07), were significantly different between sexes, but not between strains. Females of both strains exhibited a nitrogen turnover rate significantly faster than males. Females had less mass than males, which could account for the differences in tissue replacement rates between sexes. The difference in metabolic rate within a species (between strains) may not be large enough to affect the rate of tissue turnover, suggesting that field researchers may be able to assume similar turnover rates among same-sex individuals of the same species. However, it may be important to account for sexual dimorphism when studying tissue turnover and metabolism.
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Affiliation(s)
- S.E. MacAvoy
- Department of Environmental Science, American University, Washington, DC 20016, USA
| | - S. Lazaroff
- Department of Biology, American University, Washington, DC 20016, USA
| | - K. Kraeer
- Department of Biology, American University, Washington, DC 20016, USA
| | - L.S. Arneson
- Department of Biology, American University, Washington, DC 20016, USA
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72
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Graves GR, Newsome SD, Willard DE, Grosshuesch DA, Wurzel WW, Fogel ML. Nutritional stress and body condition in the Great Gray Owl (Strix nebulosa) during winter irruptive migrations. CAN J ZOOL 2012. [DOI: 10.1139/z2012-047] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The largest irruptive migration of the Great Gray Owl ( Strix nebulosa Forster, 1772) recorded since 1831 occurred in Minnesota, USA, during the winter of 2004–2005. We tested the hypothesis that morphometric indicators of nutritional stress covary with stable isotope signatures in a sample of 265 owls killed by vehicle collisions. The ratio of carbon to nitrogen in muscle (C/Nmuscle) was shown to be a reliable proxy of nutritional stress. δ13C values for liver and muscle were significantly higher in owls in poor condition, reflecting the depletion of lipid reserves in fasting individuals. On the other hand, δ15N values for liver and muscle were marginally lower or unchanged in owls in poor condition. Stomachs of emaciated owls were less likely to contain prey, implying that many nutritionally stressed individuals were too weak to hunt and were near the tipping point of irreversible fasts. In a broader context, sexual differences in the correlative relationships between stable isotope signatures, C/N, and body condition suggest that the consequences of reversed sexual size dimorphism extend to physiological processes during the nonbreeding season.
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Affiliation(s)
- Gary R. Graves
- Department of Vertebrate Zoology, MRC-116, National Museum of Natural History, Smithsonian Institution, P.O. Box 37012, Washington, DC 20013-7012, USA; Center for Macroecology, Evolution and Climate, University of Copenhagen, DK-2100, Copenhagen Ø, Denmark
| | - Seth D. Newsome
- Carnegie Institution of Washington, Geophysical Laboratory, 5251 Broad Branch Road Northwest, Washington, DC 20015, USA; Department of Zoology and Physiology, University of Wyoming, 1000 East University Avenue, Department 3166, Laramie, WY 82071, USA
| | - David E. Willard
- Zoology Department, Field Museum, 1400 South Lake Shore Drive, Chicago, IL 60605-2496, USA
| | | | - William W. Wurzel
- Carnegie Institution of Washington, Geophysical Laboratory, 5251 Broad Branch Road Northwest, Washington, DC 20015, USA; State University of New York College of Environmental Science and Forestry, SUNY-ESF, 1 Forestry Drive, Syracuse, NY 13210, USA
| | - Marilyn L. Fogel
- Carnegie Institution of Washington, Geophysical Laboratory, 5251 Broad Branch Road Northwest, Washington, DC 20015, USA
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73
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Storm-Suke A, Norris DR, Wassenaar LI, Chin E, Nol E. Factors influencing the turnover and net isotopic discrimination of hydrogen isotopes in proteinaceous tissue: experimental results using Japanese quail. Physiol Biochem Zool 2012; 85:376-84. [PMID: 22705487 DOI: 10.1086/666476] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Stable hydrogen isotopes (δ(2)H) are commonly used in studies of animal movement. Tissue that is metabolically inactive after growth (e.g., feathers) provides spatial or dietary information that reflects only the period of tissue growth, whereas tissues that are metabolically active (e.g., red blood cells) provide a moving window of forensic information. However, using δ(2)H for studies of animal movement relies on the assumption that tissue δ(2)H values reflect dietary δ(2)H values, plus or minus a net diet-tissue discrimination value, and that the turnover rate is known for metabolically active tissue. The metabolic rate of an animal may influence both diet-tissue discrimination values and isotopic tissue turnover rate, but this hypothesis has not been tested experimentally. To examine the metabolic hypothesis, an experimental group of 12 male and 15 female captive Japanese quail (Coturnix japonica) was housed at 8.9°C for 90 d to elevate their metabolic rates (mL CO(2) min(-1)), and a control group of 12 male and 13 female quail was housed at room temperature during the same period. For both experimental and control birds, diet-tissue discrimination values were estimated for red blood cells and feathers. To determine turnover rate, experimental and control birds were switched from a (2)H-enriched diet to a (2)H-depleted diet, with red blood cells sampled before and after diet switch. Metabolic rate did not influence red blood cell hydrogen isotope turnover rate (η(2)(p) = 0.24)) or diet-feather isotope discrimination values (η(2)(p) = 0.86). Diet-feather hydrogen isotopic discrimination had a significant sex plus treatment interaction effect; female feathers were depleted in (2)H relative to food regardless of treatment, whereas male feathers were enriched in (2)H. The effect of sex suggested that experimental studies should examine whether coeval males and females differ in blood δ(2)H levels during certain periods of the annual cycle.
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Affiliation(s)
- Andrea Storm-Suke
- Department of Biology, Trent University, Peterborough, Ontario K9J 7B8, Canada.
