Climate warming is projected to drive the extinction of approximately one-fifth of the world’s lizard species within the next 60 years(by 2080).However,it remains unclear to what extent and how the global lizard popu...Climate warming is projected to drive the extinction of approximately one-fifth of the world’s lizard species within the next 60 years(by 2080).However,it remains unclear to what extent and how the global lizard population will be affected by this phenomenon on a geographical scale.Furthermore,there is a need to establish a connection between extinction risk and the prioritization of conservation efforts.In this context,we aim to address concerns related to geographically isolated and critically small lizard populations,highlighting why they face an exceptionally high risk of extinction.We also explore the potential for entire populations to vanish without notice.A comprehensive understanding of these factors is essential to inform the prioritization of conservation initiatives aimed at safeguarding lizard populations in tropical countries under future climate change scenarios.展开更多
We acclimated adult males of three Eremias lizards from different latitudes to 28℃,33℃ or 38℃ to examine whether temperature acclimation affects their thermal preference and tolerance and whether thermal preference...We acclimated adult males of three Eremias lizards from different latitudes to 28℃,33℃ or 38℃ to examine whether temperature acclimation affects their thermal preference and tolerance and whether thermal preference and tolerance of these lizards correspond with their latitudinal distributions.Overall,selected body temperature(Tsel)and viable temperature range(VTR)were both highest in E.brenchleyi and lowest in E.multiocellata,with E.argus in between;critical thermal minimum(CTMin)was highest in E.multiocellata and lowest in E.brenchleyi,with E.argus in between;critical thermal maximum(CTMax)was lower in E.multiocellata than in other two species.Lizards acclimated to 28℃ and 38℃ overall selected lower body temperatures than those acclimated to 33℃;lizards acclimated to high temperatures were less tolerant of low temperatures,and vice versa;lizards acclimated to 28℃ were less tolerant of high temperatures but had a wider VTR range than those acclimated to 33℃ and 38℃.Lizards of three species acclimated to the three temperatures always differed from each other in CTMin,but not in Tsel,CTMax and VTR.Our results show that:temperature acclimation plays an important role in influencing thermal preference and tolerance in the three Eremias lizards,although the degrees to which acclimation temperature affects thermal preference and tolerance differ among species;thermal preference rather than tolerance of the three Eremias lizards corresponds with their latitudinal distributions.展开更多
We incubated eggs of five Phrynocephalus species (P. albolineatus, P. axillaries, P. grumgrzimailoi, P. helioscopus and P. przewalskii) at three constant temperatures (24℃, 28℃ and 32℃) to examine differences i...We incubated eggs of five Phrynocephalus species (P. albolineatus, P. axillaries, P. grumgrzimailoi, P. helioscopus and P. przewalskii) at three constant temperatures (24℃, 28℃ and 32℃) to examine differences in incubation length and hatchling morphology among species and among temperature treatments. We combined data from this study with those reported previously for P. frontalis and P. versicolor to examine whether embryonic stage at laying is a causal factor for interspecific variation in incubation length, and whether the phylogenetic relationship inferred from hatchling morphology is consistent with the relationship based on mitochondrial DNA data. Mean values for incubation length differed among the five species studied herein and, in all these five species, incubation length decreased at a decreasing rate as temperature increased. In none of the five species did hatchling size (snout-vent length and body mass) and other morphological variables differ among the three temperature treatments. The seven oviparous Phrynocephalus lizards found in China differ from each other in hatchling morphology, and embryonic stage at laying is a causal factor of inter- and intra-specific variation in incubation length. The phylogenetic relationship inferred from hatchling morphology is not always consistent with the currently known relationship based on mitochondrial DNA data. Data from this study and those reported previously allow the conclusion that any Phrynocephalus species may have its unique position along the axis defined by hatchling morphology.展开更多
We acclimated adults of two viviparous (Phrynocephalus guinanens& and P. vlangalii) and one oviparous (P. versicolor) species of toad-headed lizards (Agamidae) to 28 ℃, 33 ℃ and 38 ℃ to examine whether therm...We acclimated adults of two viviparous (Phrynocephalus guinanens& and P. vlangalii) and one oviparous (P. versicolor) species of toad-headed lizards (Agamidae) to 28 ℃, 33 ℃ and 38 ℃ to examine whether thermal preference (preferred body temperature, Tp) and thermal tolerance (critical thermal minimum, CTMin; critical thermal maximum, CTMax) were affected by acclimation temperature, and correlate with body size and habitat use. Both Tp and CTMax were highest in P. versicolor and lowest in P. vlangalii, with P. guinanensis in between. The two viviparous species did not differ in CTMin and thermal tolerance range, and they both were more resistant to low temperatures and had a wider range of thermal tolerance than the oviparous species. Both CTMin and CTMax shifted upward as acclimation temperature increased in all the three species. Tp was higher in the lizards acclimated to 33 ℃ than in those to 28 ℃ or 38 ℃. The range of thermal tolerance was wider in the lizards acclimated to 28 ℃ than in those to 33 ℃ or 38 ℃. The data showed that: 1) thermal preference and tolerance were affected by acclimation temperature, and differed among the three species of Phrynocephalus lizards with different body sizes and habitat uses; 2) both Tp and CTMax were higher in the species exchanging heat more rapidly with the environment, and CTMin was higher in the species using warmer habitats during the active season; and 3) thermal preference and tolerance might correlat with body size and habitat use in Phrynocephalus lizards.展开更多
Phylogeographic studies of Eremias lizards (Lacertidae) in East Asia have been limited, and the impact of major climatic events on their population dynamics remains poorly known. This study aimed to investigate popu...Phylogeographic studies of Eremias lizards (Lacertidae) in East Asia have been limited, and the impact of major climatic events on their population dynamics remains poorly known. This study aimed to investigate population histories and refugia during the Last Glacial Maximum of two sympatric Eremias lizards (E. argus and E. brenchleyi) inhabiting northern China. We sequenced partial mitochondrial DNA from the ND4 gene for 128 individuals of E. argus from nine localities, and 46 individuals of E. brenchleyi from five localities. Forty-four ND4 haplotypes were determined from E. argus samples, and 33 from E. brenchleyi samples. Population expansion events began about 0.0044 Ma in E. argus, and 0.031 Ma in E. brenchleyi. The demographic history of E. brenchleyi indicates a long-lasting population decline since the most recent common ancestor, while that of E. argus indicates a continuous population growth. Among-population structure was significant in both species, and there were multiple refugia across their range. Intermittent gene flow occurred among expanded populations across multiple refugia during warmer phases of the glacial period, and this may explain why the effective population size has remained relatively stable in E. brenchleyi and grown in E. argus.展开更多
Toads and lizards have been a part of our ecosystems for millions of years and they are good indicators of environmental health. Toads and lizards can be infected by different types of parasites; blood parasites are o...Toads and lizards have been a part of our ecosystems for millions of years and they are good indicators of environmental health. Toads and lizards can be infected by different types of parasites; blood parasites are one of the most important parasites. The present study was conducted to survey and identify different blood parasites in Mabuya sp. lizard and Buforegularis toad in two locations in Khartoum state. Fifteen samples of Mabuya sp and fifteen samples of Buforegularis were collected. All Toads and lizards were dissected and tissue from spleen and liver were examined. The microscopic diagnosis detected Sauroleishmania and Haemogregarina spp parasites in both Mabuya and B. regularis while Microfilariae spp was detected in Mabuya sp. Trypanosoma spp was detected in only one specimen of B. regularis. The results also indicated Sauroleishmania parasites and Haemogregarina spp parasites in the sampled toads and lizards in the two locations. The study of blood parasites and their effects in diversity and health of toads and lizards is necessary to determine the impacts of infections in these animals and the use of the results as indicator of hemoparasites in the environmental as well as the food chain.展开更多
