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Claunch NM, Bartoszek IA, Tillis S, Stacy NI, Ossiboff RJ, Oakey S, Schoenle LA, Wellehan JFX, Romagosa CM. Physiological effects of capture and short-term captivity in an invasive snake species, the Burmese python (Python bivittatus) in Florida. Comp Biochem Physiol A Mol Integr Physiol 2022; 267:111162. [PMID: 35149178 DOI: 10.1016/j.cbpa.2022.111162] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Revised: 02/04/2022] [Accepted: 02/04/2022] [Indexed: 02/05/2023]
Abstract
It is important to evaluate the role of captivity as a potential stressor. An understanding of stress responses to capture and transition to captivity may inform the limitations of laboratory studies on wild animals, aid in understanding the consequences of introducing animals into captive environments, and help predict which species may be successful invasives. We investigated physiological effects of captivity by comparing at-capture blood variables in wild Burmese pythons (Python bivittatus) in Florida to pythons recently brought into captivity (1-109 days). We conducted an acute restraint test by collecting samples at baseline (immediately at handling) and one hour post-restraint across wild field-sampled (n = 19) and recently-captive (n = 33) pythons to evaluate fluctuations in plasma corticosterone, bacterial killing ability, antibody response, leukogram, and serpentovirus infection. We observed higher baseline plasma corticosterone and monocytes in recently captive compared to wild snakes, which both subsided in snakes held for a longer time in captivity, and a mild decrease in lymphocytes in the middle of the captivity period. Functional immunity and viral infection were not affected by captivity, and pythons maintained restraint-induced responses in corticosterone, heterophil to lymphocyte ratio, and monocyte counts throughout captivity. Prevalence for serpentovirus was 50%, though infection status was related to sampling date rather than captivity, indicating that viral infection may be seasonal. The history of Burmese python as a common captive animal for research and pet trade, as well as its general resilience to effects of capture and short-term captivity, may contribute to its invasion success in Florida.
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Affiliation(s)
- Natalie M Claunch
- School of Natural Resources and Environment, University of Florida, USA.
| | | | - Steve Tillis
- College of Veterinary Medicine, University of Florida, USA
| | - Nicole I Stacy
- College of Veterinary Medicine, University of Florida, USA
| | | | - Samantha Oakey
- College of Veterinary Medicine, University of Georgia, USA
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Finger JW, Kelley MD, Zhang Y, Hamilton MT, Elsey RM, Mendonca MT, Kavazis A. Short-term capture stress and its effects on corticosterone levels and heat shock proteins in captive American Alligators (Alligator mississippiensis). CAN J ZOOL 2021. [DOI: 10.1139/cjz-2021-0014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Heat shock proteins (HSPs) are important mediators of the normal cellular function and the cellular stress response. As such, HSPs are often utilized to measure the effects of stressors on organisms in vivo. However, multiple variables can influence their expression, including time or season, confounding results. To investigate the utility of HSPs in measuring effects of stressors in a top-trophic carnivore, we captured 20 American Alligators (Alligator mississippiensis (Daudin, 1802)), placed them in burlap sacks for 2 h and collected blood samples over four time points (baseline, 1 and 2 h after placement into burlap sacks, and 24 h after initial capture) to measure plasma corticosterone (the main crocodilian glucocorticoid) and levels of HSP60, HSP70, and HSP90. Time point significantly affected plasma corticosterone levels in Alligators (p < 0.0001), with levels significantly elevated at 1, 2, and 24 h, relative to baseline (all p < 0.05). However, capture stress did not affect HSP60, HSP70, or HSP90 in red blood cells (all p > 0.05). Our results suggest HSPs may be important biomarkers for investigating the impacts of stressors on captive and wild crocodilians, as they are not acutely elevated by capture or handling stress.
