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Vasconcelos-Teixeira R, Titon SCM, Titon B, Pompêo MLM, Gomes FR, Assis VR. Stress Response, Immunity, and Organ Mass in Toads (Rhinella diptycha) Living in Metal-Contaminated Areas. Biol Trace Elem Res 2022; 200:800-811. [PMID: 33840055 DOI: 10.1007/s12011-021-02699-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Accepted: 03/28/2021] [Indexed: 12/20/2022]
Abstract
Mining is one of the main activities that drive the economy of Brazil. Mining activity is associated with risk of contamination of environment and local fauna by metals. Amphibians have a life cycle that requires a transition between aquatic and terrestrial environments, increasing their vulnerability to metal contamination in the water and substrate. Metals are ubiquitous, with high bioaccumulative and biomagnifying potential, and may lead to immune and endocrine disruption. In this study, we analyzed two different components of the innate immune response, bacterial killing ability (BKA) and phytohemagglutinin edema (PHA), and two stress biomarkers, corticosterone plasma levels (CORT) and the neutrophil to lymphocyte ratio (N:L), of toads (Rhinella diptycha) living in places contaminated by metals. Blood samples were collected pre- and post-restraint (1h), followed by an immune challenge with PHA and tissue collection (liver, spleen, and kidneys). Toads liver metal bioaccumulation did not correlate with the immune response or stress biomarkers. Post-restraint, animals had increased CORT and reduced BKA, independently of the collection site, and these variables were not correlated with liver metal bioaccumulation. Interestingly, toads with the larger spleen (immune organ) showed increased N:L post-restraint and greater edema after the PHA challenge. Our results indicate that toads living in metal-contaminated environments responded to acute stressor, activating the hypothalamic-pituitary-interrenal axis and the immune response. Keep tracking the physiological variables of these animals and the presence of metals in the environment and tissues should provide valuable health status indicators for the population, which is vital for proposing amphibian conservation strategies in these areas.
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Affiliation(s)
- Ronyelle Vasconcelos-Teixeira
- Laboratory of Behavior and Evolutionary Physiology, lab. 206, Department of Physiology, Institute of Biosciences, University of São Paulo, São Paulo, Brazil.
| | - Stefanny C M Titon
- Laboratory of Behavior and Evolutionary Physiology, lab. 206, Department of Physiology, Institute of Biosciences, University of São Paulo, São Paulo, Brazil
- Laboratory of Disease & Drug-Associated Receptors Knowledge, Department of Physiology, Institute of Biosciences, University of São Paulo, São Paulo, Brazil
| | - Braz Titon
- Laboratory of Ecophysiology and Evolutionary Physiology, Department of Physiology, Institute of Biosciences, University of São Paulo, São Paulo, Brazil
| | - Marcelo L M Pompêo
- Laboratory of Limnology, Department of Ecology, Institute of Biosciences, University of São Paulo, São Paulo, Brazil
| | - Fernando R Gomes
- Laboratory of Behavior and Evolutionary Physiology, lab. 206, Department of Physiology, Institute of Biosciences, University of São Paulo, São Paulo, Brazil
| | - Vania R Assis
- Laboratory of Behavior and Evolutionary Physiology, lab. 206, Department of Physiology, Institute of Biosciences, University of São Paulo, São Paulo, Brazil
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Finger JW, Hamilton MT, Kelley MD, Stacy NI, Glenn TC, Tuberville TD. Examining the Effects of Chronic Selenium Exposure on Traditionally Used Stress Parameters in Juvenile American Alligators (Alligator mississippiensis). Arch Environ Contam Toxicol 2019; 77:14-21. [PMID: 30976886 DOI: 10.1007/s00244-019-00626-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2018] [Accepted: 04/01/2019] [Indexed: 06/09/2023]
Abstract
