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Titon Junior B, Barsotti AMG, Titon SCM, Vaz RI, de Figueiredo AC, Vasconcelos-Teixeira R, Navas CA, Gomes FR. Baseline and stress-induced steroid plasma levels and immune function vary annually and are associated with vocal activity in male toads (Rhinella icterica). Gen Comp Endocrinol 2024; 354:114517. [PMID: 38615755 DOI: 10.1016/j.ygcen.2024.114517] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/07/2023] [Revised: 03/19/2024] [Accepted: 04/06/2024] [Indexed: 04/16/2024]
Abstract
Theoretical models predict that elevated androgen and glucocorticoid levels in males during the reproductive season promote immunosuppression. However, some studies report decreased stress response during this season. This study investigated annual variation in plasma corticosterone and testosterone levels, plasma bacterial killing ability (BKA), and neutrophil to lymphocyte ratio (NLR) in free-living male toads (Rhinella icterica). Toads were sampled in the field (baseline) and 1 h-post restraint over five months, and we considered the occurrence of vocal activity. Baseline corticosterone, testosterone, and BKA showed higher values during the reproductive period, specifically in calling male toads. The NLR was similar throughout the year, but higher values were observed in calling toads. Moreover, baseline NLR and BKA were positively correlated with both testosterone and corticosterone, suggesting higher steroid levels during reproduction are associated with enhanced cellular and humoral immunity. Despite fluctuation of baseline values, post-restraint corticosterone levels remained uniform over the year, indicating that toads reached similar maximum values throughout the year. Testosterone levels decreased following restraint before one specific reproductive period but increased in response to restraint during and after this period. Meanwhile, BKA decreased due to restraint only after the reproductive period, indicating immune protection and resilience to immunosuppression by stressors associated with steroid hormones during reproduction. Our results show that baseline and stress-induced hormonal and immune regulation varies throughout the year and are associated with vocal activity in R. icterica males, indicating a possible compromise between steroids and immune function in anuran males.
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Affiliation(s)
- Braz Titon Junior
- Departamento de Fisiologia, Instituto de Biociências, Universidade de São Paulo, São Paulo, São Paulo, Brasil.
| | | | | | - Renata Ibelli Vaz
- Departamento de Fisiologia, Instituto de Biociências, Universidade de São Paulo, São Paulo, São Paulo, Brasil
| | - Aymam Cobo de Figueiredo
- Departamento de Fisiologia, Instituto de Biociências, Universidade de São Paulo, São Paulo, São Paulo, Brasil
| | | | - Carlos A Navas
- Departamento de Fisiologia, Instituto de Biociências, Universidade de São Paulo, São Paulo, São Paulo, Brasil
| | - Fernando Ribeiro Gomes
- Departamento de Fisiologia, Instituto de Biociências, Universidade de São Paulo, São Paulo, São Paulo, Brasil
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2
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Hervas LS, do Amaral-Silva L, Sartori MR, Guadalupe-Silva A, Gargaglioni LH, Lerchner J, Oliveira MT, Bícego KC. Mitochondrial function in skeletal muscle contributes to reproductive endothermy in tegu lizards (Salvator merianae). Acta Physiol (Oxf) 2024; 240:e14162. [PMID: 38741523 DOI: 10.1111/apha.14162] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Revised: 04/17/2024] [Accepted: 04/28/2024] [Indexed: 05/16/2024]
Abstract
AIM In cyclic climate variations, including seasonal changes, many animals regulate their energy demands to overcome critical transitory moments, restricting their high-demand activities to phases of resource abundance, enabling rapid growth and reproduction. Tegu lizards (Salvator merianae) are ectotherms with a robust annual cycle, being active during summer, hibernating during winter, and presenting a remarkable endothermy during reproduction in spring. Here, we evaluated whether changes in mitochondrial respiratory physiology in skeletal muscle could serve as a mechanism for the increased thermogenesis observed during the tegu's reproductive endothermy. METHODS We performed high-resolution respirometry and calorimetry in permeabilized red and white muscle fibers, sampled during summer (activity) and spring (high activity and reproduction), in association with citrate synthase measurements. RESULTS During spring, the muscle fibers exhibited increased oxidative phosphorylation. They also enhanced uncoupled respiration and heat production via adenine nucleotide translocase (ANT), but not via uncoupling proteins (UCP). Citrate synthase activity was higher during the spring, suggesting greater mitochondrial density compared to the summer. These findings were consistent across both sexes and muscle types (red and white). CONCLUSION The current results highlight potential cellular thermogenic mechanisms in an ectothermic reptile that contribute to transient endothermy. Our study indicates that the unique feature of transitioning to endothermy through nonshivering thermogenesis during the reproductive phase may be facilitated by higher mitochondrial density, function, and uncoupling within the skeletal muscle. This knowledge contributes significant elements to the broader picture of models for the evolution of endothermy, particularly in relation to the enhancement of aerobic capacity.
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Affiliation(s)
- Livia Saccani Hervas
- Department of Animal Morphology and Physiology, São Paulo State University, Jaboticabal, Brazil
| | - Lara do Amaral-Silva
- Department of Biology, Wake Forest University, Winston Salem, North Carolina, USA
| | - Marina Rincon Sartori
- Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Canada
| | - Ane Guadalupe-Silva
- Department of Animal Morphology and Physiology, São Paulo State University, Jaboticabal, Brazil
| | - Luciane H Gargaglioni
- Department of Animal Morphology and Physiology, São Paulo State University, Jaboticabal, Brazil
| | - Johannes Lerchner
- Institute of Physical Chemistry, TU Bergakademie Freiberg, Freiberg, Germany
| | | | - Kênia Cardoso Bícego
- Department of Animal Morphology and Physiology, São Paulo State University, Jaboticabal, Brazil
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3
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Shankey NT, Cohen RE. Neural control of reproduction in reptiles. JOURNAL OF EXPERIMENTAL ZOOLOGY. PART A, ECOLOGICAL AND INTEGRATIVE PHYSIOLOGY 2024; 341:307-321. [PMID: 38247297 DOI: 10.1002/jez.2783] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Revised: 01/03/2024] [Accepted: 01/04/2024] [Indexed: 01/23/2024]
Abstract
Reptiles display considerable diversity in reproductive behavior, making them great models to study the neuroendocrine control of reproductive behavior. Many reptile species are seasonally breeding, such that they become reproductively active during their breeding season and regress to a nonreproductive state during their nonbreeding season, with this transition often prompted by environmental cues. In this review, we will focus on summarizing the neural and neuroendocrine mechanisms controlling reproductive behavior. Three major areas of the brain are involved in reproductive behavior: the preoptic area (POA), amygdala, and ventromedial hypothalamus (VMH). The POA and VMH are sexually dimorphic areas, regulating behaviors in males and females respectively, and all three areas display seasonal plasticity. Lesions to these areas disrupt the onset and maintenance of reproductive behaviors, but the exact roles of these regions vary between sexes and species. Different hormones influence these regions to elicit seasonal transitions. Circulating testosterone (T) and estradiol (E2) peak during the breeding season and their influence on reproduction is well-documented across vertebrates. The conversion of T into E2 and 5α-dihydrotestosterone can also affect behavior. Melatonin and corticosterone have generally inhibitory effects on reproductive behavior, while serotonin and other neurohormones seem to stimulate it. In general, there is relatively little information on the neuroendocrine control of reproduction in reptiles compared to other vertebrate groups. This review highlights areas that should be considered for future areas of research.
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Affiliation(s)
- Nicholas T Shankey
- Department of Biological Sciences, Minnesota State University, Mankato, Mankato, Minnesota, USA
| | - Rachel E Cohen
- Department of Biological Sciences, Minnesota State University, Mankato, Mankato, Minnesota, USA
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4
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Araujo JF, Valgas AAN, de Oliveira DR, Verrastro L, Oliveira GT. Pesticides compromise health: a comparison between lizards collected within and outside an agricultural area. ENVIRONMENTAL MONITORING AND ASSESSMENT 2024; 196:334. [PMID: 38430330 DOI: 10.1007/s10661-024-12498-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2023] [Accepted: 02/24/2024] [Indexed: 03/03/2024]
Abstract
Reptiles are the least studied vertebrates regarding the impact of pesticides on their health, despite being good models for ecotoxicological studies given their abundance and easy handling. Salvator merianae is widely distributed in South America and often found in agricultural cultivation areas. Here, we compared the morphological, biochemical, and physiological parameters of S. merianae from an exposed area (EA) to pesticides and a reference area (RA) or control. These parameters were measured in plasma (albumin, alanine transaminase, alkaline phosphatase, gamma-glutamyl transpeptidase, glucose, total proteins, uric acid, triglycerides, VLDL, and corticosterone) and in erythrocytes (TBARS, glutathione S-transferase, superoxide dismutase, and catalase activity). Blood samples were collected from 28 lizards (EA: three juveniles, three adult females, and three adult males; RA: nine juveniles, four females, and five males) in southern Brazil during the reproductive period. We observed a decrease in body mass, the ratio between body mass and total length and snout-vent length in juvenile lizards collected at EA. The levels of TBARS, glutathione S-transferase, triglycerides, VLDL, and uric acid were altered for juveniles in EA. When comparing the two areas, females differed in superoxide dismutase activity and total proteins, while males differed in superoxide dismutase, catalase, and glutathione S-transferase activity. This set of results shows that S. merianae, especially juveniles, suffers a negative impact when inserted in an agricultural area. The analyzed biomarkers proved suitable for monitoring these lizards and the quality of this environment.
