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The Reptile Relocation Industry in Australia: Perspectives from Operators. DIVERSITY 2023. [DOI: 10.3390/d15030343] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/05/2023]
Abstract
Thousands of reptiles are relocated annually in Australia, yet there has been relatively little research aimed at understanding how the reptile relocation industry operates. An online questionnaire was distributed to anyone who had relocated a reptile between April 2019 and April 2020, including wildlife relocators, wildlife rehabilitators and the general public. The questionnaire explored demographics, decision-making and concerns about how the industry functions, through 24 questions and two opportunities to provide open-ended comments. We received 125 responses and 123 comments from operators in all Australian states and territories. Beliefs about appropriate times and places for reptile releases were not reflected in practice for the majority of operators. Confidence about reptiles remaining at recipient sites was low regardless of how many years’ experience an operator had. Escaped captive native reptiles were encountered by most operators, and a quarter of operators were called out to exotic non-native snakes. Operators across all levels of experience indicated a need for changes within the industry, including increased training and professionalism, and more scientific studies on the outcomes of relocations to address concerns about the impacts that the industry has on the wildlife that it is trying to protect.
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Padrón DF, Mebert K, Pareja-Mejía D, Bauer A, Fernandes Vasconcelos LD, Correia D, Fernandez Giné GA, Solé M. Living in a mosaic of Brazilian Atlantic Forest and plantations: spatial ecology of five bushmaster Lachesis muta (Viperidae Crotalinae). ETHOL ECOL EVOL 2022. [DOI: 10.1080/03949370.2022.2123860] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/10/2022]
Affiliation(s)
- Diego F. Padrón
- Department of Biological Sciences, Universidade Estadual de Santa Cruz, Rodovia Jorge Amado, km 16, 45662-900 Salobrinho, Ilhéus, Brazil
| | - Konrad Mebert
- Department of Biological Sciences, Universidade Estadual de Santa Cruz, Rodovia Jorge Amado, km 16, 45662-900 Salobrinho, Ilhéus, Brazil
- IDECC, Institute of Development, Ecology, Conservation and Cooperation, Via G. Tomasi di Lampedusa 33, Rome 00144, Italy
| | - Daniela Pareja-Mejía
- Department of Biological Sciences, Universidade Estadual de Santa Cruz, Rodovia Jorge Amado, km 16, 45662-900 Salobrinho, Ilhéus, Brazil
| | - Arthur Bauer
- Department of Biological Sciences, Universidade Estadual de Santa Cruz, Rodovia Jorge Amado, km 16, 45662-900 Salobrinho, Ilhéus, Brazil
| | - Laise D. Fernandes Vasconcelos
- Department of Agricultural and Environmental Sciences, Universidade Estadual de Santa Cruz, Rodovia Jorge Amado, km 16, 45662-900 Salobrinho, Ilhéus, Brazil
| | - Diego Correia
- Department of Agricultural and Environmental Sciences, Universidade Estadual de Santa Cruz, Rodovia Jorge Amado, km 16, 45662-900 Salobrinho, Ilhéus, Brazil
| | - Gastón A. Fernandez Giné
- Department of Biological Sciences, Universidade Estadual de Santa Cruz, Rodovia Jorge Amado, km 16, 45662-900 Salobrinho, Ilhéus, Brazil
| | - Mirco Solé
- Department of Biological Sciences, Universidade Estadual de Santa Cruz, Rodovia Jorge Amado, km 16, 45662-900 Salobrinho, Ilhéus, Brazil
- Herpetology Section, Zoologisches Forschungsmuseum Alexander Koenig, Adenauerallee 160, Bonn 53113, Germany
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3
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McCallie KL, Klukowski M. Corticosterone in three species of free-ranging watersnakes: Testing for reproductive suppression and an association with body condition. Comp Biochem Physiol A Mol Integr Physiol 2022; 269:111214. [PMID: 35427765 DOI: 10.1016/j.cbpa.2022.111214] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2022] [Revised: 04/07/2022] [Accepted: 04/08/2022] [Indexed: 10/18/2022]
Abstract
The potentially suppressive effects of the hypothalamic-pituitary-adrenal (HPA) axis on the hypothalamic-pituitary-gonadal (HPG) axis revolve around the central role that glucocorticoids play in mobilizing energy. As an individual's energy balance becomes negative, the HPA axis helps mobilize energy and shifts energy expenditure away from reproduction toward maintenance and survival. While there is evidence in support of these relationships, substantial species variability exists. Studies in a greater diversity of species promise to enhance our understanding of the interactions between these axes. In this field study we tested for relationships among body condition, corticosterone, and sex steroid concentrations in three species of closely related watersnakes: the common watersnake (Nerodia sipedon), the diamondback watersnake (Nerodia rhombifer) and the queen snake (Regina septemvittata). Snakes were sampled before and after a 30 min acute confinement stressor and body condition was estimated using the scaled mass index. All three species exhibited robust elevations of corticosterone in response to acute stress, but only plasma progesterone was elevated by the acute stressor in queen snakes. There was no evidence for a suppression of sex steroid concentrations in any of the species. Body condition was negatively associated with baseline corticosterone in queen snakes and with post-stressor corticosterone in both queen and common watersnakes. Overall we found fairly strong support for the proposed link between corticosterone and energetics in two of the three watersnake species, but no support for the hypothesis that acute stressors are associated with reproductive suppression, at least as measured by steroid concentrations.