Lizards are key amniote models for studying organ regeneration. During tail regeneration in lizards, blastemas contain sparse granulocytes, macrophages, and lymphocytes among the prevalent mesenchymal cells. Using tra...Lizards are key amniote models for studying organ regeneration. During tail regeneration in lizards, blastemas contain sparse granulocytes, macrophages, and lymphocytes among the prevalent mesenchymal cells. Using transmission electron microscopy to examine scarring blastemas after third and fourth sequential tail amputations, the number of granulocytes, macrophages, and lymphocytes increased at 3-4 weeks in comparison to the first regeneration. An increase in granulocytes and agranulocytes also occurred within a week after blastema cauterization during the process of scarring Blood at the third and fourth regeneration also showed a significant increase in white blood cells compared with that under normal conditions and at the first regeneration. The extracellular matrix of the scarring blastema, especially after cauterization, was denser than that in the normal blastema and numerous white blood cells and fibroblasts were surrounded by electron-pale, fine fibrinoid material mixed with variable collagen fibrils. In addition to previous studies, the present observations support the hypothesis that an increase in inflammation and immune reactions determine scarring rather than regeneration. These new findings verify that an immune reaction against mesenchymal and epidermal cells of the regenerative blastema is one of the main causes for the failure of organ regeneration in amniotes.展开更多
Mating behavior and parturition are important components in the life history of any species. The endangered Chinese crocodile lizard(Shinisaurus crocodilurus) is suffering dramatic population decreases in the wild. Su...Mating behavior and parturition are important components in the life history of any species. The endangered Chinese crocodile lizard(Shinisaurus crocodilurus) is suffering dramatic population decreases in the wild. Successful captive breeding can provide individuals to be reintroduced into their natural habitat and help to restore the wild populations. Studying the mating behavior and parturition of these lizards in captivity will enable us understand how is this ancient species reproduction and optimize artificial reproduction protocol. We studied the mating behavior and parturition of Chinese crocodile lizards in captivity using video recordings at the Daguishan National Nature Reserve, China, from 2015 to 2017. We analyzed pre-copulation and copulation, which occurred in mid-March to late May from all studied years. Pre-copulation and copulation lasted on average 7.51(n=11) and 27.45(n=11) minutes, respectively. We found that large-bodied male lizards have longer copulation periods, a pattern seen in other lizard species. In the mating event, males always initiated sex, while the females were passive. The duration of parturition lasted 153.8 ± 26.8(n=46) minutes, and larger females had heavier clutches. In addition, even though Chinese crocodile lizards represent an ancient lizard clade with primitive characteristics, they still abide by the reproduction patterns seen in most other lizard species.展开更多
During the regeneration of the tail in the arboreal New Zealand gecko (Hoplodactylus maculatus) a new set of tail scales, modified into pads bearing setae 5-20 μm long, is also regenerated. Stages of the formation ...During the regeneration of the tail in the arboreal New Zealand gecko (Hoplodactylus maculatus) a new set of tail scales, modified into pads bearing setae 5-20 μm long, is also regenerated. Stages of the formation of these specialized scales from epidermal pegs that invaginate the dermis of the regenerating tail are described on the basis of light and electron microscopic images. Within the pegs a differentiating clear layer interfaces with the spinulae and setae of the Oberh^utchen according to a process similar to that described for the digital pads. A layer of clear cytoplasm surrounds the growing tiny setae and eventually comities around them and their spatular ends, later leaving the new setae free- standing on the epidermal surface. The fresh adhesive pads help the gecko to maintain the prehensile function of its regenerated tail as together with the axial skeleton (made of a cylinder of elastic cartilage) the pads allow the regenerated tail to curl around twigs and small branches just like the original tail. The regeneration of caudal adhesive pads represents an ideal system to study the cellular processes that determine setal formation under normal or experimental manipulation as the progressive phases of the formation of the setae can be sequentially analyzed.展开更多
Many species are shifting towards higher altitudes in response to global wa rming, but how these upslope-shifting species will respond to hypoxic environments at high altitudes remains unclear. Hypoxia can be especial...Many species are shifting towards higher altitudes in response to global wa rming, but how these upslope-shifting species will respond to hypoxic environments at high altitudes remains unclear. Hypoxia can be especially challenging for viviparous reproduction because of the limitation of oxygen supply to the female and her developing embryos. To investigate the effect of hypoxia on viviparous females and their offspring we acclimated pregnant females of a high-altitude dwelling vivipa rous liza rd(Phr ynocephalus vlangalii) to local oxygen and hypoxia conditions, respectively. We then recorded maternal body temperatures, postpartum body condition, as well as offspring morphology and locomotor performance. We found that pregnant females had higher body temperatures and advanced their parturition under hypoxic acclimation. However, maternal body condition, offspring morphology and locomotor performance were unaffected by the hypoxic conditions during gestation. Our study suggests that upslope-shifting viviparous lizards respond to hypoxic environments by plastically adjusting their body tempera tures to reduce parturition time, without short-term costs to offspring traits.展开更多
Understanding the process of adaptation is a key mission in modern evolutionary biology.Animals living at high elevations face challenges in energy meta bolism due to several environmental constraints(e.g., oxygen sup...Understanding the process of adaptation is a key mission in modern evolutionary biology.Animals living at high elevations face challenges in energy meta bolism due to several environmental constraints(e.g., oxygen supply, food availa bility,and movement time). Animal behavioral processes are intimately related to energy meta bolism, and therefore, behavioral modifica tions are expected to be an important mechanism for high-elevation adaptation. We tested this behavioral adaptation hypothesis using va ria tions of motion visual displays in toad-headed agamid lizards of the genus Phr ynocephalus. We predicted tha t complexity of visual motion displays would decrease with the increase of elevation, because motion visual displays are energetically costly. Displays of 12 Phr ynocephalus species were collected with elevations ranging from sea level to 4600 m. We quantified display complexity using the number of display components, display duration, pathways of display components, as well as display speed for each species. Association between display complexity and elevation was analyzed using the phylogenetic generalized least squares(PGLS)model. We found that both the number of display components and the average value of tail coil speed were negatively correlated with elevation, suggesting that toad-headed lizards living at high-elevation areas reduced their display complexity to cope with the environmental constraints. Our research provides direct evidence for high-elevation adaptation from a behavioral aspect and illustrates the potential impacts of environment heterogeneity on motion visual display diversification.展开更多
