J. Soors, Tom Van den Neucker, D. Halfmaerten, S. Neyrinck, Marc De Baere
Short notes have no abstract
短音符没有摘要
{"title":"On the presence of the invasive planarian Obama nungara (Carbayo, Álvarez-Presas, Jones & Riutort, 2016) (Platyhelminthes: Geoplanidae) in an urban area in Belgium","authors":"J. Soors, Tom Van den Neucker, D. Halfmaerten, S. Neyrinck, Marc De Baere","doi":"10.26496/BJZ.2019.29","DOIUrl":"https://doi.org/10.26496/BJZ.2019.29","url":null,"abstract":"Short notes have no abstract","PeriodicalId":8750,"journal":{"name":"Belgian Journal of Zoology","volume":" ","pages":""},"PeriodicalIF":1.0,"publicationDate":"2019-04-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41359880","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
One of the most widely recognized patterns in ecology is the increase in species richness from poles to tropics. Literature suggests that the Congolian lowland rainforest does not follow this pattern: the Central Congolian forest (CCLF), south of the Congo River, is thought to harbor fewer vertebrate species and endemics than the Northeastern (NELF) and Northwestern lowland rainforests (NWLF) north of the Congo River. We used data from the Global Biodiversity Information Facility (GBIF) database on terrestrial vertebrates (mammals, birds, and reptiles), to test whether differences in sampling effort caused the irregular biodiversity pattern in this region. Our results show that even though the diversity within the Congolian lowland rainforests remains to be fully mapped, current differences in richness are unlikely to be caused by undersampling alone. We argue that the lower vertebrate richness in the CCLF is due to both its relatively small size and isolated position: Forest cover fluctuated throughout the history of the Congo Basin due to climatic variability, reducing speciation and increasing extinction, while immigration towards the CCLF is limited due to the barrier effect of the Congo River. The implications of these findings are discussed in the context of both fundamental ecology and conservation management.
{"title":"Paleoclimate, ecoregion size, and degree of isolation explain regional biodiversity differences among terrestrial vertebrates within the Congo Basin","authors":"Frederik Van de Perre, H. Leirs, E. Verheyen","doi":"10.26496/BJZ.2019.28","DOIUrl":"https://doi.org/10.26496/BJZ.2019.28","url":null,"abstract":"One of the most widely recognized patterns in ecology is the increase in species richness from poles to tropics. Literature suggests that the Congolian lowland rainforest does not follow this pattern: the Central Congolian forest (CCLF), south of the Congo River, is thought to harbor fewer vertebrate species and endemics than the Northeastern (NELF) and Northwestern lowland rainforests (NWLF) north of the Congo River. We used data from the Global Biodiversity Information Facility (GBIF) database on terrestrial vertebrates (mammals, birds, and reptiles), to test whether differences in sampling effort caused the irregular biodiversity pattern in this region. Our results show that even though the diversity within the Congolian lowland rainforests remains to be fully mapped, current differences in richness are unlikely to be caused by undersampling alone. We argue that the lower vertebrate richness in the CCLF is due to both its relatively small size and isolated position: Forest cover fluctuated throughout the history of the Congo Basin due to climatic variability, reducing speciation and increasing extinction, while immigration towards the CCLF is limited due to the barrier effect of the Congo River. The implications of these findings are discussed in the context of both fundamental ecology and conservation management.","PeriodicalId":8750,"journal":{"name":"Belgian Journal of Zoology","volume":" ","pages":""},"PeriodicalIF":1.0,"publicationDate":"2019-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45779870","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
R. Clymans, C. Schaetzen, Marc Delbol, N. Ebrahimi, H. Casteels, T. Beliën, D. Bylemans
Short notes have no abstract.