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74
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Wolf N, Newsome SD, Fogel ML, del Rio CM. An experimental exploration of the incorporation of hydrogen isotopes from dietary sources into avian tissues. J Exp Biol 2012; 215:1915-22. [DOI: 10.1242/jeb.065219] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
SUMMARY
The analysis of hydrogen stable isotopes (∂D) is a potentially powerful tool for studying animal ecology. Unlike other stable isotopes used in ecological research, however, we are less familiar with the physiological processes that influence the incorporation of hydrogen isotopes from dietary resources to animal tissues. Here we present the results of a controlled feeding experiment utilizing Japanese quail (Cortunix japonica) that was designed to: (1) estimate the relative contributions of diet to the ∂D signatures of blood plasma, red blood cells, intestine, liver, muscle and feathers; (2) investigate possible differences among these same tissues in diet to tissue discrimination; and (3) explore the differences in incorporation dynamics between deuterium (2H) and a well-studied isotope, 13C, for blood plasma solids and red blood cells. Tissues differed in both the relative contribution of diet to tissue ∂D and diet to tissue discrimination. The average residence time of both hydrogen and carbon was significantly lower in plasma solids than in red blood cells. The average residence time of hydrogen was significantly lower than that of carbon in plasma solids, but not in red blood cells. Although the average residence times of hydrogen and carbon were positively correlated, the correlation was weak. Hence the incorporation of carbon seems to be a poor predictor of that of hydrogen.
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Affiliation(s)
- Nathan Wolf
- Department of Zoology and Physiology, University of Wyoming, Laramie, WY 82071, USA
| | - Seth D. Newsome
- Department of Zoology and Physiology, University of Wyoming, Laramie, WY 82071, USA
| | - Marilyn L. Fogel
- Geophysical Laboratory, Carnegie Institution of Washington, Washington, DC 20015, USA
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75
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Martínez del Rio C, Carleton SA. How fast and how faithful: the dynamics of isotopic incorporation into animal tissues: Fig. 1. J Mammal 2012. [DOI: 10.1644/11-mamm-s-165.1] [Citation(s) in RCA: 88] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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76
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Hussey NE, MacNeil MA, Olin JA, McMeans BC, Kinney MJ, Chapman DD, Fisk AT. Stable isotopes and elasmobranchs: tissue types, methods, applications and assumptions. JOURNAL OF FISH BIOLOGY 2012; 80:1449-84. [PMID: 22497393 DOI: 10.1111/j.1095-8649.2012.03251.x] [Citation(s) in RCA: 96] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Stable-isotope analysis (SIA) can act as a powerful ecological tracer with which to examine diet, trophic position and movement, as well as more complex questions pertaining to community dynamics and feeding strategies or behaviour among aquatic organisms. With major advances in the understanding of the methodological approaches and assumptions of SIA through dedicated experimental work in the broader literature coupled with the inherent difficulty of studying typically large, highly mobile marine predators, SIA is increasingly being used to investigate the ecology of elasmobranchs (sharks, skates and rays). Here, the current state of SIA in elasmobranchs is reviewed, focusing on available tissues for analysis, methodological issues relating to the effects of lipid extraction and urea, the experimental dynamics of isotopic incorporation, diet-tissue discrimination factors, estimating trophic position, diet and mixing models and individual specialization and niche-width analyses. These areas are discussed in terms of assumptions made when applying SIA to the study of elasmobranch ecology and the requirement that investigators standardize analytical approaches. Recommendations are made for future SIA experimental work that would improve understanding of stable-isotope dynamics and advance their application in the study of sharks, skates and rays.
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Affiliation(s)
- N E Hussey
- Great Lakes Institute for Environmental Research, University of Windsor, 401 Sunset Avenue, ON N9B 3P4, Canada.
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77
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Carlisle AB, Kim SL, Semmens BX, Madigan DJ, Jorgensen SJ, Perle CR, Anderson SD, Chapple TK, Kanive PE, Block BA. Using stable isotope analysis to understand the migration and trophic ecology of northeastern Pacific white sharks (Carcharodon carcharias). PLoS One 2012; 7:e30492. [PMID: 22355313 PMCID: PMC3280240 DOI: 10.1371/journal.pone.0030492] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2010] [Accepted: 12/18/2011] [Indexed: 11/29/2022] Open
Abstract
The white shark (Carcharodon carcharias) is a wide-ranging apex predator in the northeastern Pacific (NEP). Electronic tagging has demonstrated that white sharks exhibit a regular migratory pattern, occurring at coastal sites during the late summer, autumn and early winter and moving offshore to oceanic habitats during the remainder of the year, although the purpose of these migrations remains unclear. The purpose of this study was to use stable isotope analysis (SIA) to provide insight into the trophic ecology and migratory behaviors of white sharks in the NEP. Between 2006 and 2009, 53 white sharks were biopsied in central California to obtain dermal and muscle tissues, which were analyzed for stable isotope values of carbon (δ(13)C) and nitrogen (δ(15)N). We developed a mixing model that directly incorporates movement data and tissue incorporation (turnover) rates to better estimate the relative importance of different focal areas to white shark diet and elucidate their migratory behavior. Mixing model results for muscle showed a relatively equal dietary contribution from coastal and offshore regions, indicating that white sharks forage in both areas. However, model results indicated that sharks foraged at a higher relative rate in coastal habitats. There was a negative relationship between shark length and muscle δ(13)C and δ(15)N values, which may indicate ontogenetic changes in habitat use related to onset of maturity. The isotopic composition of dermal tissue was consistent with a more rapid incorporation rate than muscle and may represent more recent foraging. Low offshore consumption rates suggest that it is unlikely that foraging is the primary purpose of the offshore migrations. These results demonstrate how SIA can provide insight into the trophic ecology and migratory behavior of marine predators, especially when coupled with electronic tagging data.
