Benelkadi Hadj Aissa, Roberto C. RodrÃguez-Caro, Mansour Amroun, E. Graciá
Due to phenotypic plasticity and sex-biased selective pressures, intraspecific variation in tortoise morphology is usually assessed by studying sexual dimorphism. However, inferences may differ based on the choice of shell size measurements for analyses. In this work, we identified linear measurements that best describe sexual dimorphism for the spur-thighed tortoise Testudo graeca whitei. We assessed 34 carapace and plastron measurements in 67 individuals (24 males, 43 females) in a population at the natural Mergueb site located on the central limit of the Algerian steppe. Twenty-two out of 34 measurements significantly showed sexual size dimorphism in ANOVA tests. When analyzing sexual shape dimorphism with ANCOVAs, nine measurements showed no shared allometry with the measurements used as covariates to correct by size. Meanwhile, 17 out of the remaining 23 measurements showed significant differences in shape. PCA analyses similarly described T. graeca’s sexual dimorphism. In general, females tend to be bigger than males, especially in central scutes what is probably linked with clutch sizes commitments. On the other hand, males are larger-sized in anterior and posterior scutes, probably as a result of courtship, male fighting and copulation. Some of the analyzed measurements are revealed as being especially adequate for further studying the geographical variation of sexual dimorphism in Testudo graeca
由于表型可塑性和性别偏倚的选择压力，通常通过研究两性二态性来评估陆龟形态的种内变异。然而，根据壳尺寸测量的选择，推断可能会有所不同。在这项工作中，我们确定了线性测量，最好地描述了刺腿龟Testudo graeca whitei的两性二态性。我们在阿尔及利亚大草原中部的Mergueb自然遗址对一个种群的67只个体(24只雄性，43只雌性)进行了34项甲壳和板层测量。在方差分析中，34项测量中有22项显著显示性别尺寸二态性。当用ANCOVAs分析两性形状二态性时，9个测量值显示没有共享异速，并使用测量值作为协变量来校正尺寸。与此同时，在剩下的23项测量中，有17项显示出形状上的显著差异。PCA分析类似地描述了T. graeca的性别二态性。一般来说，雌性往往比雄性大，尤其是在中间的鱼鳞上，这可能与卵的数量有关。另一方面，雄性的前肢和后肢尺寸较大，可能是求爱、雄性争斗和交配的结果。分析结果表明，其中一些测量值特别适合于进一步研究希腊鼠两性二态性的地理变异
{"title":"The shell measurements that best describe sexual dimorphism in the spur-thighed tortoise Testudo graeca from Algeria","authors":"Benelkadi Hadj Aissa, Roberto C. RodrÃguez-Caro, Mansour Amroun, E. Graciá","doi":"10.11160/bah.217","DOIUrl":"https://doi.org/10.11160/bah.217","url":null,"abstract":"Due to phenotypic plasticity and sex-biased selective pressures, intraspecific variation in tortoise morphology is usually assessed by studying sexual dimorphism. However, inferences may differ based on the choice of shell size measurements for analyses. In this work, we identified linear measurements that best describe sexual dimorphism for the spur-thighed tortoise Testudo graeca whitei. We assessed 34 carapace and plastron measurements in 67 individuals (24 males, 43 females) in a population at the natural Mergueb site located on the central limit of the Algerian steppe. Twenty-two out of 34 measurements significantly showed sexual size dimorphism in ANOVA tests. When analyzing sexual shape dimorphism with ANCOVAs, nine measurements showed no shared allometry with the measurements used as covariates to correct by size. Meanwhile, 17 out of the remaining 23 measurements showed significant differences in shape. PCA analyses similarly described T. graeca’s sexual dimorphism. In general, females tend to be bigger than males, especially in central scutes what is probably linked with clutch sizes commitments. On the other hand, males are larger-sized in anterior and posterior scutes, probably as a result of courtship, male fighting and copulation. Some of the analyzed measurements are revealed as being especially adequate for further studying the geographical variation of sexual dimorphism in Testudo graeca","PeriodicalId":53521,"journal":{"name":"Basic and Applied Herpetology","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79877834","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Semi-controlled artificial incubation methods of crocodile eggs use low technology devices where one or more parameters cannot be controlled, but with the advantage that they are less expensive and logistically more feasible. This study evaluated the effect of different artificial incubation depths on the hatching success of eggs of Crocodylus acutus, under semi-controlled conditions, and analyzed biometric data of the hatchlings. The crocodile nests were collected from sandbanks of the two rivers (RÃo Negro and RÃo Santa Rosa), both located at Machiques de Perijá, Zulia state, Venezuela. The results showed a significant and positive effect on hatching success when the eggs were buried at 2 cm depth, compared to those at 10 cm and 20 cm. The hatching success at 2 cm depth was 82.43%. Also, we found that the size and weight of the hatchlings, as well as the relationships between these biometric variables, depend on the place of origin of the nests. The highest hatching percentage obtained at 2 cm was probably due to the effect of optimal incubation temperatures at this depth. The isolation and controlled heating system of the incubation room would prevent extreme fluctuations in temperature, favoring greater hatching at 2 cm depth. Differences in the biometric aspects of the hatchlings could be associated with differences in the size and the physiological status of the females from both sites.