Environmental contaminants, such as the trace element selenium (Se), are a continuing concern to species worldwide due to their potential pathophysiological effects, including their influence on the stress response mediated through glucocorticoids (GCs; stress hormones). Environmental concentrations of Se are increasing due to anthropogenic activities, including the incomplete combustion of coal and subsequent disposal of coal combustion wastes. However, most studies examining how Se affects GCs have been focused on lower trophic organisms. The objectives of this study were to investigate the effects of long-term Se exposure on traditionally used stress parameters and to identify which of these parameters best indicate Se accumulation in liver and kidney of the American alligator (Alligator mississippiensis), a top trophic carnivore found in the southeastern United States and known to inhabit Se-containing areas. Alligators were divided into three dietary treatments and fed prey spiked with 1000 or 2000 ppm of selenomethionine (SeMet) or deionized water (control treatment) for 7 weeks. Following the 7-week treatment protocol, blood and tissue samples were obtained to measure plasma corticosterone (CORT; the main crocodilian GC), tail scute CORT, the ratio of peripheral blood heterophils (H) to lymphocytes (L) as H/L ratio, and body condition. To evaluate which parameter best indicated Se accumulation in the liver and kidney, principal component and discriminant analyses were performed. The only parameter significantly correlated with liver and kidney Se concentrations was scute CORT. Our results suggest that measurement of CORT in tail scutes compared with plasma CORT, H/L ratios, and body condition is the best indicator of Se-exposure and accumulation in crocodilians.
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Affiliation(s)
- John W Finger
- Department of Biological Sciences, Auburn University, Auburn, AL, 36849, USA.
- Department of Environmental Health Science, University of Georgia, Athens, GA, 30602, USA.
- Savannah River Ecology Laboratory, University of Georgia, PO Drawer E, Aiken, SC, 29802, USA.
| | - Matthew T Hamilton
- Savannah River Ecology Laboratory, University of Georgia, PO Drawer E, Aiken, SC, 29802, USA
| | - Meghan D Kelley
- Department of Biological Sciences, Auburn University, Auburn, AL, 36849, USA
| | - Nicole I Stacy
- Department of Comparative, Diagnostic, and Population Medicine, College of Veterinary Medicine, University of Florida, Gainesville, FL, 32610, USA
| | - Travis C Glenn
- Department of Environmental Health Science, University of Georgia, Athens, GA, 30602, USA
| | - Tracey D Tuberville
- Savannah River Ecology Laboratory, University of Georgia, PO Drawer E, Aiken, SC, 29802, USA
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de Jong ME, Scheiber IBR, van den Brink NW, Braun A, Matson KD, Komdeur J, Loonen MJJE. Indices of stress and immune function in Arctic barnacle goslings (Branta leucopsis) were impacted by social isolation but not a contaminated grazing environment. Sci Total Environ 2017; 601-602:132-141. [PMID: 28550726 DOI: 10.1016/j.scitotenv.2017.05.183] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2017] [Revised: 05/08/2017] [Accepted: 05/20/2017] [Indexed: 06/07/2023]
Abstract
In many areas around the Arctic remains and spoil heaps of old mines can be found, which have been abandoned after their heydays. Runoff from tailings of these abandoned mines can directly contaminate the local environment with elevated concentrations of trace metals. Few studies have investigated the possible negative effects of contaminants on Arctic terrestrial animals that use these areas. Trace metals can accumulate in animals and this accumulation has been linked to negative effects on fitness. Both, the hypothalamus-pituitary-adrenal (HPA) axis and/or the immune system have been named as possible underlying causes for these observations. Free-living animals are often exposed to multiple stressors simultaneously, however, and this is often not considered in studies on the effects of contaminants on animal physiology. Here, we performed a study on Spitsbergen (Svalbard) taking both potential effects of trace metal contamination and social stress into account. We investigated experimentally effects of exposure to contaminants from a historic coal mine area on plasma corticosterone levels and on four innate immune parameters (haemolysis, haemagglutination, haptoglobin-like activity and nitric oxide) before and after social isolation in human-raised barnacle goslings (Branta leucopsis). Baseline corticosterone and immune parameters were not affected by mine-exposure. After social isolation, mine goslings tended to show decreased haemagglutination in comparison with control goslings, but we detected no difference in the other measures. Social isolation increased corticosterone and decreased haptoglobin-like activity in all goslings. Immunology and corticosterone levels of barnacle goslings thus seem unaffected, at least on the short term, by Arctic coal mining contamination.