Body size and female reproduction in the water adult females larger than 500 mm SVL and 32 adult males Ledong, Hainan under permit to our laboratory in Hainan monitor lizard (Varanus salvator) were studied. Forty-tw...Body size and female reproduction in the water adult females larger than 500 mm SVL and 32 adult males Ledong, Hainan under permit to our laboratory in Hainan monitor lizard (Varanus salvator) were studied. Forty-two larger than 400 mm SVL were donated by local people in in 2013 and 2014. The largest male and female measured 745 and 755 mm SVL, respectively. The mean SVL was greater in adult females than in adult males. Males had larger heads (head width) than females of the same SVL. The smallest reproductive female in our sample was 565 mm SVL. Females produced a single clutch of 17.1 (10-23) pliable-shelled eggs per breeding season stretching from mid-June and mid-September. Clutch size and clutch mass were all positively related to female SVL. However, there was no significant linear relationship between egg mass and female SVL. Larger females generally produced more eggs, and thus heavier clutches than did smaller ones. There was no significant linear relationship between relative clutch mass and female SVL. Phylogenetic generalized least squares (PGLS) analysis, accounting for phylogenetic relationships, showed that clutch size was positively correlated with mean maternal SVL in varanid lizards. PGLS analysis showed that phylogenetic relationships did not affect clutch (or/and egg) mass and the SVL although there were significant linear relationship between clutch (or/and egg) mass and mean maternal SVL. Therefore, we could draw some general conclusions about the body size and reproductive tactics in varanid lizards that larger females generally produced more eggs, larger eggs and thus heavier clutches than did smaller ones.展开更多
The gut microbiota has gained attention because of its importance in facilitating host survival and evolution.However,it is unclear whether gut microbial communities are determined by the host(heritable factor) or env...The gut microbiota has gained attention because of its importance in facilitating host survival and evolution.However,it is unclear whether gut microbial communities are determined by the host(heritable factor) or environment(environmental factor).In this study,we investigated the gut microbial communities and potential functional signatures of two sympatric species distributed along an elevation gradient,the toadheaded lizards Phrynocephalus axillaris and P.forsythii.Our results indicated that at high elevations,the gut microbial communities of P.axillaris and P.forsythii did not significantly differ,and the phylogenetic relationships of gut microbial communities contradicted their hosts.At low altitudes,the two lizards could be distinguished based on their significantly different gut microbial communities.Compared to low-altitude populations,Kyoto Encyclopedia of Genes and Genomes(KEGG)pathway analysis showed that at higher altitudes,energy metabolism,such as carbohydrate,lipid,and amino acids metabolism were higher in both lizards.While a larger number of pathogenic bacteria were found in the lowaltitude population of P.forsythii.This suggests that the convergence of gut microbiota of two lizards at highaltitude stem from environmental factors,as they were exposed to the same environmental stress,whereas the divergence at low-altitude stemmed from heritable factors,as they were exposed to different environmental stresses.These results provide a new perspective regarding whether heritable or environmental factors dominate the gut microbiota during exposure to environmental stress.展开更多
Residual yolk is assumed to be an important source of energy and nutrients during early life in nonmammalian amniotes.Available data show that the mean size of residual yolk is far smaller in lizards than in turtles,s...Residual yolk is assumed to be an important source of energy and nutrients during early life in nonmammalian amniotes.Available data show that the mean size of residual yolk is far smaller in lizards than in turtles,snakes,crocodiles,and birds,raising a question of whether residual yolk is of functional significance in lizards.Here,we compared data from 26 lizard species with those from other nonmammalian amniotes to test the hypothesis that residual yolk is functionally less significant in species producing more fully developed offspring.In our sample,species mean offspring water contents ranged from 73%to 84%of body wet mass;species mean proportions of carcass dry mass,fat-body dry mass,and residual yolk dry mass to offspring dry mass ranged from 84%to 99%,0%to 5.0%,and 0%to 14.4%,respectively.Lizards are,on average,more fully developed at hatching or birth than snakes,as revealed by the fact that the mean proportion of carcass dry mass to body dry mass and offspring water contents were both higher in lizards than in snakes.We conclude that the functional significance of residual yolk during early life is generally less evident in lizards.Even in the lizards where residual yolk is of potential functional significance,this portion of yolk contributes little,if any,to postembryonic growth.Future work could usefully collect data across a wider spectrum of reptile taxa to establish a precocial-altricial continuum and test the hypothesis that species with a smaller amount of residual yolk are closer to the precocial end of the continuum.展开更多
This research presents a novel nature-inspired metaheuristic algorithm called Frilled Lizard Optimization(FLO),which emulates the unique hunting behavior of frilled lizards in their natural habitat.FLO draws its inspi...This research presents a novel nature-inspired metaheuristic algorithm called Frilled Lizard Optimization(FLO),which emulates the unique hunting behavior of frilled lizards in their natural habitat.FLO draws its inspiration from the sit-and-wait hunting strategy of these lizards.The algorithm’s core principles are meticulously detailed and mathematically structured into two distinct phases:(i)an exploration phase,which mimics the lizard’s sudden attack on its prey,and(ii)an exploitation phase,which simulates the lizard’s retreat to the treetops after feeding.To assess FLO’s efficacy in addressing optimization problems,its performance is rigorously tested on fifty-two standard benchmark functions.These functions include unimodal,high-dimensional multimodal,and fixed-dimensional multimodal functions,as well as the challenging CEC 2017 test suite.FLO’s performance is benchmarked against twelve established metaheuristic algorithms,providing a comprehensive comparative analysis.The simulation results demonstrate that FLO excels in both exploration and exploitation,effectively balancing these two critical aspects throughout the search process.This balanced approach enables FLO to outperform several competing algorithms in numerous test cases.Additionally,FLO is applied to twenty-two constrained optimization problems from the CEC 2011 test suite and four complex engineering design problems,further validating its robustness and versatility in solving real-world optimization challenges.Overall,the study highlights FLO’s superior performance and its potential as a powerful tool for tackling a wide range of optimization problems.展开更多
We reported data on thermal preference, thermal tolerance and the thermal dependence of digestive performance for two Phrynocephalus lizards (P. frontalis and P. versicolor), and compared data among lizards so far s...We reported data on thermal preference, thermal tolerance and the thermal dependence of digestive performance for two Phrynocephalus lizards (P. frontalis and P. versicolor), and compared data among lizards so far studied worldwide. Mean values for selected body temperature (Tsel) and critical thermal maximum (CTMax) were greater in P versicolor, whereas mean values for critical thermal minimum (CTMin) did not differ between the two species. The two lizards differed in food intake, but not in food passage time, apparent digestive coefficient (ADC) and assimilation efficiency (AE), across the experimental tem- peratures. Four general conclusions can be drawn from published data. Firstly, thermal preference and thermal tolerance differ among lizards differing in distribution, temporal activity pattern and habitat use. Lizards in thermally more variable regions are better able to tolerate low and high temperatures. Diurnal lizards generally select higher body temperatures than nocturnal lizards, and lizards using habitats with direct sun exposure generally selected higher body temperatures and are better able to tolerate high temperatures. Secondly, CTMax is positively correlated with Tsel. Lizards more likely exposed to extremely high temperatures while active select higher body temperatures than those using shaded habitats. Thirdly, the effects of body temperature on food intake, food passage time, ADC and AE differ among lizards, but it seems to be common among lizards that ADC and AE are less thermally sensitive than food intake and food passage time. Lastly, ADC is dependent on the type of food ingested, with insectivorous lizards digesting food more efficiently than herbivorous lizards展开更多
