Viviparous squamates offer opportunities for exploring the importance of past maternal resources (yolk) and current resources (placentotrophy) to support embryonic growth during gestation, and to optimize offspring fitness. Both thermal and nutritional environment of the mother during gestation may be expected to be important in determining offspring fitness. Using a two-way factorial design, we have investigated possible interactions between food intake and thermal environment during gestation in the viviparous skink Niveoscincus metallicus . Among the females given restricted basking opportunities, fewer females gave birth, there was a significant increase in gestation length, and relative clutch mass was reduced due to smaller neonatal size; none of these parameters were influenced by nutritional status. Neonates from mothers given restricted basking opportunities were lighter, had shorter snout-vent lengths (SVL), and smaller fat bodies than neonates from mothers given optimal basking opportunities; their postnatal growth rate (over eight weeks) was also significantly lower and they showed a reduced incidence of basking behavior. There were interaction effects between thermal regime and food supply for neonate SVL and neonatal fat body weight. Sprint speed within 24 hours of birth was significantly increased in neonates from mothers given restricted thermal opportunities; however, for weeks 1-8 postnatally, there were no differences in sprint speed in offspring from any of the treatments. These results suggest that, contrary to our initial hypothesis, females maintained in nutritionally favorable conditions are unable to compensate for the gestational effects of a thermally poor environment. We now suggest that in Niveoscincus metallicus facultative placentotrophy may allow mothers to improve offspring fitness by increasing neonatal fat body size.
{"title":"Maternal effects associated with gestation conditions in a viviparous lizard, Niveoscincus metallicus","authors":"R. Swain, Sandra C. Jones","doi":"10.2307/1467056","DOIUrl":"https://doi.org/10.2307/1467056","url":null,"abstract":"Viviparous squamates offer opportunities for exploring the importance of past maternal resources (yolk) and current resources (placentotrophy) to support embryonic growth during gestation, and to optimize offspring fitness. Both thermal and nutritional environment of the mother during gestation may be expected to be important in determining offspring fitness. Using a two-way factorial design, we have investigated possible interactions between food intake and thermal environment during gestation in the viviparous skink Niveoscincus metallicus . Among the females given restricted basking opportunities, fewer females gave birth, there was a significant increase in gestation length, and relative clutch mass was reduced due to smaller neonatal size; none of these parameters were influenced by nutritional status. Neonates from mothers given restricted basking opportunities were lighter, had shorter snout-vent lengths (SVL), and smaller fat bodies than neonates from mothers given optimal basking opportunities; their postnatal growth rate (over eight weeks) was also significantly lower and they showed a reduced incidence of basking behavior. There were interaction effects between thermal regime and food supply for neonate SVL and neonatal fat body weight. Sprint speed within 24 hours of birth was significantly increased in neonates from mothers given restricted thermal opportunities; however, for weeks 1-8 postnatally, there were no differences in sprint speed in offspring from any of the treatments. These results suggest that, contrary to our initial hypothesis, females maintained in nutritionally favorable conditions are unable to compensate for the gestational effects of a thermally poor environment. We now suggest that in Niveoscincus metallicus facultative placentotrophy may allow mothers to improve offspring fitness by increasing neonatal fat body size.","PeriodicalId":56309,"journal":{"name":"Herpetological Monographs","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"2000-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2307/1467056","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68498893","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Anoles have evolved independently on each island in the Greater Antilles, producing a suite of morphologically-distinct species that utilize different microhabitats. Comparisons among islands indicate that the same set of "ecomorphs"-distantly related species that are similar in morphology, ecology, and behavior-has evolved on each island. Despite considerable work on anoles over the past three decades, much remains to be learned about evolution of the ecomorphs. In particular, previous studies have focused on external measurements of gross limb proportions, tail length, mass, and number of lamellae. Using a variety of techniques, we examined these char- acters in greater detail and investigated a wide variety of other characters. We found that the ecomorph classes represent distinct entities in morphological space when morphological characters are examined in greater detail (e.g., each limb element was treated separately). In addition, we found that the ecomorphs differ in a variety of characters not previously examined, including toe pad area, pectoral and pelvic girdle dimensions, head dimensions, and tail shape. These differences were apparent regardless of how we defined body size, although comparisons of particular characters were affected by which body size variable was used. This finding indicates that convergence in ecomorph evolutibn extends beyond traits directly linked to habitat use and locomotion. We also examined a number of other taxa that have not traditionally been considered to be members of any ecomorph class. We found that many descendants of ecomorphs living on small islands near the Greater Antilles no longer belong to the ecomorph class of their ancestor. Many Lesser Antillean anoles appear to ibe trunk-crown anoles, whereas others do not belong to any ecomorph class. Montane anoles of the Greater Antilles and Chamaelinorops also do not belong to any ecomorph class, but Chamaeleolis, and possibly Phenacosaurus, are twig anoles.