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Affiliation(s)
- Margje E de Jong
- Arctic Centre, University of Groningen, Aweg 30, 9718 CW Groningen, The Netherlands.
| | - Isabella B R Scheiber
- Behavioural and Physiological Ecology, The University of Groningen, Groningen Institute for Evolutionary Life Sciences (GELIFES), Nijenborgh 7, 9747 AG Groningen, The Netherlands
| | - Nico W van den Brink
- Department of Toxicology, Wageningen University, Stippeneng 4, 6708 WE Wageningen, The Netherlands.
| | - Anna Braun
- Behavioural and Physiological Ecology, The University of Groningen, Groningen Institute for Evolutionary Life Sciences (GELIFES), Nijenborgh 7, 9747 AG Groningen, The Netherlands
| | - Kevin D Matson
- Resource Ecology Group, Wageningen University, Droevendaalsesteeg 3a, 6708 PB Wageningen, The Netherlands.
| | - Jan Komdeur
- Behavioural and Physiological Ecology, The University of Groningen, Groningen Institute for Evolutionary Life Sciences (GELIFES), Nijenborgh 7, 9747 AG Groningen, The Netherlands.
| | - Maarten J J E Loonen
- Arctic Centre, University of Groningen, Aweg 30, 9718 CW Groningen, The Netherlands.
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Haskins DL, Hamilton MT, Stacy NI, Finger JW, Tuberville TD. Effects of selenium exposure on the hematology, innate immunity, and metabolic rate of yellow-bellied sliders (Trachemys scripta scripta). Ecotoxicology 2017; 26:1134-1146. [PMID: 28780652 DOI: 10.1007/s10646-017-1839-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 07/19/2017] [Indexed: 05/06/2023]
Abstract
Selenium (Se) is a naturally occurring essential element that can be toxic to vertebrates at high concentrations. Despite studies that have documented that wild reptile species can accumulate copious amounts of Se, little is known regarding specific toxicologic effects of Se. In this study, 70 juvenile yellow-bellied sliders (Trachemys scripta scripta) were exposed to one of three seleno-L-methionine (SetMet) treatments (control, n = 24; 15 mg/kg, n = 23; and 30 mg/kg, n = 23) via weekly oral gavage for 5 weeks. At the conclusion of the experiment, kidney, liver, muscle, and blood samples were collected for quantitative Se analysis. Turtles in the SeMet treatment groups accumulated significantly higher amounts of Se in all tissue types relative to controls (all p < 0.001). Turtles in the 30 mg/kg SeMet group also accumulated significantly higher amounts of Se compared to the 15 mg/kg group (all p < 0.001). Although toxicity thresholds for reptiles have not been established, Se concentrations in liver tissue from both SeMet treatment groups exceeded reported avian toxicity thresholds for liver tissue. Neither oxygen consumption nor innate bactericidal capacity were impacted by SeMet exposure. However, turtles in the 30 mg/kg SeMet group exhibited anemia, which has been reported in other vertebrates exposed to Se. Furthermore, juvenile T. s. scripta in the 30 mg/kg SeMet group experienced 17% mortality compared to 0% in the 15 mg/kg treatment and control groups. To our knowledge, this study is the first to report dose-dependent Se-associated anemia and mortality in a chelonian species.
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Affiliation(s)
- David L Haskins
- Savannah River Ecology Laboratory, University of Georgia, Drawer E, Aiken, SC, 29802, USA.