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Affiliation(s)
- J F Araujo
- Laboratório de Fisiologia da Conservação, Escola de Ciências da Saúde e da Vida, Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, Brazil
| | - A A N Valgas
- Laboratório de Herpetologia, Departamento de Zoologia, Universidade Federal Do Rio Grande Do Sul, Porto Alegre, Brazil
| | - D R de Oliveira
- Laboratório de Herpetologia, Departamento de Zoologia, Universidade Federal Do Rio Grande Do Sul, Porto Alegre, Brazil
| | - L Verrastro
- Laboratório de Herpetologia, Departamento de Zoologia, Universidade Federal Do Rio Grande Do Sul, Porto Alegre, Brazil
| | - Guendalina Turcato Oliveira
- Laboratório de Fisiologia da Conservação, Escola de Ciências da Saúde e da Vida, Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, Brazil.
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5
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Norris DO. Thyroid and reproduction in amphibians and reptiles. JOURNAL OF EXPERIMENTAL ZOOLOGY. PART A, ECOLOGICAL AND INTEGRATIVE PHYSIOLOGY 2023; 339:869-877. [PMID: 37522483 DOI: 10.1002/jez.2737] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Revised: 07/11/2023] [Accepted: 07/12/2023] [Indexed: 08/01/2023]
Abstract
The relationship between the thyroid gland and reproduction in amphibians and reptiles has been studied for more than 100 years. Most studies suggest a positive involvement of thyroid hormones with some aspects of reproduction, but some studies support a negative role for thyroid hormones at certain life stages. Comprehensive studies of gene activation/suppression by thyroid hormones and their absence at various levels of the hypothalamo-pituitary-gonadal axis coupled with observations of adrenocorticoid activity, reproductive performance, and metabolic involvement are needed to understand this complex relationship.
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Affiliation(s)
- David O Norris
- Department of Integrative Physiology, University of Colorado, Boulder, Colorado, USA
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6
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Parker MR, Tillman EA, Nazarian LA, Barlowe ML, Lincoln JM, Kluever BM. Skin lipids alone enable conspecific tracking in an invasive reptile, the Argentine black and white tegu lizard (Salvator merianae). PLoS One 2023; 18:e0293591. [PMID: 37906547 PMCID: PMC10617720 DOI: 10.1371/journal.pone.0293591] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2023] [Accepted: 10/17/2023] [Indexed: 11/02/2023] Open
Abstract
Locating potential mates in non-native habitats is one of the most important challenges faced by invasive vertebrate species. The Argentine black and white tegu lizard (Salvator merianae) is a major invasive reptile species in the contiguous United States and is rapidly expanding its range across Florida and the Southeast, in part due to inadequate management strategies and tools. Because a wide array of reptiles, especially squamates (snakes and lizards), have been well-studied for their reliance on chemical cues to locate conspecifics, our project aimed to isolate chemical cues from tegus and assess the ability of adult males and females to use only these cues to make navigation decisions within a Y-maze. Previously, we found that both males and females can follow conspecific scent trails, but the nature of the specific cues used by the tegus was unknown. In this study, we extracted skin lipids from male and female shed skins acquired during the breeding season then tested the extracts for bioactivity at different dilutions prior to Y-maze trials. Both sexes showed positive reactions (e.g., tongue-flicking, nose taps, scratching) to 2:1 skin lipid:hexane dilutions. In the Y-maze, males (n = 7) and females (n = 7) were run in three types of trailing scenarios with these skin lipid extracts: Male-only (pooled lipid extracts from male shed skins), Female-only (extracts from female shed skins), and Male vs. female. Regardless of the tegu lipid type present, tegus preferred to follow the conspecific lipid trail when paired with a neutral control (peanut oil; 2:1 dilution). They also preferred opposite-sex skin lipid trails when paired with same-sex skin lipid trails. We analyzed our results further by comparing them to those of Richard, Bukovich, et al. (2020). We found a synchronization effect of the skin lipids: sex differences in behavior detectable in the scent trail trials were absent when only conspecific skin lipids were present in the environment. Our results indicate that skin lipids alone are sufficient to facilitate mate tracking in S. merianae, these chemical cues induce reliable behavior, and extracted skin lipids have potential for modifying movement patterns of an invasive reptile in their non-native range. If leveraged in concert with current tegu management strategies (i.e., trapping), extracted skin lipids have the potential to bolster management efficacy but field trials are a requisite next step.
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Affiliation(s)
- M. Rockwell Parker
- Department of Biology, James Madison University, Harrisonburg, VA, United States of America
| | - Eric A. Tillman
- National Wildlife Research Center, Florida Field Station, Wildlife Services, U.S. Department of Agriculture, Gainesville, FL, United States of America
| | - Lauren A. Nazarian
- Department of Biology, James Madison University, Harrisonburg, VA, United States of America
| | - Megan L. Barlowe
- Department of Biology, James Madison University, Harrisonburg, VA, United States of America
| | - Julianna M. Lincoln
- Department of Biology, James Madison University, Harrisonburg, VA, United States of America
| | - Bryan M. Kluever
- National Wildlife Research Center, Florida Field Station, Wildlife Services, U.S. Department of Agriculture, Gainesville, FL, United States of America
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7
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Wild KH, Roe JH, Schwanz L, Rodgers E, Dissanayake DSB, Georges A, Sarre SD, Noble DWA. Metabolic consequences of sex reversal in two lizard species: a test of the like-genotype and like-phenotype hypotheses. J Exp Biol 2023; 226:jeb245657. [PMID: 37309620 PMCID: PMC10357012 DOI: 10.1242/jeb.245657] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Accepted: 06/05/2023] [Indexed: 06/14/2023]
Abstract
Vertebrate sex is typically determined genetically, but in many ectotherms sex can be determined by genes (genetic sex determination, GSD), temperature (temperature-dependent sex determination, TSD), or interactions between genes and temperature during development. TSD may involve GSD systems with either male or female heterogamety (XX/XY or ZZ/ZW) where temperature overrides chromosomal sex determination to cause a mismatch between genetic sex and phenotypic sex (sex reversal). In these temperature-sensitive lineages, phylogenetic investigations point to recurrent evolutionary shifts between genotypic and temperature-dependent sex determination. These evolutionary transitions in sex determination can occur rapidly if selection favours the reversed sex over the concordant phenotypic sex. To investigate the consequences of sex reversal on offspring phenotypes, we measured two energy-driven traits (metabolism and growth) and 6 month survival in two species of reptile with different patterns of temperature-induced sex reversal. Male sex reversal occurs in Bassiana duperreyi when chromosomal females (female XX) develop male phenotypes (maleSR XX), while female sex reversal occurs in Pogona vitticeps when chromosomal males (male ZZ) develop female phenotypes (femaleSR ZZ). We show metabolism in maleSR XX was like that of male XY; that is, reflective of phenotypic sex and lower than genotypic sex. In contrast, for Pogona vitticeps, femaleSR ZZ metabolism was intermediate between male ZZ and female ZW metabolic rate. For both species, our data indicate that differences in metabolism become more apparent as individuals become larger. Our findings provide some evidence for an energetic advantage from sex reversal in both species but do not exclude energetic processes as a constraint on the distribution of sex reversal in nature.