{"title":"ECOLOGICAL MORPHOLOGY OF CARIBBEAN ANOLES","authors":"Kevin Beuttell, J. Losos","doi":"10.2307/1467059","DOIUrl":"https://doi.org/10.2307/1467059","url":null,"abstract":"Anoles have evolved independently on each island in the Greater Antilles, producing a suite of morphologically-distinct species that utilize different microhabitats. Comparisons among islands indicate that the same set of \"ecomorphs\"-distantly related species that are similar in morphology, ecology, and behavior-has evolved on each island. Despite considerable work on anoles over the past three decades, much remains to be learned about evolution of the ecomorphs. In particular, previous studies have focused on external measurements of gross limb proportions, tail length, mass, and number of lamellae. Using a variety of techniques, we examined these char- acters in greater detail and investigated a wide variety of other characters. We found that the ecomorph classes represent distinct entities in morphological space when morphological characters are examined in greater detail (e.g., each limb element was treated separately). In addition, we found that the ecomorphs differ in a variety of characters not previously examined, including toe pad area, pectoral and pelvic girdle dimensions, head dimensions, and tail shape. These differences were apparent regardless of how we defined body size, although comparisons of particular characters were affected by which body size variable was used. This finding indicates that convergence in ecomorph evolutibn extends beyond traits directly linked to habitat use and locomotion. We also examined a number of other taxa that have not traditionally been considered to be members of any ecomorph class. We found that many descendants of ecomorphs living on small islands near the Greater Antilles no longer belong to the ecomorph class of their ancestor. Many Lesser Antillean anoles appear to ibe trunk-crown anoles, whereas others do not belong to any ecomorph class. Montane anoles of the Greater Antilles and Chamaelinorops also do not belong to any ecomorph class, but Chamaeleolis, and possibly Phenacosaurus, are twig anoles.","PeriodicalId":56309,"journal":{"name":"Herpetological Monographs","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"1999-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2307/1467059","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68498940","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Revision of the Micrurus frontalis Complex (Serpentes: Elapidae)","authors":"N. Silva, J. Sites","doi":"10.2307/1467062","DOIUrl":"https://doi.org/10.2307/1467062","url":null,"abstract":"","PeriodicalId":56309,"journal":{"name":"Herpetological Monographs","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"1999-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2307/1467062","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68498618","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The Palau islands of western Micronesia comprise one of the most physiographically varied archipelagos in the Pacific. There are some 350 islands of volcanic and coralline origin that range from Babeldaob at 333 km2 (about 80% of Palau's total land area) to others, unnamed, that are less than one hectare. A barrier reef encircles most of the archipelago creating a lagoon up to 20 km wide. The majority of the islands are uninhabited, accessible with difficulty only by boat at high tide, and are densely vegetated over steep, rocky terrain. Because of their proximity to the Philippines, New Guinea, the Moluccas, and Borneo, the Palau islands host a significantly richer herpetofauna with more unique taxa than is found on other Pacific islands to the east. As with most other Pacific island groups, however, the herpetofauna has been poorly documented. Since the earliest investigations that began in the nineteen century, Palau's herpetofauna has been uncovered piecemeal. No sustained field effort had been conducted until we began a systematic survey of the islands in 1992. Since then we have collected in Palau every month of the year at least once. This checklist of 46 species of reptiles and amphibians includes almost twice as many taxa as were known from Palau (Owen, 1977) at the beginning of our study. Among these are new species or Palauan records of Gehyra, Hemiphyllodactylus, Lepidodactylus, Nactus, Perochirus, Emoia and Sphenomorphus. Because of the difficulties in surveying so many islands we believe that additional taxa and distributional records await discovery; even the smallest island in Palau can turn up surprises. Nonetheless, it is appropriate to consolidate what is now known about this intriguing fauna and environment. We provide an historical summary of previous collecting efforts, an overview of the islands' geology and habitats, and for each species account we include distributional information, taxonomic and systematic discussion, natural history observations, and a comprehensive bibliography.
