Abstract: The Japanese fire-belly newt, Cynops pyrrhogaster, is a near threatened species that is conservation dependent. Here, we examine feeding habits across the year within a genetically divergent intraspecific lineages of this species (the Central Lineage) to provide information to support future insitu and ex-situ conservation activities. Stomach contents from newts were collected in a paddy field habitat, Kyoto City, central Honshu, Japan for two consecutive years. Throughout the year, dipteran aquatic larvae were the most important food source both for males and females, although terrestrial invertebrates were also important prey for the newts. During periods of low prey availability shed skin could also be a relatively valuable source of food. Sympatric frogs and newts appear to target different prey and this may facilitate their co-existence. Our study provides new information on suitable prey items for the Central Lineage of C. pyrrhogaster both in its natural habitat and in captivity.
{"title":"Feeding Habits of the Japanese Fire-belly Newt (Ampbihia: Urodela: Salamandridae) in Central Honshu, Japan","authors":"Kotaro Ozaki, K. Nishikawa","doi":"10.5358/hsj.42.162","DOIUrl":"https://doi.org/10.5358/hsj.42.162","url":null,"abstract":"Abstract: The Japanese fire-belly newt, Cynops pyrrhogaster, is a near threatened species that is conservation dependent. Here, we examine feeding habits across the year within a genetically divergent intraspecific lineages of this species (the Central Lineage) to provide information to support future insitu and ex-situ conservation activities. Stomach contents from newts were collected in a paddy field habitat, Kyoto City, central Honshu, Japan for two consecutive years. Throughout the year, dipteran aquatic larvae were the most important food source both for males and females, although terrestrial invertebrates were also important prey for the newts. During periods of low prey availability shed skin could also be a relatively valuable source of food. Sympatric frogs and newts appear to target different prey and this may facilitate their co-existence. Our study provides new information on suitable prey items for the Central Lineage of C. pyrrhogaster both in its natural habitat and in captivity.","PeriodicalId":56053,"journal":{"name":"Current Herpetology","volume":"42 1","pages":"162 - 170"},"PeriodicalIF":0.7,"publicationDate":"2023-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46124580","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}
Abstract: Lunar phase and weather conditions are known to affect breeding activity of the Japanese common toad, Bufo japonicus formosus. However, information on toad activity during non-breeding season is very scarce. In this study, we investigated the influence of weather conditions and lunar phase on toad activity during the non-breeding season (April-November). Surface activity during the non-breeding season was monitored in Minami-ohsawa, Hachioji Tokyo from 2010 to 2014. The effects of weather conditions and the lunar phase on the number of toads captured were analyzed using Random Forests models (an ensemble machine learning method). Toads began to forage on the soil surface from late April and activity lasted until mid-November. Some meteorological variables such as temperature, wind, and atmospheric pressure affected toad activity, but the lunar phase, which is the most important variable in breeding activity, did not have an effect on surface activity of the toads during non-breeding season. However, differences were observed among adult males and females with respect to their response to meteorological variables: males responded positively to rainfall, but females did not. A distinct difference in the effect of temperature was also observed between adults and juveniles: juveniles became more active when daily minimum temperature was >15°C, although adults did not respond to an increase in temperature. Our results on sexual differences in weather-mediated activity and lack of the lunar phase effects during non-breeding season provide useful information for our understanding of life history of these toads.