Determining the susceptibility of species to changing thermal niches is a major goal for biologists.In this paper we develop an eco-physiological model of extinction risk under climate change premised on behavioral th...Determining the susceptibility of species to changing thermal niches is a major goal for biologists.In this paper we develop an eco-physiological model of extinction risk under climate change premised on behavioral thermoregulation.Our method downscales operative environmental temperatures,which restrict hours of activity of lizards,hr,for present-day climate(1975)and future climate scenarios(2070).We apply our model using occurrence records of 20 Phrynocephalus lizards(or taxa in species complexes)drawn from literature and museum records.Our analysis is phylogenetically informed,because some clades may be more sensitive to rising temperatures.The limits for computed hr predict local extirpations among Phrynocephalus lizards at continental scales and delineate upper boundaries of thermal niches as defined by Extreme Value Distributions.Under the 8.5 Representative Concentration Pathway scenario,we predict extirpation of 64%of local populations by 2070 across 20 Phrynocephalus species,and 12 are at high risk of total extinction due to thermal limits being exceeded.In tandem with global strategies of lower CO_(2) emissions,we propose regional strategies for establishing new national parks to protect extinction-prone taxa by preserving high-elevation climate refugia within existing sites of species occurrence.We propose that evolved acclimatization–maternal plasticity–may ameliorate risk,but is poorly studied.Previous studies revealed that adaptive maternal plasticity by thermoregulating gravid females alter progeny thermal preferences by±1℃.We describe plasticity studies for extinction-prone species that could assess whether they might be buffered from climate warming–a self-rescue.We discuss an epigenetic framework for studying such maternal-effect evolution.展开更多
The evolution of many morphological structures is associated with the behavioral context of their use, particularly for structures involved in copulation. Yet, few studies have considered evolutionary relationships am...The evolution of many morphological structures is associated with the behavioral context of their use, particularly for structures involved in copulation. Yet, few studies have considered evolutionary relationships among the integrated suite of structures associated with male reproduction. In this study, we examined nine species of lizards in the genus Anolis to determine whether larger copulatory morphologies and higher potential for copulatory muscle performance evolved in association with higher copulation rates. In 10--12 adult males of each species, we measured the size of the hemipenes and related muscles, the seminiferous tubules in the testes, and the renal sex segments in the kidneys, and we assessed the fiber type composition of the muscles associated with copulation. In a series of pbylogenetically-informed analyses, we used field behavioral data to determine whether observed rates of copulation were associated with these morphologies.We found that species with larger hemipenes had larger fibers in the RPM (the retractor penis magnus, a muscle that controls hemipenis movement), and that the evolution of larg- er hemipenes and RPM fibers is associated with the evolution of higher rates of copulatory behavior. However, the sizes of the seminiferous tubules and renal sex segments, and the muscle fiber composition of the RPM, were not associated with copulation rates. Further, body size was not associated with the size of any of the reproductive structures investigated. The results of this study suggest that peripheral morphologies involved in the transfer of ejaculate may be more evolutionarily labile than internal structures involved in ejaculate production.展开更多
Animals communicate information within their environments via visual, chemical, auditory, and/or tactile modalities. The use of each modalityis generally linked to particular brain regions, but it is not yet known whe...Animals communicate information within their environments via visual, chemical, auditory, and/or tactile modalities. The use of each modalityis generally linked to particular brain regions, but it is not yet known whether the cellular morphology of neurons in these regions has evolved in association with the relative use of a modality.We investigated relationships between the behavioral use of communication modalities and neural morphologies in six lizard species. Two of these species (Anolis carol# nensis and Leiocephalus carinatus) primarily use visual signals to communicate with conspecifics and detect potential prey, and two (Aspidoscelis gularis and Scincella lateralis) communicate and forage primarily using chemical signals. Two other species (Hemidactylus turcicus and Sceloporus olivaceus) use both visual and chemical signals. For each species, we performed beha- vioral observations and quantified rates of visual and chemical behaviors. We then cryosectioned brain tissues from 9-10 males of each species and measured the soma size and density of neurons in two brain regions associated with visual behaviors (the lat- eral geniculate nucleus and the nucleus rotundus) and one region associated with chemical behaviors (the nucleus sphericus). With analyses conducted in a phylogenetic context, we found that species that performed higher rates of visual displays had a denser lateral geniculate nucleus, and species that used a higher proportion of chemical displays had larger somas in the nucleus sphericus. These relationships suggest that neural morphologies in the brain have evolved convergently in species with similar communication behaviors .展开更多
Animal habitat-use patterns cannot be isolated from scale issues. Consequently, multi-scale studies provide a complete characterization of ecological patterns that can further explain the observed variation. Liolaemus...Animal habitat-use patterns cannot be isolated from scale issues. Consequently, multi-scale studies provide a complete characterization of ecological patterns that can further explain the observed variation. Liolaemus constitutes the world's second most speciose lizard genus. In this study, we assessed the relationships between home range size and environmental variables at 3 different spatial scales. The study at a local and regional scale was focused on the habitat specialist Liolaemus multimaculatus. The lizard's home range was calculated using the minimum convex polygon method in populations from grassland sites of the coastal sand dunes of the Argentinean Pampas under 2 different conditions, with or without forestations of Acacia Iongifolia. On the other hand, at a geographical scale we considered the evolutionary implications of 20 species of Liolaemus. Home range size, phylogeny, ecological, environmental, and climatic data were ob- tained from the literature and remote sensing. L. multimaculatus home range varied from 12.66 to 570.00 m. Regionally, this species had smaller home ranges in forested habitats (X: 94.02 m2) com- pared with the non-forested sites (X: 219.78m2). Habitat structure, vegetation types, and food availability would explain the space use at finer scales. When the 20 species of Liolaernus were considered, high mean air temperature and broad thermal amplitudes showed an inverse relationship with home range size. Neither net primary productivity nor phylogeny was good predictors for home range variation at geographical scale. This study highlights the scale dependence of the explicative capability of a set of environmental and intrinsic variables on home range patterns.展开更多
文摘Climate warming is projected to drive the extinction of approximately one-fifth of the world’s lizard species within the next 60 years(by 2080).However,it remains unclear to what extent and how the global lizard population will be affected by this phenomenon on a geographical scale.Furthermore,there is a need to establish a connection between extinction risk and the prioritization of conservation efforts.In this context,we aim to address concerns related to geographically isolated and critically small lizard populations,highlighting why they face an exceptionally high risk of extinction.We also explore the potential for entire populations to vanish without notice.A comprehensive understanding of these factors is essential to inform the prioritization of conservation initiatives aimed at safeguarding lizard populations in tropical countries under future climate change scenarios.