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Affiliation(s)
- John W. Finger
- Department of Biological Sciences, Auburn University, Auburn, AL 36849, USA
| | - Meghan D. Kelley
- Department of Biological Sciences, Auburn University, Auburn, AL 36849, USA
| | - Yufeng Zhang
- College of Health Sciences, University of Memphis, Memphis, TN 38152, USA
| | - Matthew T. Hamilton
- Department of Forestry and Natural Resources, Purdue University, West Lafayette, IN 47907, USA
| | - Ruth M. Elsey
- Louisiana Department of Wildlife and Fisheries, Rockefeller Wildlife Refuge, Grand Chenier, LA 70643, USA
| | - Mary T. Mendonca
- Department of Biological Sciences, Auburn University, Auburn, AL 36849, USA
| | - Andreas Kavazis
- School of Kinesiology, Auburn University, Auburn, AL 36849, USA
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Claunch NM, Holding M, Frazier JT, Huff EM, Schonour RB, Vernasco B, Moore IT, Rokyta DR, Taylor EN. Experimental Manipulation of Corticosterone Does Not Affect Venom Composition or Functional Activity in Free-Ranging Rattlesnakes. Physiol Biochem Zool 2021; 94:286-301. [PMID: 34166170 DOI: 10.1086/714936] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
AbstractVenom is an integral feeding trait in many animal species. Although venom often varies ontogenetically, little is known about the proximate physiological mediators of venom variation within individuals. The glucocorticoid hormone corticosterone (CORT) can alter the transcription and activation of proteins, including homologues of snake venom components such as snake venom metalloproteinases (SVMPs) and phospholipase A2 (PLA2). CORT is endogenously produced by snakes, varies seasonally and also in response to stress, and is a candidate endogenous mediator of changes in venom composition and functional activity. Here, we tested the hypothesis that CORT induces changes in snake venom by sampling the venom of wild adult rattlesnakes before and after they were treated with either empty (control) or CORT-filled (treatment) Silastic implants. We measured longitudinal changes in whole-venom composition, whole-venom total protein content, and enzymatic activity of SVMP and PLA2 components of venom. We also assessed the within-individual repeatability of venom components. Despite successfully elevating plasma CORT in the treatment group, we found no effect of CORT treatment or average plasma CORT level on any venom variables measured. Except for total protein content, venom components were highly repeatable within individuals ([Formula: see text]). Our results indicate that the effects of CORT, a hormone commonly associated with stress and metabolic functions, in adult rattlesnake venom are negligible. Our findings bode well for venom researchers and biomedical applications that rely on the consistency of venoms produced from potentially stressed individuals and provide an experimental framework for future studies of proximate mediators of venom variation across an individual's life span.
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Schonour RB, Huff EM, Holding ML, Claunch NM, Ellsworth SA, Hogan MP, Wray K, McGivern J, Margres MJ, Colston TJ, Rokyta DR. Gradual and Discrete Ontogenetic Shifts in Rattlesnake Venom Composition and Assessment of Hormonal and Ecological Correlates. Toxins (Basel) 2020; 12:toxins12100659. [PMID: 33081249 PMCID: PMC7602723 DOI: 10.3390/toxins12100659] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Revised: 10/07/2020] [Accepted: 10/13/2020] [Indexed: 12/13/2022] Open
Abstract
Ontogenetic shifts in venom occur in many snakes but establishing their nature as gradual or discrete processes required additional study. We profiled shifts in venom expression from the neonate to adult sizes of two rattlesnake species, the eastern diamondback and the timber rattlesnake. We used serial sampling and venom chromatographic profiling to test if ontogenetic change occurs gradually or discretely. We found evidence for gradual shifts in overall venom composition in six of eight snakes, which sometimes spanned more than two years. Most chromatographic peaks shift gradually, but one quarter shift in a discrete fashion. Analysis of published diet data showed gradual shifts in overall diet composition across the range of body sizes attained by our eight study animals, while the shifts in abundance of different prey classes varied in form from gradual to discrete. Testosterone concentrations were correlated with the change in venom protein composition, but the relationship is not strong enough to suggest causation. Venom research employing simple juvenile versus adult size thresholds may be failing to account for continuous variation in venom composition lifespan. Our results imply that venom shifts represent adaptive matches to dietary shifts and highlight venom for studies of alternative gene regulatory mechanisms.
