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Spatial ecology of the invasive Asian common toad in Madagascar and its implications for invasion dynamics. Sci Rep 2023; 13:3526. [PMID: 36864075 PMCID: PMC9981762 DOI: 10.1038/s41598-023-29467-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Accepted: 02/06/2023] [Indexed: 03/04/2023] Open
Abstract
Invasion dynamics are determined, among other aspects, by the spatial behaviour of invasive populations. The invasive toad Duttaphrynus melanostictus is spreading inland from the eastern coast of Madagascar, causing considerable ecological impacts. Understanding the basic factors determining the spread dynamics can inform management strategies and provide insights into spatial evolutionary processes. We radio-tracked 91 adult toads in three localities along the invasion gradient to determine whether spatial sorting of dispersive phenotypes is occurring, and investigate intrinsic and extrinsic determinants of spatial behaviour. Overall, toads in our study appeared as habitat generalists, and their sheltering behaviour was tied to water proximity, with toads changing shelter more frequently closer to waterbodies. Toads showed low displacement rates (mean = 4.12 m/day) and quite a philopatric behaviour but were able to perform daily movements of over 50 m. We did not detect any spatial sorting of dispersal-relevant traits nor sex- or size-biased dispersal. Our results suggest that toads are more likely to expand their range during the wet season, and that the range expansion is probably dominated by short-distance dispersal at this stage of the invasion, although a future increase in invasion speed is expected, due to the capacity for long-distance movements of this species.
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Reproductive phenology of neotropical leptodactylid frogs (genera Physalaemus and Pseudopaludicola): Integrating gametogenic cycle, sexual maturity and age. ZOOL ANZ 2022. [DOI: 10.1016/j.jcz.2022.08.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Brum AJ, Loebens L, Prado CPA, Cechin SZ. Reproductive cycle, sexual maturity and longevity of
Odontophrynus americanus
(Anura: Odontophrynidae) in South Brazil. ACTA ZOOL-STOCKHOLM 2020. [DOI: 10.1111/azo.12359] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Amanda J.C. Brum
- Programa de Pós‐Graduação em Biodiversidade Animal Centro de Ciências Naturais e Exatas Universidade Federal de Santa Maria Santa Maria Brazil
- Laboratório de Herpetologia Departamento de Ecologia e Evolução Centro de Ciências Naturais e Exatas Universidade Federal de Santa Maria Santa Maria Brazil
| | - Luiza Loebens
- Programa de Pós‐Graduação em Biodiversidade Animal Centro de Ciências Naturais e Exatas Universidade Federal de Santa Maria Santa Maria Brazil
- Laboratório de Herpetologia Departamento de Ecologia e Evolução Centro de Ciências Naturais e Exatas Universidade Federal de Santa Maria Santa Maria Brazil
| | - Cynthia P. A. Prado
- Departamento de Morfologia e Fisiologia Animal Faculdade de Ciências Agrárias e Veterinárias Universidade Estadual Paulista São Paulo Brazil
| | - Sonia Z. Cechin
- Programa de Pós‐Graduação em Biodiversidade Animal Centro de Ciências Naturais e Exatas Universidade Federal de Santa Maria Santa Maria Brazil
- Laboratório de Herpetologia Departamento de Ecologia e Evolução Centro de Ciências Naturais e Exatas Universidade Federal de Santa Maria Santa Maria Brazil
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Caldart VM, Loebens L, Brum AJC, Bataioli L, Cechin SZ. Reproductive Cycle, Size and Age at Sexual Maturity, and Sexual Dimorphism in the Stream-Breeding Frog Crossodactylus schmidti (Hylodidae). SOUTH AMERICAN JOURNAL OF HERPETOLOGY 2019. [DOI: 10.2994/sajh-d-17-00060.1] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Affiliation(s)
- Vinícius Matheus Caldart
- Departamento de Ecologia, Instituto de Biociências, Universidade de São Paulo, Rua do Matão, trav. 14, n°321, Cidade Universitária, 05508-900, São Paulo, SP, Brazil