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Affiliation(s)
- K Louise McCallie
- Department of Biology, Middle Tennessee State University, Murfreesboro, TN 37132, USA; Natural Resources Institute, Texas A&M University, College Station, TX 77843, USA
| | - Matthew Klukowski
- Department of Biology, Middle Tennessee State University, Murfreesboro, TN 37132, USA.
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Kelley AG, Welch SM, Holloway J, Dillman JW, Atkinson A, Waldron JL. Effectiveness of long‐distance translocation of eastern diamondback rattlesnakes. WILDLIFE SOC B 2022. [DOI: 10.1002/wsb.1291] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
| | - Shane M. Welch
- Marshall University 1 John Marshall Drive Huntington WV 25703 USA
| | - John Holloway
- Natural Resources and Environmental Affairs Office Marine Corps Recruit Depot Parris Island SC 29905 USA
| | - James W. Dillman
- South Carolina Department of Natural Resources 1000 Assembly Street Columbia SC 29201 USA
| | - April Atkinson
- South Carolina Department of Natural Resources 1282 Webb Avenue Garnett SC 29922 USA
| | - Jayme L. Waldron
- Marshall University 1 John Marshall Drive Huntington WV 25703 USA
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Feuka AB, Nafus MG, Yackel Adams AA, Bailey LL, Hooten MB. Individual heterogeneity influences the effects of translocation on urban dispersal of an invasive reptile. MOVEMENT ECOLOGY 2022; 10:2. [PMID: 35033211 PMCID: PMC8761355 DOI: 10.1186/s40462-022-00300-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Accepted: 01/03/2022] [Indexed: 05/28/2023]
Abstract
BACKGROUND Invasive reptiles pose a serious threat to global biodiversity, but early detection of individuals in an incipient population is often hindered by their cryptic nature, sporadic movements, and variation among individuals. Little is known about the mechanisms that affect the movement of these species, which limits our understanding of their dispersal. Our aim was to determine whether translocation or small-scale landscape features affect movement patterns of brown treesnakes (Boiga irregularis), a destructive invasive predator on the island of Guam. METHODS We conducted a field experiment to compare the movements of resident (control) snakes to those of snakes translocated from forests and urban areas into new urban habitats. We developed a Bayesian hierarchical model to analyze snake movement mechanisms and account for attributes unique to invasive reptiles by incorporating multiple behavioral states and individual heterogeneity in movement parameters. RESULTS We did not observe strong differences in mechanistic movement parameters (turning angle or step length) among experimental treatment groups. We found some evidence that translocated snakes from both forests and urban areas made longer movements than resident snakes, but variation among individuals within treatment groups weakened this effect. Snakes translocated from forests moved more frequently from pavement than those translocated from urban areas. Snakes translocated from urban areas moved less frequently from buildings than resident snakes. Resident snakes had high individual heterogeneity in movement probability. CONCLUSIONS Our approach to modeling movement improved our understanding of invasive reptile dispersal by allowing us to examine the mechanisms that influence their movement. We also demonstrated the importance of accounting for individual heterogeneity in population-level analyses, especially when management goals involve eradication of an invasive species.