{"title":"A Checklist of the Herpetofauna of the Palau Islands (Republic of Belau), Oceania","authors":"R. Crombie, G. Pregill","doi":"10.2307/1467060","DOIUrl":"https://doi.org/10.2307/1467060","url":null,"abstract":"The Palau islands of western Micronesia comprise one of the most physiographically varied archipelagos in the Pacific. There are some 350 islands of volcanic and coralline origin that range from Babeldaob at 333 km2 (about 80% of Palau's total land area) to others, unnamed, that are less than one hectare. A barrier reef encircles most of the archipelago creating a lagoon up to 20 km wide. The majority of the islands are uninhabited, accessible with difficulty only by boat at high tide, and are densely vegetated over steep, rocky terrain. Because of their proximity to the Philippines, New Guinea, the Moluccas, and Borneo, the Palau islands host a significantly richer herpetofauna with more unique taxa than is found on other Pacific islands to the east. As with most other Pacific island groups, however, the herpetofauna has been poorly documented. Since the earliest investigations that began in the nineteen century, Palau's herpetofauna has been uncovered piecemeal. No sustained field effort had been conducted until we began a systematic survey of the islands in 1992. Since then we have collected in Palau every month of the year at least once. This checklist of 46 species of reptiles and amphibians includes almost twice as many taxa as were known from Palau (Owen, 1977) at the beginning of our study. Among these are new species or Palauan records of Gehyra, Hemiphyllodactylus, Lepidodactylus, Nactus, Perochirus, Emoia and Sphenomorphus. Because of the difficulties in surveying so many islands we believe that additional taxa and distributional records await discovery; even the smallest island in Palau can turn up surprises. Nonetheless, it is appropriate to consolidate what is now known about this intriguing fauna and environment. We provide an historical summary of previous collecting efforts, an overview of the islands' geology and habitats, and for each species account we include distributional information, taxonomic and systematic discussion, natural history observations, and a comprehensive bibliography.","PeriodicalId":56309,"journal":{"name":"Herpetological Monographs","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"1999-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2307/1467060","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68498469","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Recent paleontological evidence suggests the North American herpetofauna has been remarkably stable taxonomically and biogeographically throughout the Pleistocene. However, this paper uses paleontological, ecological, and molecular genetic data to argue that the thermophilous and xerically-adapted Collared Lizard (Crotaphytus collaris) did not persist in the northern parts of its range during glacial phases of the Pleistocene. First, a careful review of the paleontological data used to support the stability model reveals no northern fossils unambiguously dated to glacial phases. Second, environmental conditions inferred for the Ozark Plateau and Flint Hills during glacial phases were not compatible with fitness requirements of collared lizards. Third, phylogeographic analyses of an intraspecific mtDNA gene tree suggest a recent invasion of the Ozarks and Flint Hills. Finally, microsatellite data are statistically consistent with a Holocene invasion but not with long-term occupation of the Ozarks or the Flint Hills by collared lizards. These combined data sets provide strong evidence that collared lizards are able to occupy northern parts of their range only during the warmer, drier interglacials. Other thermophilous and xerically-adapted reptilian species might be expected to show similar historical patterns.