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Affiliation(s)
- Richard B. Schonour
- Department of Biological Sciences, Florida State University, Tallahassee, FL 32304, USA; (R.B.S.); (E.M.H.); (S.A.E.); (M.P.H.); (K.W.); (J.M.); (M.J.M.); (T.J.C.); (D.R.R.)
| | - Emma M. Huff
- Department of Biological Sciences, Florida State University, Tallahassee, FL 32304, USA; (R.B.S.); (E.M.H.); (S.A.E.); (M.P.H.); (K.W.); (J.M.); (M.J.M.); (T.J.C.); (D.R.R.)
| | - Matthew L. Holding
- Department of Biological Sciences, Florida State University, Tallahassee, FL 32304, USA; (R.B.S.); (E.M.H.); (S.A.E.); (M.P.H.); (K.W.); (J.M.); (M.J.M.); (T.J.C.); (D.R.R.)
- Correspondence:
| | - Natalie M. Claunch
- School of Natural Resources and Environment, University of Florida, Gainesville, FL 32611, USA;
| | - Schyler A. Ellsworth
- Department of Biological Sciences, Florida State University, Tallahassee, FL 32304, USA; (R.B.S.); (E.M.H.); (S.A.E.); (M.P.H.); (K.W.); (J.M.); (M.J.M.); (T.J.C.); (D.R.R.)
| | - Michael P. Hogan
- Department of Biological Sciences, Florida State University, Tallahassee, FL 32304, USA; (R.B.S.); (E.M.H.); (S.A.E.); (M.P.H.); (K.W.); (J.M.); (M.J.M.); (T.J.C.); (D.R.R.)
| | - Kenneth Wray
- Department of Biological Sciences, Florida State University, Tallahassee, FL 32304, USA; (R.B.S.); (E.M.H.); (S.A.E.); (M.P.H.); (K.W.); (J.M.); (M.J.M.); (T.J.C.); (D.R.R.)
| | - James McGivern
- Department of Biological Sciences, Florida State University, Tallahassee, FL 32304, USA; (R.B.S.); (E.M.H.); (S.A.E.); (M.P.H.); (K.W.); (J.M.); (M.J.M.); (T.J.C.); (D.R.R.)
| | - Mark J. Margres
- Department of Biological Sciences, Florida State University, Tallahassee, FL 32304, USA; (R.B.S.); (E.M.H.); (S.A.E.); (M.P.H.); (K.W.); (J.M.); (M.J.M.); (T.J.C.); (D.R.R.)
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA 02138, USA
- Department of Integrative Biology, University of South Florida, Tampa, FL 33620, USA
| | - Timothy J. Colston
- Department of Biological Sciences, Florida State University, Tallahassee, FL 32304, USA; (R.B.S.); (E.M.H.); (S.A.E.); (M.P.H.); (K.W.); (J.M.); (M.J.M.); (T.J.C.); (D.R.R.)
| | - Darin R. Rokyta
- Department of Biological Sciences, Florida State University, Tallahassee, FL 32304, USA; (R.B.S.); (E.M.H.); (S.A.E.); (M.P.H.); (K.W.); (J.M.); (M.J.M.); (T.J.C.); (D.R.R.)
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5
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Fresnillo B, Belliure J, Gil D, Cuervo JJ. Hormonal control of seasonal color change in female spiny-footed lizards: an observational and experimental approach. Curr Zool 2019; 65:633-642. [PMID: 31857810 PMCID: PMC6911850 DOI: 10.1093/cz/zoz012] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2018] [Accepted: 03/25/2019] [Indexed: 11/12/2022] Open
Abstract
Breeding coloration of females often signals aspects of their reproductive status, suggesting a link between color and sex steroid hormones. In this study, we examined the relationships between 2 sex steroid hormones (progesterone and β-estradiol) and reproductive coloration in female spiny-footed lizards Acanthodactylus erythrurus. We first explored natural variation in female plasma hormone levels and coloration during their reproductive cycle. β-estradiol was negatively related to brightness and positively related to red saturation, whereas progesterone was not significantly related to coloration. After identifying key relationships, plasma hormone concentrations were manipulated by creating 3 experimental female groups (β-estradiol-treated, progesterone-treated, and control), and the effects on coloration were monitored. β-estradiol-treated females, in which there was a rise in both β-estradiol and progesterone levels, lost their red coloration earlier than females in the other 2 experimental groups, whereas progesterone treatment had no significant effect on female coloration. Our results suggest that high levels of either β-estradiol alone or β-estradiol together with progesterone trigger the loss of red coloration in female spiny-footed lizards, and that progesterone alone does not affect coloration. We hypothesize that changes in female breeding color might be regulated by β-estradiol in species in which conspicuous coloration is displayed before ovulation, and by progesterone in species in which this color is displayed during gravidity.