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Affiliation(s)
- Abigail B. Feuka
- U.S. Department of Agriculture Animal and Plant Health Inspection Service, National Wildlife Research Center, 4101 Laporte Ave, Fort Collins, CO 80521-2154 USA
- Colorado State University, Department of Fish, Wildlife, and Conservation Biology and Graduate Degree Program in Ecology, Fort Collins, CO 80523-1474 USA
| | - Melia G. Nafus
- U.S. Geological Survey, Fort Collins Science Center, 2150 Centre Avenue, Building C, Fort Collins, CO 80526-8118 USA
| | - Amy A. Yackel Adams
- U.S. Geological Survey, Fort Collins Science Center, 2150 Centre Avenue, Building C, Fort Collins, CO 80526-8118 USA
| | - Larissa L. Bailey
- Colorado State University, Department of Fish, Wildlife, and Conservation Biology and Graduate Degree Program in Ecology, Fort Collins, CO 80523-1474 USA
| | - Mevin B. Hooten
- The University of Texas at Austin, Department of Statistics and Data Sciences, Welch 5.216, 105 E 24th St D9800, Austin, TX 78705-1576 USA
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Malhotra A, Wüster W, Owens JB, Hodges CW, Jesudasan A, Ch G, Kartik A, Christopher P, Louies J, Naik H, Santra V, Kuttalam SR, Attre S, Sasa M, Bravo-Vega C, Murray KA. Promoting co-existence between humans and venomous snakes through increasing the herpetological knowledge base. Toxicon X 2021; 12:100081. [PMID: 34522881 PMCID: PMC8426276 DOI: 10.1016/j.toxcx.2021.100081] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Revised: 07/28/2021] [Accepted: 08/04/2021] [Indexed: 11/23/2022] Open
Abstract
Snakebite incidence at least partly depends on the biology of the snakes involved. However, studies of snake biology have been largely neglected in favour of anthropic factors, with the exception of taxonomy, which has been recognised for some decades to affect the design of antivenoms. Despite this, within-species venom variation and the unpredictability of the correlation with antivenom cross-reactivity has continued to be problematic. Meanwhile, other aspects of snake biology, including behaviour, spatial ecology and activity patterns, distribution, and population demography, which can contribute to snakebite mitigation and prevention, remain underfunded and understudied. Here, we review the literature relevant to these aspects of snakebite and illustrate how demographic, spatial, and behavioural studies can improve our understanding of why snakebites occur and provide evidence for prevention strategies. We identify the large gaps that remain to be filled and urge that, in the future, data and relevant metadata be shared openly via public data repositories so that studies can be properly replicated and data used in future meta-analyses.
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Affiliation(s)
- Anita Malhotra
- Molecular Ecology and Evolution @ Bangor, School of Natural Sciences, Bangor University, 3rd floor ECW, Deiniol Road, Bangor, LL57 2UW, UK
| | - Wolfgang Wüster
- Molecular Ecology and Evolution @ Bangor, School of Natural Sciences, Bangor University, 3rd floor ECW, Deiniol Road, Bangor, LL57 2UW, UK
| | - John Benjamin Owens
- Molecular Ecology and Evolution @ Bangor, School of Natural Sciences, Bangor University, 3rd floor ECW, Deiniol Road, Bangor, LL57 2UW, UK
- Captive & Field Herpetology Ltd, Wales, 13 Hirfron, Holyhead, Llaingoch, Anglesey, LL65 1YU, UK
| | - Cameron Wesley Hodges
- School of Biology, Institute of Science, Suranaree University of Technology, Muang Nakhon Ratchasima, Thailand
| | - Allwin Jesudasan
- Madras Crocodile Bank Trust, Centre for Herpetology, Post bag No.4, Vadanamelli Village, East Coast Road, Mamallapuram, 603 104, Tamil Nadu, India
| | - Gnaneswar Ch
- Madras Crocodile Bank Trust, Centre for Herpetology, Post bag No.4, Vadanamelli Village, East Coast Road, Mamallapuram, 603 104, Tamil Nadu, India
| | - Ajay Kartik
- Madras Crocodile Bank Trust, Centre for Herpetology, Post bag No.4, Vadanamelli Village, East Coast Road, Mamallapuram, 603 104, Tamil Nadu, India
| | - Peter Christopher
- Madras Crocodile Bank Trust, Centre for Herpetology, Post bag No.4, Vadanamelli Village, East Coast Road, Mamallapuram, 603 104, Tamil Nadu, India
| | | | - Hiral Naik
- School of Animal, Plant and Environmental Sciences, University of the Witwatersrand, Johannesburg. P. O. Wits, 2050, Gauteng, South Africa
- Save the Snakes, R527, Blyderus, Hoedspruit, 1380, South Africa
| | - Vishal Santra
- Captive & Field Herpetology Ltd, Wales, 13 Hirfron, Holyhead, Llaingoch, Anglesey, LL65 1YU, UK
