Perching allows small Unmanned Aerial Vehicles(UAVs)to maintain their altitude while significantly extending their flight duration and reducing noise.However,current research on flying habitats is poorly adapted to un...Perching allows small Unmanned Aerial Vehicles(UAVs)to maintain their altitude while significantly extending their flight duration and reducing noise.However,current research on flying habitats is poorly adapted to unstructured environments,and lacks autonomous capabilities,requiring ideal experimental environments and remote control by personnel.To solve these problems,in this paper,we propose a bat-like UAV perching mechanism by investigating the bat upside-down perching method,which realizes double self-locking in the perching state using the ratchet and four-link dead point mechanisms.Based on this perching mechanism,this study proposes a control strategy for UAVs to track targets and accomplish flight perching autonomously by combining a binocular camera,single-point LiDAR,and pressure sensors.Autonomous perching experiments were conducted for crossbar-type objects outdoors.The experimental results show that a multirotor UAV equipped with the perching mechanism and sensors can reliably achieve autonomous flight perching and re-flying off the target outdoors.The power consumption is reduced to 2.9%of the hovering state when perched on the target object.展开更多
Energy consumption and acoustic noise can be significantly reduced through perching in the sustained flights of small Unmanned Aerial Vehicles(UAVs).However,the existing flying perching robots lack good adaptability o...Energy consumption and acoustic noise can be significantly reduced through perching in the sustained flights of small Unmanned Aerial Vehicles(UAVs).However,the existing flying perching robots lack good adaptability or loading capacity in unstructured environments.Aiming at solving these problems,a deformable UAV perching mechanism with strong adaptability and high loading capacity,which is inspired by the structure and movements of birds'feet,is presented in this paper.Three elastic toes,an inverted crank slider mechanism used to realize the opening and closing movements,and a gear mechanism used to deform between two configurations are included in this mechanism.With experiments on its performance towards different objects,Results show that it can perch on various objects reliably,and its payload is more than 15 times its weight.By integrating it with a quadcopter,it can perch on different types of targets in outdoor environments,such as tree branches,cables,eaves,and spherical lamps.In addition,the energy consumption of the UAV perching system when perching on objects can be reduced to 0.015 times that of hovering.展开更多
The key to high manoeuvre ability in bird flight lies in the combined morphing of wings and tail.The perching of a wild Haliaeetus Albicilla without running or wing flapping is recorded and investigated using a high-s...The key to high manoeuvre ability in bird flight lies in the combined morphing of wings and tail.The perching of a wild Haliaeetus Albicilla without running or wing flapping is recorded and investigated using a high-speed digital video.A shape reconstruction method is proposed to describe wing contours and tail contours during perching.The avian airfoil geometries of the Aquila Chrysaetos are extracted from noncontact surface measurements using a ROMBER 3D laser scanner.The wing planform,chord distribution and twist distribution are fitted in convenient analytical expressions to obtain a 3D wing geometry.A three-jointed arm model is proposed to associate with the 3D wing geometry,while a one-joint arm model is proposed to describe the kinematics of tail.Therefore,a 3D bird model is established.The perching sequences of the wild eagle are recaptured and regenerated with the proposed 3D bird model.A quasi-steady aerodynamic model is applied in the aerodynamic predictions,a four-step Adams-Bashforth method is used to calculate the ordinary differential equations,thus a BFGS based optimization method is established to predict the perching motions.展开更多
Considering the strong nonlinearity of Unmanned Aerial Vehicles(UAVs)resulting from high Angle of Attack(AOA)and fast maneuvering,we present a multi-model predictive control strategy for UAV maneuvering,which has a sm...Considering the strong nonlinearity of Unmanned Aerial Vehicles(UAVs)resulting from high Angle of Attack(AOA)and fast maneuvering,we present a multi-model predictive control strategy for UAV maneuvering,which has a small amount of online calculation.Firstly,we divide the maneuver envelope of UAV into several sub-regions on the basis of the gap metric theory.A novel algorithm is then developed to determine the ploytopic model for each sub-region.According to this,a Robust Model Predictive Control based on the Idea of Comprehensive optimization(ICE-RMPC)is proposed.The control law is designed offline and optimized online to reduce the computational expense.Then,the ICE-RMPC method is applied to design the controllers of sub-regions.In addition,to guarantee the stability of whole closed-loop system,a multi-model switching control strategy based on guardian maps is put forward.Finally,the tracking performance of proposed control strategy is demonstrated by an illustrative example.展开更多