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Affiliation(s)
- Aaron B Carlisle
- Hopkins Marine Station of Stanford University, Pacific Grove, California, United States of America.
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78
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Hahn S, Hoye BJ, Korthals H, Klaassen M. From food to offspring down: tissue-specific discrimination and turn-over of stable isotopes in herbivorous waterbirds and other avian foraging guilds. PLoS One 2012; 7:e30242. [PMID: 22312422 PMCID: PMC3270017 DOI: 10.1371/journal.pone.0030242] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2011] [Accepted: 12/16/2011] [Indexed: 11/18/2022] Open
Abstract
Isotopic discrimination and turn-over are fundamental to the application of stable isotope ecology in animals. However, detailed information for specific tissues and species are widely lacking, notably for herbivorous species. We provide details on tissue-specific carbon and nitrogen discrimination and turn-over times from food to blood, feathers, claws, egg tissues and offspring down feathers in four species of herbivorous waterbirds. Source-to-tissue discrimination factors for carbon (δ¹³C) and nitrogen stable isotope ratios (δ¹⁵N) showed little variation across species but varied between tissues. Apparent discrimination factors ranged between -0.5 to 2.5‰ for δ¹³C and 2.8 to 5.2‰ for δ¹⁵N, and were more similar between blood components than between keratinous tissues or egg tissue. Comparing these results with published data from other species we found no effect of foraging guild on discrimination factors for carbon but a significant foraging-guild effect for nitrogen discrimination factors.Turn-over of δ¹³C in tissues was most rapid in blood plasma, with a half-life of 4.3 d, whereas δ¹³C in blood cells had a half-life of approximately 32 d. Turn-over times for albumen and yolk in laying females were similar to those of blood plasma, at 3.2 and 6.0 d respectively. Within yolk, we found decreasing half-life times of δ¹³C from inner yolk (13.3 d) to outer yolk (3.1 d), related to the temporal pattern of tissue formation.We found similarities in tissue-specific turn-over times across all avian species studied to date. Yet, while generalities regarding discrimination factors and tissue turn-over times can be made, a large amount of variation remains unexplained.
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Affiliation(s)
- Steffen Hahn
- Swiss Ornithological Institute, Sempach, Switzerland.
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79
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Murray IW, Wolf BO. Tissue carbon incorporation rates and diet-to-tissue discrimination in ectotherms: tortoises are really slow. Physiol Biochem Zool 2012; 85:96-105. [PMID: 22237293 DOI: 10.1086/663867] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Abstract Understanding carbon incorporation rates and diet-to-tissue discrimination (Δ(13)C(tissue-diet)) in animals is necessary to interpret stable isotope data collected from animals in the field. Our current understanding of the carbon dynamics in terrestrial ectotherms such as snakes, lizards, and turtles is poorly developed. Here we use a diet switch experiment to estimate carbon incorporation rates and diet-to-tissue discrimination factors in growing desert tortoises (Gopherus agassizii). Average carbon retention times for red blood cells (RBCs) and plasma were 126.7 ± 40.3 and 32.9 ± 14.5 days, respectively. Tissue carbon incorporation rates were affected by both growth and metabolism, with growth accounting for 50% of the carbon turnover in RBCs and 13% of carbon turnover in plasma. At equilibrium, scute keratin (0.8 ± 0.1) and plasma (1.0 ± 0.2) showed enriched discrimination values (Δ(13)C) compared to the test diet, but RBC Δ(13)C values were indistinguishable from diet (0.2 ± 0.3). We also found that new keratin continued to contribute significant material to previously grown keratin rings on the tortoise's shell. Changes in the δ(13)C of previously laid down growth rings indicated that the old rings closest to the region of new growth received about 73% of the carbon from the current diet; these data suggest that the interpretation of dietary history using growth rings must recognize that each ring may represent the weighted average of the diet over several seasons. These results continue to highlight the importance of laboratory experiments in interpreting isotopic data derived from field studies.
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Affiliation(s)
- Ian W Murray
- Department of Biology, University of New Mexico, Albuquerque, New Mexico 87131
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80
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Authier M, Martin C, Ponchon A, Steelandt S, Bentaleb I, Guinet C. Breaking the sticks: a hierarchical change-point model for estimating ontogenetic shifts with stable isotope data. Methods Ecol Evol 2011. [DOI: 10.1111/j.2041-210x.2011.00162.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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81
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Maldonado K, Bozinovic F, Rojas JM, Sabat P. Within-Species Digestive Tract Flexibility in Rufous-Collared Sparrows and the Climatic Variability Hypothesis. Physiol Biochem Zool 2011; 84:377-84. [DOI: 10.1086/660970] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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82
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Stable isotopes in southern rockhopper penguins: foraging areas and sexual differences in the non-breeding period. Polar Biol 2011. [DOI: 10.1007/s00300-011-1026-x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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83
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Hipfner JM, Hobson KA, Elliott JE. Ecological factors differentially affect mercury levels in two species of sympatric marine birds of the North Pacific. THE SCIENCE OF THE TOTAL ENVIRONMENT 2011; 409:1328-1335. [PMID: 21276602 DOI: 10.1016/j.scitotenv.2010.12.022] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2010] [Revised: 12/10/2010] [Accepted: 12/15/2010] [Indexed: 05/30/2023]
Abstract
In 2003 and 2004, we measured mercury concentrations and δ¹⁵N and δ¹³C values in the whole blood of adults of two species of seabirds, Cassin's auklet (Ptychoramphus aleuticus) and rhinoceros auklet (Cerorhinca monocerata), during their prelaying, incubation, and provisioning periods. We also collected whole blood from the offspring of both seabirds. Among prey items, δ¹⁵N values were higher in fish than in crustaceans, while δ¹³C did not vary systematically between prey types. Mercury concentrations in prey showed little relationship with either stable isotope. In the zooplanktivorous Cassin's auklet, year, reproductive stage, and δ¹⁵N and δ¹³C stable isotope values explained only 14% of the variation in mercury concentrations in adult blood, and none of these variables had a statistically significant effect. In contrast, these same variables explained 41% of the variation in mercury levels in the more piscivorous rhinoceros auklet, and all but δ¹⁵N values had statistically significant effects. Mercury concentrations in adult rhinoceros auklets were higher in 2003 than in 2004; higher prior to laying than during the incubation or provisioning periods; and increased with δ¹³C values--but in just one of two years. In both species, mercury concentrations were substantially higher in adults than in nestlings. Our results accord with previous studies in showing that mercury concentrations can vary among years, species and age classes, while the marked variation with reproductive stage is noteworthy because it is so rarely considered. Our results may help to explain the disparate conclusions of previous studies: while many factors influence mercury concentrations in marine predators, they apparently do so in a manner that defies easy characterization. We believe that there is a need for more studies that consider a range of physiological, ecological and behavioral factors that might affect mercury burdens in marine predators.