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Affiliation(s)
- Kristoffer H. Wild
- Division of Ecology and Evolution, Research School of Biology, The Australian National University, Canberra, ACT 2601, AUS
- Centre for Conservation Ecology and Genomics, Institute for Applied Ecology, University of Canberra, Canberra, ACT 2617, AUS
| | - John H. Roe
- Department of Biology, University of North Carolina Pembroke, Pembroke, NC 28372-1510, USA
| | - Lisa Schwanz
- Evolution and Ecology Research Centre, School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, NSW 2052, Australia
| | - Essie Rodgers
- Centre for Sustainable Aquatic Ecosystems, Harry Butler Institute, Murdoch University, Murdoch, WA 6150, Australia
| | - Duminda S. B. Dissanayake
- Centre for Conservation Ecology and Genomics, Institute for Applied Ecology, University of Canberra, Canberra, ACT 2617, AUS
| | - Arthur Georges
- Centre for Conservation Ecology and Genomics, Institute for Applied Ecology, University of Canberra, Canberra, ACT 2617, AUS
| | - Stephen D. Sarre
- Centre for Conservation Ecology and Genomics, Institute for Applied Ecology, University of Canberra, Canberra, ACT 2617, AUS
| | - Daniel W. A. Noble
- Division of Ecology and Evolution, Research School of Biology, The Australian National University, Canberra, ACT 2601, AUS
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8
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Branco JM, Hingst-Zaher E, Dillon D, Jordan-Ward R, Siegrist J, Fischer JD, Schiesari L, von Hippel FA, Buck CL. A novel method for extraction and quantification of feather triiodothyronine (T3) and application to ecotoxicology of Purple Martin (Progne subis). ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2023; 332:121943. [PMID: 37301461 DOI: 10.1016/j.envpol.2023.121943] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2023] [Revised: 05/29/2023] [Accepted: 05/30/2023] [Indexed: 06/12/2023]
Abstract
Seventy-three percent of aerial insectivore species of birds breeding in North America have declined in the past five years. This decline is even greater in migratory insectivorous species, which face stressors in both their breeding and non-breeding ranges. The Purple Martin (Progne subis) is an aerial insectivore swallow that overwinters in South America and migrates to North America to breed. Purple Martin populations have declined by an estimated 25% since 1966. The eastern subspecies (P. subis subis) has declined the most and overwinters in the Amazon Basin, a region rich in environmental mercury (Hg) contamination. Previous studies reported elevated levels of Hg in feathers of this subspecies, which correlated negatively with body mass and fat reserves. Given the propensity of Hg to disrupt the endocrine system, and the role of thyroid hormones in regulating fat metabolism, this study quantifies concentrations of Hg and the thyroid hormone triiodothyronine (T3) in the feathers of P. subis subis. To our knowledge, this is the first study to extract and quantify T3 in feathers; thus, we developed, tested, and optimized a method for extracting T3 from feather tissue and validated an enzyme immunoassay (EIA) to quantify T3 in Purple Martin feathers. The developed method yielded acceptable results for both parallelism and accuracy. The observed T3 concentrations were statistically modeled along with total Hg (THg) concentrations, but these variables were not significantly correlated. This suggests that the observed variation in THg concentration may be insufficient to cause a discernible change in T3 concentration. Furthermore, the observed effect of breeding location on feather T3 concentration might have obscured any effect of Hg.
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Affiliation(s)
- Jonathan M Branco
- Departmento de Ecologia, Universidade de São Paulo - Rua Do Matão, 321 - Trav. 14, São Paulo, SP, CEP 05508090, Brazil.
| | - Erika Hingst-Zaher
- Museu Biologico, Instituto Butantan - Av Vital Brasil 1500, São Paulo, SP, CEP 05503-900, Brazil
| | - Danielle Dillon
- Department of Biological Sciences, Northern Arizona University - 617 S Beaver, Flagstaff, AZ, 86011, USA
| | - Renee Jordan-Ward
- Department of Biological Sciences, Northern Arizona University - 617 S Beaver, Flagstaff, AZ, 86011, USA
| | - Joe Siegrist
- Purple Martin Conservation Association - 301 Peninsula Drive, Suite 6 Erie, PA, 16505, USA
| | - Jason D Fischer
- Disney's Animals, Science and Environment, Lake Buena Vista, FL, 32830, USA
| | - Luis Schiesari
- Escola de Artes, Ciências e Humanidades, Universidade de São Paulo, Rua Arlindo Bettio, 1000, São Paulo, SP, CEP 03828-000, Brazil
| | - Frank A von Hippel
- Department of Community, Environment and Policy, University of Arizona - 1295 N. Martin Avenue, Tucson, AZ, 85724, USA
| | - C Loren Buck
- Department of Biological Sciences, Northern Arizona University - 617 S Beaver, Flagstaff, AZ, 86011, USA
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9
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da Cruz AL, Vilela B, Klein W. Morphological and physiological traits of the respiratory system in Iguana iguana and other non-avian reptiles. ZOOLOGY 2023; 157:126079. [PMID: 36868103 DOI: 10.1016/j.zool.2023.126079] [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: 03/30/2022] [Revised: 02/08/2023] [Accepted: 02/18/2023] [Indexed: 02/23/2023]
Abstract
Functional morphology considers form and function to be intrinsically related. To understand organismal functions, a detailed knowledge of morphological and physiological traits is necessary. Regarding the respiratory system, the combined knowledge about pulmonary morphology and respiratory physiology is fundamental to understand how animals exchange gases and regulate critical functions to sustain metabolic activity. In the present study, the paucicameral lungs of Iguana iguana were analyzed morphometrically through stereological analysis using light and transmission electron images and compared with unicameral and multicameral lungs of six other non-avian reptiles. The morphological data were combined with physiological information to perform a principal component analysis (PCA) and phylogenetic tests of the relationship of the respiratory system. Iguana iguana, Lacerta viridis, and Salvator merianae presented similar pulmonary morphologies and physiologies when compared to Varanus examthematicus, Gekko gecko, Trachemys scripta, and Crocodylus niloticus. The former species showed an elevated respiratory surface area (%AR), a high diffusion capacity, a low volume of total parenchyma (VP), a low percentage of parenchyma concerning the lung volume (VL), and a higher surface/volume ratio of the parenchyma (SAR/VP), with high respiratory frequency (fR) and consequently total ventilation. The total parenchymal surface area (SA), effective parenchymal surface-to-volume ratio (SAR/VP), respiratory surface area (SAR), and anatomical diffusion factor (ADF) showed a phylogenetic signal, evidence that the morphological traits are more strongly correlated with the species' phylogeny than the physiological traits. In sum, our results indicated that the pulmonary morphology is intrinsically related to physiological traits of the respiratory system. Furthermore, phylogenetic signal tests also indicate that morphological traits are more likely to be evolutionary conserved than physiological traits, suggesting that evolutive physiological adaptations in the respiratory system could happen faster than morphological changes.
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Affiliation(s)
- André Luis da Cruz
- Institute of Biology, Federal University of Bahia, Rua Barão de Jeremoabo 147, Ondina, CEP 40170-115 Salvador, Bahia, Brazil.
| | - Bruno Vilela
- Institute of Biology, Federal University of Bahia, Rua Barão de Jeremoabo 147, Ondina, CEP 40170-115 Salvador, Bahia, Brazil.
| | - Wilfried Klein
- School of Philosophy, Sciences and Literature of Ribeirão Preto, University of São Paulo, Avenida Bandeirantes 3900. Monte Alegre, CEP 14040-900 Ribeirão Preto, São Paulo, Brazil.
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10
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McCaffrey KR, Balaguera-Reina SA, Falk BG, Gati EV, Cole JM, Mazzotti FJ. How to estimate body condition in large lizards? Argentine black and white tegu (Salvator merianae, Duméril and Bibron, 1839) as a case study. PLoS One 2023; 18:e0282093. [PMID: 36827271 PMCID: PMC9955610 DOI: 10.1371/journal.pone.0282093] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Accepted: 02/06/2023] [Indexed: 02/25/2023] Open
Abstract
Body condition is a measure of the health and fitness of an organism represented by available energy stores, typically fat. Direct measurements of fat are difficult to obtain non-invasively, thus body condition is usually estimated by calculating body condition indices (BCIs) using mass and length. The utility of BCIs is contingent on the relationship of BCIs and fat, thereby validation studies should be performed to select the best performing BCI before application in ecological investigations. We evaluated 11 BCIs in 883 Argentine black and white tegus (Salvator merianae) removed from their non-native range in South Florida, United States. Because the length-mass relationship in tegus is allometric, a segmented linear regression model was fit to the relationship between mass and length to define size classes. We evaluated percent, residual, and scaled fat and determined percent fat was the best measure of fat, because it was the least-associated with snout-vent length (SVL). We evaluated performance of BCIs with the full dataset and within size classes and identified Fulton's K as the best performing BCI for our sampled population, explaining up to 19% of the variation in fat content. Overall, we found that BCIs: 1) maintained relatively weak relationships with measures of fat and 2) splitting data into size classes reduced the strength of the relationship (i.e., bias) between percent fat and SVL but did not improve the performance of BCIs. We postulate that the weak performance of BCIs in our dataset was likely due to the weak association of fat with SVL, the body plan and life-history traits of tegus, and potentially inadequate accounting of available energy resources. We caution against assuming that BCIs are strong indicators of body condition across species and suggest that validation studies be implemented, or that alternative or complimentary measures of health or fitness should be considered.