鳄鱼卵的半受控人工孵化方法使用技术含量较低的设备，其中一个或多个参数无法控制，但其优点是成本较低，在后勤上更可行。本研究在半受控条件下，评估了不同人工孵化深度对尖鳄卵孵化成功率的影响，并分析了孵化后的生物特征数据。鳄鱼巢是在两条河(RÃ-o Negro和RÃ-o Santa Rosa)的沙洲上收集的，这两条河都位于委内瑞拉苏利亚州的machques de PerijÃ。结果表明，与埋于10 cm和20 cm的卵相比，埋于2 cm的卵对孵化成功率有显著的正向影响。2 cm深度的孵化成功率为82.43%。此外，我们还发现，雏鸟的体型和体重，以及这些生物特征变量之间的关系，都取决于它们筑巢的原产地。在2厘米处获得的最高孵化率可能是由于该深度的最佳孵化温度的影响。孵化室的隔离和控制加热系统将防止温度的极端波动，有利于在2厘米深的地方孵化更多的卵。幼鱼的生物特征差异可能与两地雌鱼体型和生理状态的差异有关。
{"title":"Effects of depth in semi-controlled artificial incubation on egg hatching success of Crocodylus acutus (Cuvier, 1807) and hatchlings biometry","authors":"J. Larreal, Enrique Quintero-Torres, T. Barros","doi":"10.11160/bah.234","DOIUrl":"https://doi.org/10.11160/bah.234","url":null,"abstract":"Semi-controlled artificial incubation methods of crocodile eggs use low technology devices where one or more parameters cannot be controlled, but with the advantage that they are less expensive and logistically more feasible. This study evaluated the effect of different artificial incubation depths on the hatching success of eggs of Crocodylus acutus, under semi-controlled conditions, and analyzed biometric data of the hatchlings. The crocodile nests were collected from sandbanks of the two rivers (RÃo Negro and RÃo Santa Rosa), both located at Machiques de Perijá, Zulia state, Venezuela. The results showed a significant and positive effect on hatching success when the eggs were buried at 2 cm depth, compared to those at 10 cm and 20 cm. The hatching success at 2 cm depth was 82.43%. Also, we found that the size and weight of the hatchlings, as well as the relationships between these biometric variables, depend on the place of origin of the nests. The highest hatching percentage obtained at 2 cm was probably due to the effect of optimal incubation temperatures at this depth. The isolation and controlled heating system of the incubation room would prevent extreme fluctuations in temperature, favoring greater hatching at 2 cm depth. Differences in the biometric aspects of the hatchlings could be associated with differences in the size and the physiological status of the females from both sites.","PeriodicalId":53521,"journal":{"name":"Basic and Applied Herpetology","volume":"10 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-04-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76405696","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
J. Braga, L. P. C. Oitaven, M. M. T. Da Rocha, S. Vieira, Diego Terenciano Rúbio, Sávio Stefanini Sant’anna, K. Grego
Snake venom is an expensive metabolic weapon used for digestion and defense. Detailed studies on the production of venoms are important for the manufacture of antivenoms and for the therapeutic management of snakebites. Bothrops leucurus is one of the snakes of medical importance responsible for a large number of accidents in Northeast Brazil. To establish the correlation between Bothrops leucurus venom (Blv) yield, under captive conditions, and the morphological characteristics (body mass and length), sex and age, 31 specimens were milked during one year, grouped by sex and age (juvenile, adult and long-lived), totaling 106 extractions in that period. We evaluated the electrophoretic profile (SDS-PAGE) under reducing conditions, the 50% lethal dose (LD50) and the minimum coagulant dose (DMC) of the extracted venoms. The body size was positively correlated with venom production in B. leucurus snakes. Regardless of sex and age, the venom showed no differences between liquid and solid composition or between right and left fang, however, the production of venom in females was twice the one found in males and more lethal. The clotting ability was lost as the animals aged, indicating that older snakes are not the best choice for venom pools in the production of antivenoms. These results are important for the choice of animals to antivenom production, and to understand the biological effects of snake venoms under captive conditions.