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Affiliation(s)
- J M Hipfner
- Environment Canada, Pacific Wildlife Research Centre, RR#1 5421 Robertson Road, Delta, BC V4K3N2, Canada.
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84
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Divergent trophic levels in two cryptic sibling bat species. Oecologia 2011; 166:69-78. [PMID: 21340613 DOI: 10.1007/s00442-011-1940-1] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2010] [Accepted: 02/03/2011] [Indexed: 10/18/2022]
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85
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Caut S, Laran S, Garcia-Hartmann E, Das K. Stable isotopes of captive cetaceans (killer whales and bottlenose dolphins). J Exp Biol 2011; 214:538-45. [DOI: 10.1242/jeb.045104] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
SUMMARY
There is currently a great deal of interest in using stable isotope methods to investigate diet, trophic level and migration in wild cetaceans. In order to correctly interpret the results stemming from these methods, it is crucial to understand how diet isotopic values are reflected in consumer tissues. In this study, we investigated patterns of isotopic discrimination between diet and blood constituents of two species of cetaceans (killer whale, Orcinus orca, and bottlenose dolphin, Tursiops truncatus) fed controlled diets over 308 and 312 days, respectively. Diet discrimination factors (Δ; mean ± s.d.) for plasma were estimated to Δ13C=2.3±0.6‰ and Δ15N=1.8±0.3‰, respectively, for both species and to Δ13C=2.7±0.3‰ and Δ15N=0.5±0.1‰ for red blood cells. Delipidation did not have a significant effect on carbon and nitrogen isotopic values of blood constituents, confirming that cetacean blood does not serve as a reservoir of lipids. In contrast, carbon isotopic values were higher in delipidated samples of blubber, liver and muscle from killer whales. The potential for conflict between fisheries and cetaceans has heightened the need for trophic information about these taxa. These results provide the first published stable isotope incorporation data for cetaceans, which are essential if conclusions are to be drawn on issues concerning trophic structures, carbon sources and diet reconstruction.
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Affiliation(s)
- Stéphane Caut
- Estación Biológica de Doñana, CSIC, Apdo. 1056, E-41080 Sevilla, Spain
- Laboratory of Oceanology, MARE, University of Liège, Allée de la Chimie, 17, B-4000 Liège, Belgium
| | - Sophie Laran
- Marineland, 306 av. Mozart, 06600 Antibes, France
| | | | - Krishna Das
- Laboratory of Oceanology, MARE, University of Liège, Allée de la Chimie, 17, B-4000 Liège, Belgium
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86
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Pecquerie L, Nisbet RM, Fablet R, Lorrain A, Kooijman SALM. The impact of metabolism on stable isotope dynamics: a theoretical framework. Philos Trans R Soc Lond B Biol Sci 2010; 365:3455-68. [PMID: 20921045 PMCID: PMC2981971 DOI: 10.1098/rstb.2010.0097] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Stable isotope analysis is a powerful tool used for reconstructing individual life histories, identifying food-web structures and tracking flow of elemental matter through ecosystems. The mechanisms determining isotopic incorporation rates and discrimination factors are, however, poorly understood which hinders a reliable interpretation of field data when no experimental data are available. Here, we extend dynamic energy budget (DEB) theory with a limited set of new assumptions and rules in order to study the impact of metabolism on stable isotope dynamics in a mechanistic way. We calculate fluxes of stable isotopes within an organism by following fluxes of molecules involved in a limited number of macrochemical reactions: assimilation, growth but also structure turnover that is here explicitly treated. Two mechanisms are involved in the discrimination of isotopes: (i) selection of molecules occurs at the partitioning of assimilation, growth and turnover into anabolic and catabolic sub-fluxes and (ii) reshuffling of atoms occurs during transformations. Such a framework allows for isotopic routing which is known as a key, but poorly studied, mechanism. As DEB theory specifies the impact of environmental conditions and individual state on molecule fluxes, we discuss how scenario analysis within this framework could help reveal common mechanisms across taxa.
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Affiliation(s)
- Laure Pecquerie
- Ecology, Evolution and Marine Biology Department, University of California Santa Barbara, Santa Barbara, CA 93106-9620, USA.