{"title":"A Multidisciplinary Investigation of the Applicability of the Pleistocene Herpetofaunal Stability Model to Collared Lizards (Crotaphytus collaris)","authors":"D. Hutchison, S. Malcomber, L. S. Pletscher","doi":"10.2307/1467061","DOIUrl":"https://doi.org/10.2307/1467061","url":null,"abstract":"Recent paleontological evidence suggests the North American herpetofauna has been remarkably stable taxonomically and biogeographically throughout the Pleistocene. However, this paper uses paleontological, ecological, and molecular genetic data to argue that the thermophilous and xerically-adapted Collared Lizard (Crotaphytus collaris) did not persist in the northern parts of its range during glacial phases of the Pleistocene. First, a careful review of the paleontological data used to support the stability model reveals no northern fossils unambiguously dated to glacial phases. Second, environmental conditions inferred for the Ozark Plateau and Flint Hills during glacial phases were not compatible with fitness requirements of collared lizards. Third, phylogeographic analyses of an intraspecific mtDNA gene tree suggest a recent invasion of the Ozarks and Flint Hills. Finally, microsatellite data are statistically consistent with a Holocene invasion but not with long-term occupation of the Ozarks or the Flint Hills by collared lizards. These combined data sets provide strong evidence that collared lizards are able to occupy northern parts of their range only during the warmer, drier interglacials. Other thermophilous and xerically-adapted reptilian species might be expected to show similar historical patterns.","PeriodicalId":56309,"journal":{"name":"Herpetological Monographs","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"1999-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2307/1467061","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68498515","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"The Systematics of Chuckwallas (Sauromalus) with a Phylogenetic Analysis of Other Iguanid Lizards","authors":"Bradford D. Hollingsworth","doi":"10.2307/1467020","DOIUrl":"https://doi.org/10.2307/1467020","url":null,"abstract":"","PeriodicalId":56309,"journal":{"name":"Herpetological Monographs","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"1998-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2307/1467020","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68496896","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"To Bury in Sand: Phylogenetic Relationships among Lizard Species of the Boulengeri Group, Liolaemus (Reptilia: Squamata: Tropiduridae), Based on Behavioral Characters","authors":"M. Halloy, R. Etheridge, G. Burghardt","doi":"10.2307/1467019","DOIUrl":"https://doi.org/10.2307/1467019","url":null,"abstract":"","PeriodicalId":56309,"journal":{"name":"Herpetological Monographs","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"1998-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2307/1467019","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68496767","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Skull characters were examined and combined with postcranial osteological, external, allozyme, DNA sequence, and chromosome data from the literature to estimate the phylogenetic relationships of the Hispaniolan dwarf twig Anolis (A. sheplani, A. insolitus, and A. placidus). A survey of most species of Anolis species for which skeletons are available found two osteological character states unique to these species, a convex parietal roof and crenulated parietal edges, thus suggesting that the Hispaniolan twig dwarfs form a monophyletic group. To assess this hypothesis of monophyly and to estimate the phyletic placement of these species in the genus Anolis, parsimony analyses were undertaken including all proposed close relatives of the Hispaniolan twig dwarfs and a taxonomically and geographically diverse sample of congeners. Diagnostic synapomorphies found in this analysis were surveyed more widely in Anolis. Characterization difficulties of the skull data were addressed by using three coding methods to differentially code intraspecific and continuous variation. Confidence in the Hispaniolan twig dwarf relationships was assessed with the bootstrap, the test of Templeton, and the agreement between results from the three coding methods. The monophyly of the Hispaniolan twig dwarfs was strongly supported. The nearest relatives of the Hispaniolan twig dwarfs appear to be twig species from Hispaniola (A. darlingtoni), Puerto Rico (A. occultus), and South America (tigrinus group, i.e., A. solitarius), and Phenacosaurus. Wider taxonomic and character sampling is needed to assess the robustness of these clades, but present evidence suggests an invasion of Hispaniola or Puerto Rico from South America and, counter to the usual opinions of ecomorph occurrence by intra-island adaptive radiation, a clade of twig species on three different land masses.