{"title":"Factors Affecting the Surface Activity of Japanese Common Toad, Bufo japonicus formosus (Amphibia: Bufonidae) during the Non-breeding Season","authors":"T. Kusano, Tomoyo Miura, S. Terui, Y. Shiga","doi":"10.5358/hsj.42.17","DOIUrl":"https://doi.org/10.5358/hsj.42.17","url":null,"abstract":"Abstract: Lunar phase and weather conditions are known to affect breeding activity of the Japanese common toad, Bufo japonicus formosus. However, information on toad activity during non-breeding season is very scarce. In this study, we investigated the influence of weather conditions and lunar phase on toad activity during the non-breeding season (April-November). Surface activity during the non-breeding season was monitored in Minami-ohsawa, Hachioji Tokyo from 2010 to 2014. The effects of weather conditions and the lunar phase on the number of toads captured were analyzed using Random Forests models (an ensemble machine learning method). Toads began to forage on the soil surface from late April and activity lasted until mid-November. Some meteorological variables such as temperature, wind, and atmospheric pressure affected toad activity, but the lunar phase, which is the most important variable in breeding activity, did not have an effect on surface activity of the toads during non-breeding season. However, differences were observed among adult males and females with respect to their response to meteorological variables: males responded positively to rainfall, but females did not. A distinct difference in the effect of temperature was also observed between adults and juveniles: juveniles became more active when daily minimum temperature was >15°C, although adults did not respond to an increase in temperature. Our results on sexual differences in weather-mediated activity and lack of the lunar phase effects during non-breeding season provide useful information for our understanding of life history of these toads.","PeriodicalId":56053,"journal":{"name":"Current Herpetology","volume":"42 1","pages":"17 - 26"},"PeriodicalIF":0.7,"publicationDate":"2023-02-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46733498","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}
Abstract: Burrowing is one of the important seasonal behaviors in amphibians that could be related to physiological ecology and environmental factors. Burrowing characteristics and temporal variability in burrowing behaviors were explored and examined from three sampling surveys in northeastern Thailand in 2017–2018. Four species of burrowing frogs were identified with overwhelmingly abundant specimens in two species, Glyphoglossus molossus and Kaloula mediolineata. In general, K. mediolineata burrowed deeper than G. molossus although their body size were not different. There were no clear relationships between burrowing depth and frog body size in each species, although G. molossus showed larger SVL in dry seasons than that in rainy seasons. In contrast to K. mediolineata which preferred to burrow deeper in dry seasons, burrowing depth of G. molossus was almost stable among seasons. The results of this study highlighted an interaction between season and species in the burrowing depth of these two frog species in northeastern Thailand.
{"title":"Deeper or Shallower? Interactions and Temporal Variability in Choosing Burrowing Depth between Species of Economic Burrowing Frogs of Forest Area from Northeastern Thailand","authors":"Akeapot Srifa, K. Lauprasert","doi":"10.5358/hsj.42.35","DOIUrl":"https://doi.org/10.5358/hsj.42.35","url":null,"abstract":"Abstract: Burrowing is one of the important seasonal behaviors in amphibians that could be related to physiological ecology and environmental factors. Burrowing characteristics and temporal variability in burrowing behaviors were explored and examined from three sampling surveys in northeastern Thailand in 2017–2018. Four species of burrowing frogs were identified with overwhelmingly abundant specimens in two species, Glyphoglossus molossus and Kaloula mediolineata. In general, K. mediolineata burrowed deeper than G. molossus although their body size were not different. There were no clear relationships between burrowing depth and frog body size in each species, although G. molossus showed larger SVL in dry seasons than that in rainy seasons. In contrast to K. mediolineata which preferred to burrow deeper in dry seasons, burrowing depth of G. molossus was almost stable among seasons. The results of this study highlighted an interaction between season and species in the burrowing depth of these two frog species in northeastern Thailand.","PeriodicalId":56053,"journal":{"name":"Current Herpetology","volume":"42 1","pages":"35 - 42"},"PeriodicalIF":0.7,"publicationDate":"2023-02-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47058798","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}
Abstract: We describe a new species of very small (male body length 22.0–22.8 mm), green treefrog in the pelodryadid genus Litoria Tschudi from lowland rainforest on the southern margin of Papua New Guinea's central cordillera. The new species is morphologically most similar to Litoria leucova, a small green treefrog known only from the north-flowing Sepik River catchment in western Papua New Guinea. It differs from that species by having longer limbs (TL/SVL 0.56–0.60 vs. 0.53–0.55), a poorly defined (vs. prominent) tympanum, in having a distinct lemon yellow mid-lateral line, and in its unique advertisement call comprising a slowly repeated series of short clicks followed by a discrete group of pulses produced rapidly but with highly variable inter-pulse intervals. Although genetic data are not available, the new species' association with a fast-flowing rocky stream suggests that its relationships may lie with other torrent-dwelling Litoria species.