短文没有摘要。
{"title":"Anthonomus spilotus (Coleoptera: Curculionidae): new to the Belgian fauna","authors":"R. Clymans, C. Schaetzen, Marc Delbol, N. Ebrahimi, H. Casteels, T. Beliën, D. Bylemans","doi":"10.26496/BJZ.2019.27","DOIUrl":"https://doi.org/10.26496/BJZ.2019.27","url":null,"abstract":"Short notes have no abstract.","PeriodicalId":8750,"journal":{"name":"Belgian Journal of Zoology","volume":" ","pages":""},"PeriodicalIF":1.0,"publicationDate":"2019-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43244391","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Anne L. Rutten, J. Casaer, T. Onkelinx, L. D. Smet, N. Witters, F. Huysentruyt, H. Leirs
Wild boar (Sus scrofa L.) reappeared in Flanders (northern Belgium) in 2006 after almost half a century of absence. Interactions between wild boar and human activities are frequent due to extensive fragmentation of the landscape in Flanders. Complaints about agricultural damage are increasing but the actual extent of crop damage remains unknown. The goal of this study was to assess the current risk and the spatial distribution of crop damage, as well as factors influencing damage distribution in the province of Limburg (eastern Flanders). An online survey was sent to farmers by email. Moreover, as we expected potential respondent bias towards farmers that already experienced damage, we also conducted a follow-up non-respondent check by telephone. Our study showed that the current crop damage probability on a farm lies between 42% (likely an overestimation due to respondent bias in the online survey) and 22% (an underestimation based on the non-respondent check). There is considerable geographical variation in the proportion of farms that report boar damage; probability for crop damage due to wild boar is relatively high for farmers in Limburg but shows a geographically heterogeneous spread. Factors explaining the crop damage probability differed strongly between the online survey and the non-respondent check and no consistent results could be found. Our results show that using the online survey, it was possible to get an initial insight in the geographical distribution of crop damage. However, as we found differences between the results of the online survey and the non-respondent check, taking management decisions based solely on online survey results without conducting a non-respondent check could lead to misguided actions.
{"title":"Using an online survey to assess the spatial distribution of wild boar (Sus scrofa L.) crop damage and factors influencing this distribution and severity in Limburg province, Belgium","authors":"Anne L. Rutten, J. Casaer, T. Onkelinx, L. D. Smet, N. Witters, F. Huysentruyt, H. Leirs","doi":"10.26496/BJZ.2019.26","DOIUrl":"https://doi.org/10.26496/BJZ.2019.26","url":null,"abstract":"Wild boar (Sus scrofa L.) reappeared in Flanders (northern Belgium) in 2006 after almost half a century of absence. Interactions between wild boar and human activities are frequent due to extensive fragmentation of the landscape in Flanders. Complaints about agricultural damage are increasing but the actual extent of crop damage remains unknown. The goal of this study was to assess the current risk and the spatial distribution of crop damage, as well as factors influencing damage distribution in the province of Limburg (eastern Flanders). An online survey was sent to farmers by email. Moreover, as we expected potential respondent bias towards farmers that already experienced damage, we also conducted a follow-up non-respondent check by telephone. Our study showed that the current crop damage probability on a farm lies between 42% (likely an overestimation due to respondent bias in the online survey) and 22% (an underestimation based on the non-respondent check). There is considerable geographical variation in the proportion of farms that report boar damage; probability for crop damage due to wild boar is relatively high for farmers in Limburg but shows a geographically heterogeneous spread. Factors explaining the crop damage probability differed strongly between the online survey and the non-respondent check and no consistent results could be found. Our results show that using the online survey, it was possible to get an initial insight in the geographical distribution of crop damage. However, as we found differences between the results of the online survey and the non-respondent check, taking management decisions based solely on online survey results without conducting a non-respondent check could lead to misguided actions.","PeriodicalId":8750,"journal":{"name":"Belgian Journal of Zoology","volume":"1 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2019-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41345120","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
It is well-known that ecological and evolutionary processes can occur on similar time scales resulting in eco-evolutionary dynamics. One of the main questions in eco-evolutionary dynamics involves the assessment of the relative contribution of evolution, ecology and their interaction in the eco-evolutionary change under study. This has led to the development of several methods aimed to quantify the contributions of ecology and evolution to observed trait change, here referred to as eco-evolutionary partitioning metrics. This study provides an overview on currently-used partitioning metrics with a focus on methods that can quantify evolutionary and non-evolutionary contributions to population and community trait change. I highlight key differences between these metrics found in previous studies. Additionally, I also provide a detailed comparison between the ‘Geber’ method and the reaction norm approach. Next, I provide a guideline for researchers to assess which metrics are best suited for their data, give an overview on the type of data needed for these metrics, and how this data can be collected with a focus on community data.