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Affiliation(s)
- Kelly R. McCaffrey
- Department of Wildlife Ecology and Conservation, Fort Lauderdale Research and Education Center, University of Florida, Davie, Florida, United States of America
- * E-mail:
| | - Sergio A. Balaguera-Reina
- Department of Wildlife Ecology and Conservation, Fort Lauderdale Research and Education Center, University of Florida, Davie, Florida, United States of America
| | - Bryan G. Falk
- South Florida Natural Resources Center, National Park Service, Homestead, Florida, United States of America
| | - Emily V. Gati
- Department of Wildlife Ecology and Conservation, Fort Lauderdale Research and Education Center, University of Florida, Davie, Florida, United States of America
| | - Jenna M. Cole
- Department of Wildlife Ecology and Conservation, Fort Lauderdale Research and Education Center, University of Florida, Davie, Florida, United States of America
| | - Frank J. Mazzotti
- Department of Wildlife Ecology and Conservation, Fort Lauderdale Research and Education Center, University of Florida, Davie, Florida, United States of America
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11
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Pewhom A, Supapakorn T, Srakaew N. Male reproductive cycle in a population of the endemic butterfly lizard, Leiolepis ocellata Peters, 1971 (Squamata: Agamidae) from northern Thailand. BMC ZOOL 2022; 7:45. [PMID: 37170386 PMCID: PMC10127433 DOI: 10.1186/s40850-022-00145-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Accepted: 07/18/2022] [Indexed: 11/10/2022] Open
Abstract
Abstract
Background
Fundamental knowledge on the seasonal reproductive microanatomy and endocrinology of reptiles has been collected from several studies of various species. The present study was to determine annual changes in hormonal profiles, and detailed histomorphometric and histochemical characteristics of the entire male reproductive system of the tropical agamid lizard, Leiolepis ocellata.
Results
Male L. ocellata individuals (n = 75) collected from the territory of two provinces (Lampang and Tak) in northern Thailand exhibited annual variation in sex hormonal, histomorphometric, and histochemical characteristics of the male reproductive system. The reproductive cycle was subdivided into eight reproductive periods (early first active, first active, resting, second recrudescent, second active, regressive, quiescent, and first recrudescent), thus displaying a bimodal pattern with two actively reproductive periods. Circulating sex hormones (testosterone, estradiol, and progesterone) peaked in the first active (February) and the second active (June–July) periods. Likewise, gonadosomatic index (GSI) and histomorphometric variables of the testes and of the genital ducts (rete testis, ductuli efferentes, ductus epididymis, and ductus deferens) revealed their highest values in the first active period. Marked increase in protein and carbohydrate production was detectable in the ductuli efferentes during the active periods.
Conclusions
The male reproductive cycle of L. ocellata showed a biannual pattern of the hormonal profile, and detailed histomorphometric and histochemical characteristics of the entire reproductive system. Hence, the present study provides improved basic knowledge on the reptilian reproductive biology with comparative viewpoints to other reptiles.
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12
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Yu S, Wang Z, Zhang L, Nie Y, Deng Y, Liu R, Diao J, Zhou Z. Possible changes in trade-off strategy in female lizards (Eremias argus) during hibernation following exposure to chlorantraniliprole: Impact on the HPG axis and the energy mobilization. PESTICIDE BIOCHEMISTRY AND PHYSIOLOGY 2022; 184:105059. [PMID: 35715026 DOI: 10.1016/j.pestbp.2022.105059] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Revised: 02/17/2022] [Accepted: 02/17/2022] [Indexed: 06/15/2023]
Abstract
Hibernation is a short-term survival strategy for ectotherms to cope with cold weather and food shortages. The energy sources stored before hibernation are used not only in the winter, but also in preparation for reproduction. Reproductive physiology and behavior are primarily regulated by the hypothalamus-pituitary-gonad (HPG) axis. In this study, we examined endocrine hormone changes in the HPG axis of female lizards (Eremias argus) after chlorantraniliprole insecticide (CAP) exposure during hibernation. The levels of gonadotropin-releasing hormone, luteinizing hormone, follicle-stimulating hormone and progesterone were significantly decreased and the level of testosterone (T) was significantly increased after 135d experiment. This study verified the possible endocrine disrupting effects of CAP. More energy material consumption was observed in CAP treated group. Female E. argus preferred to invest energy to present survival when exposed to CAP, rather than to reserve material for following reproductive activity.
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Affiliation(s)
- Simin Yu
- Department of Applied Chemistry, China Agricultural University, No. 2 West Yuanmingyuan Road, Beijing 100193, PR China
| | - Zikang Wang
- Department of Applied Chemistry, China Agricultural University, No. 2 West Yuanmingyuan Road, Beijing 100193, PR China
| | - Luyao Zhang
- Department of Applied Chemistry, China Agricultural University, No. 2 West Yuanmingyuan Road, Beijing 100193, PR China
| | - Yufan Nie
- Department of Applied Chemistry, China Agricultural University, No. 2 West Yuanmingyuan Road, Beijing 100193, PR China
| | - Yue Deng
- Department of Applied Chemistry, China Agricultural University, No. 2 West Yuanmingyuan Road, Beijing 100193, PR China
| | - Rui Liu
- Department of Applied Chemistry, China Agricultural University, No. 2 West Yuanmingyuan Road, Beijing 100193, PR China
| | - Jinling Diao
- Department of Applied Chemistry, China Agricultural University, No. 2 West Yuanmingyuan Road, Beijing 100193, PR China
| | - Zhiqiang Zhou
- Department of Applied Chemistry, China Agricultural University, No. 2 West Yuanmingyuan Road, Beijing 100193, PR China.
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13
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Cruz-Cano NB, Sánchez-Rivera UÁ, Álvarez-Rodríguez C, Dávila-Govantes R, Cárdenas-León M, Martínez-Torres M. Sex steroids are correlated with environmental factors and body condition during the reproductive cycle in females of the lizard Sceloporus torquatus. Gen Comp Endocrinol 2021; 314:113921. [PMID: 34606744 DOI: 10.1016/j.ygcen.2021.113921] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Revised: 09/25/2021] [Accepted: 09/29/2021] [Indexed: 12/06/2022]
Abstract
Reproduction is regulated by multiple factors that influence physiology and behavior to ensure the continuity of species. However, more work is needed to examine the complex relationships between environmental factors and endocrine transducers that modulate reproductive cycles, particularly in lizards. Here, we aimed to characterize the variation in plasma sex steroid levels in different stages of the reproductive cycle in the lizard Sceloporus torquatus and assess whether sex steroid levels were related to environmental factors (temperature, photoperiod, precipitation, and relative humidity) and body condition. Plasma concentrations of estradiol (E2) and progesterone (P4) from blood samples were quantified by enzyme-linked immunosorbent assay (ELISA) and radioimmunoanalysis (RIA), respectively. Our results indicate that sex steroid concentrations were positively related to follicular development but negatively related to temperature and precipitation. E2 increased as the follicles grew, and its concentrations were highest in the preovulatory phase. P4 showed a similar pattern and persisted during pregnancy. Changes in body condition were non-significant and mainly unrelated to the reproductive stage and plasma sex steroids. Our findings indicate that sex steroids change depending on the season and reproductive stage. We observed high concentrations of E2 and P4 in the late vitellogenic and preovulatory stages, probably because of their role in promoting vitellogenesis and ovulation. Additionally, we observed that follicular development is correlated with temperature and photoperiod. To better understand the mechanisms underlying reproduction, future studies of captive populations where environmental factors can be manipulated are needed.