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Affiliation(s)
- Belén Fresnillo
- Department of Life Sciences, Ecology Section, University of Alcalá, Madrid, Spain
- Department of Functional and Evolutionary Ecology, Estación Experimental de Zonas Áridas (CSIC), Carretera de Sacramento s/n, Almería, Spain
| | - Josabel Belliure
- Department of Life Sciences, Ecology Section, University of Alcalá, Madrid, Spain
| | - Diego Gil
- Department of Evolutionary Ecology, Museo Nacional de Ciencias Naturales (CSIC), Madrid, Spain
| | - José J Cuervo
- Department of Evolutionary Ecology, Museo Nacional de Ciencias Naturales (CSIC), Madrid, Spain
- Address correspondence to José J. Cuervo. E-mail:
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6
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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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7
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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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8
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Dayger CA, LeMaster MP, Lutterschmidt DI. Physiological correlates of reproductive decisions: Relationships among body condition, reproductive status, and the hypothalamus-pituitary-adrenal axis in a reptile. Horm Behav 2018; 100:1-11. [PMID: 29452075 DOI: 10.1016/j.yhbeh.2018.02.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/28/2017] [Revised: 02/04/2018] [Accepted: 02/05/2018] [Indexed: 12/22/2022]
Abstract
When opportunities to feed and reproduce are limited, females are often unable to recover sufficient energy stores to reproduce in consecutive years. Body condition has been used as a proxy for recent reproductive history in such species. We previously found that glucocorticoid responses to capture stress vary with body condition in female red-sided garter snakes (Thamnophis sirtalis parietalis), a species with limited seasonal breeding opportunities. Because variation in glucocorticoid receptor (GR) protein in the brain could explain these differences, we first assessed GR protein content in females in different body conditions. To investigate if body condition during the spring mating season accurately reflects recent reproductive history, we measured glucocorticoid responses to stress in females with different body conditions, assessed their mating behavior and brought mated females to our lab to determine which females would give birth during the summer (i.e., were parturient). Female red-sided garter snakes reproduce biennially, and therefore mated females that did not give birth were deemed non-parturient. In this study, glucocorticoid stress responses and mating behavior did not vary with body condition, nor was body condition related to brain GR or reproductive condition (parturient vs non-parturient). Only unreceptive females showed a significant stress-induced increase in glucocorticoids, suggesting that reduced stress responsiveness is associated with receptivity. Parturient females mated faster (were more proceptive) than non-parturient females. These data suggest that HPA axis activity modulates receptivity, while proceptivity is related primarily to reproductive condition.
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Affiliation(s)
- Catherine A Dayger
- Dept. of Biology, Portland State University, 1719 SW 10(th) Ave, Portland, OR 97201, United States.
| | - Michael P LeMaster
- Dept. of Biology, Western Oregon University, 345 N. Monmouth Ave, Monmouth, OR 97361, United States.
| | - Deborah I Lutterschmidt
- Dept. of Biology, Portland State University, 1719 SW 10(th) Ave, Portland, OR 97201, United States.