| | - Luiza Loebens
- Programa de Pós-Graduação em Biodiversidade Animal, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria. Av. Roraima 1000, Camobi, 97105-900, Santa Maria, Rio Grande do Sul, Brazil
| | - Amanda Jamile Carvalho Brum
- Programa de Pós-Graduação em Biodiversidade Animal, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria. Av. Roraima 1000, Camobi, 97105-900, Santa Maria, Rio Grande do Sul, Brazil
| | - Lívia Bataioli
- Programa de Pós-Graduação em Biodiversidade Animal, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria. Av. Roraima 1000, Camobi, 97105-900, Santa Maria, Rio Grande do Sul, Brazil
| | - Sonia Zanini Cechin
- Programa de Pós-Graduação em Biodiversidade Animal, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria. Av. Roraima 1000, Camobi, 97105-900, Santa Maria, Rio Grande do Sul, Brazil
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Joshi AM, Narayan EJ, Gramapurohit NP. Interrelationship among annual cycles of sex steroids, corticosterone and body condition in Nyctibatrachus humayuni. Gen Comp Endocrinol 2018; 260:151-160. [PMID: 29339182 DOI: 10.1016/j.ygcen.2018.01.013] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/07/2017] [Revised: 12/18/2017] [Accepted: 01/11/2018] [Indexed: 11/30/2022]
Abstract
Synergism between extrinsic and intrinsic factors is crucial for the seasonality of reproduction. Environmental factors such as photoperiod and temperature activate the hypothalamus-pituitary-gonadal axis leading to the secretion of steroid hormones that are crucial for reproduction. Sex steroids are not only essential for the maturation of gonads, but also for development of secondary sexual characters in males and reproductive behaviour of both the sexes. In the present study, we quantified the urinary testosterone (UTM) and corticosterone (UCM) metabolites in males and urinary estradiol metabolites (UEM) and UCM in females of Nyctibatrachus humayuni for two consecutive years to determine annual and seasonal variation in the levels of sex steroids, corticosterone and body condition index (BCI). The results show that sex steroids were highest during the breeding season and lowest during the non-breeding season in both the sexes. An increase in UTM and UEM was observed in males and females respectively during the breeding season. Testicular histology showed the presence of all stages of spermatogenesis throughout the year indicating that spermatogenesis is potentially continuous. Ovarian histology showed the presence of vitellogenic follicles only during the breeding season indicating that oogenesis is strictly seasonal. In males, UCM levels were highest during the breeding season, while in females their levels were highest just prior to the breeding season. In males, BCI was highest during the pre-breeding season, declined during the breeding season to increase again during the post-breeding season. In females, BCI was comparable throughout the year. In males, UTM levels were positively correlated with UCM levels but negatively correlated with BCI. Interestingly, UEM, UCM and BCI were not correlated in females. These results indicate that N. humayuni exhibits an associated pattern of reproduction. Quantification of urinary progesterone metabolites (UPM) during the breeding season showed UPM levels were higher in post-spawning females, suggesting the significance of progesterone in ovulation. Further, non-invasive enzyme immunoassay has been successfully standardized in N. humayuni for the quantification of urinary metabolites of steroid hormones.
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Affiliation(s)
- A M Joshi
- Department of Zoology, Savitribai Phule Pune University, Pune 411007, India
| | - E J Narayan
- School of Science and Health, Western Sydney University, Locked Bag 1797, Penrith, NSW 2751, Australia
| | - N P Gramapurohit
- Department of Zoology, Savitribai Phule Pune University, Pune 411007, India.