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Affiliation(s)
- Norma Berenice Cruz-Cano
- Posgrado en Ciencias Biológicas, Universidad Nacional Autónoma de México, Edificio D, 1° Piso, Circuito de Posgrados, Ciudad Universitaria, Coyoacán, Ciudad de México, México; Laboratorio de Biología de la Reproducción, Facultad de Estudios Superiores Iztacala, Universidad Nacional Autónoma de México, Avenida de los Barrios s/n, Los Reyes Iztacala, Tlalnepantla, Estado de México, C.P. 54110, México.
| | - Uriel Ángel Sánchez-Rivera
- Laboratorio de Biología de la Reproducción, Facultad de Estudios Superiores Iztacala, Universidad Nacional Autónoma de México, Avenida de los Barrios s/n, Los Reyes Iztacala, Tlalnepantla, Estado de México, C.P. 54110, México
| | - Carmen Álvarez-Rodríguez
- Laboratorio de Biología de la Reproducción, Facultad de Estudios Superiores Iztacala, Universidad Nacional Autónoma de México, Avenida de los Barrios s/n, Los Reyes Iztacala, Tlalnepantla, Estado de México, C.P. 54110, México
| | - Rodrigo Dávila-Govantes
- Laboratorio de Biología de la Reproducción, Facultad de Estudios Superiores Iztacala, Universidad Nacional Autónoma de México, Avenida de los Barrios s/n, Los Reyes Iztacala, Tlalnepantla, Estado de México, C.P. 54110, México
| | - Mario Cárdenas-León
- Laboratorio de Biología de la Reproducción, Facultad de Estudios Superiores Iztacala, Universidad Nacional Autónoma de México, Avenida de los Barrios s/n, Los Reyes Iztacala, Tlalnepantla, Estado de México, C.P. 54110, México; Laboratorio de Hormonas Proteicas, Departamento de Biología de la Reproducción, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Avenida Vasco de Quiroga No. 15, Colonia Belisario Domínguez Sección XVI, Delegación Tlalpan, C.P. 14080, Ciudad de México, México
| | - Martín Martínez-Torres
- Laboratorio de Biología de la Reproducción, Facultad de Estudios Superiores Iztacala, Universidad Nacional Autónoma de México, Avenida de los Barrios s/n, Los Reyes Iztacala, Tlalnepantla, Estado de México, C.P. 54110, México.
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14
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Barr JI, Boisvert CA, Bateman PW. At What Cost? Trade-Offs and Influences on Energetic Investment in Tail Regeneration in Lizards Following Autotomy. J Dev Biol 2021; 9:53. [PMID: 34940500 PMCID: PMC8709428 DOI: 10.3390/jdb9040053] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2021] [Revised: 11/16/2021] [Accepted: 11/23/2021] [Indexed: 01/20/2023] Open
Abstract
Caudal autotomy, the ability to shed a portion of the tail, is a widespread defence strategy among lizards. Following caudal autotomy, and during regeneration, lizards face both short- and long-term costs associated with the physical loss of the tail and the energy required for regeneration. As such, the speed at which the individual regenerates its tail (regeneration rate) should reflect the fitness priorities of the individual. However, multiple factors influence the regeneration rate in lizards, making inter-specific comparisons difficult and hindering broader scale investigations. We review regeneration rates for lizards and tuatara from the published literature, discuss how species' fitness priorities and regeneration rates are influenced by specific, life history and environmental factors, and provide recommendations for future research. Regeneration rates varied extensively (0-4.3 mm/day) across the 56 species from 14 family groups. Species-specific factors, influencing regeneration rates, varied based on the type of fracture plane, age, sex, reproductive season, and longevity. Environmental factors including temperature, photoperiod, nutrition, and stress also affected regeneration rates, as did the method of autotomy induction, and the position of the tail also influenced regeneration rates for lizards. Additionally, regeneration could alter an individual's behaviour, growth, and reproductive output, but this varied depending on the species.
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Affiliation(s)
- James I. Barr
- School of Molecular and Life Sciences, Curtin University, Kent Street, Bentley, WA 6102, Australia
| | - Catherine A. Boisvert
- School of Molecular and Life Sciences, Curtin University, Kent Street, Bentley, WA 6102, Australia
| | - Philip W. Bateman
- School of Molecular and Life Sciences, Curtin University, Kent Street, Bentley, WA 6102, Australia
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15
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Sánchez-Loria O, Gomez E, Arce O, Chamut S. Metabolic and Hormonal Changes Associated with Vitellogenesis in Salvator merianae Lizards. Zoolog Sci 2021; 38:459-465. [PMID: 34664921 DOI: 10.2108/zs210013] [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: 03/05/2021] [Accepted: 07/10/2021] [Indexed: 11/17/2022]
Abstract
Vitellogenesis in oviparous vertebrates is a critical marker of the restart of seasonal reproductive activity. During this process of multihormonal regulation, females allocate a considerable amount of organic and mineral reserves to the synthesis of yolk, with changes in their plasma values. In this work, we determined plasma levels of various metabolites and steroid hormones throughout the reproductive cycle in females of Salvator merianae who developed vitellogenic and non-vitellogenic follicular cycles. We worked for two consecutive years with 20 adult females from the Experimental Hatchery of the Facultad de Agronomía y Zootecnia of the Universidad Nacional de Tucumán. Values of metabolites: glucose, triglycerides, cholesterol, calcium, phosphorus, albumin, total proteins, and hormones: estradiol, progesterone, and testosterone, were determined during the following stages of the annual cycle: hibernation, hibernation emergence, courtship-mating, oviposition, and incubation. Vitellogenic females showed significantly higher plasma levels of triglycerides, calcium, phosphorus, and albumin than non-vitellogenic females, mainly in the courtship-mating stage (advanced vitellogenesis). In contrast, annual cholesterol averages were lower in vitellogenic females. Glucose showed changes throughout the annual cycle regardless of the vitellogenic condition. Total proteins plasma levels had very few fluctuations during the cycle. Among the hormones studied, only testosterone showed differences related to vitellogenic condition, with higher levels in non-vitellogenic females during the entire reproductive cycle. The knowledge of these changes associated with vitellogenesis will improve zootechnical management and will allow optimizing the reproductive efficiency of Salvator lizards in captivity.
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Affiliation(s)
- Olga Sánchez-Loria
- Facultad de Agronomía y Zootecnia. Universidad Nacional de Tucumán. F. Ameghino s/n. 4105. Tucumán. Argentina,
| | - Eliana Gomez
- Facultad de Agronomía y Zootecnia. Universidad Nacional de Tucumán. F. Ameghino s/n. 4105. Tucumán. Argentina
| | - Osvaldo Arce
- Facultad de Agronomía y Zootecnia. Universidad Nacional de Tucumán. F. Ameghino s/n. 4105. Tucumán. Argentina
| | - Silvia Chamut
- Facultad de Agronomía y Zootecnia. Universidad Nacional de Tucumán. F. Ameghino s/n. 4105. Tucumán. Argentina
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16
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Seasonal changes in steroid and thyroid hormone content in shed skins of the tegu lizard Salvator merianae. J Comp Physiol B 2021; 192:127-139. [PMID: 34379176 DOI: 10.1007/s00360-021-01397-3] [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: 01/10/2021] [Revised: 06/30/2021] [Accepted: 08/02/2021] [Indexed: 10/20/2022]
Abstract
Sampling blood for endocrine analysis from some species may not be practical or ethical. Quantification of hormones extracted from nontypical sample types, such as keratinized tissues, offers a less invasive alternative to the traditional collection and analysis of blood. Here, we aimed to validate assays by using parallelism and accuracy tests for quantification of testosterone, corticosterone, progesterone, and triiodothyronine (T3) in shed skins of tegu lizards. We assessed whether hormone content of sheds varied across one year similar to what was previously detected in plasma samples. In addition, we aimed to identify the phase relationship between hormone levels of shed skin and plasma levels obtained from the same animals. High frequency of shedding occurred during the active season for tegus (spring/summer), while shedding ceased during hibernation (winter). All hormones measured in shed skins exhibited seasonal changes in concentration. Levels of testosterone in shed skins of male tegus correlated positively with plasma testosterone levels, while corticosterone in both males and females exhibited an inverse relationship between sample types for the same month of collection. An inverse relationship was found when accounting for a lag time of 3 and 4 months between sheds and plasma testosterone. These results indicate that endocrine content of sheds may be confounded by factors (i.e., seasons, environmental temperature, thermoregulatory behavior, among others) that affect frequency of molting, skin blood perfusion, and therefore hormone transfer from the bloodstream and deposition in sheds of squamates.