{"title":"A New Species of Small Green Treefrog (Pelodryadidae: Litoria) from the Lakekamu Basin in Southern Papua New Guinea","authors":"S. Richards, David P Bickford","doi":"10.5358/hsj.42.43","DOIUrl":"https://doi.org/10.5358/hsj.42.43","url":null,"abstract":"Abstract: We describe a new species of very small (male body length 22.0–22.8 mm), green treefrog in the pelodryadid genus Litoria Tschudi from lowland rainforest on the southern margin of Papua New Guinea's central cordillera. The new species is morphologically most similar to Litoria leucova, a small green treefrog known only from the north-flowing Sepik River catchment in western Papua New Guinea. It differs from that species by having longer limbs (TL/SVL 0.56–0.60 vs. 0.53–0.55), a poorly defined (vs. prominent) tympanum, in having a distinct lemon yellow mid-lateral line, and in its unique advertisement call comprising a slowly repeated series of short clicks followed by a discrete group of pulses produced rapidly but with highly variable inter-pulse intervals. Although genetic data are not available, the new species' association with a fast-flowing rocky stream suggests that its relationships may lie with other torrent-dwelling Litoria species.","PeriodicalId":56053,"journal":{"name":"Current Herpetology","volume":"42 1","pages":"43 - 54"},"PeriodicalIF":0.7,"publicationDate":"2023-02-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43780590","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}
Abstract: High abundance of invasive red-eared slider (RES) turtles (Trachemys scripta elegans) in Japan has been a serious issue in freshwater ecosystems. Information on reproductive parameters, such as sex ratios, of RES turtles is needed to effectively control the invasive species. We conducted a long-term field study on RES turtles at two study sites: the Taisho River (a shallow river) and Teradaike Pond (an irrigation reservoir that was irregularly drained to maintain the embankment and water quality) in western Japan. Using trapping and muddling methods, we captured RES turtles and checked for sex, carapace length, and body weight. We also examined whether the population of RES turtles could be reduced by continuously removing the turtles captured at each study site. The sex ratio (male/both sexes) of RES turtles that could be sexed by external morphology (presumably adult turtles) was 0.27 at the Taisho River and 0.26 at Teradaike Pond. At both sites, these sex ratios were almost the same as those of RES turtles that could be sexed only by necropsy after euthanasia (presumably juvenile turtles). These sex ratios were markedly biased toward females and consistent between the adult and the juvenile turtles, thus suggesting that more females had been produced than males. At the Taisho River, a total of 1,366 RES turtles were captured and eliminated over more than ten years. Nevertheless, the annual catch did not tend to decrease and only an effect of preventing population growth was observed. At Teradaike Pond, a total of 1,831 RES turtles were captured over nine years. Nearly half of them were caught for the initial two years, during which the pond was drained. Thereafter, the annual catch of RES turtles clearly decreased. These results suggest that it is difficult to control RES turtles established in rivers but that it is feasible to effectively control RES turtles in enclosed small water bodies, such as irrigation reservoirs, by intensively capturing and eliminating the turtles during the drainage period.