- Society for Nature Conservation, Research and Community Engagement (CONCERN), Nalikul, Hooghly, West Bengal 712407, India
| | - Sourish Rajagopalan Kuttalam
- Society for Nature Conservation, Research and Community Engagement (CONCERN), Nalikul, Hooghly, West Bengal 712407, India
| | - Shaleen Attre
- Durrell Institute of Conservation and Ecology, School of Anthropology and Conservation, Marlowe Building, University of Kent, Canterbury, Kent, CT2 7NR, UK
| | - Mahmood Sasa
- Instituto Clodomiro Picado, Universidad de Costa Rica, San José, Costa Rica
- Escuela de Biología, Universidad de Costa Rica, San José, Costa Rica
| | - Carlos Bravo-Vega
- Research Group in Mathematical and Computational Biology (BIOMAC), Department of Biomedical Engineering, University of the Andes, Bogotá, Colombia
| | - Kris A. Murray
- MRC Centre for Global Infectious Disease Analysis, Imperial College London, UK
- MRC Unit The Gambia at London School of Hygiene and Tropical Medicine, Atlantic Boulevard, Fajara, Gambia
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Argaez V, Pruett JA, Seddon RJ, Solano-Zavaleta I, Hews DK, Zúñiga-Vega JJ. Steroid hormones, ectoparasites, and color: Sex, species, and seasonal differences in Sceloporus lizards. Gen Comp Endocrinol 2021; 304:113717. [PMID: 33476662 DOI: 10.1016/j.ygcen.2021.113717] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Revised: 11/06/2020] [Accepted: 01/14/2021] [Indexed: 12/20/2022]
Abstract
Testosterone, in addition to promoting the expression of sexual ornaments can negatively affect immune function, leaving individuals more susceptible to parasites (immunocompetence handicap hypothesis). Immunosuppressive effects of testosterone also can occur indirectly, through increased glucocorticoid hormones (corticosterone, cortisol). Therefore, the expression of sexual ornaments and the ability to respond to parasites and diseases may be influenced by the interaction between testosterone and corticosterone. In this study we examined correlations of both testosterone and corticosterone with ectoparasite load and with expression of colorful sexual ornaments (patches on belly and throat) in three species of Sceloporus lizards (S. grammicus, S. megalepidurus, S. torquatus). In addition, we evaluated contributions of sex, body condition, and reproductive season. We expected that individuals with higher testosterone and lower corticosterone levels would have more colorful ornaments than individuals with higher corticosterone levels. In addition, if testosterone has negative effects on immune function but only at higher corticosterone levels, individuals with higher levels of testosterone and corticosterone should have higher ectoparasite loads. Contrary to these expectations, we did not detect an interaction between testosterone and corticosterone statistically affecting either ectoparasite load or the expression of colorful ornaments. Further, we did not find a positive association of either testosterone or corticosterone on ectoparasite loads in any of the three study species. Only in S. grammicus males was a hormone statistically associated with ectoparasite load, but it was a negative association with testosterone. The relationships between both hormones and different aspects of the colorful patches (brightness and chroma) varied drastically among the three species as well as between sexes. Hence, even among congeneric species, we did not observe consistent patterns among color, steroid hormones and ectoparasites. Different associations between these variables may reflect different physiological strategies for the production of colorful signals and immune defense.
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Affiliation(s)
- Víctor Argaez
- Posgrado en Ciencias Biológicas, Universidad Nacional Autónoma de México, Ciudad Universitaria, 04510 Ciudad de México, Mexico.
| | - Jake A Pruett
- Department of Biology, Indiana State University, Terre Haute, IN 47809, USA; Department of Biological Sciences, Southeastern Oklahoma State University, Durant, OK 74701, USA.
| | - Ryan J Seddon
- Department of Biology, Indiana State University, Terre Haute, IN 47809, USA.
| | - Israel Solano-Zavaleta
- Departamento de Ecología y Recursos Naturales, Facultad de Ciencias, Universidad Nacional Autónoma de México, Ciudad Universitaria, 04510 Ciudad de México, Mexico.
| | - Diana K Hews
- Department of Biology, Indiana State University, Terre Haute, IN 47809, USA.
| | - J Jaime Zúñiga-Vega
- Departamento de Ecología y Recursos Naturales, Facultad de Ciencias, Universidad Nacional Autónoma de México, Ciudad Universitaria, 04510 Ciudad de México, Mexico.