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17
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Holden KG, Gangloff EJ, Gomez-Mancillas E, Hagerty K, Bronikowski AM. Surviving winter: Physiological regulation of energy balance in a temperate ectotherm entering and exiting brumation. Gen Comp Endocrinol 2021; 307:113758. [PMID: 33771532 DOI: 10.1016/j.ygcen.2021.113758] [Citation(s) in RCA: 6] [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: 10/20/2020] [Revised: 01/24/2021] [Accepted: 03/08/2021] [Indexed: 12/21/2022]
Abstract
Characterizing the physiological response to prolonged cold exposure is essential for understanding the maintenance of long-term energy balance. As part of their natural life cycle, temperate ectotherms are often exposed to seasonal variation in temperatures, including extended periods of cold well below their activity range. Relatively little is known about variation in physiological responses as vertebrate ectotherms enter and exit brumation in response to sustained cold temperatures. We tested the influence of temperature on physiology before, during, and after a simulated brumation in the checkered garter snake (Thamnophis marcianus), a widespread ectothermic vertebrate. We tested for the relative effect of immediate temperature and physiological context (entering or exiting brumation) on hormones regulating energy balance, indicators of energy availability, and resting metabolic rate (V̇O2). Plasma corticosterone, glucose, and insulin, as well as immune cell heterophil: lymphocyte ratios responded to temperature, though they did so with different thermal response curves. Thermal sensitivity varied both among and within physiological measures depending on whether animals were going into or coming out of brumation. Additionally, V̇O2 was regulated beyond simple temperature-dependence, whereby post-brumation measures were depressed relative to pre-brumation measures at the same temperature. This pattern was characterized by a change in the temperature coefficient (Q10), with a larger pre-brumation Q10, suggesting reduced thermal sensitivity of metabolic rate following a period of extended cold exposure. The integrated physiological response presented here demonstrates not only temperature dependence across physiological axes, but seasonal variation in thermal responsiveness. Our results suggest that energy allocation decisions and hormonal regulation of underlying processes promote differing levels of thermal sensitivity when entering or exiting brumation.
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Affiliation(s)
- Kaitlyn G Holden
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, IA 50011, USA.
| | - Eric J Gangloff
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, IA 50011, USA; Department of Zoology, Ohio Wesleyan University, Delaware, OH 43015, USA
| | | | - Kelsi Hagerty
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, IA 50011, USA
| | - Anne M Bronikowski
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, IA 50011, USA
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18
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Madelaire CB, Zena LA, Dillon D, Silva DP, Hunt KE, Loren Buck C, Bícego KC, Gomes FR. Who rules over immunology? Sseasonal variation in body temperature,, steroid hormones, and immune variables in a tegu lizard. Integr Comp Biol 2021; 61:1867-1880. [PMID: 34022037 DOI: 10.1093/icb/icab093] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Multiple factors can influence the immune response of ectothermic vertebrates, including body temperature, gonadal steroids, and seasonality, in ways that are thought to reflect trade-offs between energetic investment in immunity vs. reproduction. Hibernating tegu lizards (Salvator merianae) are a unique model to investigate how immunocompetence might be influenced by different factors during their annual cycle. We assessed immunological measures (plasma bacterial killing ability, total and differential leukocyte count), plasma hormone levels (testosterone in males, estradiol and progesterone in females, and corticosterone in both sexes), body temperature, and body condition from adult tegus during each stage of their annual cycle: reproduction, post-reproduction/preparation for hibernation, and hibernation. Our hypothesis that immune traits present higher values during the reproductive phase, and a sharp decrease during hibernation, was partially supported. Immune variables did not change between life history stages, except for total number of leukocytes, which was higher at the beginning of the reproductive season (September) in both males and females. Average body temperature of the week prior to sampling was positively correlated with number of eosinophils, basophils, monocytes and azurophils, corroborating other studies showing that when animals maintain a high Tb, there is an increase in immune activity. Surprisingly, no clear relationship between immune traits and gonadal steroids or corticosterone levels was observed, even when including life history stage in the model. When gonadal hormones peaked in males and females, heterophil:lymphocyte ratio (which often elevates during physiological stress) also increased. Additionally, we did not observe any trade-off between reproduction and immunity traits, sex differences in immune traits or a correlation between body condition and immune response. Our results suggest that variation in patterns of immune response and correlations with body condition and hormone secretion across the year can depend upon the specific hormone and immune trait, and that experienced Tb is an important variable determining immune response in ectotherms.
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Affiliation(s)
- Carla B Madelaire
- Department of Biological Sciences, Northern Arizona University, 1899 S San Francisco St, Flagstaff, AZ, 86001, USA.,Department of Physiology, Institute of Biosciences, University of São Paulo, Trav. 14 da Rua do Matão, 321, São Paulo, SP, 05508-090, Brazil
| | - Lucas A Zena
- Department of Biological Sciences, Northern Arizona University, 1899 S San Francisco St, Flagstaff, AZ, 86001, USA.,Department of Physiology, Institute of Biosciences, University of São Paulo, Trav. 14 da Rua do Matão, 321, São Paulo, SP, 05508-090, Brazil.,Department of Animal Morphology and Physiology, College of Agricultural and Veterinary Sciences, São Paulo State University, Via de Acesso Prof. Paulo Donato Castellane s/n, Jaboticabal, SP, 14884-900, Brazil
| | - Danielle Dillon
- Department of Biological Sciences, Northern Arizona University, 1899 S San Francisco St, Flagstaff, AZ, 86001, USA
| | - Diego P Silva
- Smithsonian-Mason School of Conservation & George Mason University, 1500 Remount Rd, Front Royal, VA, 22630, USA
| | - Kathleen E Hunt
- Department of Biological Sciences, Northern Arizona University, 1899 S San Francisco St, Flagstaff, AZ, 86001, USA
| | - C Loren Buck
- Department of Biological Sciences, Northern Arizona University, 1899 S San Francisco St, Flagstaff, AZ, 86001, USA
| | - Kênia C Bícego
- Department of Animal Morphology and Physiology, College of Agricultural and Veterinary Sciences, São Paulo State University, Via de Acesso Prof. Paulo Donato Castellane s/n, Jaboticabal, SP, 14884-900, Brazil
| | - Fernando R Gomes
- Department of Physiology, Institute of Biosciences, University of São Paulo, Trav. 14 da Rua do Matão, 321, São Paulo, SP, 05508-090, Brazil
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19
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Titon SCM, Titon Junior B, Assis VR, Vasconcelos-Teixeira R, Garcia Neto PG, Lima AS, Ferreira LDF, Fernandes PA, Gomes FR, Markus RP. Hormonal daily variation co-varies with immunity in captive male bullfrogs (Lithobates catesbeianus). Gen Comp Endocrinol 2021; 303:113702. [PMID: 33359060 DOI: 10.1016/j.ygcen.2020.113702] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Revised: 08/12/2020] [Accepted: 12/13/2020] [Indexed: 11/25/2022]
Abstract
Almost all physiological processes within the organism, including immune parameters and hormones, follow a circadian rhythm. These daily fluctuations are often observed in free-living organisms; however, little is known regarding hormonal and immune daily variations in anurans, particularly under laboratory conditions. This study aimed to investigate the hormonal and immune daily variation in captive-bred Bullfrogs (Lithobates catesbeianus) under constant conditions (21 °C and 12:12 LD cycle). Our results showed a daily variation for plasma corticosterone (CORT), testosterone (T), and melatonin (MEL), as well as for blood leukocyte profile, phagocytic activity, and plasma bacterial killing ability (BKA). Hormonal profile and immune activity were higher at the dark when compared with the light phase; however, monocytes and lymphocytes followed the opposite pattern. Moreover, CORT was positively correlated with phagocytosis percentage of blood cells, BKA, and monocytes, while MEL and T showed a positive correlation with PP. Our results demonstrate the daily covariation of different immune variables and immunomodulatory hormones. These 24 h-day variations and covariation certainly have broad implications and need to be considered for better understanding anuran physiology both in the context of laboratory and field studies.