{"title":"Eco-evolutionary partitioning metrics: a practical guide for biologists","authors":"L. Govaert","doi":"10.26496/BJZ.2018.25","DOIUrl":"https://doi.org/10.26496/BJZ.2018.25","url":null,"abstract":"It is well-known that ecological and evolutionary processes can occur on similar time scales resulting in eco-evolutionary dynamics. One of the main questions in eco-evolutionary dynamics involves the assessment of the relative contribution of evolution, ecology and their interaction in the eco-evolutionary change under study. This has led to the development of several methods aimed to quantify the contributions of ecology and evolution to observed trait change, here referred to as eco-evolutionary partitioning metrics. This study provides an overview on currently-used partitioning metrics with a focus on methods that can quantify evolutionary and non-evolutionary contributions to population and community trait change. I highlight key differences between these metrics found in previous studies. Additionally, I also provide a detailed comparison between the ‘Geber’ method and the reaction norm approach. Next, I provide a guideline for researchers to assess which metrics are best suited for their data, give an overview on the type of data needed for these metrics, and how this data can be collected with a focus on community data.","PeriodicalId":8750,"journal":{"name":"Belgian Journal of Zoology","volume":" ","pages":""},"PeriodicalIF":1.0,"publicationDate":"2018-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45308022","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Skeletal deformities, one of the major threats for aquaculture, have been studied extensively. These include opercular malformations in gilthead sea bream (Sparus aurata), a key fish species for Mediterranean aquaculture. What is causing it and at what morphogenetic level it arises, however, is still unclear. Here we focus on bone formation, at the level of bone mineralization. Several methods have been used to study bone mineralization density (BMD), however, these are frequently limited when targeting a high-resolution, three-dimensional mapping of BMD. We used micro-computed tomography (micro-CT) data to perform such a 3D quantification of BMD levels in gilthead sea bream that showed different levels of opercular bone deformations. This approach has the advantage of not having to rely on calibration phantoms, as long as relative BMD values are needed. The results show an increased BMD in deformed opercles compared to normal ones, especially in a bilaterally-deformed specimen. Furthermore, we show that opercular deformations are not necessarily associated with similar mineralization patterns in other mineralized cranial elements, except for the otoliths. Also, mineralization seems to occur left-right independently, matching earlier observations of such an independency of the opercular phenotype as a whole. This study confirms that a quantitative characterization of BMD patterns in 3D is feasible, even in smaller specimens, and that it has several advantages over other commonly used approaches.
{"title":"A 3D quantitative method for analyzing bone mineral densities: a case study on skeletal deformities in the gilthead sea bream, Sparus aurata (Linnaeus, 1758)","authors":"N. P. Thuong, M. Dierick, T. D. Wolf, D. Adriaens","doi":"10.26496/BJZ.2018.24","DOIUrl":"https://doi.org/10.26496/BJZ.2018.24","url":null,"abstract":"Skeletal deformities, one of the major threats for aquaculture, have been studied extensively. These include opercular malformations in gilthead sea bream (Sparus aurata), a key fish species for Mediterranean aquaculture. What is causing it and at what morphogenetic level it arises, however, is still unclear. Here we focus on bone formation, at the level of bone mineralization. Several methods have been used to study bone mineralization density (BMD), however, these are frequently limited when targeting a high-resolution, three-dimensional mapping of BMD. We used micro-computed tomography (micro-CT) data to perform such a 3D quantification of BMD levels in gilthead sea bream that showed different levels of opercular bone deformations. This approach has the advantage of not having to rely on calibration phantoms, as long as relative BMD values are needed. The results show an increased BMD in deformed opercles compared to normal ones, especially in a bilaterally-deformed specimen. Furthermore, we show that opercular deformations are not necessarily associated with similar mineralization patterns in other mineralized cranial elements, except for the otoliths. Also, mineralization seems to occur left-right independently, matching earlier observations of such an independency of the opercular phenotype as a whole. This study confirms that a quantitative characterization of BMD patterns in 3D is feasible, even in smaller specimens, and that it has several advantages over other commonly used approaches.","PeriodicalId":8750,"journal":{"name":"Belgian Journal of Zoology","volume":" ","pages":""},"PeriodicalIF":1.0,"publicationDate":"2018-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47780765","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Evelien Deboelpaep, Pieter-Jan Keleman, B. Vanschoenwinkel, N. Koedam
While escape responses are shown to differ in areas with varying levels of human disturbance, it is not known to what extent these reactions depend on the composition of local species assemblages. We investigated variation in three flight response metrics for the invasive Canada Goose (Branta canadensis) in Belgium in three locations with different human accessibility. Results indicate that heterospecific birds and flock size affected flight initiation distances of the Canada Goose, but that these effects are location-specific. Escape responses were most pronounced in the nature reserve with the lowest human accessibility, and highly reduced in the recreational park. This study illustrates that, when buffer zones are being developed, generalising escape behaviour of birds may lead to potentially dangerous overestimations of their tolerance to human disturbance.