研究人员分析了西班牙矮枝Anolis (A. sheplani, A. solitus和A. placidus)的颅骨特征，并结合文献中的颅后骨学、外部、同工酶、DNA序列和染色体数据来估计其系统发育关系。一项对大多数有骨骼的Anolis物种的调查发现，这些物种有两种独特的骨特征状态，即凸顶骨和有圆齿的顶骨边缘，从而表明伊斯帕尼奥拉细枝侏儒形成了一个单系群体。为了评估这种单系假说，并估计这些物种在Anolis属中的种系位置，我们进行了简约性分析，包括所有提出的伊斯帕尼奥拉树枝侏儒的近亲，以及在分类和地理上多样化的同系物样本。在本分析中发现的诊断性突触在Anolis中被更广泛地调查。通过使用三种编码方法对种内和连续变异进行差异编码，解决了颅骨数据的表征困难。用自举法、邓普顿检验和三种编码方法结果之间的一致性来评估伊斯帕尼诺兰树枝矮化关系的置信度。伊斯帕尼奥拉小树枝侏儒的单系性得到了强有力的支持。伊斯帕尼奥拉岛树枝侏儒最近的亲戚似乎是来自伊斯帕尼奥拉岛(A. darlingtoni)、波多黎各(A. occultus)和南美洲(tigrinus群，即A. solitarius)和Phenacosaurus的树枝种。需要更广泛的分类和特征采样来评估这些分支的稳稳性，但目前的证据表明，伊斯帕尼奥拉岛或波多黎各是从南美洲入侵的，并且与通常的岛屿内适应性辐射的生态形态发生的观点相反，在三个不同的陆地块上有一个小枝物种的分支。
{"title":"Skull Characters and the Cladistic Relationships of the Hispaniolan Dwarf Twig Anolis","authors":"S. Poe","doi":"10.2307/1467021","DOIUrl":"https://doi.org/10.2307/1467021","url":null,"abstract":"Skull characters were examined and combined with postcranial osteological, external, allozyme, DNA sequence, and chromosome data from the literature to estimate the phylogenetic relationships of the Hispaniolan dwarf twig Anolis (A. sheplani, A. insolitus, and A. placidus). A survey of most species of Anolis species for which skeletons are available found two osteological character states unique to these species, a convex parietal roof and crenulated parietal edges, thus suggesting that the Hispaniolan twig dwarfs form a monophyletic group. To assess this hypothesis of monophyly and to estimate the phyletic placement of these species in the genus Anolis, parsimony analyses were undertaken including all proposed close relatives of the Hispaniolan twig dwarfs and a taxonomically and geographically diverse sample of congeners. Diagnostic synapomorphies found in this analysis were surveyed more widely in Anolis. Characterization difficulties of the skull data were addressed by using three coding methods to differentially code intraspecific and continuous variation. Confidence in the Hispaniolan twig dwarf relationships was assessed with the bootstrap, the test of Templeton, and the agreement between results from the three coding methods. The monophyly of the Hispaniolan twig dwarfs was strongly supported. The nearest relatives of the Hispaniolan twig dwarfs appear to be twig species from Hispaniola (A. darlingtoni), Puerto Rico (A. occultus), and South America (tigrinus group, i.e., A. solitarius), and Phenacosaurus. Wider taxonomic and character sampling is needed to assess the robustness of these clades, but present evidence suggests an invasion of Hispaniola or Puerto Rico from South America and, counter to the usual opinions of ecomorph occurrence by intra-island adaptive radiation, a clade of twig species on three different land masses.","PeriodicalId":56309,"journal":{"name":"Herpetological Monographs","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"1998-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2307/1467021","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68496929","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A population of rough green snakes (Opheodrys aestivus) was studied by markrecapture at Ransom Lake (RL) in north-central Arkansas over 7 yr (1986-1992). Results are compared to those obtained previously from a population in similar habitat located 12 km distant (Bald Knob Lake, BKL). Over 2700 captures made along the RL shoreline were nonrandomly distributed within areas of dense vegetation. Green snakes lived within home ranges averaging 67 m in shoreline length and differing in location between years by about 50 m. Individuals were recaptured on average every 19 days, in which time they had moved linearly along the