New types of aerial robots(NTARs)have found extensive applications in the military,civilian contexts,scientific research,disaster management,and various other domains.Compared with traditional aerial robots,NTARs exhi...New types of aerial robots(NTARs)have found extensive applications in the military,civilian contexts,scientific research,disaster management,and various other domains.Compared with traditional aerial robots,NTARs exhibit a broader range of morphological diversity,locomotion capabilities,and enhanced operational capacities.Therefore,this study defines aerial robots with the four characteristics of morphability,biomimicry,multi-modal locomotion,and manipulator attachment as NTARs.Subsequently,this paper discusses the latest research progress in the materials and manufacturing technology,actuation technology,and perception and control technology of NTARs.Thereafter,the research status of NTAR systems is summarized,focusing on the frontier development and application cases of flapping-wing microair vehicles,perching aerial robots,amphibious robots,and operational aerial robots.Finally,the main challenges presented by NTARs in terms of energy,materials,and perception are analyzed,and the future development trends of NTARs are summarized in terms of size and endurance,mechatronics,and complex scenarios,providing a reference direction for the follow-up exploration of NTARs.展开更多
The Red-footed Falcon(Falco vespertinus)is a species of high international conservation interest.We analyzed its hunting behavior at the two largest colonies in Italy during the nestling period.Using accurate data-log...The Red-footed Falcon(Falco vespertinus)is a species of high international conservation interest.We analyzed its hunting behavior at the two largest colonies in Italy during the nestling period.Using accurate data-loggers,we tracked three adult Red-footed Falcons in June and July,2019 and collected 4703 GPS points.We detected clear patterns of hovering and perching activity(HPA)in both time and space.HPA occupied one-third of the Red-footed Falcons’day,and showed two peaks just after sunrise(between 35 and 40%of the monitoring time)and just before sunset(50‒60%)in both June and July,and minimum(20‒30%)at night and during the hottest time interval(10:00 a.m.‒4:00 p.m.).Almost 40%of HPA occurred within 50 m from nests.Our findings,although preliminary,have important implications for the conservation of these two colonies that are located within two Natura 2000 sites.The detected spatio-temporal patterns of Red-footed Falcons’hunting behavior suggests the creation of two nested protection belts:the inner one is a narrow belt(up to 50 m from the two rows of trees that host the two colonies)with integral conservation,and hopefully increase the alfalfa crops and fallow land,and the outer belt(50 m‒2 km)with optimized agricultural activities.展开更多
Iron and manganese oxides are common components of soils. They frequently occur in nodules constituting important soil sorbents and play a crucial role in a number of chemical reactions in the soil environment. In add...Iron and manganese oxides are common components of soils. They frequently occur in nodules constituting important soil sorbents and play a crucial role in a number of chemical reactions in the soil environment. In addition, the oxides are very sensitive to environmental changes (moisture, pH, Eh) constituting important indicators of soil-forming processes and water movement in the landscape. The objectives of the study were: i) to examine the distribution and size of Fe-Mn nodules in Albeluvisols containing a fragipan horizon; ii) to determine the morphology and chemical composition of the nodules, and iii) to estimate the effect of the fragipan horizon on water movement within the soil profile. An investigation was carried out on five soil profiles containing a fragipan horizon and classified as Fragic Albeluvisols within the Carpathian Foothills in Poland. In the Albeluvisols studied, the maximum concentration of Fe-Mn nodules occurred in the horizon lying directly on the fragipan horizon. This suggests that the pan acts as a natural barrier restricting water infiltration and leads to the seasonal development of a perched water table promoting redox processes. The most common are coarse (1-0.5 mm) and medium (0.5-0.25 mm) irregular Fe-Mn nodules showing a gradual boundary and undifferentiated internal fabric. Eluvial horizons contained also larger amounts of round and dense nodules with a sharp boundary, suggesting frequent oxidation and reduction. The fragipan horizon contained mainly irregular and soft nodules, suggesting longer saturation with water during the year. Concentrations of trace elements (Cu, Zn) and P were higher within Fe-Mn nodules than in the surrounding soil materials, showing that iron and manganese oxides adsorbed and immobilised these elements.展开更多
Serum immunoglobulin from the mandarin fish, or the so called Chinese perch, Siniperca chuatsi (Basilewsky), was successfully purified using affinity chromatography. Heavy and light chains were detected on electrophor...Serum immunoglobulin from the mandarin fish, or the so called Chinese perch, Siniperca chuatsi (Basilewsky), was successfully purified using affinity chromatography. Heavy and light chains were detected on electrophoresis gel, with molecular weights being estimated at 72 and 29 kDa, respectively. The tetrameric IgM of S. chuatsi was calculated to be 808 kDa. The rabbit polyclonal antisera against the purifed immunoglobulin were developed and tested by Western blot analysis. The antisera reacted strongly with the heavy chains of S. chuatsi immunoglobulin. Humoral immune responses of the mandarin fish can then be examined using the developed polyclonal antibody.展开更多