{"title":"Female-biased Sex Ratios and Control Effects Observed in Two Local Populations of Red-eared Slider Turtles (Trachemys scripta elegans) in Western Japan","authors":"Tomoko Nishibori, N. Tada, M. Saka","doi":"10.5358/hsj.42.27","DOIUrl":"https://doi.org/10.5358/hsj.42.27","url":null,"abstract":"Abstract: High abundance of invasive red-eared slider (RES) turtles (Trachemys scripta elegans) in Japan has been a serious issue in freshwater ecosystems. Information on reproductive parameters, such as sex ratios, of RES turtles is needed to effectively control the invasive species. We conducted a long-term field study on RES turtles at two study sites: the Taisho River (a shallow river) and Teradaike Pond (an irrigation reservoir that was irregularly drained to maintain the embankment and water quality) in western Japan. Using trapping and muddling methods, we captured RES turtles and checked for sex, carapace length, and body weight. We also examined whether the population of RES turtles could be reduced by continuously removing the turtles captured at each study site. The sex ratio (male/both sexes) of RES turtles that could be sexed by external morphology (presumably adult turtles) was 0.27 at the Taisho River and 0.26 at Teradaike Pond. At both sites, these sex ratios were almost the same as those of RES turtles that could be sexed only by necropsy after euthanasia (presumably juvenile turtles). These sex ratios were markedly biased toward females and consistent between the adult and the juvenile turtles, thus suggesting that more females had been produced than males. At the Taisho River, a total of 1,366 RES turtles were captured and eliminated over more than ten years. Nevertheless, the annual catch did not tend to decrease and only an effect of preventing population growth was observed. At Teradaike Pond, a total of 1,831 RES turtles were captured over nine years. Nearly half of them were caught for the initial two years, during which the pond was drained. Thereafter, the annual catch of RES turtles clearly decreased. These results suggest that it is difficult to control RES turtles established in rivers but that it is feasible to effectively control RES turtles in enclosed small water bodies, such as irrigation reservoirs, by intensively capturing and eliminating the turtles during the drainage period.","PeriodicalId":56053,"journal":{"name":"Current Herpetology","volume":"42 1","pages":"27 - 34"},"PeriodicalIF":0.7,"publicationDate":"2023-02-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49659308","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}
Abstract: Phylogenetic analyses using mtDNA gene sequences revealed the presence of two genetic clades in the genus Leptobrachella (former Leptolalax) from northern Thailand. One formed a clade including L. ventripunctata and L. aerea, while another included L. bourrreti and L. laoi. The first clade contained L. cf. minima from Doi Suthep, while the second clade contained L. murphyi and two undescribed species, one from Doi Inthanon, at a high altitude of 2,300 m asl, and another from Mae Hong Son, at Myanmar border. These form a clade, that is sister to L. murphyi. Morphologically, the first species is generally similar to L. murphyi, while the second species resembles L. cf. minima. However, they are clearly distinguished from those described species by great genetic differences, and we describe them as L. korifi sp. nov. and L. sinorensis sp. nov., respectively.
{"title":"Two New Species of Leptobrachella from Northern Thailand (Amphibia, Anura, Megophryidae)","authors":"M. Matsui, S. Panha, Koshiro Eto","doi":"10.5358/hsj.42.83","DOIUrl":"https://doi.org/10.5358/hsj.42.83","url":null,"abstract":"Abstract: Phylogenetic analyses using mtDNA gene sequences revealed the presence of two genetic clades in the genus Leptobrachella (former Leptolalax) from northern Thailand. One formed a clade including L. ventripunctata and L. aerea, while another included L. bourrreti and L. laoi. The first clade contained L. cf. minima from Doi Suthep, while the second clade contained L. murphyi and two undescribed species, one from Doi Inthanon, at a high altitude of 2,300 m asl, and another from Mae Hong Son, at Myanmar border. These form a clade, that is sister to L. murphyi. Morphologically, the first species is generally similar to L. murphyi, while the second species resembles L. cf. minima. However, they are clearly distinguished from those described species by great genetic differences, and we describe them as L. korifi sp. nov. and L. sinorensis sp. nov., respectively.","PeriodicalId":56053,"journal":{"name":"Current Herpetology","volume":"8 1","pages":"83 - 97"},"PeriodicalIF":0.7,"publicationDate":"2023-02-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70621523","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}
Abstract: Skeletochronology is a reliable method for estimating the age and growth rate of many ectothermic vertebrates, including amphibians. The Levant green frog, Pelophylax bedriagae (Ranidae), is a relatively large frog distributed in the western and northern parts of Iran. The age structure of Pelophylax bedriagae was determined by examining 52 females and 39 males collected from Kohgilouyeh and Bouyerahmad Provinces (Yasouj and Basht). The age range of the two populations is three to 10 years. The maximum age for males and females is 10 and eight years, respectively. The highest age distribution for males is six years (17.6%) and four and six years (15.4%) for females. On average, males (6.2±1.4 years) are older than females (5.2±1.3 years). Male and female body size is correlated with age within both populations. However, despite being significantly different in average body size, the average age of the two populations (Yasouj vs. Basht) is not significantly different.