{"title":"Gallant geese, fearful flocks? Flock size and heterospecifics alter the escape behaviour of an invasive goose","authors":"Evelien Deboelpaep, Pieter-Jan Keleman, B. Vanschoenwinkel, N. Koedam","doi":"10.26496/BJZ.2018.23","DOIUrl":"https://doi.org/10.26496/BJZ.2018.23","url":null,"abstract":"While escape responses are shown to differ in areas with varying levels of human disturbance, it is not known to what extent these reactions depend on the composition of local species assemblages. We investigated variation in three flight response metrics for the invasive Canada Goose (Branta canadensis) in Belgium in three locations with different human accessibility. Results indicate that heterospecific birds and flock size affected flight initiation distances of the Canada Goose, but that these effects are location-specific. Escape responses were most pronounced in the nature reserve with the lowest human accessibility, and highly reduced in the recreational park. This study illustrates that, when buffer zones are being developed, generalising escape behaviour of birds may lead to potentially dangerous overestimations of their tolerance to human disturbance.","PeriodicalId":8750,"journal":{"name":"Belgian Journal of Zoology","volume":"1 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2018-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44277614","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"The impact of Psittacula krameri (Scopoli, 1769) on orchards: first quantitative evidence for Southern Europe","authors":"Lorenzo Mentil, C. Battisti, G. Carpaneto","doi":"10.26496/BJZ.2018.22","DOIUrl":"https://doi.org/10.26496/BJZ.2018.22","url":null,"abstract":"This is a Short Note without an abstract.","PeriodicalId":8750,"journal":{"name":"Belgian Journal of Zoology","volume":" ","pages":""},"PeriodicalIF":1.0,"publicationDate":"2018-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49293501","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
R. Brabant, Y. Laurent, Umit Dolap, S. Degraer, B. J. Poerink
Commercially available automated bat identification software packages are widely used in environmental studies to identify bat species from recordings of bat echolocation calls. Caution is, however, needed if the results are used without further verification, as the programs do not guarantee that the results are correct, and wrong species identifications often happen. Taking automated species identifications for granted might hence lead to erroneous conclusions in environmental studies.The goal of our study was to objectively assess the performance of four commercially available and commonly used automated identification software programs by processing an identical reference dataset with all four programs. The reference dataset consisted of nine species selected based on their preference for open habitats in Western Europe or because they occur as vagrants at sea and therefore are vulnerable to the development of onshore and offshore wind farms. Offshore areas are being increasingly examined, as recent studies have identified possible conflicts of offshore wind farms and certain bat species.In our test, we included two automated identification programs that have not yet been tested in other studies, and a reference dataset from a different geographical region (Western-Europe) with a different species composition compared to other studies. Our data hence add to the knowledge base needed for an appropriate assessment of the reliability of analytical software.In general, BatIdent (77% correct species identifications) and Kaleidoscope (71%) seem to be relatively reliable while the performance of BatExplorer (31%) is relatively poor. SonoChiro correctly identified 65% of the sequences to species level. While the tested programs may be considered valuable tools to detect bat calls from the recordings, a trained bat expert needs to cross-check the automated species identifications to avoid erroneous conclusions. Our test hence affirms the conclusions of previous studies in Northern Europe and the USA.