基金supported by a grant from Natural Science Foundation of China(Project No.30670281)
文摘We acclimated adult males of three Eremias lizards from different latitudes to 28℃,33℃ or 38℃ to examine whether temperature acclimation affects their thermal preference and tolerance and whether thermal preference and tolerance of these lizards correspond with their latitudinal distributions.Overall,selected body temperature(Tsel)and viable temperature range(VTR)were both highest in E.brenchleyi and lowest in E.multiocellata,with E.argus in between;critical thermal minimum(CTMin)was highest in E.multiocellata and lowest in E.brenchleyi,with E.argus in between;critical thermal maximum(CTMax)was lower in E.multiocellata than in other two species.Lizards acclimated to 28℃ and 38℃ overall selected lower body temperatures than those acclimated to 33℃;lizards acclimated to high temperatures were less tolerant of low temperatures,and vice versa;lizards acclimated to 28℃ were less tolerant of high temperatures but had a wider VTR range than those acclimated to 33℃ and 38℃.Lizards of three species acclimated to the three temperatures always differed from each other in CTMin,but not in Tsel,CTMax and VTR.Our results show that:temperature acclimation plays an important role in influencing thermal preference and tolerance in the three Eremias lizards,although the degrees to which acclimation temperature affects thermal preference and tolerance differ among species;thermal preference rather than tolerance of the three Eremias lizards corresponds with their latitudinal distributions.
基金supported by grants from the National Natural Science Foundation of China (31071910 and 31200282)Priority Academic Program Development of Jiangsu Higher Education Institutions and High Academic Talent Foundation of Nanjing Forestry University (GXL201306)
文摘We incubated eggs of five Phrynocephalus species (P. albolineatus, P. axillaries, P. grumgrzimailoi, P. helioscopus and P. przewalskii) at three constant temperatures (24℃, 28℃ and 32℃) to examine differences in incubation length and hatchling morphology among species and among temperature treatments. We combined data from this study with those reported previously for P. frontalis and P. versicolor to examine whether embryonic stage at laying is a causal factor for interspecific variation in incubation length, and whether the phylogenetic relationship inferred from hatchling morphology is consistent with the relationship based on mitochondrial DNA data. Mean values for incubation length differed among the five species studied herein and, in all these five species, incubation length decreased at a decreasing rate as temperature increased. In none of the five species did hatchling size (snout-vent length and body mass) and other morphological variables differ among the three temperature treatments. The seven oviparous Phrynocephalus lizards found in China differ from each other in hatchling morphology, and embryonic stage at laying is a causal factor of inter- and intra-specific variation in incubation length. The phylogenetic relationship inferred from hatchling morphology is not always consistent with the currently known relationship based on mitochondrial DNA data. Data from this study and those reported previously allow the conclusion that any Phrynocephalus species may have its unique position along the axis defined by hatchling morphology.
基金supported by the grants from the National Natural Science Foundation of China(31071910 and 31200282)the Priority Academic Program Development of Jiangsu Higher Education Institutions
文摘We acclimated adults of two viviparous (Phrynocephalus guinanens& and P. vlangalii) and one oviparous (P. versicolor) species of toad-headed lizards (Agamidae) to 28 ℃, 33 ℃ and 38 ℃ to examine whether thermal preference (preferred body temperature, Tp) and thermal tolerance (critical thermal minimum, CTMin; critical thermal maximum, CTMax) were affected by acclimation temperature, and correlate with body size and habitat use. Both Tp and CTMax were highest in P. versicolor and lowest in P. vlangalii, with P. guinanensis in between. The two viviparous species did not differ in CTMin and thermal tolerance range, and they both were more resistant to low temperatures and had a wider range of thermal tolerance than the oviparous species. Both CTMin and CTMax shifted upward as acclimation temperature increased in all the three species. Tp was higher in the lizards acclimated to 33 ℃ than in those to 28 ℃ or 38 ℃. The range of thermal tolerance was wider in the lizards acclimated to 28 ℃ than in those to 33 ℃ or 38 ℃. The data showed that: 1) thermal preference and tolerance were affected by acclimation temperature, and differed among the three species of Phrynocephalus lizards with different body sizes and habitat uses; 2) both Tp and CTMax were higher in the species exchanging heat more rapidly with the environment, and CTMin was higher in the species using warmer habitats during the active season; and 3) thermal preference and tolerance might correlat with body size and habitat use in Phrynocephalus lizards.
基金supported by grants from Chinese Ministry of Education (20070319006)the Priority Academic Program Development of Jiangsu Higher Education Institutions
文摘Phylogeographic studies of Eremias lizards (Lacertidae) in East Asia have been limited, and the impact of major climatic events on their population dynamics remains poorly known. This study aimed to investigate population histories and refugia during the Last Glacial Maximum of two sympatric Eremias lizards (E. argus and E. brenchleyi) inhabiting northern China. We sequenced partial mitochondrial DNA from the ND4 gene for 128 individuals of E. argus from nine localities, and 46 individuals of E. brenchleyi from five localities. Forty-four ND4 haplotypes were determined from E. argus samples, and 33 from E. brenchleyi samples. Population expansion events began about 0.0044 Ma in E. argus, and 0.031 Ma in E. brenchleyi. The demographic history of E. brenchleyi indicates a long-lasting population decline since the most recent common ancestor, while that of E. argus indicates a continuous population growth. Among-population structure was significant in both species, and there were multiple refugia across their range. Intermittent gene flow occurred among expanded populations across multiple refugia during warmer phases of the glacial period, and this may explain why the effective population size has remained relatively stable in E. brenchleyi and grown in E. argus.