The mineral stability and solute activities of soil solution extracted from selected horizons of seven studied pedons of Alfisols in Kentucky, USA, and the relationship between distribution of iron-manganese concretio...The mineral stability and solute activities of soil solution extracted from selected horizons of seven studied pedons of Alfisols in Kentucky, USA, and the relationship between distribution of iron-manganese concretions and the restrictive layers were investigated. The results showed that the genesis and development of these soils and mineral weathering trends were strongly influenced by the depth of bedrock and the presence of perched water tables at lithic (limestone) interfaces due to the dissolution and buffering effect of limestone bedrock. The extractable Mg/Ca ratio as depth function and soil depth above bedrock could be used as indices of weathering and degree of soil development. Maximum iron-manganese concretion accumulation was found to occur in the horizon overlying clay horizon (>40% clay) with a sharp increase in clay content (>10%), which suggested that zones of Fe-Mn concretion accumulation in soils of the Inner Bluegrass Region appeared to be a sensitive genetic indicator of argillic horizons with restrictive permeability.展开更多
Fish maw(the dried swimbladders of fish) is ranked in the list of the four sea treasures in Chinese cuisine. Fish maw is mainly produced from croaker, which is the most highly priced. However, some of the fish maw bei...Fish maw(the dried swimbladders of fish) is ranked in the list of the four sea treasures in Chinese cuisine. Fish maw is mainly produced from croaker, which is the most highly priced. However, some of the fish maw being sold as croaker maw are in fact not from croaker, but from the Nile perch Lates niloticus. The present work determined and compared the proximate composition, amino acid and fatty acid composition of croaker Protonibea diacanthus maw and perch L. niloticus maw. The results indicated that both maws were high protein sources and low in fat content. The dominant amino acids in both maws were glycine, proline, glutamic acid, alanine and arginine. These amino acids constituted 66.2% and 66.4% of the total amino acids in P. diacanthus and L. niloticus, respectively. The ratio of FAA: TAA(functional amino acids: total amino acids) in both maws were 0.69. This is a good explanation for why fish maws have been widely utilized as a traditional tonic and remedy in Asia. Except valine and histidine, all the essential amino acid contents in P. diacanthus were higher than in L. niloticus. Moreover, croaker P. diacanthus maw contained more AA and DHA than perch L. niloticus maw, showing a higher ratio of n-3 / n-6, which is more desirable.展开更多
The persistence of malachite green (MG), and its metabolite leucomalachite green (LMG), in fish tissues is still unclear, leading to many trade disputes. In this research, we established and evaluated an HPLC method t...The persistence of malachite green (MG), and its metabolite leucomalachite green (LMG), in fish tissues is still unclear, leading to many trade disputes. In this research, we established and evaluated an HPLC method that could detect MG and LMG simultaneously, and then investigated the persistence of these two toxins in the tissues of juvenile perch (Lateolabrax japonicus) post sub-chronic MG exposure at 1.0 mg/L. Exposure lasted for 2 h everyday and was repeated six times. The perch were then placed in MG-free seawater for 100 d to eliminate the toxins. Results show that MG accumulated in the tissues, including the gills, liver, muscle, blood and viscera, and then was metabolized rapidly to LMG. The concentrations of these two toxins increased significantly with the accumulation process. In general, the highest concentrations of MG and LMG in all tissue exceeded 1 000 μg/kg, except for MG in the muscle. The order of accumulation levels (highest to lowest) of MG was gill>blood>liver>viscera>muscle, while that of LMG was liver>blood>gill>viscera>muscle. High levels of MG or LMG could persist for several hours but decreased rapidly during the elimination process. The concentration of LMG was much higher than that of MG during the experiment, especially in the gill, liver and blood. Therefore, the three tissues play important roles in toxin accumulation, biotransformation, and elimination. Although the MG and LMG concentrations in muscle were much lower than in other tissues, the content still exceeded the European minimum required performance limit (MRPL), even after 2 400 h (100 d) of elimination. This demonstrates that it is extremely difficult to eliminate MG and LMG from tissues of perch, and therefore use of these toxins is of concern to public health.展开更多