{"title":"Skeletochronology of the Levant Green Frog, Pelophylax bedriagae (Camerano, 1882), in Southern Iran","authors":"Maryam Khaloei, B. Fathinia, A. Shafaeipour","doi":"10.5358/hsj.42.55","DOIUrl":"https://doi.org/10.5358/hsj.42.55","url":null,"abstract":"Abstract: Skeletochronology is a reliable method for estimating the age and growth rate of many ectothermic vertebrates, including amphibians. The Levant green frog, Pelophylax bedriagae (Ranidae), is a relatively large frog distributed in the western and northern parts of Iran. The age structure of Pelophylax bedriagae was determined by examining 52 females and 39 males collected from Kohgilouyeh and Bouyerahmad Provinces (Yasouj and Basht). The age range of the two populations is three to 10 years. The maximum age for males and females is 10 and eight years, respectively. The highest age distribution for males is six years (17.6%) and four and six years (15.4%) for females. On average, males (6.2±1.4 years) are older than females (5.2±1.3 years). Male and female body size is correlated with age within both populations. However, despite being significantly different in average body size, the average age of the two populations (Yasouj vs. Basht) is not significantly different.","PeriodicalId":56053,"journal":{"name":"Current Herpetology","volume":"42 1","pages":"55 - 53"},"PeriodicalIF":0.7,"publicationDate":"2023-02-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47431569","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}
Ruiying Xu, Ke Li, He Zhang, Hao He, Fei Zhu, Yayong Wu, P. Guo
Abstract: Achalinus yangdatongi Hou, Wang, Guo, Chen, Yuan & Che, 2021 was described based on single specimen. After morphological examination of recently collected specimens from the type locality and close region, several specimens (3 females and 1 male) were identified as this species. Genetic distances (p-distance) calculated from a fragment of the mtDNA gene, cytochrome c oxidase subunit I (COI) were less than 1.8% between the newly collected specimens and the type specimen. Achalinus yangdatongi is redescribed and several of its diagnostics are revised accordingly: dorsal body scales 23 rows throughout; ventrals 155–171; subcaudals 59–76, unpaired; maxillary teeth 24–26.
{"title":"Expanded Description of Achalinus yangdatongi (Serpentes: Xenodermidae)","authors":"Ruiying Xu, Ke Li, He Zhang, Hao He, Fei Zhu, Yayong Wu, P. Guo","doi":"10.5358/hsj.42.1","DOIUrl":"https://doi.org/10.5358/hsj.42.1","url":null,"abstract":"Abstract: Achalinus yangdatongi Hou, Wang, Guo, Chen, Yuan & Che, 2021 was described based on single specimen. After morphological examination of recently collected specimens from the type locality and close region, several specimens (3 females and 1 male) were identified as this species. Genetic distances (p-distance) calculated from a fragment of the mtDNA gene, cytochrome c oxidase subunit I (COI) were less than 1.8% between the newly collected specimens and the type specimen. Achalinus yangdatongi is redescribed and several of its diagnostics are revised accordingly: dorsal body scales 23 rows throughout; ventrals 155–171; subcaudals 59–76, unpaired; maxillary teeth 24–26.","PeriodicalId":56053,"journal":{"name":"Current Herpetology","volume":"42 1","pages":"1 - 8"},"PeriodicalIF":0.7,"publicationDate":"2023-02-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49427829","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}
Abstract: The African clawed frog Xenopus laevis is a largely aquatic frog occurring from central to southern Africa. This species has been used as experimental animal, and has been introduced in many countries including Japan. However, despite its importance as an experimental animal and invasive alien species across the world, but there are few studies on basic biology of X. laevis including individual variation. In this study, we investigated individual variation in external morphology and allometric patterns. Traits not directly related to the skeleton showed high variability, but ecologically important traits like eye size at the youngest stage, showed low variability. No significant external left-right differences were identified. Allometric analysis showed that males have larger heads and eyes than females, suggesting male-male combat during breeding. Male forelimb suggests also showed a faster growth rate, suggesting that longer forelimbs are advantageous for males in breeding.