{"title":"Influence of size, sex and age on venom yield of Bothrops leucurus (Serpentes, Viperidae) in captivity conditions","authors":"J. Braga, L. P. C. Oitaven, M. M. T. Da Rocha, S. Vieira, Diego Terenciano Rúbio, Sávio Stefanini Sant’anna, K. Grego","doi":"10.11160/bah.233","DOIUrl":"https://doi.org/10.11160/bah.233","url":null,"abstract":"Snake venom is an expensive metabolic weapon used for digestion and defense. Detailed studies on the production of venoms are important for the manufacture of antivenoms and for the therapeutic management of snakebites. Bothrops leucurus is one of the snakes of medical importance responsible for a large number of accidents in Northeast Brazil. To establish the correlation between Bothrops leucurus venom (Blv) yield, under captive conditions, and the morphological characteristics (body mass and length), sex and age, 31 specimens were milked during one year, grouped by sex and age (juvenile, adult and long-lived), totaling 106 extractions in that period. We evaluated the electrophoretic profile (SDS-PAGE) under reducing conditions, the 50% lethal dose (LD50) and the minimum coagulant dose (DMC) of the extracted venoms. The body size was positively correlated with venom production in B. leucurus snakes. Regardless of sex and age, the venom showed no differences between liquid and solid composition or between right and left fang, however, the production of venom in females was twice the one found in males and more lethal. The clotting ability was lost as the animals aged, indicating that older snakes are not the best choice for venom pools in the production of antivenoms. These results are important for the choice of animals to antivenom production, and to understand the biological effects of snake venoms under captive conditions.","PeriodicalId":53521,"journal":{"name":"Basic and Applied Herpetology","volume":"34 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73720888","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Sea turtles constitute a threatened group of fauna, thus to know caveats in their knowledge it is crucial to lead research efforts. The present study aims to analyse the scientific literature published on marine turtles in Cabo Verde by means of a bibliographic analysis. We analysed the temporal and geographical variation in the publications, the number of authors and nationalities involved, and the extent of study of different research topics by species. The number of publications grew through the analysed time period (1979-2020), as well as the number of authors. The countries with the highest number of publications were Spain followed by Cabo Verde. Research areas of greater investigation effort were “Breeding and reproductive successâ€, followed by “Conservation and management†and “Population dynamicsâ€. However, there were differences between species and islands. Most of the studies were conducted at Boa Vista, followed by Sal and Maio Islands. The most studied species was Caretta caretta. This analysis contributes to understand trends and caveats in sea turtle knowledge that could help guide future research lines in areas of particular concern.
We report the first cases of mortality in anurans associated with the presence of the fungus Batrachochytrium dendrobatidis at four different localities from Catalonia (NE Iberian Peninsula, Spain). All cases were confirmed by both molecular techniques and histology. The infected individuals were two Mediterranean painted frogs (Discoglossus pictus) from Girona province found in 2018 and 2020, one Iberian waterfrog (Pelophylax perezi) from Tarragona province found in 2018, and one European common frog (Rana temporaria) from Barcelona province found in 2019. This is the first time that mortality associated with this pathogen has been confirmed in D. pictus and P. perezi. The role of the fungus as an agent possibly leading to death, in association with other external environmental factors, is discussed. These findings could suggest a recent increase of the incidence of this disease in the region. Some of these cases are particularly worrying because of their occurrence close to sites where some endemic amphibian species with extremely reduced distributions inhabit.