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87
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Melintescu A, Galeriu D. Energy metabolism used as a tool to model the transfer of 14C and 3H in animals. RADIATION AND ENVIRONMENTAL BIOPHYSICS 2010; 49:657-672. [PMID: 20532542 DOI: 10.1007/s00411-010-0302-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2009] [Accepted: 05/22/2010] [Indexed: 05/29/2023]
Abstract
The transfer through the environment of (3)H and (14)C must be modelled differently than that of other radionuclides released from nuclear reactors because hydrogen and carbon enter straight into the life cycle. A solid understanding of the behaviour of (3)H and (14)C in the food chain is essential because (3)H may be released in large quantities from future thermonuclear reactors, and (14)C accumulates in the environment because of its long half-life. For the present study, the hypothesis that both (3)H and (14)C metabolism in mammals can be modelled based on the understanding of energy metabolism has been tested. Recently published results demonstrate that the loss rate of organically bound tritium and (14)C from tissues of laboratory and farm animals can be assessed based upon their specific metabolic rates and enthalpy of combustion; the same is true for human beings. The improved model presented here relates the dynamics of organically bound tritium and (14)C within organs to the whole body and has been expanded to account for the growth of ruminants. The improved model has been expanded and applied for (14)C transfer in wild mammals and has been modified to apply to birds.
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Affiliation(s)
- A Melintescu
- Life and Environmental Physics Department, Horia Hulubei National Institute for Physics and Nuclear Engineering, Bucharest, Romania.
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88
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Warne RW, Gilman CA, Wolf BO. Tissue-carbon incorporation rates in lizards: implications for ecological studies using stable isotopes in terrestrial ectotherms. Physiol Biochem Zool 2010; 83:608-17. [PMID: 20441446 DOI: 10.1086/651585] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Carbon stable isotope (delta(13)C) analysis can be used to infer the origin and to estimate the flow of nutrient resources through animals and across ecological compartments. These applications require knowledge of the rates at which carbon is incorporated into animal tissues and diet-to-tissue discrimination factors (Delta(13)C). Studies of carbon dynamics in terrestrial vertebrates to date have focused almost solely on endothermic animals; ectotherms such as reptiles have received little attention. Here we determined carbon incorporation rates and Delta(13)C in tissues of prairie lizards (Sceloporus undulatus consobrinus) and collared lizards (Crotaphytus collaris). The smaller lizard, S. undulatus, had carbon retention times of 25 and 61 d in plasma and red blood cells (RBC), respectively, compared with 44 and 311 d for the larger C. collaris. Liver, muscle, and skin carbon retention times for S. undulatus were 21, 81, and 94 d. Growth contributed 9%-19% of the carbon incorporated into these tissues. This contribution is similar to endotherms measured at comparable developmental stages. Mean Delta(13)C for plasma (-0.2 per thousand +/- 0.4 per thousand Vienna Pee Dee Belemnite Standard) and RBCs (-1.3 per thousand +/- 0.8 per thousand) were similar to values reported for other vertebrates. Carbon incorporation rates for these ectotherms, however, are seven times slower than in similarly sized adult endotherms. Although a limited comparison with data for warm-water fishes suggests comparable incorporation rates between aquatic and terrestrial ectotherms, this study highlights the lack of experimental data for isotope dynamics in ectotherms across a range of temperatures, body sizes, and developmental stages.
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Affiliation(s)
- Robin W Warne
- Biology Department, University of New Mexico, Albuquerque, NM 87131-0001, USA.
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89
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DeMots RL, Novak JM, Gaines KF, Gregor AJ, Romanek CS, Soluk DA. Tissue–diet discrimination factors and turnover of stable carbon and nitrogen isotopes in white-footed mice (Peromyscus leucopus). CAN J ZOOL 2010. [DOI: 10.1139/z10-063] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Stable isotope analysis has become an increasingly valuable tool in investigating animal ecology. Here we document the turnover rates for carbon in the liver, muscle, and whole blood tissue, as well as the tissue–diet discrimination values for carbon and nitrogen isotopes in the liver, whole blood, muscle, and hair, of the white-footed mouse ( Peromyscus leucopus (Rafinesque, 1818)). A 168-day diet-switching experiment was conducted with a laboratory population of white-footed mice. The δ13C values for all tissues deviated less than 1‰ from those of the diet except for whole blood, which had a slightly higher tissue–diet discrimination factor of 1.8‰. All tissues were enriched in 15N by approximately 3‰ relative to the diet except for liver tissue, which was 4.5‰ higher than the dietary δ15N value. Turnover rates for tissues of white-footed mice were ranked liver > whole blood > muscle. The half-lives calculated for liver tissue differed significantly between the two diet switches performed in this experiment. We demonstrate that there is potential for variation in tissue–diet discrimination values and tissue turnover rates between even closely related species. These findings highlight the importance of determining species-specific estimates of these parameters prior to the use of stable isotope analysis in field investigations of animal ecology.