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Spermatogenic and Testosterone Cycles in a Desert-Adapted Amphibian Odontophrynus barrioi from the Monte Desert, Argentina. J HERPETOL 2018. [DOI: 10.1670/16-070] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Karraker NE, Fischer S, Aowphol A, Sheridan J, Poo S. Signals of forest degradation in the demography of common Asian amphibians. PeerJ 2018; 6:e4220. [PMID: 29404203 PMCID: PMC5797445 DOI: 10.7717/peerj.4220] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Accepted: 12/12/2017] [Indexed: 11/25/2022] Open
Abstract
BACKGROUND Lowland areas in tropical East and Southeast Asia have a long history of conversion from forestland to agricultural land, with many remaining forests being chronically degraded by wood cutting, livestock grazing, and burning. Wetland-breeding amphibians that have evolved in lowland forests in the region have adjusted to changes in habitat composition caused by humans' activities, and populations continue to persist. However, we have little understanding of the impacts of forest disturbance on these species beyond assessments of abundance and distribution, and species considered to be common and widespread have been largely neglected. METHODS We examined body condition and sex ratios of toads (Duttaphrynus melanostictus), predation risk in treefrogs (2 Polypedates spp.), and growth and survival of leaf litter frogs (2 Microhyla spp.) in agricultural land, degraded forest, and intact forest in two study areas, Thailand and Hong Kong. RESULTS Toad populations exhibited higher body condition and female-biased sex ratios in intact forest. Predation of treefrog embryos by flies was lower in intact and degraded forests than in agricultural land. Embryonic survival and larval growth and survival in leaf litter frogs were lower in intact forests than in agricultural land. Results for each study were similar between study areas. DISCUSSION For three of five of these common amphibian species, we documented signals of forest loss and disturbance in their populations. Although these species occur in disturbed habitats, loss of forest cover continues to degrade aspects of their population demography. We urge conservation biologists to consider that populations of species appearing to be common, widespread, and tolerant of human disturbance may be eroding over time.
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Affiliation(s)
- Nancy E. Karraker
- Department of Natural Resources Science, University of Rhode Island, Kingston, RI, United States of America
| | - Samantha Fischer
- Natural Resources Institute, University of Manitoba, Winnipeg, Canada
| | | | | | - Sinlan Poo
- Department of Conservation and Research, Memphis Zoo, Memphis, TN, United States of America
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CHAVES MARCIOF, TENÓRIO FERNANDAC, SANTOS IGORL, J.C.L. NETO CLOVIS, TEXEIRA VALERIAW, MOURA GERALDOJ, TEXEIRA ÁLVAROA. Correlations of condition factor and gonadosomatic, hepatosomatic and lipo-somatic relations of Leptodactylus macrosternum (ANURA: Leptodactylidae) in the Brazilian Semi-arid. ACTA ACUST UNITED AC 2017; 89:1591-1599. [DOI: 10.1590/0001-3765201720160221] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Accepted: 03/03/2017] [Indexed: 11/22/2022]
Affiliation(s)
- MARCIO F. CHAVES
- Universidade Federal Rural de Pernambuco, Brazil; Universidade Federal de Campina Grande, Brazil
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Montezol M, Cassel M, Silva D, Ferreira A, Mehanna M. Gametogenesis and reproductive dynamics ofRhinella schneideri(Anura: Bufonidae): Influence of environmental and anthropogenic factors. ACTA ZOOL-STOCKHOLM 2017. [DOI: 10.1111/azo.12195] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Affiliation(s)
- Michel Montezol
- Biology Institute; State University of Campinas; São Paulo SP Brazil
| | - Mônica Cassel
- Department of Cell and Developmental Biology; Institute of Biomedical Sciences; University of São Paulo; São Paulo SP Brazil
| | - Débora Silva
- Biology Institute; State University of Campinas; São Paulo SP Brazil
| | - Adelina Ferreira
- Institute of Biosciences; Federal University of Mato Grosso; Mato Grosso Brazil
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Titon SCM, de Assis VR, Titon B, Barsotti AMG, Flanagan SP, Gomes FR. Calling rate, corticosterone plasma levels and immunocompetence of Hypsiboas albopunctatus. Comp Biochem Physiol A Mol Integr Physiol 2016; 201:53-60. [DOI: 10.1016/j.cbpa.2016.06.023] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2015] [Revised: 06/16/2016] [Accepted: 06/17/2016] [Indexed: 10/21/2022]