D. Escoriza, Santiago Poch, Pau Sunyer-Sala, D. Boix
Emys orbicularis is a semi-aquatic turtle with great longevity being able to reach 50 years. In this study, we estimated the growth rates (in carapace length and body mass) in a population of E. orbicularis from the northeastern Iberian Peninsula over a period of 23 years. We compared their growth rates among age groups, sexes, and years and across different types of habitats (small forest ponds, large forest ponds, and slow-flow streams). We hypothesized that the subpopulation that inhabits the small forest ponds may show slower growth rates because these habitats have lower solar exposure and lower water temperature. The study population showed sexual dimorphism in size, with females being larger and heavier than males. The analyses confirmed that the individuals from small forest ponds are smaller and grow at slower rates. Our results also revealed significant inter-annual variability in the growth rates of E. orbicularis, emphasizing the importance of conducting long-term studies of species with great longevity.
{"title":"Growth patterns of Emys orbicularis across a range of aquatic habitats: a long-term study","authors":"D. Escoriza, Santiago Poch, Pau Sunyer-Sala, D. Boix","doi":"10.11160/BAH.228","DOIUrl":"https://doi.org/10.11160/BAH.228","url":null,"abstract":"Emys orbicularis is a semi-aquatic turtle with great longevity being able to reach 50 years. In this study, we estimated the growth rates (in carapace length and body mass) in a population of E. orbicularis from the northeastern Iberian Peninsula over a period of 23 years. We compared their growth rates among age groups, sexes, and years and across different types of habitats (small forest ponds, large forest ponds, and slow-flow streams). We hypothesized that the subpopulation that inhabits the small forest ponds may show slower growth rates because these habitats have lower solar exposure and lower water temperature. The study population showed sexual dimorphism in size, with females being larger and heavier than males. The analyses confirmed that the individuals from small forest ponds are smaller and grow at slower rates. Our results also revealed significant inter-annual variability in the growth rates of E. orbicularis, emphasizing the importance of conducting long-term studies of species with great longevity.","PeriodicalId":53521,"journal":{"name":"Basic and Applied Herpetology","volume":"51 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77855453","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We studied the female reproductive cycle of a population of Ophisops elegans lizard from the herpetology collection of the Natural History Museum of the Lebanese University. Females collected during spring and summer showed vitellogenesis in their ovaries with oviposition occurring from May to July followed by a subsequent quiescent period. They produced up to two clutches. Mean clutch size was 3.2 ± 1, range 2-5 eggs. Clutch size was independent of female body size. The smallest female attaining sexual maturity had a snout vent length of 45 mm. Sexual maturity can be attained within one year of age. We found no significant difference in body size between female and male adult lizards. Seasonal variations in the reproductive activity of females were well synchronized with those of males.
Daniel Fernández Ortín, G. Montes, Í. Martínez‐Solano
Monfragüe National Park (Cáceres, Extremadura, Spain) is a protected area in central-western Iberia,including some of the best preserved primary Mediterranean vegetation. Legal protection dates back to 1979 (first as a Natural Park and then as a National Park), but knowledge about its reptile communities is so far limited to sparse records. In this paper we present an updated species list based on 521 records covering 163 1x1 km UTM grids in the study area, compiled in the period 2000-2019. We detected 20 native species, representing 71.4% of the reptile fauna in Extremadura and 35% of the ibero-balearic reptile fauna. Additionally, based on molecular analyses populations of the amphisbaenid genus Blanus in the study area are assigned to the oriental Iberian taxon, B. cinereus. The new records extend the known distribution of the different reptile species in the study area in 56 10x10 km UTM grids. Species presenting more restricted distributions in Monfragüe are Lacerta schreiberi (one 1x1 grid), Emys orbicularis, and Acanthodactylus erythrurus (four 10x10 grids each).