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Affiliation(s)
- Rachel L. DeMots
- University of South Dakota, Department of Biology, 414 East Clark Street, Vermillion, SD 57069, USA
- Eastern Illinois University, Department of Biological Sciences, 600 Lincoln Avenue, Charleston, IL 61920-3099, USA
- Savannah River Ecology Laboratory, P.O. Drawer E, Aiken, SC 29802, USA
| | - James M. Novak
- University of South Dakota, Department of Biology, 414 East Clark Street, Vermillion, SD 57069, USA
- Eastern Illinois University, Department of Biological Sciences, 600 Lincoln Avenue, Charleston, IL 61920-3099, USA
- Savannah River Ecology Laboratory, P.O. Drawer E, Aiken, SC 29802, USA
| | - Karen F. Gaines
- University of South Dakota, Department of Biology, 414 East Clark Street, Vermillion, SD 57069, USA
- Eastern Illinois University, Department of Biological Sciences, 600 Lincoln Avenue, Charleston, IL 61920-3099, USA
- Savannah River Ecology Laboratory, P.O. Drawer E, Aiken, SC 29802, USA
| | - Aaron J. Gregor
- University of South Dakota, Department of Biology, 414 East Clark Street, Vermillion, SD 57069, USA
- Eastern Illinois University, Department of Biological Sciences, 600 Lincoln Avenue, Charleston, IL 61920-3099, USA
- Savannah River Ecology Laboratory, P.O. Drawer E, Aiken, SC 29802, USA
| | - Christopher S. Romanek
- University of South Dakota, Department of Biology, 414 East Clark Street, Vermillion, SD 57069, USA
- Eastern Illinois University, Department of Biological Sciences, 600 Lincoln Avenue, Charleston, IL 61920-3099, USA
- Savannah River Ecology Laboratory, P.O. Drawer E, Aiken, SC 29802, USA
| | - Daniel A. Soluk
- University of South Dakota, Department of Biology, 414 East Clark Street, Vermillion, SD 57069, USA
- Eastern Illinois University, Department of Biological Sciences, 600 Lincoln Avenue, Charleston, IL 61920-3099, USA
- Savannah River Ecology Laboratory, P.O. Drawer E, Aiken, SC 29802, USA
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90
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Matich P, Heithaus MR, Layman CA. Contrasting patterns of individual specialization and trophic coupling in two marine apex predators. J Anim Ecol 2010; 80:294-305. [PMID: 20831730 DOI: 10.1111/j.1365-2656.2010.01753.x] [Citation(s) in RCA: 135] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Philip Matich
- Marine Sciences Program, Florida International University, 3000 NE 151st, North Miami, FL 33181, USA
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91
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Salvante KG, Vézina F, Williams TD. Evidence for within-individual energy reallocation in cold-challenged, egg-producing birds. ACTA ACUST UNITED AC 2010; 213:1991-2000. [PMID: 20511512 DOI: 10.1242/jeb.036319] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Recent studies have shown that the metabolic cost of avian egg production involves a 16-27% increase in metabolic rate (MR) above non-reproductive basal or resting values (BMR and RMR, respectively). To determine how the metabolic cost of egg production interacted with the costs of other essential processes (such as cold acclimation and active heat production), we measured the MR of non-breeding and egg-producing zebra finches (Taeniopygia guttata) while (a) warm-acclimated (to 19-21 degrees C) and measured within their thermoneutral zone (at 35 degrees C), (b) cold-acclimated (to 7 degrees C) and measured at thermoneutrality (at 35 degrees C, i.e. not actively producing heat), and (c) cold-acclimated and measured below thermoneutrality (at 7 degrees C) (i.e. during active heat production). The metabolic cost of egg production was small (24% above BMR) compared with the additive costs of cold acclimation and active heat production (224% above BMR). Exposure to low ambient temperatures was accompanied by an increase in seed consumption (by 72%) and a decrease in locomotor activity (by 72%) compared with warm-acclimated, non-breeding values. By contrast, egg production in heat-producing females was associated with an 11% decrease in MR and a 22% decrease in seed consumption compared with non-breeding thermoregulating values. Our data suggest that while the increase in MR associated with egg production is small in relation to the birds' capacity to increase MR in response to other energetically demanding processes, the addition of egg production to these metabolically costly activities may be enough to necessitate the use of energy-saving strategies, such as internal energy reallocation, to cope with the additional energetic demands.
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Affiliation(s)
- Katrina G Salvante
- Department of Biological Sciences, Simon Fraser University, 8888 University Drive, Burnaby, British Columbia, Canada, V5A 1S6.
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92
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Ben-Hamo M, Pinshow B, McCue MD, McWilliams SR, Bauchinger U. Fasting triggers hypothermia, and ambient temperature modulates its depth in Japanese quail Coturnix japonica. Comp Biochem Physiol A Mol Integr Physiol 2010; 156:84-91. [DOI: 10.1016/j.cbpa.2009.12.020] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2009] [Revised: 12/30/2009] [Accepted: 12/31/2009] [Indexed: 11/26/2022]
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93
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Carleton SA, Del Rio CM. Growth and catabolism in isotopic incorporation: a new formulation and experimental data. Funct Ecol 2010. [DOI: 10.1111/j.1365-2435.2010.01700.x] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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94
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Klaassen M, Piersma T, Korthals H, Dekinga A, Dietz MW. Single-point isotope measurements in blood cells and plasma to estimate the time since diet switches. Funct Ecol 2010. [DOI: 10.1111/j.1365-2435.2010.01689.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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95
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Bauchinger U, McWilliams S. Carbon turnover in tissues of a passerine bird: allometry, isotopic clocks, and phenotypic flexibility in organ size. Physiol Biochem Zool 2010; 82:787-97. [PMID: 19785542 DOI: 10.1086/605548] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Stable isotopes are an important tool for physiological and behavioral ecologists, although their usefulness depends on a thorough understanding of the dynamics of isotope incorporation into tissue(s) over time. In contrast to hair, claws, and feathers, most animal tissues continuously incorporate carbon (and other elements), and so carbon isotope values may change over time, depending on resource use and tissue-specific metabolic rates. Here we report the carbon turnover rate for 12 tissues from a passerine bird, the zebra finch (Taeniopygia guttata). We measured average carbon retention time (tau) for 8 d for small intestine; 10-13 d for gizzard, kidney, liver, pancreas, and proventriculus; 17-21 d for heart, brain, blood, and flight muscle; and 26-28 d for leg muscle and skin. We used these data, along with the few other published estimates, to confirm that the fractional rate of isotopic turnover for red blood cells, whole blood, liver, and leg muscle scales with body mass to approximately the -1/4 power. Our data also support several key assumptions of the "isotopic-clock" model, which uses differences in isotope value between tissues, along with estimates of turnover rate of these tissues, to predict time elapsed since a diet shift. Finally, we show that between-tissues differences in turnover rate largely, but not entirely, explain the extent of phenotypic flexibility in organs of garden warblers during their long-distance flight across the Sahara Desert during spring. More studies that measure tissue-specific protein synthesis, metabolic rate, and elemental turnover in many tissues from a variety of animals are needed.