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9
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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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10
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Dayger CA, Lutterschmidt DI. Patterns of stress responses shift during seasonal life-history transitions: An analysis comparing baseline, maximal and integrated corticosterone in female red-sided garter snakes (Thamnophis sirtalis parietalis). Gen Comp Endocrinol 2017; 246:29-36. [PMID: 28322762 DOI: 10.1016/j.ygcen.2017.03.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/16/2016] [Revised: 02/20/2017] [Accepted: 03/15/2017] [Indexed: 10/19/2022]
Abstract
Glucocorticoids often rise and fall with a variety of external and internal cues and frequently vary among life-history stages. This suggests that changing glucocorticoids may coordinate life-history transitions. To explore this hypothesis, we asked if the time-course of stress-induced glucocorticoid levels differ between two life-history transitions (i.e., spring and fall migration) in female red-sided garter snakes (Thamnophis sirtalis parietalis). We collected non-migratory females from a communal den and migratory females from a road along the migration route and treated them with 4h of capture stress; plasma corticosterone was measured before, during and after capture stress. During the spring, den-collected females exhibited a stress-induced peak in corticosterone at an earlier sampling time than migrating, road-collected females. Because the pattern of corticosterone responses varied with migratory state, negative feedback on and/or sensitivity of the hypothalamus-pituitaryadrenal (HPA) axis may be linked to spring migration. During the fall, capture stress elicited an increase in corticosterone in den-collected females but not in migrating, road-collected females. Baseline corticosterone was higher and both maximal and integrated corticosterone responses were lower during the fall compared to spring, indicating that stress responses are smaller when baseline corticosterone is elevated, perhaps due to a "ceiling effect". These data suggest that HPA axis regulation changes during seasonal migration, possibly via altering negative feedback, HPA axis sensitivity, or some other mechanism. This study supports the hypothesis that glucocorticoids coordinate life-history events and suggests that examining a suite of stress response characteristics is most informative for understanding the function of HPA modulation.
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Affiliation(s)
- Catherine A Dayger
- Portland State University, Department of Biology, 1719 SW 10th Ave., Portland, OR 97201, United States.
| | - Deborah I Lutterschmidt
- Portland State University, Department of Biology, 1719 SW 10th Ave., Portland, OR 97201, United States.
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11
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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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12
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Geographic variation and within-individual correlations of physiological stress markers in a widespread reptile, the common garter snake (Thamnophis sirtalis). Comp Biochem Physiol A Mol Integr Physiol 2017; 205:68-76. [DOI: 10.1016/j.cbpa.2016.12.019] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2016] [Revised: 12/16/2016] [Accepted: 12/16/2016] [Indexed: 01/14/2023]
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13
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Heiken KH, Brusch GA, Gartland S, Escallón C, Moore IT, Taylor EN. Effects of long distance translocation on corticosterone and testosterone levels in male rattlesnakes. Gen Comp Endocrinol 2016; 237:27-33. [PMID: 27468956 DOI: 10.1016/j.ygcen.2016.07.023] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/24/2016] [Revised: 06/03/2016] [Accepted: 07/24/2016] [Indexed: 11/18/2022]
Abstract
Translocation is an increasingly common conservation tool used to augment declining populations or to remove nuisance animals from areas of human conflict. Studies show that venomous snakes translocated long distances may wander and experience increased mortality. However, potential sub-lethal physiological effects on translocated snakes remain unknown. We conducted an experimental study on free-ranging rattlesnakes to test the hypothesis that long distance translocation is stressful. The glucocorticoid response to translocation was variable among snakes. There was some evidence that translocation may be stressful, as baseline corticosterone levels in most snakes rose following translocation, whereas levels remained consistent in control snakes. Interestingly, testosterone levels rose dramatically following translocation, possibly reflecting effects of interaction with new environmental cues and/or resident snakes, or effects of navigation in a new environment. Corticosterone and testosterone were positively correlated. Our study shows that long distance translocation can affect steroid hormone concentrations in rattlesnakes, a result that should be taken into consideration when managing nuisance snakes or repatriating animals to the wild.
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Affiliation(s)
- Kory H Heiken
- Department of Biological Sciences, California Polytechnic State University, San Luis Obispo, CA 93401, USA.
| | - George A Brusch
- Department of Biological Sciences, California Polytechnic State University, San Luis Obispo, CA 93401, USA.
| | - Sarah Gartland
- Department of Biological Sciences, California Polytechnic State University, San Luis Obispo, CA 93401, USA
| | - Camilo Escallón
- 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 93401, USA.