shoreline about 28 m. About 3% of all movements were over water. Each of these spatial parameters at RL was very similar to those obtained at BKL. Growth rates of individual snakes decreased linearly with snout-vent length (SVL) and were similar to those characterizing snakes at BKL. However, greater variance in growth rates at RL resulted in a weaker relationship between body size and age. Females grew to be larger than males. Body size of females was slightly larger at RL than at BKL. Younger age groups were proportionally larger at RL than at BKL. Sex ratio was 1:1 both in adults and in all snakes combined. In 1987 and 1988 when about 60% of the population consisted of adult snakes, sex and age structure of the population were similar between years. Maximum population density was about 800 snakes/ha. Catchability of individual snakes in monthly samples was equal in 1987 but equivocal in 1988. Survivorship was measured directly by agespecific recapture proportions. Adult survivorship (males 28%, females 41%) was less at RL than at BKL. Calculated overall first-year survivorship (21.5%) was similar to that at BKL and was slightly greater than hatchling survivorship measured directly by recapture (15-19%). Survivorship for ages -0 in both sexes showed a linear logarithmic decline with age (type II survivorship curve). As at BKL, overall clutch size at RL averaged 6 eggs. Unlike at BKL, clutch size at RL differed among years concordant with body condition (weight-length ratio) of snakes. As at BKL, the net reproductive rate at RL (RO = 0.60) was insufficient for sustaining the population over the long term. Estimated population size varied fivefold over 7 yr and decreased from approximately 350-500 snakes in the first 3 yr (1986-1988) to 100-200 in the last 4 yr (1989-1992). The rapid population decline apparently was due to unusually high mortality among adults, and the increased mortality, in turn, was correlated with unusually hot and dry weather leading to a decrease in the body condition of snakes. Predation by snakes and birds may have contributed to the decline. Although snake populations are often regarded as being relatively stable, this study demonstrates that populations of a small insectivorous species are not immune to environmental vagaries and may respond by decreasing density as do other vertebrates.
1986-1992年在美国阿肯色州中北部的兰森湖(RL)进行了7年的野外捕获，研究了粗绿蛇(Opheodrys aestivus)种群。结果与之前在12公里外的相似栖息地(Bald Knob Lake, BKL)获得的结果进行了比较。超过2700次的捕获是非随机分布在密集植被的地区。青蛇生活在海岸线平均67米长的范围内，每年的位置相差约50米。平均每19天捕获一次，在此期间，它们沿着海岸线直线移动约28米。大约3%的飞行是在水上进行的。这些空间参数在RL与BKL非常相似。单株蛇的生长速率随鼻口长度(SVL)呈线性下降，与BKL的特征相似。然而，RL生长速率的较大差异导致体型与年龄之间的关系较弱。雌性长得比雄性大。雌体尺寸在RL比BKL略大。年轻年龄组在RL的比例大于BKL。成年蛇和所有蛇的性别比例都是1:1。在1987年和1988年，大约60%的种群由成年蛇组成，种群的性别和年龄结构在年份之间相似。最大种群密度约为800条/公顷。1987年每个月样本中单个蛇的可捕性是相等的，而1988年则是模棱两可的。生存率由年龄特异性复发比例直接测量。成年生存率(男性28%，女性41%)RL低于BKL。计算的第一年总体存活率(21.5%)与BKL相似，略高于直接捕获的孵化存活率(15-19%)。年龄-0岁时，两性的生存率随年龄呈线性对数下降(II型生存率曲线)。与BKL一样，RL的总卵数平均为6枚。与BKL不同的是，RL的产蛋数与蛇的身体状况(体重比)一致，在不同的年份之间存在差异。与BKL一样，RL的净繁殖率(RO = 0.60)不足以长期维持种群。估计种群规模在7年内变化了5倍，从前3年(1986-1988年)的约350-500条蛇减少到后4年(1989-1992年)的100-200条。数量的快速下降显然是由于成年蛇的死亡率异常高，而死亡率的增加反过来又与异常炎热和干燥的天气有关，导致蛇的身体状况下降。蛇和鸟类的捕食可能导致了数量的减少。尽管蛇的种群通常被认为是相对稳定的，但这项研究表明，一种小型食虫物种的种群并不能对环境的变幻莫测免疫，它们可能会像其他脊椎动物一样，通过减少密度来应对。