Three continuous marine fish cell lines of FG (i.e., Flounder Gill) from flounder ( Paralichthys olivaceus) gill, SPH (i.e., Sea Perch Heart) from sea perch ( Lateolabrax japonicus ) heart and RSBF (i.e., Red Sea...Three continuous marine fish cell lines of FG (i.e., Flounder Gill) from flounder ( Paralichthys olivaceus) gill, SPH (i.e., Sea Perch Heart) from sea perch ( Lateolabrax japonicus ) heart and RSBF (i.e., Red Sea Bream Fin) from red sea bream ( Pagrosomus major ) fin, were characterized by lactate dehydrogenase (LDH) isozyme and morphological analysis. The LDH isozyme patterns of these three cell lines and their corresponding tissues of origin were investigated and compared. The results showed: (1) No difference was found in the LDH isozyme patterns of FG and flounder gill tissue. However, the LDH isozyme patterns of SPH and RSBF were significantly different from their corresponding tissues of origin; (2) LDH isozyme patterns of FG, SPH and RSBF were markedly different from each other and could serve as genetic markers for species identification and detection of cross contamination. Morphological change analysis of these three cell lines in comparison to their original tissues indicated that FG cells still appeared epithelioid without morphological transformation. However, morphological changes were found in SPH and RSBF compared to their original tissues. Therefore, the cellular morphology was still plastic in the relatively stable culture conditions, and it was possible that change of LDH patterns was related to morphological changes of fish cells in vitro .展开更多
The technology of homology cloning and anchored PCR was used to clone the IL-1β gene from the Japanese sea perch （Lateolabrax iaponicus）. The full-length cDNA of sea perch IL-1β was 1 310 bp, including a 5＇ untra...The technology of homology cloning and anchored PCR was used to clone the IL-1β gene from the Japanese sea perch （Lateolabrax iaponicus）. The full-length cDNA of sea perch IL-1β was 1 310 bp, including a 5＇ untranslated regiop （UTR） of 136 bp, a 3＇ UTR ot 430 bp, and an ORF of 774 bp encoding a polypeptide of 258 amino acids with an estimated molecular mass of 29.31 kDa. The searches for nucleotides and protein sequence similarities with the BLAST analysis indicated that the deduced amino acid sequence of sea perch IL-1β was homological to the IL-1β in other fish species and even the mammalian. Conserved signature sequences of the IL-1β gene family were found in the sea perch IL-1β deduced amino acid sequence. Temporal expressions of the IL-1β gene in LPS or iridovirus challenged group and in control group were measured by the semi-quantitative RT-PCR. The mRNA transcripts of IL-1β could be detected in head-kidney, spleen, liver, gill and heart of the healthy individuals, and the expression level of IL-1β in head-kidney, spleen and gill was higher than that in liver and heart, but it was hard to be detected in the brain. After being stimulated by the LPS or iridovirus, the IL-1β expression in most of examined tissues was up-regulated, and also could be detected in the brain. These results indicated that the expression of sea perch IL-1β was constitutive and could be up-regulated by immune effector stimulation. Therefore the sea perch IL-1β could play a critical role in the host-pathogen interaction.展开更多
Predation is thought to be one of the main structuring forces in animal communities. However, se- lective predation is often measured on isolated traits in response to a single predatory species, but only rarely are s...Predation is thought to be one of the main structuring forces in animal communities. However, se- lective predation is often measured on isolated traits in response to a single predatory species, but only rarely are selective forces on several traits quantified or even compared between different predators naturally occurring in the same system. In the present study, we therefore measured be- havioral and morphological traits in young-of-the-year Eurasian perch Perca fluviatilis and com- pared their selective values in response to the 2 most common predators, adult perch and pike Esox lucius. Using mixed effects models and model averaging to analyze our data, we quantified and compared the selectivity of the 2 predators on the different morphological and behavioral traits. We found that selection on the behavioral traits was higher than on morphological traits and perch predators preyed overall more selectively than pike predators. Pike tended to positively se- lect shallow bodied and nonvigilant individuals （i.e. individuals not performing predator inspec- tion）. In contrast, perch predators selected mainly for bolder juvenile perch （i.e. individuals spend- ing more time in the open, more active）, which was most important. Our results are to the best of our knowledge the first that analyzed behavioral and morphological adaptations of juvenile perch facing 2 different predation strategies. We found that relative specific predation intensity for the di- vergent traits differed between the predators, providing some additional ideas why juvenile perch display such a high degree of phenotypic plasticity.展开更多