Monfragüe国家公园(Côceres，埃斯特雷马杜拉，西班牙)是伊比利亚中西部的一个保护区，包括一些保存最完好的地中海原始植被。法律保护可以追溯到1979年(最初作为自然公园，然后作为国家公园)，但迄今为止，对其爬行动物群落的了解仅限于稀疏的记录。在本文中，我们基于2000年至2019年期间在研究区域内覆盖163 1x1 km UTM网格的521条记录，提出了一份更新的物种清单。我们发现了20种本地物种，占埃斯特雷马杜拉爬行动物区系的71.4%和伊比利亚-巴利阿里爬行动物区系的35%。此外，基于分子分析，研究区双鳃鱼属的种群归属于东方伊比利亚分类单元B. cinereus。新记录将研究区域内已知的56个10x10公里的UTM网格中不同爬行动物物种的分布范围扩大了。在Monfragüe中分布较为有限的物种有Lacerta schreiberi(1个1x1格)、Emys orbicularis和Acanthodactylus erythrurus(各4个10x10格)。
{"title":"A catalogue of reptiles of Monfragüe National Park (Spain), with molecular characterization of populations of Blanus Wagler, 1830 in this protected area","authors":"Daniel Fernández Ortín, G. Montes, Í. Martínez‐Solano","doi":"10.11160/bah.173","DOIUrl":"https://doi.org/10.11160/bah.173","url":null,"abstract":"Monfragüe National Park (Cáceres, Extremadura, Spain) is a protected area in central-western Iberia,including some of the best preserved primary Mediterranean vegetation. Legal protection dates back to 1979 (first as a Natural Park and then as a National Park), but knowledge about its reptile communities is so far limited to sparse records. In this paper we present an updated species list based on 521 records covering 163 1x1 km UTM grids in the study area, compiled in the period 2000-2019. We detected 20 native species, representing 71.4% of the reptile fauna in Extremadura and 35% of the ibero-balearic reptile fauna. Additionally, based on molecular analyses populations of the amphisbaenid genus Blanus in the study area are assigned to the oriental Iberian taxon, B. cinereus. The new records extend the known distribution of the different reptile species in the study area in 56 10x10 km UTM grids. Species presenting more restricted distributions in Monfragüe are Lacerta schreiberi (one 1x1 grid), Emys orbicularis, and Acanthodactylus erythrurus (four 10x10 grids each). ","PeriodicalId":53521,"journal":{"name":"Basic and Applied Herpetology","volume":"37 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86546142","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
D. Escoriza, Badis Bakhouche, Tiar Ghoulam, Djemadi Imed, Draidi khalil
The Mediterranean stripe-necked terrapin is a freshwater turtle widely distributed in southwestern Europe and northwestern Africa, but whose natural history is little known. In this study we investigated the ecology of a population in northern Algeria (Reghaïa Lake Ramsar Reserve), with special emphasis on its phenology, demographic structure and diet, based on capture and recapture methods. Our results indicated that there is a short inactivity period in January and possibly the activity is also reduced during the month of August. The best Jolly-Seber model indicated that the population within the survey station had a minimum size of 653 specimens. The population contained a higher proportion of males (0.68 - 0.76) and a proportion of juveniles between 0.02 - 0.16. Females were larger and relatively heavier than males. Analysis of stomach contents showed that M. leprosa feeds with high frequency on aquatic arthropods. Specifically, we found insects: Diptera (Chironomidae, Culicidae, Dixidae, Syrphidae), Heteroptera (Corixidae, Notonectidae) and Coleoptera (Dytiscidae), crustaceans (Branchiopoda, Ostracoda), plant matter (Typha angustifolia), fish (Gambusia holbrooki), and unidentified materials.
{"title":"Phenology and population structure of the Mediterranean stripe-necked terrapin Mauremys leprosa (Schweigger, 1812) in the Reghaïa Lake (northern Algeria)","authors":"D. Escoriza, Badis Bakhouche, Tiar Ghoulam, Djemadi Imed, Draidi khalil","doi":"10.11160/bah.170","DOIUrl":"https://doi.org/10.11160/bah.170","url":null,"abstract":" \u0000 \u0000The Mediterranean stripe-necked terrapin is a freshwater turtle widely distributed in southwestern Europe and northwestern Africa, but whose natural history is little known. In this study we investigated the ecology of a population in northern Algeria (Reghaïa Lake Ramsar Reserve), with special emphasis on its phenology, demographic structure and diet, based on capture and recapture methods. Our results indicated that there is a short inactivity period in January and possibly the activity is also reduced during the month of August. The best Jolly-Seber model indicated that the population within the survey station had a minimum size of 653 specimens. The population contained a higher proportion of males (0.68 - 0.76) and a proportion of juveniles between 0.02 - 0.16. Females were larger and relatively heavier than males. Analysis of stomach contents showed that M. leprosa feeds with high frequency on aquatic arthropods. Specifically, we found insects: Diptera (Chironomidae, Culicidae, Dixidae, Syrphidae), Heteroptera (Corixidae, Notonectidae) and Coleoptera (Dytiscidae), crustaceans (Branchiopoda, Ostracoda), plant matter (Typha angustifolia), fish (Gambusia holbrooki), and unidentified materials. ","PeriodicalId":53521,"journal":{"name":"Basic and Applied Herpetology","volume":"18 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87696020","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Habitat use and thermal biology are closely related, because thermal microclimates vary spatially. The use of habitat and microhabitat by different species influences many