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Claunch N, Moore I, Waye H, Schoenle L, Oakey SJ, Reed RN, Romagosa C. Understanding metrics of stress in the context of invasion history: the case of the brown treesnake ( Boiga irregularis). CONSERVATION PHYSIOLOGY 2021; 9:coab008. [PMID: 35145697 PMCID: PMC8631081 DOI: 10.1093/conphys/coab008] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Revised: 01/01/2021] [Accepted: 01/16/2021] [Indexed: 06/14/2023]
Abstract
Invasive species can exert rapid depletion of resources after introduction and, in turn, affect their own population density. Additionally, management actions can have direct and indirect effects on demography. Physiological variables can predict demographic change but are often restricted to snapshots-in-time and delayed confirmation of changes in population density reduces their utility. To evaluate the relationships between physiology and demography, we assessed metrics of individual and demographic stress (baseline and 1-h corticosterone (CORT), body condition and bacterial killing ability) in the invasive snake Boiga irregularis on Guam collected in intervals of 10-15 years. We also assessed potential discrepancies between different methods of measuring hormones [radioimmunoassay (RIA) versus enzyme immunoassay (EIA)]. The magnitude of difference between RIA and EIA was negligible and did not change gross interpretation of our results. We found that body condition was higher in recent samples (2003 and 2018) versus older (1992-93) samples. We found corresponding differences in baseline CORT, with higher baseline CORT in older, poorer body condition samples. Hormonal response to acute stress was higher in 2018 relative to 2003. We also found a weak relationship between circulating CORT and bacterial killing ability among 2018 samples, but the biological significance of the relationship is not clear. In an effort to develop hypotheses for future investigation of the links between physiology and demography in this and other systems, we discuss how the changes in CORT and body condition may reflect changes in population dynamics, resource availability or management pressure. Ultimately, we advocate for the synchronization of physiology and management studies to advance the field of applied conservation physiology.
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Affiliation(s)
- Natalie Claunch
- School of Natural Resources and Environment, University of
Florida, 103 Black Hall, Gainesville, FL 32611, USA
| | - Ignacio Moore
- Department of Biological Sciences, Virginia Tech,
Blacksburg, VA 24061, USA
| | - Heather Waye
- Division of Science and Mathematics, University of Minnesota
Morris, Morris, MN 56267, USA
| | - Laura Schoenle
- Office of Undergraduate Biology, Cornell University,
Ithaca, NY 14853, USA
| | - Samantha J Oakey
- University of Georgia College of Veterinary Medicine,
Athens, GA 30602, USA
| | - Robert N Reed
- US Geological Survey, Fort Collins Science Center, Fort
Collins, CO 80526, USA
| | - Christina Romagosa
- Department of Wildlife Ecology and Conservation,
University of Florida, 110 Newins-Ziegler Hall, Gainesville, FL 32611, USA
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Prado DMA, Gomes FR, Madelaire CB. Effects of corticosterone treatment and wound healing on reproductive traits of American bullfrogs. JOURNAL OF EXPERIMENTAL ZOOLOGY PART 2021; 335:275-285. [PMID: 33411410 DOI: 10.1002/jez.2439] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Revised: 11/20/2020] [Accepted: 12/18/2020] [Indexed: 11/05/2022]
Abstract
During reproductive season, calling anuran males display high testosterone (T) and episodically high corticosterone (CORT) plasma levels, which are positively associated with higher calling rates and immunocompetence. However, exposure to constant stress stimuli can result in chronically elevated CORT levels, possibly leading to inhibition of reproductive and immune activity. Reproduction and immune responses are energetically expensive, so when an animal is immunologically challenged, a tradeoff might be expressed, with CORT potentially mediating it. Our aim was to test how episodic and chronic CORT treatments, alongside wound healing, would affect reproduction in American bullfrog males (Lithobates catesbeianus). Forty animals were divided in four groups: Episodic CORT (daily transdermic application of CORT), placebo (daily transdermic application of sesame oil), chronic CORT (subcutaneous CORT silastic implants), and sham control (subcutaneous empty silastic implants). One week after treatments began, animals were punctured in the leg with a biopsy needle and the wound was photographed after 45 days to determine wound healing status (WS). Blood samples were collected throughout the experiment to measure CORT and T plasma levels. After animal euthanasia, testes were dissected, fixed, and analyzed histologically to determine spermatogenic activity (germinative cyst [GmC] morphometrics). As expected, the episodic CORT treatment had no effect on T plasma levels or spermatogenic activity. On the other hand, chronic CORT treatment reduced GmC morphometric traits, indicating suppression of reproduction, although T levels were not altered. In addition, animals from sham control and chronic CORT treatments with higher T levels presented higher WS, which indicates an immune-enhancing T effect.