Background:For all vertebrates in general,a concerted effort to move beyond single season research is vital to improve our understanding of species ecology.Knowledge of habitat use and selection by Eurasian Bullfinche...Background:For all vertebrates in general,a concerted effort to move beyond single season research is vital to improve our understanding of species ecology.Knowledge of habitat use and selection by Eurasian Bullfinches(Pyrrhula pyrrhula)is limited with regard to the non-breeding season.To date,research on the habitat of the Iberian subspecies iberiae consists of very general descriptions.In relation to space use,only broad features are available for the entire distribution range of Eurasian Bullfinches,including Iberia.Methods:In this study,seasonal preferences regarding habitat and space in a population of Eurasian Bullfinches are examined for the first time in the Iberian Peninsula,through direct observation during a six-year period.The essential habitat components,substrate selection and perch height were assessed.Results:Hedgerows were the key essential habitat component for bullfinches during all seasons.Nevertheless,small poplar plantations became increasingly important from winter to summer-autumn.Bullfinches perched mostly in shrubs/trees throughout the year,but there were significant seasonal changes in substrate use,ground and herbs being of considerable importance during spring-summer.Throughout the year,over half of the records corresponded to feeding,reaching almost 90%in winter.Generally,bullfinches perched noticeably lower while feeding.Male bullfinches perched markedly higher than females,notably singing males in spring-summer.Juveniles perched at a height not much lower than that of males.In all seasons,males tended to feed at greater heights than females.Bullfinches of different ages and sexes were seen bathing in all seasons except winter.Conclusions:Hedgerow habitat in general appeared to be valuable for bullfinches throughout the year.In summer and autumn,they selected sites with an abundance of food and shade,as well as shelter,a much-needed requirement for fledglings and moulting individuals.There was usually a close link between the most used and most consumed plant species in each season.Males appeared to assume a more important role in vigilance,and often they accompanied dependent young in June and July.Bullfinch conservation strategies should consider seasonal demand for habitat and space.展开更多
Fish size and harvest density generally exhibit a negative relationship in pond culture, but the influence that pond substrate type can have on this relationship is not well understood. To evaluate the influence of po...Fish size and harvest density generally exhibit a negative relationship in pond culture, but the influence that pond substrate type can have on this relationship is not well understood. To evaluate the influence of pond substrate type on yellow perch (<i></span><i><span style="font-family:Verdana;">Perca flavescens</span></i><span style="font-family:Verdana;"></i></span><span style="font-family:Verdana;">), harvest density (number/hectare) was linearly regressed against individual fingerling size (grams) for lined (n = 48) and earthen (n = 40) substrate ponds that were treated similarly in terms of organic fertilizer use and the number of days in the pond over 12 culture seasons at Blue Dog Lake State Hatchery, South Dakota, USA. Harvest density explained 45 and 39% of the variation in yellow perch size in lined and earthen-substrate ponds (all <i></span><i><span style="font-family:Verdana;">P</span></i><span style="font-family:Verdana;"></i></span><span style="font-family:Verdana;"> < 0.01). Comparison of regression lines indicated that fingerling size decreased as harvest density increased at a similar rate in both pond types (slope comparison, <i></span><i><span style="font-family:Verdana;">P</span></i><span style="font-family:Verdana;"></i></span><span style="font-family:Verdana;"> = 0.62);however, fingerling size was significantly larger in lined ponds regardless of density that varied from near 0 to 700,000 per hectare (y-intercept comparison, <i></span><i><span style="font-family:Verdana;">P</span></i><span style="font-family:Verdana;"></i></span><span style="font-family:Verdana;"> < 0.01). At the same harvest density, lined ponds will tend to produce larger yellow perch fingerlings compared to earthen ponds when similar organic fertilizers are used.展开更多
Plinian pumice fall from the Holocene eruption of Mount Mazama in the Cascade volcanic arc is an unconfined, perched aquifer in south-central Oregon. The pumice aquifer provides near-surface groundwater storage that m...Plinian pumice fall from the Holocene eruption of Mount Mazama in the Cascade volcanic arc is an unconfined, perched aquifer in south-central Oregon. The pumice aquifer provides near-surface groundwater storage that maintains biologically diverse wetland environments. Wetland environments reflect post-eruption disruption of the once uniform pumice blanket by fluvial and lacustrine processes operating within the template of the pre-eruption landscape. In the 8.6 km<sup>2</sup> Round Meadow watershed the pumice aquifer interacts with a seasonally flooded meadow, fen, springs, and perennial stream. The laterally uniform, isotropic pumice aquifer is disrupted by flat-bottomed ephemeral stream valleys that drain to the seasonally flooded meadow. Surface water levels in the seasonally flooded meadow are controlled by a knickpoint developed on bedrock. The underlying aquifer is confined by a layer of glass-rich diatomaceous silt grading upward to organic-rich silt. Here, the aquifer is comprised of remnants of the pumice deposit, lag sand, and reworked pumice. The water level in the confined aquifer is maintained by recharge from the unconfined pumice aquifer following flow pathways beneath ephemeral stream valleys. The fen is developed on a down-thrown block of welded tuff and pre-eruption diatomaceous silt. Water levels in the fen are sensitive to inter-annual variations in precipitation. Low discharge, low temperature (5.0°C to 6.5°C), and low conductivity (30 to 50 μS/cm) springs appear to be fracture controlled and rising through welded tuff. Spring discharge and seepage through pumice from the welded tuff support perennial flow in the creek that also carries discharge from the seasonally flooded meadow when water levels are high enough to cross the knickpoint.展开更多