{"title":"Intrapopulation Morphological Variation in Introduced African Clawed Frog, Xenopus laevis (Amphibia: Anura: Pipidae) in Japan","authors":"Kento Takata, K. Nishikawa, Yuta Otsu, Hiroaki Ui","doi":"10.5358/hsj.42.64","DOIUrl":"https://doi.org/10.5358/hsj.42.64","url":null,"abstract":"Abstract: The African clawed frog Xenopus laevis is a largely aquatic frog occurring from central to southern Africa. This species has been used as experimental animal, and has been introduced in many countries including Japan. However, despite its importance as an experimental animal and invasive alien species across the world, but there are few studies on basic biology of X. laevis including individual variation. In this study, we investigated individual variation in external morphology and allometric patterns. Traits not directly related to the skeleton showed high variability, but ecologically important traits like eye size at the youngest stage, showed low variability. No significant external left-right differences were identified. Allometric analysis showed that males have larger heads and eyes than females, suggesting male-male combat during breeding. Male forelimb suggests also showed a faster growth rate, suggesting that longer forelimbs are advantageous for males in breeding.","PeriodicalId":56053,"journal":{"name":"Current Herpetology","volume":"42 1","pages":"64 - 73"},"PeriodicalIF":0.7,"publicationDate":"2023-02-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41832845","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}
Abstract: Long-term field studies have provided evidence of worldwide declines in vertebrate populations, including amphibians and reptiles. However, studies investigating the decline in snake populations are scarce. As obligate predators, snakes play important roles in local ecosystems and are in turn affected by their food resources. In the present study we investigated the seasonal abundance of snakes and their food habits in a rice paddy field and compared the results of the present study with those of a previous study that was conducted at the same site approximately 30 years ago. Our results showed that Elaphe quadrivirgata, a dietary generalist snake that had been one of the dominant species at the site, has drastically declined and that Rhabdophis tigrinus and Gloydius blomhoffii have remained as dominant species. Furthermore, in the present study, most of the stomach contents of R. tigrinus consisted of the Japanese tree frog, Dryophytes japonicus, whereas three frog species, D. japonicus, Rana japonica, and Pelophylax porosus porosus, had been the main prey of R. tigrinus 30 years ago. In addition, fewer individuals of R. tigrinus and G. blomhoffii contained food in their stomachs than 30 years ago. Our findings imply that a change in prey availability may have affected the guild structure of snakes at this study site, although further investigation is necessary to verify the reasons for the decline of the dietary generalist, E. quadrivirgata.
{"title":"Change in the Guild Structure of a Snake Community in Japan over 30 Years","authors":"Kiyoto Sawada, S. Kadowaki","doi":"10.5358/hsj.42.74","DOIUrl":"https://doi.org/10.5358/hsj.42.74","url":null,"abstract":"Abstract: Long-term field studies have provided evidence of worldwide declines in vertebrate populations, including amphibians and reptiles. However, studies investigating the decline in snake populations are scarce. As obligate predators, snakes play important roles in local ecosystems and are in turn affected by their food resources. In the present study we investigated the seasonal abundance of snakes and their food habits in a rice paddy field and compared the results of the present study with those of a previous study that was conducted at the same site approximately 30 years ago. Our results showed that Elaphe quadrivirgata, a dietary generalist snake that had been one of the dominant species at the site, has drastically declined and that Rhabdophis tigrinus and Gloydius blomhoffii have remained as dominant species. Furthermore, in the present study, most of the stomach contents of R. tigrinus consisted of the Japanese tree frog, Dryophytes japonicus, whereas three frog species, D. japonicus, Rana japonica, and Pelophylax porosus porosus, had been the main prey of R. tigrinus 30 years ago. In addition, fewer individuals of R. tigrinus and G. blomhoffii contained food in their stomachs than 30 years ago. Our findings imply that a change in prey availability may have affected the guild structure of snakes at this study site, although further investigation is necessary to verify the reasons for the decline of the dietary generalist, E. quadrivirgata.","PeriodicalId":56053,"journal":{"name":"Current Herpetology","volume":"42 1","pages":"74 - 82"},"PeriodicalIF":0.7,"publicationDate":"2023-02-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44350555","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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