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Madelaire CB, Gomes FR. Breeding under unpredictable conditions: Annual variation in gonadal maturation, energetic reserves and plasma levels of androgens and corticosterone in anurans from the Brazilian semi-arid. Gen Comp Endocrinol 2016; 228:9-16. [PMID: 26808964 DOI: 10.1016/j.ygcen.2016.01.011] [Citation(s) in RCA: 30] [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: 07/10/2015] [Revised: 01/13/2016] [Accepted: 01/21/2016] [Indexed: 11/20/2022]
Abstract
Anurans living in arid and semi-arid habitats are subjected to unpredictable rain patterns. Consequently, they should be prepared to reproduce at the onset of rain events. We investigated the covariation between calling behavior, testicular maturation, abdominal fat body index (FBI), plasma levels of androgens (T-DHT) and corticosterone (CORT) of males from three species of anurans in the Brazilian semi-arid during the reproductive period and drought. One of these species aestivates during the drought, while the other two species remain foraging. Although the three species display different behavioral strategies during the dry period, they present the same general reproductive patterns. T-DHT levels on the plasma and germinative cyst diameters were higher during the reproductive and breeding period compared to the drought. Additionally, the germinative cysts had all cell stages including sperm bundles during the dry season, however, it was only during the breeding event that free spermatozoa were found in the cyst lumen. These results suggest that these species present the reproductive pattern typical of desert anurans, consisting of opportunistic breeders that reproduce when triggered by a rain stimulus. Rhinella jimi and Pleurodema diplolister had higher CORT when males were calling. Moreover, Rhinella granulosa and P. diplolister showed lower FBI during breeding event, when males were calling. The high levels of CORT and lower FBI during reproductive period are associated, indicating that CORT modulates the recruitment of energy stores to prepare and maintain reproduction, particularly the expensive calling effort.
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Affiliation(s)
- Carla Bonetti Madelaire
- USP - Universidade de São Paulo, Instituto de Biociências, Departamento de Fisiologia, Rua do Matão, trav. 14, n° 321, Cidade Universitária, São Paulo, SP 05508-090, Brazil.
| | - Fernando Ribeiro Gomes
- USP - Universidade de São Paulo, Instituto de Biociências, Departamento de Fisiologia, Rua do Matão, trav. 14, n° 321, Cidade Universitária, São Paulo, SP 05508-090, Brazil.
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Raquet MA, Measey GJ, Exbrayat JM. Annual variation of ovarian structures of Boulengerula taitana (Loveridge 1935), a Kenyan caecilian. AFR J HERPETOL 2015. [DOI: 10.1080/21564574.2015.1103787] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- M. A. Raquet
- Université de Lyon, UMRS 449, Laboratoire de Biologie générale, UCLy, Reproduction et développement comparé, EPHE, 25 rue du Plat, F-69288 Lyon cedex, France
| | - G. J. Measey
- Centre for Invasion Biology, Department of Botany & Zoology, Stellenbosch University, Stellenbosch, South Africa
| | - J. M. Exbrayat
- Université de Lyon, UMRS 449, Laboratoire de Biologie générale, UCLy, Reproduction et développement comparé, EPHE, 25 rue du Plat, F-69288 Lyon cedex, France
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Curi LM, Olea GB, Álvarez BB, Céspedez JA, Lombardo DM. Reproductive aspects of Dendropsophus sanborni (Anura, Hylidae) in northeastern Argentina. IHERINGIA. SERIE ZOOLOGIA 2014. [DOI: 10.1590/1678-476620141044432438] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Reproductive aspects of Dendropsophus sanborni (Anura, Hylidae) in northeastern Argentina. The aim of this investigation was to characterize reproductive aspects of Dendropsophus sanborni (Schmidt, 1944) (Anura, Hylidae) in the northwest of Corrientes province, in northeastern Argentina. The reproductive cycles of males and females, the existence of sexual dimorphism and the male’s vocalization period were analyzed. Samplings were made from September 2011 to August 2012. Dendropsophus sanborni showed a prolonged reproductive pattern because reproductive activity was observed during most part of the year. Calling males were recorded all months except in July. The spermatogenic cycle can be characterized as potentially continuous. In males, snout-vent length was significantly correlated with mean testicular volume. The species showed sexual dimorphism in body mass, with females larger than males. Post-ovulatory females were found from March to June and most females had oocytes at different stages of maturity, with abundant post-vitellogenic oocytes from August to December.