The simultaneous study of demography and behavior might provide a more comprehensive understanding about animal responses to anthropogenic disturbances.The White-winged Dove(Zenaida asiatica)is a frequent dweller of u...The simultaneous study of demography and behavior might provide a more comprehensive understanding about animal responses to anthropogenic disturbances.The White-winged Dove(Zenaida asiatica)is a frequent dweller of urban and agricultural habitats in North America,Central America,and the Caribbean.Still,research on the species is heavily biased to the USA.We analyzed the response of the species to human disturbances during winter across an urban-agricultural landscape in northwestern Mexico through a demographic and behavioral approach.We modeled the effect of disturbance types(pedestrians,cars,pavement and building cover)on the density of the species.Also,we investigated if surveillance behavior varied across the landscape by estimating and comparing perching proportion among land uses(urban grey areas,urban green areas,cropfields,shrublands).We did not detect the species within cropfields,possibly because food resources were not available for the dove during winter in this land use.Pavement cover limited species’density,as it might reduce the surface of the preferred feeding substrates of the dove.Pedestrians and building cover increased the density of the species,as they might provide food and shelter for the dove,respectively.Surveillance behavior peaked in urban grey areas,whereas it dropped in urban green areas.Differences on threat levels,threat type,and protective cover among land uses might in-fluence such behavioral pattern.Our approach contributes to the knowledge of the species and demonstrates that both demographic and behavioral cues provide complementary evidence for analyzing the impact of human disturbances on animals.展开更多
New born hatchlings of Calotes versicolor were reared in terrarium having narrow or wide perches for a period of 4-month and their snout vent length（SVL）, tail, fore and hindlimb lengths were measured at monthly int...New born hatchlings of Calotes versicolor were reared in terrarium having narrow or wide perches for a period of 4-month and their snout vent length（SVL）, tail, fore and hindlimb lengths were measured at monthly intervals. Limb postures（closer to the body or spread away from the body） were also recorded. The sprint speed was recorded in two and four-month old lizards on a 1 m long race track providing 45° or 60° slope. In both the groups, SVL and tail lengths were comparable but the limb lengths and their growth rates were significantly greater in lizards of wider perch group. The lizards reared with narrow perches positioned their limbs closer to the body; while those reared on wider perches spread their limbs away from their body. Further, the latter exhibited significantly higher sprint speed regardless of the slope of the race track over those of narrow perch group. Sprint speeds of lizards in both groups were correlated with the limb sizes. The study showed that the lizards reared on narrow or wide perches exhibited divergent adaptive responses（phenotypic plasticity） by developing longer or shorter limbs and corresponding changes in their sprint speeds. These findings support the idea that availability of perch structure during early development evokes adaptive plasticity in the limb development and associated locomotory performance in arboreal lizards like C. versicolor.展开更多
基金financially supported by National Key Research&Development Program of China[Grant No.2020YFB1313000]National Natural Science Foundation of China[Grant No.62003060]+1 种基金China Postdoctoral Science Foundation[2022M720566]Natural Science Foundation of Chongqing,China[CSTB2022NSCQ-MSX1297].
文摘Perching allows small Unmanned Aerial Vehicles(UAVs)to maintain their altitude while significantly extending their flight duration and reducing noise.However,current research on flying habitats is poorly adapted to unstructured environments,and lacks autonomous capabilities,requiring ideal experimental environments and remote control by personnel.To solve these problems,in this paper,we propose a bat-like UAV perching mechanism by investigating the bat upside-down perching method,which realizes double self-locking in the perching state using the ratchet and four-link dead point mechanisms.Based on this perching mechanism,this study proposes a control strategy for UAVs to track targets and accomplish flight perching autonomously by combining a binocular camera,single-point LiDAR,and pressure sensors.Autonomous perching experiments were conducted for crossbar-type objects outdoors.The experimental results show that a multirotor UAV equipped with the perching mechanism and sensors can reliably achieve autonomous flight perching and re-flying off the target outdoors.The power consumption is reduced to 2.9%of the hovering state when perched on the target object.
基金supported by the National Key R&D Program of China[Grant No.2020YFB1313000]National Natural Science Foundation of China[Grant No.51975070,62003060,62073211].