文摘Toads and lizards have been a part of our ecosystems for millions of years and they are good indicators of environmental health. Toads and lizards can be infected by different types of parasites; blood parasites are one of the most important parasites. The present study was conducted to survey and identify different blood parasites in Mabuya sp. lizard and Buforegularis toad in two locations in Khartoum state. Fifteen samples of Mabuya sp and fifteen samples of Buforegularis were collected. All Toads and lizards were dissected and tissue from spleen and liver were examined. The microscopic diagnosis detected Sauroleishmania and Haemogregarina spp parasites in both Mabuya and B. regularis while Microfilariae spp was detected in Mabuya sp. Trypanosoma spp was detected in only one specimen of B. regularis. The results also indicated Sauroleishmania parasites and Haemogregarina spp parasites in the sampled toads and lizards in the two locations. The study of blood parasites and their effects in diversity and health of toads and lizards is necessary to determine the impacts of infections in these animals and the use of the results as indicator of hemoparasites in the environmental as well as the food chain.
文摘Lizards are key amniote models for studying organ regeneration. During tail regeneration in lizards, blastemas contain sparse granulocytes, macrophages, and lymphocytes among the prevalent mesenchymal cells. Using transmission electron microscopy to examine scarring blastemas after third and fourth sequential tail amputations, the number of granulocytes, macrophages, and lymphocytes increased at 3-4 weeks in comparison to the first regeneration. An increase in granulocytes and agranulocytes also occurred within a week after blastema cauterization during the process of scarring Blood at the third and fourth regeneration also showed a significant increase in white blood cells compared with that under normal conditions and at the first regeneration. The extracellular matrix of the scarring blastema, especially after cauterization, was denser than that in the normal blastema and numerous white blood cells and fibroblasts were surrounded by electron-pale, fine fibrinoid material mixed with variable collagen fibrils. In addition to previous studies, the present observations support the hypothesis that an increase in inflammation and immune reactions determine scarring rather than regeneration. These new findings verify that an immune reaction against mesenchymal and epidermal cells of the regenerative blastema is one of the main causes for the failure of organ regeneration in amniotes.
基金financially support by the National Key Research & Development Program of China (2016YFC0503200)the Natural Science Foundation of China (31760623)the Financial Project of State Forestry Administration (V2130211)
文摘Mating behavior and parturition are important components in the life history of any species. The endangered Chinese crocodile lizard(Shinisaurus crocodilurus) is suffering dramatic population decreases in the wild. Successful captive breeding can provide individuals to be reintroduced into their natural habitat and help to restore the wild populations. Studying the mating behavior and parturition of these lizards in captivity will enable us understand how is this ancient species reproduction and optimize artificial reproduction protocol. We studied the mating behavior and parturition of Chinese crocodile lizards in captivity using video recordings at the Daguishan National Nature Reserve, China, from 2015 to 2017. We analyzed pre-copulation and copulation, which occurred in mid-March to late May from all studied years. Pre-copulation and copulation lasted on average 7.51(n=11) and 27.45(n=11) minutes, respectively. We found that large-bodied male lizards have longer copulation periods, a pattern seen in other lizard species. In the mating event, males always initiated sex, while the females were passive. The duration of parturition lasted 153.8 ± 26.8(n=46) minutes, and larger females had heavier clutches. In addition, even though Chinese crocodile lizards represent an ancient lizard clade with primitive characteristics, they still abide by the reproduction patterns seen in most other lizard species.
基金supported by a New Zealand University Grants Committee Scholarship
文摘During the regeneration of the tail in the arboreal New Zealand gecko (Hoplodactylus maculatus) a new set of tail scales, modified into pads bearing setae 5-20 μm long, is also regenerated. Stages of the formation of these specialized scales from epidermal pegs that invaginate the dermis of the regenerating tail are described on the basis of light and electron microscopic images. Within the pegs a differentiating clear layer interfaces with the spinulae and setae of the Oberh^utchen according to a process similar to that described for the digital pads. A layer of clear cytoplasm surrounds the growing tiny setae and eventually comities around them and their spatular ends, later leaving the new setae free- standing on the epidermal surface. The fresh adhesive pads help the gecko to maintain the prehensile function of its regenerated tail as together with the axial skeleton (made of a cylinder of elastic cartilage) the pads allow the regenerated tail to curl around twigs and small branches just like the original tail. The regeneration of caudal adhesive pads represents an ideal system to study the cellular processes that determine setal formation under normal or experimental manipulation as the progressive phases of the formation of the setae can be sequentially analyzed.
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences (XDA20050201 and XDB31000000)the Second Tibetan Plateau Scientific Expedition and Research Program (2019QZKK0501)the National Natural Science Fund of China (31801987 and 31870391)。
文摘Many species are shifting towards higher altitudes in response to global wa rming, but how these upslope-shifting species will respond to hypoxic environments at high altitudes remains unclear. Hypoxia can be especially challenging for viviparous reproduction because of the limitation of oxygen supply to the female and her developing embryos. To investigate the effect of hypoxia on viviparous females and their offspring we acclimated pregnant females of a high-altitude dwelling vivipa rous liza rd(Phr ynocephalus vlangalii) to local oxygen and hypoxia conditions, respectively. We then recorded maternal body temperatures, postpartum body condition, as well as offspring morphology and locomotor performance. We found that pregnant females had higher body temperatures and advanced their parturition under hypoxic acclimation. However, maternal body condition, offspring morphology and locomotor performance were unaffected by the hypoxic conditions during gestation. Our study suggests that upslope-shifting viviparous lizards respond to hypoxic environments by plastically adjusting their body tempera tures to reduce parturition time, without short-term costs to offspring traits.
基金supported by grants from the National Natural Science Foundation of China(grant numbers:31872233,31572273)to Y.QI。
文摘Understanding the process of adaptation is a key mission in modern evolutionary biology.Animals living at high elevations face challenges in energy meta bolism due to several environmental constraints(e.g., oxygen supply, food availa bility,and movement time). Animal behavioral processes are intimately related to energy meta bolism, and therefore, behavioral modifica tions are expected to be an important mechanism for high-elevation adaptation. We tested this behavioral adaptation hypothesis using va ria tions of motion visual displays in toad-headed agamid lizards of the genus Phr ynocephalus. We predicted tha t complexity of visual motion displays would decrease with the increase of elevation, because motion visual displays are energetically costly. Displays of 12 Phr ynocephalus species were collected with elevations ranging from sea level to 4600 m. We quantified display complexity using the number of display components, display duration, pathways of display components, as well as display speed for each species. Association between display complexity and elevation was analyzed using the phylogenetic generalized least squares(PGLS)model. We found that both the number of display components and the average value of tail coil speed were negatively correlated with elevation, suggesting that toad-headed lizards living at high-elevation areas reduced their display complexity to cope with the environmental constraints. Our research provides direct evidence for high-elevation adaptation from a behavioral aspect and illustrates the potential impacts of environment heterogeneity on motion visual display diversification.