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14
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Dayger CA, Lutterschmidt DI. Seasonal and sex differences in responsiveness to adrenocorticotropic hormone contribute to stress response plasticity in red-sided garter snakes (Thamnophis sirtalis parietalis). J Exp Biol 2016; 219:1022-30. [DOI: 10.1242/jeb.130450] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2015] [Accepted: 01/20/2016] [Indexed: 11/20/2022]
Abstract
Like many vertebrates, hormonal responses to stress vary seasonally in red-sided garter snakes (Thamnophis sirtalis parietalis). For example, males generally exhibit reduced glucocorticoid responses to a standard stressor during the spring mating season. We asked whether variation in adrenal sensitivity to adrenocorticotropic hormone (ACTH) explains why glucocorticoid responses to capture stress vary with sex, season, and body condition in red-sided garter snakes. We measured glucocorticoids at 0, 1, and 4 hours after injection with ACTH (0.1 IU/g body mass) or vehicle in males and females during the spring mating season and fall pre-hibernation period. Because elevated glucocorticoids can influence sex steroids, we also examined androgen and estradiol responses to ACTH. ACTH treatment increased glucocorticoids in both sexes and seasons. Spring-collected males had a smaller integrated glucocorticoid response to ACTH than fall-collected males. The integrated glucocorticoid response to ACTH differed with sex during the spring, with males having a smaller glucocorticoid response than females. Although integrated glucocorticoid responses to ACTH did not vary with body condition, we observed an interaction among season, sex and body condition. In males, ACTH treatment did not alter androgens in either season, but androgens decreased during the sampling period. Similar to previous studies, plasma estradiol was low or undetectable during the spring and fall and therefore any effect of ACTH treatment on estradiol could not be determined. These data provide support for a mechanism that partly explains how the HPA axis integrates information about season, sex, and body condition: namely, variation in adrenal responsiveness to ACTH.
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Affiliation(s)
- Catherine A. Dayger
- Portland State University, Department of Biology, 1719 SW 10th Ave, Portland, OR 97201, USA
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15
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Cutaneous Water Loss and Epidermal Lipids in Two Sympatric and Congeneric Pitvipers. J HERPETOL 2014. [DOI: 10.1670/13-116] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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16
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Hoss SK, Garcia MJ, Earley RL, Clark RW. Fine-scale hormonal patterns associated with birth and maternal care in the cottonmouth (Agkistrodon piscivorus), a North American pitviper snake. Gen Comp Endocrinol 2014; 208:85-93. [PMID: 25169835 DOI: 10.1016/j.ygcen.2014.08.011] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/12/2014] [Revised: 08/10/2014] [Accepted: 08/17/2014] [Indexed: 01/06/2023]
Abstract
Steroid hormones regulate many aspects of reproductive physiology and behavior, including parental care. Reptiles display a variety of egg- and neonate-directed parental behaviors, yet few studies have addressed their endocrine correlates. Viviparous female pitvipers remain at the birth site with their young for one to two weeks until neonates complete their first shed cycle ('ecdysis'). To study possible relationships between steroid hormones and these behaviors, we conducted a captive study on wild-caught pregnant cottonmouths. Females were divided into two treatment groups: Maternal Attendance (MA) - females were allowed a maternal attendance period, where neonates were left with the mother until they completed ecdysis and then were removed; Separated (SE) - females had their neonates removed within 24h of birth. Serial blood samples were collected from MA females at various points during and after attendance; SE females had samples collected on a similar temporal schedule. Plasma levels of progesterone (P), estradiol (E2), testosterone (T), and corticosterone (CORT) were measured in all samples. We did not find a difference in the overall pattern of P, E2, or T between MA and SE females; however, MA females exhibited a significant peak in CORT on the day that neonates shed that was not observed in SE females. It is possible that the elevated CORT observed in MA females was stimulated by increased activity and/or changing chemical cues of shedding neonates. Based on evidence that free-ranging pitvipers cease MA when all offspring complete ecdysis, we hypothesize that CORT has a role in signaling mothers to terminate care and disperse.
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Affiliation(s)
- Shannon K Hoss
- Department of Biology, San Diego State University, 5500 Campanile Drive, San Diego, CA 92182, USA.
| | - Mark J Garcia
- Department of Biological Sciences, The University of Alabama, 300 Hackberry Lane, Box 870344, Tuscaloosa, AL 35487, USA.
| | - Ryan L Earley
- Department of Biological Sciences, The University of Alabama, 300 Hackberry Lane, Box 870344, Tuscaloosa, AL 35487, USA.
| | - Rulon W Clark
- Department of Biology, San Diego State University, 5500 Campanile Drive, San Diego, CA 92182, USA.