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Affiliation(s)
| | - Braz Titon Junior
- Departamento de Fisiologia, Instituto de Biociências, Universidade de São Paulo, São Paulo, São Paulo, Brazil
| | - Vania Regina Assis
- Departamento de Fisiologia, Instituto de Biociências, Universidade de São Paulo, São Paulo, São Paulo, Brazil
| | | | | | - Alan Siqueira Lima
- Departamento de Fisiologia, Instituto de Biociências, Universidade de São Paulo, São Paulo, São Paulo, Brazil
| | - Letícia de França Ferreira
- Departamento de Fisiologia, Instituto de Biociências, Universidade de São Paulo, São Paulo, São Paulo, Brazil
| | - Pedro A Fernandes
- Departamento de Fisiologia, Instituto de Biociências, Universidade de São Paulo, São Paulo, São Paulo, Brazil
| | - Fernando Ribeiro Gomes
- Departamento de Fisiologia, Instituto de Biociências, Universidade de São Paulo, São Paulo, São Paulo, Brazil
| | - Regina P Markus
- Departamento de Fisiologia, Instituto de Biociências, Universidade de São Paulo, São Paulo, São Paulo, Brazil
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20
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Fernández Ajó AA, Hunt KE, Giese AC, Sironi M, Uhart M, Rowntree VJ, Marón CF, Dillon D, DiMartino M, Buck CL. Retrospective analysis of the lifetime endocrine response of southern right whale calves to gull wounding and harassment: A baleen hormone approach. Gen Comp Endocrinol 2020; 296:113536. [PMID: 32540491 DOI: 10.1016/j.ygcen.2020.113536] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/06/2019] [Revised: 05/28/2020] [Accepted: 06/08/2020] [Indexed: 11/30/2022]
Abstract
Physiological measurements are informative in assessing the relative importance of stressors that potentially impact the health of wildlife. Kelp Gulls, Larus dominicanus (KG), resident to the region of Península Valdés, Argentina, have developed a unique behavior of landing on the backs of southern right whale adults and calves, Eubalaena australis (SRW), where they feed on their skin and blubber. This parasitic behavior results in large open wounds on the dorsal surface of the whale. Coincidently, the SRW population off the coast of Península Valdés has experienced elevated calf mortality. We quantified levels of glucocorticoids and thyroid hormone extracted from baleen of dead calves to evaluate, retrospectively, the endocrine response of whale calves to gull wounding and harassment. Baleen accumulates hormones as it grows, allowing evaluation of long-term trends in physiological condition. While glucocorticoids (GCs) are known to increase in response to stressors such as disturbance, the metabolic hormone triiodothyronine (T3) has been shown to decrease under sustained food deprivation but is largely unaffected by disturbance stress. We quantified lifetime patterns of GCs and T3 in baleen recovered at necropsy from 36 southern right whale calves with varying severity of wounding from KGs. GC levels in baleen correlated positively with the degree of wounding, while T3 levels remained stable irrespective of the severity of the wounding. Our results suggest no evidence of malnutrition in low vs. severely wounded whales. However, the positive correlation of GCs with wound severity indicates that heavily wounded calves are suffering high levels of physiological stress before they die. This suggests that KG wounding may have contributed to the high southern right whale calf mortality observed in the Península Valdés region of Argentina.
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Affiliation(s)
- Alejandro A Fernández Ajó
- Department of Biological Sciences, Northern Arizona University, 617 S. Beaver St., PO Box 5640, Flagstaff, AZ 86011, USA; Instituto de Conservación de Ballenas, Capital Federal, O'Higgins 4380, Ciudad Autónoma de Buenos Aires 1429, Argentina.
| | - Kathleen E Hunt
- George Mason University, Smithsonian-Mason School of Conservation 1500 Remount Rd, Front Royal, VA 22630, USA
| | - A Carolina Giese
- Instituto Patagónico Para el Estudio de los Ecosistemas Continentales. IPEEC-CONICET, Bvd. Brown 2915 (9120), Puerto Madryn, Argentina
| | - Mariano Sironi
- Instituto de Conservación de Ballenas, Capital Federal, O'Higgins 4380, Ciudad Autónoma de Buenos Aires 1429, Argentina; Southern Right Whale Health Monitoring Program, Los Alerces 3376, Puerto Madryn, Chubut 9120, Argentina; Facultad de Ciencias Exactas, Físicas y Naturales (FCEFyN), Universidad Nacional de Córdoba, Av. Vélez Sársfield 299, Córdoba 5000, Argentina
| | - Marcela Uhart
- Southern Right Whale Health Monitoring Program, Los Alerces 3376, Puerto Madryn, Chubut 9120, Argentina; Wildlife Health Center, School of Veterinary Medicine, University of California, 1089 Veterinary Medicine Drive, VM3B Ground Floor, Davis, CA 95616, USA
| | - Victoria J Rowntree
- Instituto de Conservación de Ballenas, Capital Federal, O'Higgins 4380, Ciudad Autónoma de Buenos Aires 1429, Argentina; Southern Right Whale Health Monitoring Program, Los Alerces 3376, Puerto Madryn, Chubut 9120, Argentina; Department of Biology, University of Utah, 257 South 1400 East University of Utah, Salt Lake City, UT 84112, USA; Ocean Alliance/Whale Conservation Institute, 32 Horton St, Gloucester, MA 01930, USA
| | - Carina F Marón
- Instituto de Conservación de Ballenas, Capital Federal, O'Higgins 4380, Ciudad Autónoma de Buenos Aires 1429, Argentina; Facultad de Ciencias Exactas, Físicas y Naturales (FCEFyN), Universidad Nacional de Córdoba, Av. Vélez Sársfield 299, Córdoba 5000, Argentina
| | - Danielle Dillon
- Department of Biological Sciences, Northern Arizona University, 617 S. Beaver St., PO Box 5640, Flagstaff, AZ 86011, USA
| | - Matias DiMartino
- Southern Right Whale Health Monitoring Program, Los Alerces 3376, Puerto Madryn, Chubut 9120, Argentina
| | - C Loren Buck
- Department of Biological Sciences, Northern Arizona University, 617 S. Beaver St., PO Box 5640, Flagstaff, AZ 86011, USA
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21
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Richard SA, Bukovich IMG, Tillman EA, Jayamohan S, Humphrey JS, Carrington PE, Bruce WE, Kluever BM, Avery ML, Parker MR. Conspecific chemical cues facilitate mate trailing by invasive Argentine black and white tegus. PLoS One 2020; 15:e0236660. [PMID: 32785239 PMCID: PMC7423067 DOI: 10.1371/journal.pone.0236660] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2020] [Accepted: 07/09/2020] [Indexed: 11/19/2022] Open
Abstract
Squamate reptiles (snakes and lizards) rely on chemical cues from conspecifics to search the environment for potential mates. How such cues are used by invasive species to facilitate reproduction, especially seasonally, is a key question that can inform management practices. The Argentine black and white tegu (Salvator merianae) is an invasive reptile species in south Florida threatening native fauna in biodiverse regions such as Everglades National Park. While some information exists on the reproductive ecology of this species in its native range in South America, the chemical ecology of S. merianae is unclear especially in its invasive range. By testing both male (n = 7) and female (n = 7) tegus in a Y-maze apparatus, we assessed if either sex follows chemical trails left by conspecifics and if behaviors were sex- or season-specific. We conducted three types of trials where conspecifics created odor trails: Male-only (male scent only in base and one arm of Y), Female-only, and Male vs. female. Males did not preferentially follow scent trails from either sex, but they did differentially investigate conspecific scent from both sexes. Seasonally, males showed increased rates of chemosensory sampling (rates of tongue-flicking) during the spring (breeding season; March-May) compared to fall (non-breeding season; September-November). Males also had reduced turning and pausing behavior while trailing in the spring. Female tegus exhibited stronger conspecific trailing abilities than males, following both male and female scent trails, and they explored the maze less before making an arm choice. Females also investigated the scent trails intensely compared to males (more passes in scented arms, more time with scent trails). Our results demonstrate for the first time that females of an invasive reptile species can follow conspecific scent trails. Given the strong female responses to odor, sex-specific targeting of tegus via application of a conspecific chemical cue in traps could enhance removal rates of females during the breeding season.