of their traits, such as their physiology, and may, therefore exert a direct effect on survival. Ectothermal animals, such as lizards, are affected by thermal and biophysical environments they inhabit, and the particular use of a given substrate reflects an overlap between thermally adequate microhabitats, and behavioral preferences. By exploiting certain microhabitats and avoiding others, many lizards tend to maintain their body temperature within a range that allows maximum performance. Here, we evaluate how two syntopic species of lizards, Liolaemus pacha and L. ramirezae, use substrates with different exposure to solar radiation. Our hypothesis is that L. pacha uses both soil and rock substrates indistinctly, due to being a generalist species, whereas L. ramirezae uses the rock substrate more frequently, due to its saxicolous habits. We expect temperatures to be different both in substrates, and in different exposures, and thermal characteristics of each species to condition their use. For example, because the body temperature range of L. pacha is wider, we predict that substrate use will be wider. A pre-established 100x75 m area was monitored during four Austral springs and summers between 2011 and 2015, in Los Cardones, Amaicha del Valle, Tucumán, Argentina. Species' substrate where the lizard was found (soil or rock), and exposure to solar radiation: sun, filtered shade or full shade was recorded. After capture, lizard body temperature (Tb), substrate temperature (Ts), and air temperature (Ta) were recorded in the place of the first observation of the lizard. Obtained results show that L. pacha and L. ramirezae had a more persistent use of the rock than the soil substrate, thus considering them saxicolous species. Further, they were frequently observed exposed to direct sunlight. Average body temperature was higher than environmental temperature (Ts and Ta), and significantly different in each exposure type (sun, filtered shade and full shade), and in both substrates (rock and soil). Differential use of substrate and the relationship between body temperature and microhabitat temperatures suggests that L. pacha and L. ramirezae are “active thermoregulatorsâ€, using both substrate surfaces and solar radiation as heat sources.
{"title":"Substrate use and its effect on body temperature in two syntopic Liolaemus lizards in northwestern Argentina","authors":"C. Robles, Gilda Luciana Vivas, M. Halloy","doi":"10.11160/BAH.160","DOIUrl":"https://doi.org/10.11160/BAH.160","url":null,"abstract":"Habitat use and thermal biology are closely related, because thermal microclimates vary spatially. The use of habitat and microhabitat by different species influences many of their traits, such as their physiology, and may, therefore exert a direct effect on survival. Ectothermal animals, such as lizards, are affected by thermal and biophysical environments they inhabit, and the particular use of a given substrate reflects an overlap between thermally adequate microhabitats, and behavioral preferences. By exploiting certain microhabitats and avoiding others, many lizards tend to maintain their body temperature within a range that allows maximum performance. Here, we evaluate how two syntopic species of lizards, Liolaemus pacha and L. ramirezae, use substrates with different exposure to solar radiation. Our hypothesis is that L. pacha uses both soil and rock substrates indistinctly, due to being a generalist species, whereas L. ramirezae uses the rock substrate more frequently, due to its saxicolous habits. We expect temperatures to be different both in substrates, and in different exposures, and thermal characteristics of each species to condition their use. For example, because the body temperature range of L. pacha is wider, we predict that substrate use will be wider. A pre-established 100x75 m area was monitored during four Austral springs and summers between 2011 and 2015, in Los Cardones, Amaicha del Valle, Tucumán, Argentina. Species' substrate where the lizard was found (soil or rock), and exposure to solar radiation: sun, filtered shade or full shade was recorded. After capture, lizard body temperature (Tb), substrate temperature (Ts), and air temperature (Ta) were recorded in the place of the first observation of the lizard. Obtained results show that L. pacha and L. ramirezae had a more persistent use of the rock than the soil substrate, thus considering them saxicolous species. Further, they were frequently observed exposed to direct sunlight. Average body temperature was higher than environmental temperature (Ts and Ta), and significantly different in each exposure type (sun, filtered shade and full shade), and in both substrates (rock and soil). Differential use of substrate and the relationship between body temperature and microhabitat temperatures suggests that L. pacha and L. ramirezae are “active thermoregulatorsâ€, using both substrate surfaces and solar radiation as heat sources.","PeriodicalId":53521,"journal":{"name":"Basic and Applied Herpetology","volume":"53 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-08-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91268030","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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