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Affiliation(s)
- Ulf Bauchinger
- Department Biologie II, Ludwig-Maximilians-Universität München, Grosshaderner Strasse 2, 82152 Planegg-Martinsried, Germany.
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96
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Morrissey CA, Elliott JE, Ormerod SJ. Diet shifts during egg laying: Implications for measuring contaminants in bird eggs. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2010; 158:447-454. [PMID: 19782447 DOI: 10.1016/j.envpol.2009.08.040] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2009] [Revised: 07/30/2009] [Accepted: 08/29/2009] [Indexed: 05/28/2023]
Abstract
We combined stable isotope tracers of blood plasma, blood cells and egg contents with faecal analysis during pre-breeding and egg laying phases in two dipper species Cinclus cinclus and Cinclus mexicanus to determine the occurrence of dietary shifts during egg production and to assess consequences for egg contaminant loads. In both species, changes in delta(13)C (C. cinclus) or delta(15)N (C. mexicanus) in female plasma relative to red blood cells indicated a dietary shift during laying that was not observed in males. Eurasian dippers increased prey consumption as breeding approached, shifting from primarily trichopteran insect larvae to ephemeropterans and plecopterans. In American dippers, egg-laying females switched to feeding at a higher trophic level by consuming more fish. Eggs derived from higher trophic level diets contained more mercury (American dipper), polychlorinated biphenyls and some organochlorines, especially DDT metabolites. The results demonstrate how dietary changes during egg laying accompany the demands for egg production with consequences for contaminant deposition in avian eggs.
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Affiliation(s)
- Christy A Morrissey
- Catchment Research Group, School of Biosciences, Cardiff University, Cardiff CF10 3AX, United Kingdom
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97
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Inger R, McDonald RA, Rogowski D, Jackson AL, Parnell A, Jane Preston S, Harrod C, Goodwin C, Griffiths D, Dick JT, Elwood RW, Newton J, Bearhop S. Do non-native invasive fish support elevated lamprey populations? J Appl Ecol 2010. [DOI: 10.1111/j.1365-2664.2009.01761.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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98
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Bauchinger U, Keil J, McKinney RA, Starck JM, McWilliams SR. Exposure to cold but not exercise increases carbon turnover rates in specific tissues of a passerine. J Exp Biol 2010; 213:526-34. [DOI: 10.1242/jeb.037408] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
SUMMARY
Carbon turnover differs between tissues within an animal, but the extent to which ecologically relevant increases in metabolism affect carbon turnover rates is largely unknown. We tested the energy expenditure and protein turnover hypotheses that predict increased carbon turnover, either in association with increased daily energy expenditure, or in concert with tissue-specific increased protein metabolism. We used stable-isotope-labeled diets to quantify the rate of carbon turnover in 12 different tissues for three groups of zebra finches (Taeniopygia guttata): cold-exposed birds kept at ambient temperatures below their thermoneutral zone, exercised birds that were flown for 2 h per day in a flight arena, and control birds that were kept at ambient temperatures within their thermoneutral zone and that were not exercised. We found that increases in metabolism associated with cold-exposure but not exercise produced measurable increases in carbon turnover rate of, on average, 2.4±0.3 days for pectoral muscle, gizzard, pancreas and heart, even though daily energy intake was similar for exercised and cold-exposed birds. This evidence does not support the energy expenditure hypothesis, and we invoke two physiological processes related to protein metabolism that can explain these treatment effects: organ mass increase and tissue-specific increase in activity. Such changes in carbon turnover rate associated with cold temperatures translate into substantial variation in the estimated time window for which resource use is estimated and this has important ecological relevance.
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Affiliation(s)
- U. Bauchinger
- Department Biology II, University of Munich (LMU), Großhaderner Straße 2, 82152 Planegg-Martinsried, Germany
- University of Rhode Island (URI), Kingston, RI 02881, USA
| | - J. Keil
- Department Biology II, University of Munich (LMU), Großhaderner Straße 2, 82152 Planegg-Martinsried, Germany
| | - R. A. McKinney
- US Environmental Protection Agency, Office of Research and Development, National Health and Environmental Effects Research Lab, Atlantic Ecology Division, Narragansett, RI 02882, USA
| | - J. M. Starck
- Department Biology II, University of Munich (LMU), Großhaderner Straße 2, 82152 Planegg-Martinsried, Germany
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99
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Smith JJ, Millar JS, Longstaffe FJ, Boonstra R. The effect of metabolic rate on stable carbon and nitrogen isotope compositions in deer mice, Peromyscus maniculatus. CAN J ZOOL 2010. [DOI: 10.1139/z09-116] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The stable isotopic compositions of nitrogen and carbon in animal tissues reflect diet. However, factors other than diet can also affect these stable isotope ratios, leading to misinterpretations of diet composition. To test the hypothesis that variation in metabolic rate alters the isotopic compositions of tissues, deer mice ( Peromyscus maniculatus (Wagner, 1845)) were kept at three temperatures (thermoneutral (23 °C), cool (5 °C), and cold (–10 °C)) and fed ad libitum. The changes in carbon and nitrogen isotope compositions of liver associated with the thermoneutral versus cool and cold conditions were very small in comparison with those arising from differences in diet. We conclude that temperature-induced variations in metabolic rate are insufficient to produce differences in the stable carbon or nitrogen isotope compositions that could be mistaken for changes in diet.