基金Financial supports were provided by grants from Natural Science Foundation of China (31270571)Hainan Key Program of Science and Technology (ZDXM20110008)131 Talent Project of Hangzhou City
文摘Body size and female reproduction in the water adult females larger than 500 mm SVL and 32 adult males Ledong, Hainan under permit to our laboratory in Hainan monitor lizard (Varanus salvator) were studied. Forty-two larger than 400 mm SVL were donated by local people in in 2013 and 2014. The largest male and female measured 745 and 755 mm SVL, respectively. The mean SVL was greater in adult females than in adult males. Males had larger heads (head width) than females of the same SVL. The smallest reproductive female in our sample was 565 mm SVL. Females produced a single clutch of 17.1 (10-23) pliable-shelled eggs per breeding season stretching from mid-June and mid-September. Clutch size and clutch mass were all positively related to female SVL. However, there was no significant linear relationship between egg mass and female SVL. Larger females generally produced more eggs, and thus heavier clutches than did smaller ones. There was no significant linear relationship between relative clutch mass and female SVL. Phylogenetic generalized least squares (PGLS) analysis, accounting for phylogenetic relationships, showed that clutch size was positively correlated with mean maternal SVL in varanid lizards. PGLS analysis showed that phylogenetic relationships did not affect clutch (or/and egg) mass and the SVL although there were significant linear relationship between clutch (or/and egg) mass and mean maternal SVL. Therefore, we could draw some general conclusions about the body size and reproductive tactics in varanid lizards that larger females generally produced more eggs, larger eggs and thus heavier clutches than did smaller ones.
基金supported by the National Natural Science Foundation of China (No.31471988 and N0.31200287)。
文摘The gut microbiota has gained attention because of its importance in facilitating host survival and evolution.However,it is unclear whether gut microbial communities are determined by the host(heritable factor) or environment(environmental factor).In this study,we investigated the gut microbial communities and potential functional signatures of two sympatric species distributed along an elevation gradient,the toadheaded lizards Phrynocephalus axillaris and P.forsythii.Our results indicated that at high elevations,the gut microbial communities of P.axillaris and P.forsythii did not significantly differ,and the phylogenetic relationships of gut microbial communities contradicted their hosts.At low altitudes,the two lizards could be distinguished based on their significantly different gut microbial communities.Compared to low-altitude populations,Kyoto Encyclopedia of Genes and Genomes(KEGG)pathway analysis showed that at higher altitudes,energy metabolism,such as carbohydrate,lipid,and amino acids metabolism were higher in both lizards.While a larger number of pathogenic bacteria were found in the lowaltitude population of P.forsythii.This suggests that the convergence of gut microbiota of two lizards at highaltitude stem from environmental factors,as they were exposed to the same environmental stress,whereas the divergence at low-altitude stemmed from heritable factors,as they were exposed to different environmental stresses.These results provide a new perspective regarding whether heritable or environmental factors dominate the gut microbiota during exposure to environmental stress.
基金supported by grants from the National Natural Science Foundation of China(Nos.31870390,31672277,31470471,31071910,32171498 and 39270124)the Spanish Ministry of Science and Technology(No.CGL2007-60187/BOS)+2 种基金the Second Tibetan Plateau Scientific Expedition and Research Program(STEP)(No.2019QZKK05010216)the Chinese Ministry of Education(No,20070319006)the Natural Science Foundation of Zhejiang Province(No.RC97019).
文摘Residual yolk is assumed to be an important source of energy and nutrients during early life in nonmammalian amniotes.Available data show that the mean size of residual yolk is far smaller in lizards than in turtles,snakes,crocodiles,and birds,raising a question of whether residual yolk is of functional significance in lizards.Here,we compared data from 26 lizard species with those from other nonmammalian amniotes to test the hypothesis that residual yolk is functionally less significant in species producing more fully developed offspring.In our sample,species mean offspring water contents ranged from 73%to 84%of body wet mass;species mean proportions of carcass dry mass,fat-body dry mass,and residual yolk dry mass to offspring dry mass ranged from 84%to 99%,0%to 5.0%,and 0%to 14.4%,respectively.Lizards are,on average,more fully developed at hatching or birth than snakes,as revealed by the fact that the mean proportion of carcass dry mass to body dry mass and offspring water contents were both higher in lizards than in snakes.We conclude that the functional significance of residual yolk during early life is generally less evident in lizards.Even in the lizards where residual yolk is of potential functional significance,this portion of yolk contributes little,if any,to postembryonic growth.Future work could usefully collect data across a wider spectrum of reptile taxa to establish a precocial-altricial continuum and test the hypothesis that species with a smaller amount of residual yolk are closer to the precocial end of the continuum.
文摘This research presents a novel nature-inspired metaheuristic algorithm called Frilled Lizard Optimization(FLO),which emulates the unique hunting behavior of frilled lizards in their natural habitat.FLO draws its inspiration from the sit-and-wait hunting strategy of these lizards.The algorithm’s core principles are meticulously detailed and mathematically structured into two distinct phases:(i)an exploration phase,which mimics the lizard’s sudden attack on its prey,and(ii)an exploitation phase,which simulates the lizard’s retreat to the treetops after feeding.To assess FLO’s efficacy in addressing optimization problems,its performance is rigorously tested on fifty-two standard benchmark functions.These functions include unimodal,high-dimensional multimodal,and fixed-dimensional multimodal functions,as well as the challenging CEC 2017 test suite.FLO’s performance is benchmarked against twelve established metaheuristic algorithms,providing a comprehensive comparative analysis.The simulation results demonstrate that FLO excels in both exploration and exploitation,effectively balancing these two critical aspects throughout the search process.This balanced approach enables FLO to outperform several competing algorithms in numerous test cases.Additionally,FLO is applied to twenty-two constrained optimization problems from the CEC 2011 test suite and four complex engineering design problems,further validating its robustness and versatility in solving real-world optimization challenges.Overall,the study highlights FLO’s superior performance and its potential as a powerful tool for tackling a wide range of optimization problems.
文摘We reported data on thermal preference, thermal tolerance and the thermal dependence of digestive performance for two Phrynocephalus lizards (P. frontalis and P. versicolor), and compared data among lizards so far studied worldwide. Mean values for selected body temperature (Tsel) and critical thermal maximum (CTMax) were greater in P versicolor, whereas mean values for critical thermal minimum (CTMin) did not differ between the two species. The two lizards differed in food intake, but not in food passage time, apparent digestive coefficient (ADC) and assimilation efficiency (AE), across the experimental tem- peratures. Four general conclusions can be drawn from published data. Firstly, thermal preference and thermal tolerance differ among lizards differing in distribution, temporal activity pattern and habitat use. Lizards in thermally more variable regions are better able to tolerate low and high temperatures. Diurnal lizards generally select higher body temperatures than nocturnal lizards, and lizards using habitats with direct sun exposure generally selected higher body temperatures and are better able to tolerate high temperatures. Secondly, CTMax is positively correlated with Tsel. Lizards more likely exposed to extremely high temperatures while active select higher body temperatures than those using shaded habitats. Thirdly, the effects of body temperature on food intake, food passage time, ADC and AE differ among lizards, but it seems to be common among lizards that ADC and AE are less thermally sensitive than food intake and food passage time. Lastly, ADC is dependent on the type of food ingested, with insectivorous lizards digesting food more efficiently than herbivorous lizards
基金BS and DBM were supported by NSF Macrosystems(Grant EF-1241848)FRM was supported by PAPIIT UNAM 210116YQ was supported by China’s Biodiversity Observation Network(Sino-BON).