- D.B. Warnell School of Forestry and Natural Resources, University of Georgia, Athens, GA, 30602, USA.
| | - Matthew T Hamilton
- Savannah River Ecology Laboratory, University of Georgia, Drawer E, Aiken, SC, 29802, USA
- D.B. Warnell School of Forestry and Natural Resources, University of Georgia, Athens, GA, 30602, USA
| | - Nicole I Stacy
- Large Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, Gainesville, FL, 32610, USA
| | - John W Finger
- Savannah River Ecology Laboratory, University of Georgia, Drawer E, Aiken, SC, 29802, USA
- Department of Biological Sciences, Auburn University, Auburn, AL, 36849, USA
| | - Tracey D Tuberville
- Savannah River Ecology Laboratory, University of Georgia, Drawer E, Aiken, SC, 29802, USA
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Haskins DL, Hamilton MT, Jones AL, Finger JW, Bringolf RB, Tuberville TD. Accumulation of coal combustion residues and their immunological effects in the yellow-bellied slider (Trachemys scripta scripta). Environ Pollut 2017; 224:810-819. [PMID: 28284546 DOI: 10.1016/j.envpol.2017.01.048] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2016] [Revised: 01/03/2017] [Accepted: 01/17/2017] [Indexed: 06/06/2023]
Abstract
Anthropogenic activities such as industrial processes often produce copious amounts of contaminants that have the potential to negatively impact growth, survival, and reproduction of exposed wildlife. Coal combustion residues (CCRs) represent a major source of pollutants globally, resulting in the release of potentially harmful trace elements such as arsenic (As), cadmium (Cd), and selenium (Se) into the environment. In the United States, CCRs are typically stored in aquatic settling basins that may become attractive nuisances to wildlife. Trace element contaminants, such as CCRs, may pose a threat to biota yet little is known about their sublethal effects on reptiles. To assess the effects of CCR exposure in turtles, we sampled 81 yellow-bellied sliders (Trachemys scripta scripta) in 2014-2015 from CCR-contaminated and uncontaminated reference wetlands located on the Savannah River Site (Aiken, SC, USA). Specific aims were to (1) compare the accumulation of trace elements in T. s. scripta claw and blood samples between reference and CCR-contaminated site types, (2) evaluate potential immunological effects of CCRs via bacterial killing assays and phytohaemagglutinin (PHA) assays, and (3) quantify differences in hemogregarine parasite loads between site types. Claw As, Cd, copper (Cu), and Se (all p ≤ 0.001) and blood As, Cu, Se, and strontium (Sr; p ≤ 0.015) were significantly elevated in turtles from CCR-contaminated wetlands compared to turtles from reference wetlands. Turtles from reference wetlands exhibited lower bacterial killing (p = 0.015) abilities than individuals from contaminated sites but neither PHA responses (p = 0.566) nor parasite loads (p = 0.980) differed by site type. Despite relatively high CCR body burdens, sliders did not exhibit apparent impairment of immunological response or parasite load. In addition, the high correlation between claw and blood concentrations within individuals suggests that nonlethal tissue sampling may be useful for monitoring CCR exposure in turtles.
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Affiliation(s)
- David L Haskins
- Savannah River Ecology Lab, University of Georgia, Drawer E, Aiken, SC 29802, USA; D.B. Warnell School of Forestry and Natural Resources, University of Georgia, Athens, GA 30602, USA.