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Affiliation(s)
- Débora M A Prado
- Departamento de Fisiologia, Instituto de Biociências, Universidade de São Paulo (USP), São Paulo, São Paulo State, Brazil
| | - Fernando R Gomes
- Departamento de Fisiologia, Instituto de Biociências, Universidade de São Paulo (USP), São Paulo, São Paulo State, Brazil
| | - Carla B Madelaire
- Departamento de Fisiologia, Instituto de Biociências, Universidade de São Paulo (USP), São Paulo, São Paulo State, Brazil
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Stepanek J, Claunch NM, Frazier JA, Moore IT, Vernasco BJ, Escallón C, Taylor EN. Corticosterone and Color Change in Southern Pacific Rattlesnakes (Crotalus helleri). HERPETOLOGICA 2019. [DOI: 10.1655/d-18-00008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- John Stepanek
- Department of Biological Sciences, California Polytechnic State University, San Luis Obispo, CA 93407, USA
| | - Natalie M. Claunch
- Department of Biological Sciences, California Polytechnic State University, San Luis Obispo, CA 93407, USA
| | - Julius A. Frazier
- Department of Biological Sciences, California Polytechnic State University, San Luis Obispo, CA 93407, USA
| | - Ignacio T. Moore
- Department of Biological Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA
| | - Ben J. Vernasco
- Department of Biological Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA
| | - Camilo Escallón
- Department of Biological Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA
| | - Emily N. Taylor
- Department of Biological Sciences, California Polytechnic State University, San Luis Obispo, CA 93407, USA
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11
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Fabrício-Neto A, Madelaire CB, Gomes FR, Andrade DV. Exposure to fluctuating temperatures leads to reduced immunity and to stress response in rattlesnakes. J Exp Biol 2019; 222:jeb.208645. [DOI: 10.1242/jeb.208645] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2019] [Accepted: 10/23/2019] [Indexed: 01/17/2023]
Abstract
Ectothermic organisms often experience considerable variation in their body temperature throughout the circadian cycle. However, studies focusing on the measurement of physiological traits are usually performed under constant temperature regimes. This mismatch between thermal exposure in the field and experimental conditions could act as a stressor agent, since physiological functions are strongly influenced by temperature. Herein, we asked the question whether constant thermal regimes would cause a stress response and impact the immunity of the South American rattlesnake (Crotalus durissus) when compared to a fluctuating thermal regime. We addressed this question by determining heterophil:lymphocyte ratio (H:L), plasma bacteria killing ability (BKA) and corticosterone levels (CORT) in snakes kept under a constant temperature regime at 30°C, and under a fluctuating regime that oscillated between 25°C at nighttime to 35°C at daytime. The experiments had a mirrored design, in which half of the snakes were subjected to a fluctuating-to-constant treatment, while the other half was exposed to a constant-to-fluctuating treatment. The shift from constant to fluctuating thermal regime was accompanied by an increase in plasma CORT levels indicating the activation of a stress response. Exposure to a fluctuating thermal regime at the onset of the experiments induced a decrease in the BKA of rattlesnakes. H:L was not affected by treatments and, therefore, the shift between thermal regimes seems to have acted as a low intensity stressor. Our results suggest that the removal from temperatures close to the snakés preferred body temperature triggers a stress response in rattlesnakes.