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Affiliation(s)
- J. J. Smith
- Department of Biology, The University of Western Ontario, 1151 Richmond Street, London, ON N6A 5B7, Canada
- Department of Earth Sciences, The University of Western Ontario, 1151 Richmond Street, London, ON N6A 5B7, Canada
- Centre for the Neurobiology of Stress, Department of Biological Sciences, University of Toronto Scarborough, 1265 Military Trail, Toronto, ON M1C 1A4, Canada
| | - J. S. Millar
- Department of Biology, The University of Western Ontario, 1151 Richmond Street, London, ON N6A 5B7, Canada
- Department of Earth Sciences, The University of Western Ontario, 1151 Richmond Street, London, ON N6A 5B7, Canada
- Centre for the Neurobiology of Stress, Department of Biological Sciences, University of Toronto Scarborough, 1265 Military Trail, Toronto, ON M1C 1A4, Canada
| | - F. J. Longstaffe
- Department of Biology, The University of Western Ontario, 1151 Richmond Street, London, ON N6A 5B7, Canada
- Department of Earth Sciences, The University of Western Ontario, 1151 Richmond Street, London, ON N6A 5B7, Canada
- Centre for the Neurobiology of Stress, Department of Biological Sciences, University of Toronto Scarborough, 1265 Military Trail, Toronto, ON M1C 1A4, Canada
| | - R. Boonstra
- Department of Biology, The University of Western Ontario, 1151 Richmond Street, London, ON N6A 5B7, Canada
- Department of Earth Sciences, The University of Western Ontario, 1151 Richmond Street, London, ON N6A 5B7, Canada
- Centre for the Neurobiology of Stress, Department of Biological Sciences, University of Toronto Scarborough, 1265 Military Trail, Toronto, ON M1C 1A4, Canada
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100
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Beaulieu M, Spée M, Lazin D, Ropert-Coudert Y, le Maho Y, Ancel A, Raclot T. Ecophysiological response of Adélie penguins facing an experimental increase in breeding constraints. J Exp Biol 2010; 213:33-9. [DOI: 10.1242/jeb.035378] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
SUMMARY
Foraging strategies play a key role in breeding effort. Little is known, however, about their connection with hormonal and nutritional states, especially when breeding constraints vary. Here, we experimentally increased foraging costs and thus breeding constraints by handicapping Adélie penguins (Pygoscelis adeliae) with dummy devices representing 3–4% of the penguins' cross-sectional area. We examined food-related stress (via plasma corticosterone concentration) and nutritional state (via metabolite levels). Concurrently, we investigated the use of ecological niches via the isotopic signature of red blood cells indicating the trophic position (δ15N) and the spatial distribution (δ13C) of penguins. Handicapped birds performed ∼70% longer foraging trips and lost ∼60% more body mass than controls and their partners. However, corticosterone levels and the nutritional state were unchanged. The isotopic signature revealed that males and females differed in their foraging behaviour: upper trophic levels contributed more in the males' diet, who foraged in more pelagic areas. Handicapped and partner birds adopted the same strategy at sea: a shift towards higher δ13C values suggested that they foraged in more coastal areas than controls. This change in foraging decisions may optimize feeding time by decreasing travelling time. This may partly compensate for the presumed lower foraging efficiency of handicapped birds and for the energetic debt of their partners who had to fast ∼70% longer on the nest. We propose that this flexible use of ecological niches may allow birds facing increased breeding constraints to avoid chronic stress and to minimize the impact on their body condition.
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Affiliation(s)
- M. Beaulieu
- Institut Pluridisciplinaire Hubert Curien (IPHC), Département Ecologie, Physiologie et Ethologie (DEPE), UMR 7178 CNRS-UdS, 23 rue Becquerel, 67087 Strasbourg, France
| | - M. Spée
- Institut Pluridisciplinaire Hubert Curien (IPHC), Département Ecologie, Physiologie et Ethologie (DEPE), UMR 7178 CNRS-UdS, 23 rue Becquerel, 67087 Strasbourg, France
| | - D. Lazin
- Institut Pluridisciplinaire Hubert Curien (IPHC), Département Ecologie, Physiologie et Ethologie (DEPE), UMR 7178 CNRS-UdS, 23 rue Becquerel, 67087 Strasbourg, France
| | - Y. Ropert-Coudert
- Institut Pluridisciplinaire Hubert Curien (IPHC), Département Ecologie, Physiologie et Ethologie (DEPE), UMR 7178 CNRS-UdS, 23 rue Becquerel, 67087 Strasbourg, France
| | - Y. le Maho
- Institut Pluridisciplinaire Hubert Curien (IPHC), Département Ecologie, Physiologie et Ethologie (DEPE), UMR 7178 CNRS-UdS, 23 rue Becquerel, 67087 Strasbourg, France
| | - A. Ancel
- Institut Pluridisciplinaire Hubert Curien (IPHC), Département Ecologie, Physiologie et Ethologie (DEPE), UMR 7178 CNRS-UdS, 23 rue Becquerel, 67087 Strasbourg, France
| | - T. Raclot
- Institut Pluridisciplinaire Hubert Curien (IPHC), Département Ecologie, Physiologie et Ethologie (DEPE), UMR 7178 CNRS-UdS, 23 rue Becquerel, 67087 Strasbourg, France
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