| | - Matthew T Hamilton
- Savannah River Ecology Lab, University of Georgia, Drawer E, Aiken, SC 29802, USA; D.B. Warnell School of Forestry and Natural Resources, University of Georgia, Athens, GA 30602, USA
| | - Amanda L Jones
- Savannah River Ecology Lab, University of Georgia, Drawer E, Aiken, SC 29802, USA
| | - John W Finger
- Savannah River Ecology Lab, University of Georgia, Drawer E, Aiken, SC 29802, USA; Dept. of Biological Sciences, Auburn University, Auburn, AL 36849, USA
| | - Robert B Bringolf
- D.B. Warnell School of Forestry and Natural Resources, University of Georgia, Athens, GA 30602, USA
| | - Tracey D Tuberville
- Savannah River Ecology Lab, University of Georgia, Drawer E, Aiken, SC 29802, USA; D.B. Warnell School of Forestry and Natural Resources, University of Georgia, Athens, GA 30602, USA
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Meillère A, Brischoux F, Bustamante P, Michaud B, Parenteau C, Marciau C, Angelier F. Corticosterone levels in relation to trace element contamination along an urbanization gradient in the common blackbird (Turdus merula). Sci Total Environ 2016; 566-567:93-101. [PMID: 27213675 DOI: 10.1016/j.scitotenv.2016.05.014] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Revised: 05/01/2016] [Accepted: 05/02/2016] [Indexed: 06/05/2023]
Abstract
In a rapidly urbanizing world, trace element pollution may represent a threat to human health and wildlife, and it is therefore crucial to assess both exposition levels and associated effects of trace element contamination on urban vertebrates. In this study, we investigated the impact of urbanization on trace element contamination and stress physiology in a wild bird species, the common blackbird (Turdus merula), along an urbanization gradient (from rural to moderately urbanized areas). Specifically, we described the contamination levels of blackbirds by 4 non-essential (Ag, Cd, Hg, Pb) and 9 essential trace elements (As, Co, Cr, Cu, Fe, Mn, Ni, Se, Zn), and explored the putative disrupting effects of the non-essential element contamination on corticosterone levels (a hormonal proxy for environmental challenges). We found that non-essential trace element burden (Cd and Pb specifically) increased with increasing urbanization, indicating a significant trace element contamination even in medium sized cities and suburban areas. Interestingly, the increased feather non-essential trace element concentrations were also associated with elevated feather corticosterone levels, suggesting that urbanization probably constrains birds and that this effect may be mediated by trace element contamination. Future experimental studies are now required to disentangle the influence of multiple urban-related constraints on corticosterone levels and to specifically test the influence of each of these trace elements on corticosterone secretion.
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Affiliation(s)
- Alizée Meillère
- Centre d'Études Biologiques de Chizé (CEBC), UMR 7372 CNRS-Université de La Rochelle, F-79360 Villiers-en-Bois, France.
| | - François Brischoux
- Centre d'Études Biologiques de Chizé (CEBC), UMR 7372 CNRS-Université de La Rochelle, F-79360 Villiers-en-Bois, France
| | - Paco Bustamante
- Littoral Environnement et Sociétés (LIENSs), UMR 7266 CNRS-Université de La Rochelle, F-17000 La Rochelle, France
| | - Bruno Michaud
- Centre d'Études Biologiques de Chizé (CEBC), UMR 7372 CNRS-Université de La Rochelle, F-79360 Villiers-en-Bois, France
| | - Charline Parenteau
- Centre d'Études Biologiques de Chizé (CEBC), UMR 7372 CNRS-Université de La Rochelle, F-79360 Villiers-en-Bois, France
| | - Coline Marciau
- Centre d'Études Biologiques de Chizé (CEBC), UMR 7372 CNRS-Université de La Rochelle, F-79360 Villiers-en-Bois, France
| | - Frédéric Angelier
- Centre d'Études Biologiques de Chizé (CEBC), UMR 7372 CNRS-Université de La Rochelle, F-79360 Villiers-en-Bois, France
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Pracheil BM, Marshall Adams S, Bevelhimer MS, Fortner AM, Greeley MS, Murphy CA, Mathews TJ, Peterson MJ. Relating fish health and reproductive metrics to contaminant bioaccumulation at the Tennessee Valley Authority Kingston coal ash spill site. Ecotoxicology 2016; 25:1136-1149. [PMID: 27154845 DOI: 10.1007/s10646-016-1668-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 04/27/2016] [Indexed: 06/05/2023]
Abstract