文摘Energy consumption and acoustic noise can be significantly reduced through perching in the sustained flights of small Unmanned Aerial Vehicles(UAVs).However,the existing flying perching robots lack good adaptability or loading capacity in unstructured environments.Aiming at solving these problems,a deformable UAV perching mechanism with strong adaptability and high loading capacity,which is inspired by the structure and movements of birds'feet,is presented in this paper.Three elastic toes,an inverted crank slider mechanism used to realize the opening and closing movements,and a gear mechanism used to deform between two configurations are included in this mechanism.With experiments on its performance towards different objects,Results show that it can perch on various objects reliably,and its payload is more than 15 times its weight.By integrating it with a quadcopter,it can perch on different types of targets in outdoor environments,such as tree branches,cables,eaves,and spherical lamps.In addition,the energy consumption of the UAV perching system when perching on objects can be reduced to 0.015 times that of hovering.
基金Project supported by the National Natural Science Foundation of China(Grant No.51705459)the China Postdoctoral Science Foundation.
文摘The key to high manoeuvre ability in bird flight lies in the combined morphing of wings and tail.The perching of a wild Haliaeetus Albicilla without running or wing flapping is recorded and investigated using a high-speed digital video.A shape reconstruction method is proposed to describe wing contours and tail contours during perching.The avian airfoil geometries of the Aquila Chrysaetos are extracted from noncontact surface measurements using a ROMBER 3D laser scanner.The wing planform,chord distribution and twist distribution are fitted in convenient analytical expressions to obtain a 3D wing geometry.A three-jointed arm model is proposed to associate with the 3D wing geometry,while a one-joint arm model is proposed to describe the kinematics of tail.Therefore,a 3D bird model is established.The perching sequences of the wild eagle are recaptured and regenerated with the proposed 3D bird model.A quasi-steady aerodynamic model is applied in the aerodynamic predictions,a four-step Adams-Bashforth method is used to calculate the ordinary differential equations,thus a BFGS based optimization method is established to predict the perching motions.
基金co-supported by the National Natural Science Foundation of China(Nos.61873126,11572149)。
文摘Considering the strong nonlinearity of Unmanned Aerial Vehicles(UAVs)resulting from high Angle of Attack(AOA)and fast maneuvering,we present a multi-model predictive control strategy for UAV maneuvering,which has a small amount of online calculation.Firstly,we divide the maneuver envelope of UAV into several sub-regions on the basis of the gap metric theory.A novel algorithm is then developed to determine the ploytopic model for each sub-region.According to this,a Robust Model Predictive Control based on the Idea of Comprehensive optimization(ICE-RMPC)is proposed.The control law is designed offline and optimized online to reduce the computational expense.Then,the ICE-RMPC method is applied to design the controllers of sub-regions.In addition,to guarantee the stability of whole closed-loop system,a multi-model switching control strategy based on guardian maps is put forward.Finally,the tracking performance of proposed control strategy is demonstrated by an illustrative example.
基金supported in part by the National Key Research and Development Program of China(2022YFB4701800 and 2021ZD0114503)the National Natural Science Foundation of China(62103140,U22A2057,62173132,and 62133005)+3 种基金the Hunan Leading Talent of Technological Innovation(2022RC3063)the Top Ten Technical Research Projects of Hunan Province(2024GK1010)the Key Research and Development Program of Hunan Province(2023GK2068)the Science and Technology Innovation Program of Hunan Province(2023RC1049).
文摘New types of aerial robots(NTARs)have found extensive applications in the military,civilian contexts,scientific research,disaster management,and various other domains.Compared with traditional aerial robots,NTARs exhibit a broader range of morphological diversity,locomotion capabilities,and enhanced operational capacities.Therefore,this study defines aerial robots with the four characteristics of morphability,biomimicry,multi-modal locomotion,and manipulator attachment as NTARs.Subsequently,this paper discusses the latest research progress in the materials and manufacturing technology,actuation technology,and perception and control technology of NTARs.Thereafter,the research status of NTAR systems is summarized,focusing on the frontier development and application cases of flapping-wing microair vehicles,perching aerial robots,amphibious robots,and operational aerial robots.Finally,the main challenges presented by NTARs in terms of energy,materials,and perception are analyzed,and the future development trends of NTARs are summarized in terms of size and endurance,mechatronics,and complex scenarios,providing a reference direction for the follow-up exploration of NTARs.
文摘The Red-footed Falcon(Falco vespertinus)is a species of high international conservation interest.We analyzed its hunting behavior at the two largest colonies in Italy during the nestling period.Using accurate data-loggers,we tracked three adult Red-footed Falcons in June and July,2019 and collected 4703 GPS points.We detected clear patterns of hovering and perching activity(HPA)in both time and space.HPA occupied one-third of the Red-footed Falcons’day,and showed two peaks just after sunrise(between 35 and 40%of the monitoring time)and just before sunset(50‒60%)in both June and July,and minimum(20‒30%)at night and during the hottest time interval(10:00 a.m.‒4:00 p.m.).Almost 40%of HPA occurred within 50 m from nests.Our findings,although preliminary,have important implications for the conservation of these two colonies that are located within two Natura 2000 sites.The detected spatio-temporal patterns of Red-footed Falcons’hunting behavior suggests the creation of two nested protection belts:the inner one is a narrow belt(up to 50 m from the two rows of trees that host the two colonies)with integral conservation,and hopefully increase the alfalfa crops and fallow land,and the outer belt(50 m‒2 km)with optimized agricultural activities.