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Affiliation(s)
- Ailton Fabrício-Neto
- Departamento de Zoologia, Instituto de Biociências, Universidade Estadual Paulista, 13506-900, Rio Claro, São Paulo, Brazil
| | - Carla B. Madelaire
- Departamento de Fisiologia, Instituto de Biociências, Universidade de São Paulo, 05508-900, São Paulo, São Paulo, Brazil
| | - Fernando R. Gomes
- Departamento de Fisiologia, Instituto de Biociências, Universidade de São Paulo, 05508-900, São Paulo, São Paulo, Brazil
| | - Denis V. Andrade
- Departamento de Zoologia, Instituto de Biociências, Universidade Estadual Paulista, 13506-900, Rio Claro, São Paulo, Brazil
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12
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Lind CM, Moore IT, Vernasco BJ, Farrell TM. Seasonal testosterone and corticosterone patterns in relation to body condition and reproduction in a subtropical pitviper, Sistrurus miliarius. Gen Comp Endocrinol 2018; 267:51-58. [PMID: 29807034 DOI: 10.1016/j.ygcen.2018.05.027] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/09/2018] [Revised: 04/17/2018] [Accepted: 05/25/2018] [Indexed: 11/26/2022]
Abstract
Seasonal constraints on the timing and intensity of reproductive events shape observed variation in life history strategies across latitudes. Selection acts on the endocrine mechanisms that underlie reproductive investment. It is therefore important to examine the seasonal relationship between hormones and reproduction in geographically and phylogenetically diverse taxa. Snakes have proven to be a valuable model in investigations of seasonal hormone production and behavior in field-active vertebrates, but most research has focused on temperate populations from highly seasonal environments. To reduce this bias, we provide a description of the seasonal relationships among testosterone, corticosterone, body condition, and reproductive behavior in a subtropical population of Pygmy Rattlesnakes, Sistrurus miliarius. In central Florida, Sistrurus miliarius exhibits a prolonged breeding season (September-January) compared to most temperate zone snakes. Despite the extended breeding season, the pattern of testosterone in the population was highly seasonal and very similar to temperate pitvipers with a shorter mating season. Testosterone declined steadily through the mating season, but males sampled while engaging in mating behaviors had higher testosterone compared to solitary males throughout the mating season. Testosterone was negatively related to corticosterone throughout the breeding season and during times of year when the gonads were presumed to be quiescent and no mating behavior was observed. Testosterone was positively related to individual body condition both within and outside of the breeding season. A review of the literature reveals no consistent pattern regarding the relationship between corticosterone and testosterone in snakes, but suggests that the condition-dependence of steroid production may be consistent across snake taxa.
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Affiliation(s)
- Craig M Lind
- Department of Biology, Stetson University, Deland, FL 32723, USA; Department of Natural Sciences and Mathematics, Stockton University, Galloway, NJ 08201, USA.
| | - Ignacio T Moore
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA 24061, USA
| | - Ben J Vernasco
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA 24061, USA
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Wolfe AK, Fleming PA, Bateman PW. Impacts of translocation on a large urban-adapted venomous snake. WILDLIFE RESEARCH 2018. [DOI: 10.1071/wr17166] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Context
Translocation as a tool for management of nuisance or ‘problem’ snakes near urban areas is currently used worldwide with limited success. Translocated snakes experience modified behaviours, spatial use and survivorship, and few studies have investigated the impacts of translocation within a metropolitan area.
Aims
In the present study, we investigated the impacts of translocation on the most commonly encountered snake in Perth Western Australia, the dugite (Pseudonaja affinis, Elapidae), by comparing the space use of resident and translocated snakes.
Methods
We captured 10 dugites and attached telemetry packages, composed of a radio-telemetry transmitter and global positioning system (GPS) data-logger, externally to their tails. Snakes were either released within 200 m of their initial capture sites (residents, n = 6) or moved to new unconnected habitat at least 3 km away (translocated, n = 4). Spatial-use data were analysed using general linear models to identify differences between resident and translocated dugites.
Key results
Translocation influenced space use of dugites and detrimentally affected their survivorship. Translocated snakes had larger activity ranges than did residents, and there was a trend towards travelling greater distances over time. Mortality for all snakes was high: 100% for translocated snakes, and 50% for residents.
Conclusions
Urban dugites face many threats, and snakes were negatively affected by translocation. The GPS technology we used did not improve the quality of the data over traditional radio-telemetry methods, owing to the cryptic nature of the snakes that spent much of their time under cover or underground.
Implications
These findings support the growing body of evidence that translocating ‘problem’ snakes is a not a humane method of animal management, and alternatives such as public education, may be more appropriate.