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Reproductive activity and advertisement calls of the Asian common toad Duttaphrynus melanostictus (Amphibia, Anura, Bufonidae) from Bach Ma National Park, Vietnam. Zool Stud 2013. [DOI: 10.1186/1810-522x-52-12] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Gramapurohit NP, Radder RS. Changes in Plasma Sex Steroids in Relation to Reproductive Behavior of the Toad, Bufo melanostictus (Schn.). COPEIA 2013. [DOI: 10.1643/cp-11-100] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Santos LRDS, Franco-Belussi L, Oliveira CD. Germ Cell Dynamics during the Annual Reproductive Cycle ofDendropsophus minutus(Anura: Hylidae). Zoolog Sci 2011; 28:840-4. [DOI: 10.2108/zsj.28.840] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Nucleolar cycle and chromatoid body formation: is there a relationship between these two processes during spermatogenesis of Dendropsophus minutus (Amphibia, Anura)? Micron 2010; 42:87-96. [PMID: 20829051 DOI: 10.1016/j.micron.2010.07.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2010] [Revised: 07/20/2010] [Accepted: 07/23/2010] [Indexed: 11/21/2022]
Abstract
The goals of this study were to monitor the nucleolar material distribution during Dendropsophus minutus spermatogenesis using cytological and cytochemical techniques and ultrastructural analysis, as well as to compare the nucleolar material distribution to the formation of the chromatoid body (CB) in the germ epithelium of this amphibian species. Nucleolar fragmentation occurred during the pachytene of prophase I and nucleolus reorganization occurred in the early spermatid nucleus. The area of the spermatogonia nucleolus was significantly larger than that of the earlier spermatid nucleolus. Ultrastructural analysis showed an accumulation of nuages in the spermatogonia cytoplasm, which form the CB before nucleolar fragmentation. The CB was observed in association with mitochondrial clusters in the cytoplasm of primary spermatocytes, as well as in those of earlier spermatids. In conclusion, the nucleolus seems to be related to CB formation during spermatogenesis of D. minutus, because, at the moment of nucleolus fragmentation in the primary spermatocytes, the CB area reaches a considerable size and is able to execute its important functions during spermatogenesis. The reorganized nucleolus of the earlier spermatids has a smaller area due to several factors, among them the probable migration of nucleolar fragments from the nucleus to the cytoplasm, and plays a part in the CB chemical composition.
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Oliveira CD, Santos LRDS, Zieri R. Variações anatômicas no aparelho reprodutor masculino de Chaunus ornatus (Wied-Neuwied, 1821) (Anura, Bufonidae). BIOTA NEOTROPICA 2007. [DOI: 10.1590/s1676-06032007000100006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Este trabalho descreve variações morfológicas nos órgãos e estruturas do aparelho reprodutor masculino em Chaunus ornatus, analisados independentemente das alterações promotoras de variações estruturais. Foram utilizados sete exemplares adultos da espécie, coletados no Município de Botucatu (São Paulo, Brazil) na época de atividade reprodutiva. Os espécimes foram dissecados e medidas do comprimento rostro-cloacal, análises anatômicas descritivas e biométricas foram obtidas. Três destes animais foram encaminhados à rotina histológica para a análise da arquitetura testicular e esquematizada em papel vegetal com caneta nanquim. Análises estatísticas (média, desvio-padrão, teste de Shapiro-Wilk, teste t de Student e Regressão Linear Simples) foram empregadas para interpretação dos resultados. Os testículos de C. ornatus são cilíndricos com coloração branco-leitosa e possuem uma estrutura ovariana rudimentar, o órgão de Bidder, em sintopia com a extremidade testicular cranial. O aparelho reprodutor masculino de C. ornatus apresenta conspícuas variações anatômicas intra e interindividuais, especialmente no que concerne à forma e tamanho dos testículos e dos órgãos de Bidder, os quais não apresentaram relação com o tamanho do indivíduo. Quanto à localização, os testículos dispõem-se ventralmente aos rins, mas ocorrem em alturas diferentes, acompanhando diferenças atribuídas à própria posição dos rins. Nos corpos adiposos abdominais, a disposição e número de prolongamentos que o constitui é variável entre os membros do par, e conseqüentemente entre indivíduos. Histologicamente não foram observadas diferenças quanto ao arranjo do epitélio germinativo na constituição do lóculo seminífero, portanto estas características parecem seguir o padrão da descrição para os demais anuros. A heterogeneidade morfológica quanto às variações anatômicas nessa espécie teve uma constatação pouco significativa. Assim, outros estudos ainda são necessários para o estabelecimento de relações morfológicas e suas implicações filogenéticas, bem como para compreender como as pressões evolutivas atuam moldando a anatomia dessas estruturas nos anuros.