A 4.1 million m(3) coal ash release into the Emory and Clinch rivers in December 2008 at the Tennessee Valley Authority's Kingston Fossil Plant in east Tennessee, USA, prompted a long-term, large-scale biological monitoring effort to determine if there are chronic effects of this spill on resident biota. Because of the magnitude of the ash spill and the potential for exposure to coal ash-associated contaminants [e.g., selenium (Se), arsenic (As), and mercury (Hg)] which are bioaccumulative and may present human and ecological risks, an integrative, bioindicator approach was used. Three species of fish were monitored-bluegill (Lepomis macrochirus), redear sunfish (L. microlophus), and largemouth bass (Micropterus salmoides)-at ash-affected and reference sites annually for 5 years following the spill. On the same individual fish, contaminant burdens were measured in various tissues, blood chemistry parameters as metrics of fish health, and various condition and reproduction indices. A multivariate statistical approach was then used to evaluate relationships between contaminant bioaccumulation and fish metrics to assess the chronic, sub-lethal effects of exposure to the complex mixture of coal ash-associated contaminants at and around the ash spill site. This study suggests that while fish tissue concentrations of some ash-associated contaminants are elevated at the spill site, there was no consistent evidence of compromised fish health linked with the spill. Further, although relationships between elevated fillet burdens of ash-associated contaminants and some fish metrics were found, these relationships were not indicative of exposure to coal ash or spill sites. The present study adds to the weight of evidence from prior studies suggesting that fish populations have not incurred significant biological effects from spilled ash at this site: findings that are relevant to the current national discussions on the safe disposal of coal ash waste.
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Affiliation(s)
- Brenda M Pracheil
- Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA.
| | - S Marshall Adams
- Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Mark S Bevelhimer
- Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Allison M Fortner
- Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Mark S Greeley
- Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Cheryl A Murphy
- Department of Fisheries and Wildlife, Lyman Briggs College, Michigan State University, East Lansing, MI, 48824, USA
| | - Teresa J Mathews
- Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Mark J Peterson
- Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
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Beck ML, Hopkins WA, Hawley DM. Relationships among plumage coloration, blood selenium concentrations, and immune responses of adult and nestling tree swallows. J Exp Biol 2015; 218:3415-24. [DOI: 10.1242/jeb.123794] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2015] [Accepted: 08/26/2015] [Indexed: 12/18/2022]
Abstract
In a number of taxa, males and females both display ornaments that may be associated with individual quality and could be reliable signals to potential mates or rivals. We examined the iridescent blue/green back and white breast of adult tree swallows (Tachycineta bicolor) to determine if plumage reflectance was related to adult or offspring immune responses. We simultaneously addressed the influence of blood selenium levels and the interaction between blood selenium and plumage coloration on adult and nestling immunity. Selenium is a well-known antioxidant necessary for mounting a robust immune response but its importance in wild birds remains poorly understood. In females, the brightness of white breast coloration was positively associated with bactericidal capacity, but there was no association with blood selenium. In contrast, male bactericidal capacity was associated with an interactive effect between dorsal plumage coloration and blood selenium concentrations. Males with bluer hues and greater blue chroma showed increased bactericidal capacity as blood selenium concentrations increased, while bactericidal capacity declined in greener males at higher blood selenium concentrations. In nestlings, bactericidal capacity was positively associated with nestling blood selenium concentrations and white brightness of both social parents. These results suggest that white plumage reflectance is indicative of quality in tree swallows and that greater attention should be paid to the reflectance of large white plumage patches. Additionally, the role of micronutrients, such as selenium, in mediating relationships between physiology and signals of quality, should be explored further.
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Affiliation(s)
- Michelle L. Beck
- 106 Cheatham Hall, Department of Fish and Wildlife Conservation, Virginia Tech, Blacksburg, VA 24061-0321, USA
| | - William A. Hopkins
- 106 Cheatham Hall, Department of Fish and Wildlife Conservation, Virginia Tech, Blacksburg, VA 24061-0321, USA
| | - Dana M. Hawley
- 2125 Derring Hall, Department of Biology, Virginia Tech, Blacksburg, VA 24061-0406, USA
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