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Claunch NM, Frazier JA, Escallón C, Vernasco BJ, Moore IT, Taylor EN. Physiological and behavioral effects of exogenous corticosterone in a free-ranging ectotherm. Gen Comp Endocrinol 2017; 248:87-96. [PMID: 28237812 DOI: 10.1016/j.ygcen.2017.02.008] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/04/2016] [Revised: 01/11/2017] [Accepted: 02/17/2017] [Indexed: 10/20/2022]
Abstract
In the face of global change, free-ranging organisms are expected to experience more unpredictable stressors. An understanding of how organisms with different life history strategies will respond to such changes is an integral part of biodiversity conservation. Corticosterone (CORT) levels are often used as metrics to assess the population health of wild vertebrates, despite the fact that the stress response and its effects on organismal function are highly variable. Our understanding of the stress response is primarily derived from studies on endotherms, leading to some contention on the effects of chronic stress across and within taxa. We assessed the behavioral and hormonal responses to experimentally elevated stress hormone levels in a free-ranging, arid-adapted ectotherm, the Southern Pacific rattlesnake (Crotalus helleri). Plasma CORT was significantly elevated in CORT-implanted snakes 15days after implantation. Implantation with CORT did not affect testosterone (T) levels or defensive behavior. Interestingly, we observed increased defensive behavior in snakes with more stable daily body temperatures and in snakes with higher plasma T during handling (tubing). Regardless of treatment group, those individuals with lower baseline CORT levels and higher body temperatures tended to exhibit greater increases in CORT levels following a standardized stressor. These results suggest that CORT may not mediate physiological and behavioral trait expression in arid-adapted ectotherms such as rattlesnakes.
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Affiliation(s)
- Natalie M Claunch
- Biological Sciences Department, California Polytechnic State University, San Luis Obispo, CA 93401, USA.
| | - Julius A Frazier
- Biological Sciences Department, California Polytechnic State University, San Luis Obispo, CA 93401, USA
| | - Camilo Escallón
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA 24061, USA
| | - Ben J Vernasco
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA 24061, USA
| | - Ignacio T Moore
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA 24061, USA
| | - Emily N Taylor
- Biological Sciences Department, California Polytechnic State University, San Luis Obispo, CA 93401, USA
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Claunch NM, Holding ML, Escallón C, Vernasco B, Moore IT, Taylor EN. Good vibrations: Assessing the stability of snake venom composition after researcher-induced disturbance in the laboratory. Toxicon 2017; 133:127-135. [PMID: 28487160 DOI: 10.1016/j.toxicon.2017.05.010] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2017] [Revised: 05/04/2017] [Accepted: 05/05/2017] [Indexed: 01/13/2023]
Abstract
Phenotypic plasticity contributes to intraspecific variation in traits of many animal species. Venom is an integral trait to the success and survival of many snake species, and potential plasticity in venom composition is important to account for in the context of basic research as well as in human medicine for treating the various symptoms of snakebite and producing effective anti-venoms. Researchers may unknowingly induce changes in venom variation by subjecting snakes to novel disturbances and potential stressors. We explored phenotypic plasticity in snake venom composition over time in captive Pacific rattlesnakes (Crotalus oreganus) exposed to vibration treatment, compared to an undisturbed control group. Venom composition did not change significantly in response to vibration, nor was there a detectable effect of overall time in captivity, even though snakes re-synthesized venom stores while subjected to novel disturbance in the laboratory. This result indicates that venom composition is a highly repeatable phenotype over short time spans and that the composition of venom within adult individuals may be resistant to or unaffected by researcher-induced disturbance. On the other hand, the change in venom composition, measured as movement along the first principle component of venom phenotype space, was associated with baseline corticosterone (CORT) levels in the snakes. While differential forms of researcher-induced disturbance may not affect venom composition, significant changes in baseline CORT, or chronic stress, may affect the venom phenotype, and further investigations will be necessary to assess the nature of the relationship between CORT and venom protein expression.
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Affiliation(s)
- Natalie M Claunch
- Department of Biological Sciences, California Polytechnic State University, San Luis Obispo, CA 93407, USA.
| | - Matthew L Holding
- Department of Evolution, Ecology, and Evolutionary Biology, The Ohio State University, Columbus, OH 43210, USA
| | - Camilo Escallón
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA 24061, USA
| | - Ben Vernasco
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA 24061, USA
| | - Ignacio T Moore
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA 24061, USA
| | - Emily N Taylor
- Department of Biological Sciences, California Polytechnic State University, San Luis Obispo, CA 93407, USA
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