文摘Determining the susceptibility of species to changing thermal niches is a major goal for biologists.In this paper we develop an eco-physiological model of extinction risk under climate change premised on behavioral thermoregulation.Our method downscales operative environmental temperatures,which restrict hours of activity of lizards,hr,for present-day climate(1975)and future climate scenarios(2070).We apply our model using occurrence records of 20 Phrynocephalus lizards(or taxa in species complexes)drawn from literature and museum records.Our analysis is phylogenetically informed,because some clades may be more sensitive to rising temperatures.The limits for computed hr predict local extirpations among Phrynocephalus lizards at continental scales and delineate upper boundaries of thermal niches as defined by Extreme Value Distributions.Under the 8.5 Representative Concentration Pathway scenario,we predict extirpation of 64%of local populations by 2070 across 20 Phrynocephalus species,and 12 are at high risk of total extinction due to thermal limits being exceeded.In tandem with global strategies of lower CO_(2) emissions,we propose regional strategies for establishing new national parks to protect extinction-prone taxa by preserving high-elevation climate refugia within existing sites of species occurrence.We propose that evolved acclimatization–maternal plasticity–may ameliorate risk,but is poorly studied.Previous studies revealed that adaptive maternal plasticity by thermoregulating gravid females alter progeny thermal preferences by±1℃.We describe plasticity studies for extinction-prone species that could assess whether they might be buffered from climate warming–a self-rescue.We discuss an epigenetic framework for studying such maternal-effect evolution.
文摘The evolution of many morphological structures is associated with the behavioral context of their use, particularly for structures involved in copulation. Yet, few studies have considered evolutionary relationships among the integrated suite of structures associated with male reproduction. In this study, we examined nine species of lizards in the genus Anolis to determine whether larger copulatory morphologies and higher potential for copulatory muscle performance evolved in association with higher copulation rates. In 10--12 adult males of each species, we measured the size of the hemipenes and related muscles, the seminiferous tubules in the testes, and the renal sex segments in the kidneys, and we assessed the fiber type composition of the muscles associated with copulation. In a series of pbylogenetically-informed analyses, we used field behavioral data to determine whether observed rates of copulation were associated with these morphologies.We found that species with larger hemipenes had larger fibers in the RPM (the retractor penis magnus, a muscle that controls hemipenis movement), and that the evolution of larg- er hemipenes and RPM fibers is associated with the evolution of higher rates of copulatory behavior. However, the sizes of the seminiferous tubules and renal sex segments, and the muscle fiber composition of the RPM, were not associated with copulation rates. Further, body size was not associated with the size of any of the reproductive structures investigated. The results of this study suggest that peripheral morphologies involved in the transfer of ejaculate may be more evolutionarily labile than internal structures involved in ejaculate production.
基金We thank the members of the Johnson Lab at Trinity University for assistance in the field and labor- atory - particularly Bonnie Kircher, Alisa Dill, Michelle Ob- emdorf, Adam Silva, Taren Blackmon, Jordan Bush, McKen- zie Quinn, EUee Cook, Grayam Sailor-Tynes, and Collin Shinkle. We also thank David Ribble, Troy Murphy, Jimmy Roberts, Kevin McIntyre, and three reviewers for comments on an earlier version of this work, and Kevin McIntyre and Kimberly Phillips for statistical advice. This work was funded by a Sigma Xi GIAR (to C.D.R.), a Trinity University Mind Science Foundation grant (to C.D.R.), Trinity University's HHMI and Biology Summer Undergraduate Research Fel- lowships (to C.D.R.), Texas Ecolab, and the National Science Foundation (IOS 1257021 to M.A.J.). All procedures were approved by Trinity University's Animal Research Committee (protocol # 050213_MAJ2).
文摘Animals communicate information within their environments via visual, chemical, auditory, and/or tactile modalities. The use of each modalityis generally linked to particular brain regions, but it is not yet known whether the cellular morphology of neurons in these regions has evolved in association with the relative use of a modality.We investigated relationships between the behavioral use of communication modalities and neural morphologies in six lizard species. Two of these species (Anolis carol# nensis and Leiocephalus carinatus) primarily use visual signals to communicate with conspecifics and detect potential prey, and two (Aspidoscelis gularis and Scincella lateralis) communicate and forage primarily using chemical signals. Two other species (Hemidactylus turcicus and Sceloporus olivaceus) use both visual and chemical signals. For each species, we performed beha- vioral observations and quantified rates of visual and chemical behaviors. We then cryosectioned brain tissues from 9-10 males of each species and measured the soma size and density of neurons in two brain regions associated with visual behaviors (the lat- eral geniculate nucleus and the nucleus rotundus) and one region associated with chemical behaviors (the nucleus sphericus). With analyses conducted in a phylogenetic context, we found that species that performed higher rates of visual displays had a denser lateral geniculate nucleus, and species that used a higher proportion of chemical displays had larger somas in the nucleus sphericus. These relationships suggest that neural morphologies in the brain have evolved convergently in species with similar communication behaviors .
文摘Animal habitat-use patterns cannot be isolated from scale issues. Consequently, multi-scale studies provide a complete characterization of ecological patterns that can further explain the observed variation. Liolaemus constitutes the world's second most speciose lizard genus. In this study, we assessed the relationships between home range size and environmental variables at 3 different spatial scales. The study at a local and regional scale was focused on the habitat specialist Liolaemus multimaculatus. The lizard's home range was calculated using the minimum convex polygon method in populations from grassland sites of the coastal sand dunes of the Argentinean Pampas under 2 different conditions, with or without forestations of Acacia Iongifolia. On the other hand, at a geographical scale we considered the evolutionary implications of 20 species of Liolaemus. Home range size, phylogeny, ecological, environmental, and climatic data were ob- tained from the literature and remote sensing. L. multimaculatus home range varied from 12.66 to 570.00 m. Regionally, this species had smaller home ranges in forested habitats (X: 94.02 m2) com- pared with the non-forested sites (X: 219.78m2). Habitat structure, vegetation types, and food availability would explain the space use at finer scales. When the 20 species of Liolaernus were considered, high mean air temperature and broad thermal amplitudes showed an inverse relationship with home range size. Neither net primary productivity nor phylogeny was good predictors for home range variation at geographical scale. This study highlights the scale dependence of the explicative capability of a set of environmental and intrinsic variables on home range patterns.