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17
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Lind CM, Beaupre SJ. Natural variation in steroid hormone profiles of male Timber Rattlesnakes, Crotalus horridus, in northwest Arkansas. Gen Comp Endocrinol 2014; 206:72-9. [PMID: 24997417 DOI: 10.1016/j.ygcen.2014.06.026] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/09/2014] [Revised: 06/18/2014] [Accepted: 06/20/2014] [Indexed: 11/27/2022]
Abstract
We describe the seasonal profile of circulating steroid hormones (testosterone and corticosterone) in relation to the breeding season in free ranging male Timber Rattlesnakes, Crotalus horridus, over the course of three active seasons. In addition, we examine variation in steroid concentrations across years and in relation to body condition. We found that seasonal profiles of plasma testosterone were different compared to other crotalines with similar mating patterns. Concentrations of testosterone were elevated above baseline in the three months leading up to the single late summer breeding season. Testosterone peaked in July at the onset of the breeding season and dropped to baseline during the peak months of breeding (August and September). Testosterone concentrations also varied annually. Although the exact cause of annual variation could not be established, our results indicate that weather patterns may have driven observed differences. Testosterone concentrations were positively related to body condition, indicating that testosterone production is modulated according to energetic status (particularly in the two months prior to the breeding season). Corticosterone did not vary seasonally or with any measured variable, a result similar to other studied crotalines. Our results highlight the importance of long-term descriptive studies of the regulatory mechanisms that underlie behavior and physiology in diverse taxa, as these mechanisms can vary greatly within and among populations and are valuable in elucidating the intrinsic and extrinsic sources of such variation.
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Affiliation(s)
- Craig M Lind
- Department of Biological Sciences, University of Arkansas, 850 West Dickson Street, SCEN 601, Fayetteville, AR 72701, USA.
| | - Steven J Beaupre
- Department of Biological Sciences, University of Arkansas, 850 West Dickson Street, SCEN 601, Fayetteville, AR 72701, USA
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18
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Physiological and Behavioral Effects of Repeated Handling and Short-Distance Translocations on Free-Ranging Northern Pacific Rattlesnakes (Crotalus oreganus oreganus). J HERPETOL 2014. [DOI: 10.1670/11-314] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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19
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Holding ML, Frazier JA, Dorr SW, Pollock NB, Muelleman PJ, Branske A, Henningsen SN, Eikenaar C, Escallón C, Montgomery CE, Moore IT, Taylor EN. Wet- and Dry-Season Steroid Hormone Profiles and Stress Reactivity of an Insular Dwarf Snake, the Hog Island Boa (Boa constrictor imperator). Physiol Biochem Zool 2014; 87:363-73. [DOI: 10.1086/675938] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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20
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Dayger CA, Cease AJ, Lutterschmidt DI. Responses to capture stress and exogenous corticosterone vary with body condition in female red-sided garter snakes (Thamnophis sirtalis parietalis). Horm Behav 2013; 64:748-54. [PMID: 24075831 DOI: 10.1016/j.yhbeh.2013.09.003] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/03/2013] [Revised: 08/20/2013] [Accepted: 09/20/2013] [Indexed: 10/26/2022]
Abstract
This study examined whether hormonal and behavioral responses to capture stress and exogenous corticosterone (CORT) vary with body condition in female red-sided garter snakes (Thamnophis sirtalis parietalis). Female snakes were collected during the spring mating season and treated with 4 h of capture stress. We measured plasma CORT and estradiol before, during and after capture stress treatment followed by latency to copulate, a measure of female receptivity. Body condition was determined as the residual from a regression of body mass on snout-vent-length. Baseline CORT did not differ between females in positive and negative body condition, but females in negative body condition showed a significantly larger increase in plasma CORT in response to capture stress. Estradiol, which is generally low during the mating season in this population, did not change in response to capture stress. Body condition, but not capture stress, influenced latency to copulate, suggesting that females are resistant to the behavioral effects of capture stress during the spring mating season. In a second experiment, only females in negative body condition increased latency to copulate in response to injection of a physiological (15 μg) dose of exogenous CORT, while all females responded to a pharmacological (60 μg) dose. These results indicate that behavioral responses to exogenous CORT vary with female body condition during the short mating season. Taken together, our data suggest that variation in body condition may be associated with differences in HPA axis sensitivity and/or glucocorticoid receptor density in the brain.