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Moore FL, Boyd SK, Kelley DB. Historical perspective: Hormonal regulation of behaviors in amphibians. Horm Behav 2005; 48:373-83. [PMID: 15992801 DOI: 10.1016/j.yhbeh.2005.05.011] [Citation(s) in RCA: 121] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/16/2005] [Revised: 05/15/2005] [Accepted: 05/18/2005] [Indexed: 10/25/2022]
Abstract
This review focuses on research into the hormonal control of behaviors in amphibians that was conducted prior to the 21st century. Most advances in this field come from studies of a limited number of species and investigations into the hormonal mechanisms that regulate reproductive behaviors in male frogs and salamanders. From this earlier research, we highlight five main generalizations or conclusions. (1) Based on studies of vocalization behaviors in anurans, testicular androgens induce developmental changes in cartilage and muscles fibers in the larynx and thereby masculinize peripheral structures that influence the properties of advertisement calls by males. (2) Gonadal steroid hormones act to enhance reproductive behaviors in adult amphibians, but causal relationships are not as well established in amphibians as in birds and mammals. Research into the relationships between testicular androgens and male behaviors, mainly using castration/steroid treatment studies, generally supports the conclusion that androgens are necessary but not sufficient to enhance male behaviors. (3) Prolactin acts synergistically with androgens and induces reproductive development, sexual behaviors, and pheromone production. This interaction between prolactin and gonadal steroids helps to explain why androgens alone sometimes fail to stimulate amphibian behaviors. (4) Vasotocin also plays an important role and enhances specific types of behaviors in amphibians (frog calling, receptivity in female frogs, amplectic clasping in newts, and non-clasping courtship behaviors). Gonadal steroids typically act to maintain behavioral responses to vasotocin. Vasotocin modulates behavioral responses, at least in part, by acting within the brain on sensory pathways that detect sexual stimuli and on motor pathways that control behavioral responses. (5) Corticosterone acts as a potent and rapid suppressor of reproductive behaviors during periods of acute stress. These rapid stress-induced changes in behaviors use non-genomic mechanisms and membrane-associated corticosterone receptors.
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Affiliation(s)
- Frank L Moore
- Department of Zoology, Oregon State University, Corvallis, OR 97331-2914, USA.
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Huang WS, Yu JYL. Reproductive Characteristics of Bufo bankorensis at Two Elevations in Taiwan. Zoolog Sci 2005; 22:111-7. [PMID: 15684591 DOI: 10.2108/zsj.22.111] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
We compared the reproductive characteristics of two populations of Bufo bankorensis in central Taiwan, one inhabiting a temperate climate (Meifong, 2100 m), the other inhabiting a subtropical climate (Wushe, 1100 m). We determined ovary status, spermatogenetic activity, fat body and liver mass cycles, and plasma 17-betaestradiol and androgen levels over a 14 month period. B. bankorensis from both populations are prolonged breeders but the temperate population exhibits breeding activity throughout the year, while the subtropical population only breeds from September to March. Their spermatogenic cycles are continuous, and their spermatogenetic activities are invariably at stage 6, in which spermatozoa are predominant in the seminiferous tubule. Both populations show monthly variations in plasma androgen and 17-betaestradiol levels, but follow different patterns. Ovary mass is larger in the temperate than in the subtropical population. The reproduction differences of two elevation toads could be reflected by adaptations to the local environmental regimes of its habitat. The reproductive patterns of these populations of Bufo bankorensis are also compared to those of sympatric and allopatric populations of five anurans studied from sites throughout Taiwan.
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Affiliation(s)
- Wen-San Huang
- Department of Zoology, National Museum of Natural Science, 1, Kuan Chien Rd., Taichung, Taiwan 404, ROC.
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