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Affiliation(s)
- Shannon A. Richard
- Department of Biology, James Madison University, Harrisonburg, VA, United States of America
| | | | - Eric A. Tillman
- National Wildlife Research Center, Florida Field Station, U.S. Department of Agriculture, Gainesville, FL, United States of America
| | - Sanjiv Jayamohan
- Department of Biology, James Madison University, Harrisonburg, VA, United States of America
| | - John S. Humphrey
- National Wildlife Research Center, Florida Field Station, U.S. Department of Agriculture, Gainesville, FL, United States of America
| | - Paige E. Carrington
- Department of Biology, James Madison University, Harrisonburg, VA, United States of America
| | - William E. Bruce
- National Wildlife Research Center, Florida Field Station, U.S. Department of Agriculture, Gainesville, FL, United States of America
| | - Bryan M. Kluever
- National Wildlife Research Center, Florida Field Station, U.S. Department of Agriculture, Gainesville, FL, United States of America
| | - Michael L. Avery
- National Wildlife Research Center, Florida Field Station, U.S. Department of Agriculture, Gainesville, FL, United States of America
| | - M. Rockwell Parker
- Department of Biology, James Madison University, Harrisonburg, VA, United States of America
- * E-mail:
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22
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Zena LA, Dillon D, Hunt KE, Navas CA, Buck CL, Bícego KC. Hormonal correlates of the annual cycle of activity and body temperature in the South-American tegu lizard (Salvator merianae). Gen Comp Endocrinol 2020; 285:113295. [PMID: 31580883 DOI: 10.1016/j.ygcen.2019.113295] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Revised: 08/19/2019] [Accepted: 09/29/2019] [Indexed: 01/29/2023]
Abstract
Life history transitions and hormones are known to interact and influence many aspects of animal physiology and behavior. The South-American tegu lizard (Salvator merianae) exhibits a profound seasonal shift in metabolism and body temperature, characterized by high daily activity during warmer months, including reproductive endothermy in spring, and metabolic suppression during hibernation in winter. This makes S. merianae an interesting subject for studies of interrelationships between endocrinology and seasonal changes in physiology/behavior. We investigated how plasma concentrations of hormones involved in regulation of energy metabolism (thyroid hormones T4 and T3; corticosterone) and reproduction (testosterone in males and estrogen/progesterone in females) correlate with activity and body temperature (Tb) across the annual cycle of captive held S. merianae in semi-natural conditions. In our initial model, thyroid hormones and corticosterone showed a positive relationship with activity and Tb with independent of sex: T3 positively correlated with activity and Tb, while T4 and corticosterone correlated positively with changes in Tb only. This suggests that thyroid hormones and glucocorticoids may be involved in metabolic transitions of annual cycle events. When accounting for sex-steroid hormones, our sex separated models showed a positive relationship between testosterone and Tb in males and progesterone and activity in females. Coupling seasonal endocrine measures with activity and Tb may expand our understanding of the relationship between animal's physiology and its environment. Manipulative experiments are required in order to unveil the directionality of influences existing among abiotic factors and the hormonal signaling of annual cyclicity in physiology/behavior.
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Affiliation(s)
- Lucas A Zena
- Department of Physiology, Institute of Biosciences, University of São Paulo, 05508-090 São Paulo, SP, Brazil; Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ, USA.
| | - Danielle Dillon
- Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ, USA
| | - Kathleen E Hunt
- Department of Biology, George Mason University, Fairfax, VA, USA
| | - Carlos A Navas
- Department of Physiology, Institute of Biosciences, University of São Paulo, 05508-090 São Paulo, SP, Brazil
| | - C Loren Buck
- Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ, USA
| | - Kênia C Bícego
- Department of Animal Morphology and Physiology, College of Agricultural and Veterinary Sciences, São Paulo State University, 14884-900 Jaboticabal, São Paulo, Brazil.
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23
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Frýdlová P, Mrzílková J, Šeremeta M, Křemen J, Dudák J, Žemlička J, Němec P, Velenský P, Moravec J, Koleška D, Zahradníčková V, Jirásek T, Kodym P, Frynta D, Zach P. Universality of indeterminate growth in lizards rejected: the micro-CT reveals contrasting timing of growth cartilage persistence in iguanas, agamas, and chameleons. Sci Rep 2019; 9:18913. [PMID: 31831851 PMCID: PMC6908584 DOI: 10.1038/s41598-019-54573-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2019] [Accepted: 11/06/2019] [Indexed: 02/06/2023] Open
Abstract
Squamate reptiles are considered to exhibit indeterminate growth. Nevertheless, current literature disputes the available definitions of this growth type, presents new theoretical models, and questions its universality in cold-blooded vertebrates. We have followed up on our previous research employing micro-CT to explore growth plate cartilage (GPC) in the epiphysis of long bones, which is responsible for longitudinal skeletal growth by the endochondral ossification process. We focused on numerous and highly diversified group of the Iguania clade comprising Acrodonta (agamas and chameleons) and Pleurodonta ("iguanas"). We recorded the absence of GPC in most of the examined adult Pleurodonta specimens and interpret it as an irreversible arrest of skeletal growth. This finding clearly rejects the universality of indeterminate growth in lizards. On the other hand, we found apparent GPC preservation in most of the adult specimens belonging to Acrodonta. This suggests a preserved ability to continue body growth throughout most of their life. We discuss the uncovered disparity between Acrodonta and Pleurodonta and emphasize the importance of GPC degradation timing.
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Affiliation(s)
- Petra Frýdlová
- Department of Zoology, Faculty of Science, Charles University, Viničná 7, CZ-12844, Prague, Czech Republic
- Department of Anatomy, Third Faculty of Medicine, Charles University, Ruská 2411/87, CZ-10000, Prague, Czech Republic
| | - Jana Mrzílková
- Specialized laboratory of experimental imaging, Ruská 2411/87, CZ-10000, Prague, Czech Republic
- Department of Anatomy, Third Faculty of Medicine, Charles University, Ruská 2411/87, CZ-10000, Prague, Czech Republic
| | - Martin Šeremeta
- Specialized laboratory of experimental imaging, Ruská 2411/87, CZ-10000, Prague, Czech Republic
- Department of Anatomy, Third Faculty of Medicine, Charles University, Ruská 2411/87, CZ-10000, Prague, Czech Republic
| | - Jan Křemen
- Specialized laboratory of experimental imaging, Ruská 2411/87, CZ-10000, Prague, Czech Republic
- Department of Anatomy, Third Faculty of Medicine, Charles University, Ruská 2411/87, CZ-10000, Prague, Czech Republic
| | - Jan Dudák
- Institute of Experimental and Applied Physics, Czech Technical University in Prague, Husova 5, CZ-11000, Prague, Czech Republic
| | - Jan Žemlička
- Institute of Experimental and Applied Physics, Czech Technical University in Prague, Husova 5, CZ-11000, Prague, Czech Republic
| | - Pavel Němec
- Department of Zoology, Faculty of Science, Charles University, Viničná 7, CZ-12844, Prague, Czech Republic
| | - Petr Velenský
- Prague Zoo, U Trojského Zámku 3, CZ-17100, Prague, Czech Republic
| | - Jiří Moravec
- Department of Zoology, National Museum, Cirkusová 1740, CZ-19300, Prague, Czech Republic
| | - Daniel Koleška
- Department of Zoology and Fisheries, Faculty of Agrobiology, Food and Natural Resources, Czech University of Life Sciences Prague, Kamýcká 129, CZ-16500, Prague, Czech Republic
| | - Veronika Zahradníčková
- Department of Zoology, Faculty of Science, Charles University, Viničná 7, CZ-12844, Prague, Czech Republic
| | - Tomáš Jirásek
- Zoological and Botanical Garden Pilsen, Pod Vinicemi 9, CZ-30116, Pilsen, Czech Republic
| | - Petr Kodym
- National Institute of Public Health, Šrobárova 48, CZ-10042, Prague, Czech Republic
| | - Daniel Frynta
- Department of Zoology, Faculty of Science, Charles University, Viničná 7, CZ-12844, Prague, Czech Republic.
| | - Petr Zach
- Specialized laboratory of experimental imaging, Ruská 2411/87, CZ-10000, Prague, Czech Republic
- Department of Anatomy, Third Faculty of Medicine, Charles University, Ruská 2411/87, CZ-10000, Prague, Czech Republic
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24
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Seasonal variation of hypoxic and hypercarbic ventilatory responses in the lizard Tropidurus torquatus. Comp Biochem Physiol A Mol Integr Physiol 2019; 237:110534. [PMID: 31401309 DOI: 10.1016/j.cbpa.2019.110534] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Revised: 07/27/2019] [Accepted: 08/01/2019] [Indexed: 12/23/2022]
Abstract
Carbon dioxide (CO2) and oxygen (O2) influence the breathing pattern of reptiles, especially when CO2 is in excess or O2 at low concentrations and the effects of these gases on the respiratory response varies according to the species. In addition to respiratory gases, seasonal changes can also modulate breathing pattern and ventilatory responses to hypoxia and hypercarbia. Therefore, the present study investigated the breathing pattern and ventilatory responses to hypercarbia (5% CO2) and hypoxia (5% O2) of the Neotropical lizard Tropidurus torquatus over a period of one year, covering all seasons (summer, autumn, winter and spring). Our data suggest that like other ectothermic sauropsids, Tropidurus torquatus possesses distinct ventilatory responses to hypoxia and hypercarbia, being more sensitive to changes in CO2 than in O2. Additionally, the ventilatory responses to hypoxia were more pronounced during summer and hypercanic and pos-hypercapnic ventilatory response was reduced during spring, suggesting that seasonality modulates the control of ventilation in this species.
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