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Affiliation(s)
- Catherine A Dayger
- Department of Biology, Portland State University, 1719 SW 10th Ave., Portland, OR, 97201, USA.
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21
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Narayan EJ, Hero JM. Repeatability of Baseline Corticosterone and Acute Stress Responses to Capture, and Patterns of Reproductive Hormones in Vitellogenic and Non-Vitellogenic Female Fijian Ground Frog (Platymantis vitiana). ACTA ACUST UNITED AC 2013; 319:471-81. [DOI: 10.1002/jez.1810] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2013] [Revised: 05/13/2013] [Accepted: 06/03/2013] [Indexed: 11/09/2022]
Affiliation(s)
- Edward J. Narayan
- Environmental Futures Centre; School of Environment; Griffith University; Gold Coast Campus; Gold Coast, QLD; Australia
| | - Jean-Marc Hero
- Environmental Futures Centre; School of Environment; Griffith University; Gold Coast Campus; Gold Coast, QLD; Australia
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22
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The breeding season duration hypothesis: acute handling stress and total plasma concentrations of corticosterone and androgens in male and female striped plateau lizards (Sceloporus virgatus). J Comp Physiol B 2013; 183:933-46. [DOI: 10.1007/s00360-013-0766-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2012] [Revised: 05/06/2013] [Accepted: 05/13/2013] [Indexed: 12/28/2022]
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23
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Cockrem JF. Individual variation in glucocorticoid stress responses in animals. Gen Comp Endocrinol 2013; 181:45-58. [PMID: 23298571 DOI: 10.1016/j.ygcen.2012.11.025] [Citation(s) in RCA: 214] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/10/2012] [Revised: 11/15/2012] [Accepted: 11/18/2012] [Indexed: 12/30/2022]
Abstract
When stimuli from the environment are perceived to be a threat or potential threat then animals initiate stress responses, with activation of the hypothalamo-pituitary-adrenal axis and secretion of glucocorticoid hormones (cortisol and corticosterone). Whilst standard deviation or standard error values are always reported, it is only when graphs of individual responses are shown that the extensive variation between animals is apparent. Some animals have little or no response to a stressor that evokes a relatively large response in others. Glucocorticoid responses of fish, amphibian, reptiles, birds, and mammals are considered in this review. Comparisons of responses between animals and groups of animals focused on responses to restraint or confinement as relatively standard stressors. Individual graphs could not be found in the literature for glucocorticoid responses to capture or restraint in fish or reptiles, with just one graph in mammals with the first sample was collected when animals were initially restrained. Coefficients of variation (CVs) calculated for parameters of glucocorticoid stress responses showed that the relative magnitudes of variation were similar in different vertebrate groups. The overall mean CV for glucocorticoid concentrations in initial (0 min) samples was 74.5%, and CVs for samples collected over various times up to 4 h were consistently between 50% and 60%. The factors that lead to the observed individual variation and the extent to which this variation is adaptive or non-adaptive are little known in most animals, and future studies of glucocorticoid responses in animals can focus on individual responses and their origins and significance.
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Affiliation(s)
- John F Cockrem
- Institute of Veterinary, Animal and Biomedical Sciences, Massey University, Palmerston North 4442, New Zealand.
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24
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Uhrig EJ, Lutterschmidt DI, Mason RT, LeMaster MP. Pheromonal Mediation of Intraseasonal Declines in the Attractivity of Female Red-Sided Garter Snakes, Thamnophis sirtalis parietalis. J Chem Ecol 2012; 38:71-80. [DOI: 10.1007/s10886-011-0054-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2011] [Revised: 11/06/2011] [Accepted: 12/19/2011] [Indexed: 11/30/2022]
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25
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A review of the evolution of viviparity in squamate reptiles: the past, present and future role of molecular biology and genomics. J Comp Physiol B 2011; 181:575-94. [DOI: 10.1007/s00360-011-0584-0] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2011] [Revised: 04/19/2011] [Accepted: 04/20/2011] [Indexed: 12/06/2022]
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