{"title":"Comparing the results of four widely used automated bat identification software programs to identify nine bat species in coastal Western Europe","authors":"R. Brabant, Y. Laurent, Umit Dolap, S. Degraer, B. J. Poerink","doi":"10.26496/BJZ.2018.21","DOIUrl":"https://doi.org/10.26496/BJZ.2018.21","url":null,"abstract":"Commercially available automated bat identification software packages are widely used in environmental studies to identify bat species from recordings of bat echolocation calls. Caution is, however, needed if the results are used without further verification, as the programs do not guarantee that the results are correct, and wrong species identifications often happen. Taking automated species identifications for granted might hence lead to erroneous conclusions in environmental studies.The goal of our study was to objectively assess the performance of four commercially available and commonly used automated identification software programs by processing an identical reference dataset with all four programs. The reference dataset consisted of nine species selected based on their preference for open habitats in Western Europe or because they occur as vagrants at sea and therefore are vulnerable to the development of onshore and offshore wind farms. Offshore areas are being increasingly examined, as recent studies have identified possible conflicts of offshore wind farms and certain bat species.In our test, we included two automated identification programs that have not yet been tested in other studies, and a reference dataset from a different geographical region (Western-Europe) with a different species composition compared to other studies. Our data hence add to the knowledge base needed for an appropriate assessment of the reliability of analytical software.In general, BatIdent (77% correct species identifications) and Kaleidoscope (71%) seem to be relatively reliable while the performance of BatExplorer (31%) is relatively poor. SonoChiro correctly identified 65% of the sequences to species level. While the tested programs may be considered valuable tools to detect bat calls from the recordings, a trained bat expert needs to cross-check the automated species identifications to avoid erroneous conclusions. Our test hence affirms the conclusions of previous studies in Northern Europe and the USA.","PeriodicalId":8750,"journal":{"name":"Belgian Journal of Zoology","volume":" ","pages":""},"PeriodicalIF":1.0,"publicationDate":"2018-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48483452","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The reproductive function in anurans depends on interactions between the hypothalamus, adenohypophysis and gonads, which are mediated by an endocrine circuit. We studied the relationship between reproductive and histological parameters, variation in spermatogenic activity, and plasma testosterone concentration cycle for a population of Rhinella arenarum under field conditions in the Monte Desert of Argentina. We captured 28 adult male R. arenarum from December 2009 to November 2010, and define two seasons (wet and dry seasons). We performed histological analyses of the testes and used radioimmunoassay to determine plasma testosterone concentrations. Our results showed no difference in testicular volume between the wet and dry seasons, but found that changes in the fat body mass were higher in the dry season. The spematogenic cycle was characterized by the prominent presence of spermatogonia at the end of the dry season and the wet season. We also observed a higher percentage of primary spermatocytes in the wet season. In addition, we found that R. arenarum showed a continuous spermatogenic cycle, and spermatogenesis produced a high percentage of sperm bundles in the dry season, concordant with high levels of testosterone. Testosterone levels were highest during the dry season (33.89 ± 7.85 ng/ml). Our data indicate that plasma testosterone showed a “dissociation” from reproductive activity such that the two parameters are asynchronous during the reproductive season. The characteristics of the reproductive cycle of R. arenarum allow this species the plasticity to colonize different environments, from tropical regions to deserts.
{"title":"Spermatogenesis and plasma testosterone levels under field conditions, in males of the common toad (Rhinella arenarum Hensel, 1867), from the Monte Desert, Argentina","authors":"L. Quiroga, E. Sanabria, G. Jahn, M. Fornés","doi":"10.26496/BJZ.2018.20","DOIUrl":"https://doi.org/10.26496/BJZ.2018.20","url":null,"abstract":"The reproductive function in anurans depends on interactions between the hypothalamus, adenohypophysis and gonads, which are mediated by an endocrine circuit. We studied the relationship between reproductive and histological parameters, variation in spermatogenic activity, and plasma testosterone concentration cycle for a population of Rhinella arenarum under field conditions in the Monte Desert of Argentina. We captured 28 adult male R. arenarum from December 2009 to November 2010, and define two seasons (wet and dry seasons). We performed histological analyses of the testes and used radioimmunoassay to determine plasma testosterone concentrations. Our results showed no difference in testicular volume between the wet and dry seasons, but found that changes in the fat body mass were higher in the dry season. The spematogenic cycle was characterized by the prominent presence of spermatogonia at the end of the dry season and the wet season. We also observed a higher percentage of primary spermatocytes in the wet season. In addition, we found that R. arenarum showed a continuous spermatogenic cycle, and spermatogenesis produced a high percentage of sperm bundles in the dry season, concordant with high levels of testosterone. Testosterone levels were highest during the dry season (33.89 ± 7.85 ng/ml). Our data indicate that plasma testosterone showed a “dissociation” from reproductive activity such that the two parameters are asynchronous during the reproductive season. The characteristics of the reproductive cycle of R. arenarum allow this species the plasticity to colonize different environments, from tropical regions to deserts.","PeriodicalId":8750,"journal":{"name":"Belgian Journal of Zoology","volume":" ","pages":""},"PeriodicalIF":1.0,"publicationDate":"2018-05-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44495320","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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