{"title":"Population ecology of green snakes (Opheodrys aestivus) revisited","authors":"M. Plummer","doi":"10.2307/1467008","DOIUrl":"https://doi.org/10.2307/1467008","url":null,"abstract":"A population of rough green snakes (Opheodrys aestivus) was studied by markrecapture at Ransom Lake (RL) in north-central Arkansas over 7 yr (1986-1992). Results are compared to those obtained previously from a population in similar habitat located 12 km distant (Bald Knob Lake, BKL). Over 2700 captures made along the RL shoreline were nonrandomly distributed within areas of dense vegetation. Green snakes lived within home ranges averaging 67 m in shoreline length and differing in location between years by about 50 m. Individuals were recaptured on average every 19 days, in which time they had moved linearly along the shoreline about 28 m. About 3% of all movements were over water. Each of these spatial parameters at RL was very similar to those obtained at BKL. Growth rates of individual snakes decreased linearly with snout-vent length (SVL) and were similar to those characterizing snakes at BKL. However, greater variance in growth rates at RL resulted in a weaker relationship between body size and age. Females grew to be larger than males. Body size of females was slightly larger at RL than at BKL. Younger age groups were proportionally larger at RL than at BKL. Sex ratio was 1:1 both in adults and in all snakes combined. In 1987 and 1988 when about 60% of the population consisted of adult snakes, sex and age structure of the population were similar between years. Maximum population density was about 800 snakes/ha. Catchability of individual snakes in monthly samples was equal in 1987 but equivocal in 1988. Survivorship was measured directly by agespecific recapture proportions. Adult survivorship (males 28%, females 41%) was less at RL than at BKL. Calculated overall first-year survivorship (21.5%) was similar to that at BKL and was slightly greater than hatchling survivorship measured directly by recapture (15-19%). Survivorship for ages -0 in both sexes showed a linear logarithmic decline with age (type II survivorship curve). As at BKL, overall clutch size at RL averaged 6 eggs. Unlike at BKL, clutch size at RL differed among years concordant with body condition (weight-length ratio) of snakes. As at BKL, the net reproductive rate at RL (RO = 0.60) was insufficient for sustaining the population over the long term. Estimated population size varied fivefold over 7 yr and decreased from approximately 350-500 snakes in the first 3 yr (1986-1988) to 100-200 in the last 4 yr (1989-1992). The rapid population decline apparently was due to unusually high mortality among adults, and the increased mortality, in turn, was correlated with unusually hot and dry weather leading to a decrease in the body condition of snakes. Predation by snakes and birds may have contributed to the decline. Although snake populations are often regarded as being relatively stable, this study demonstrates that populations of a small insectivorous species are not immune to environmental vagaries and may respond by decreasing density as do other vertebrates.","PeriodicalId":56309,"journal":{"name":"Herpetological Monographs","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"1997-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2307/1467008","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68496572","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Phylogeny of the spiny lizards (Sceloporus) based on molecular and morphological evidence","authors":"J. Wiens, T. Reeder","doi":"10.2307/1467007","DOIUrl":"https://doi.org/10.2307/1467007","url":null,"abstract":"","PeriodicalId":56309,"journal":{"name":"Herpetological Monographs","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"1997-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2307/1467007","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68496463","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：