基金Supported by the Polish State Committee for Scientific Research (No. N N305 120934)
文摘Iron and manganese oxides are common components of soils. They frequently occur in nodules constituting important soil sorbents and play a crucial role in a number of chemical reactions in the soil environment. In addition, the oxides are very sensitive to environmental changes (moisture, pH, Eh) constituting important indicators of soil-forming processes and water movement in the landscape. The objectives of the study were: i) to examine the distribution and size of Fe-Mn nodules in Albeluvisols containing a fragipan horizon; ii) to determine the morphology and chemical composition of the nodules, and iii) to estimate the effect of the fragipan horizon on water movement within the soil profile. An investigation was carried out on five soil profiles containing a fragipan horizon and classified as Fragic Albeluvisols within the Carpathian Foothills in Poland. In the Albeluvisols studied, the maximum concentration of Fe-Mn nodules occurred in the horizon lying directly on the fragipan horizon. This suggests that the pan acts as a natural barrier restricting water infiltration and leads to the seasonal development of a perched water table promoting redox processes. The most common are coarse (1-0.5 mm) and medium (0.5-0.25 mm) irregular Fe-Mn nodules showing a gradual boundary and undifferentiated internal fabric. Eluvial horizons contained also larger amounts of round and dense nodules with a sharp boundary, suggesting frequent oxidation and reduction. The fragipan horizon contained mainly irregular and soft nodules, suggesting longer saturation with water during the year. Concentrations of trace elements (Cu, Zn) and P were higher within Fe-Mn nodules than in the surrounding soil materials, showing that iron and manganese oxides adsorbed and immobilised these elements.
文摘Serum immunoglobulin from the mandarin fish, or the so called Chinese perch, Siniperca chuatsi (Basilewsky), was successfully purified using affinity chromatography. Heavy and light chains were detected on electrophoresis gel, with molecular weights being estimated at 72 and 29 kDa, respectively. The tetrameric IgM of S. chuatsi was calculated to be 808 kDa. The rabbit polyclonal antisera against the purifed immunoglobulin were developed and tested by Western blot analysis. The antisera reacted strongly with the heavy chains of S. chuatsi immunoglobulin. Humoral immune responses of the mandarin fish can then be examined using the developed polyclonal antibody.
基金Project (No. Y97D02061) supported by the Natural Science Foundation of Shandong Province, China.
文摘The mineral stability and solute activities of soil solution extracted from selected horizons of seven studied pedons of Alfisols in Kentucky, USA, and the relationship between distribution of iron-manganese concretions and the restrictive layers were investigated. The results showed that the genesis and development of these soils and mineral weathering trends were strongly influenced by the depth of bedrock and the presence of perched water tables at lithic (limestone) interfaces due to the dissolution and buffering effect of limestone bedrock. The extractable Mg/Ca ratio as depth function and soil depth above bedrock could be used as indices of weathering and degree of soil development. Maximum iron-manganese concretion accumulation was found to occur in the horizon overlying clay horizon (>40% clay) with a sharp increase in clay content (>10%), which suggested that zones of Fe-Mn concretion accumulation in soils of the Inner Bluegrass Region appeared to be a sensitive genetic indicator of argillic horizons with restrictive permeability.
基金supported by the National Natural Science Foundation of China (No.31201999)the Natural Science Foundation of Guangdong Province, China (No.2014A030307022)+5 种基金the Special Support Program of Guangdong Province, China (No.2014TQ01N621)the Foundation for Distinguished Young Teachers in Higher Education of Guangdong, China (No.Yq2014115)the Foundation of Education Bureau of Guangdong Province (No.2014KTSCX159)the Technology Program of Guangdong Province (No.2015A030302089)the Overseas Scholarship Program for Elite Young and Middle-aged Teachers of Lingnan Normal University, the Technology Program of Zhanjiang (Nos.2015A03017, 2014A03011)the Guangxi Key Laboratory of Beibu Gulf Marine Biodiversity Conservation, Qinzhou University (No.2015KB04)
文摘Fish maw(the dried swimbladders of fish) is ranked in the list of the four sea treasures in Chinese cuisine. Fish maw is mainly produced from croaker, which is the most highly priced. However, some of the fish maw being sold as croaker maw are in fact not from croaker, but from the Nile perch Lates niloticus. The present work determined and compared the proximate composition, amino acid and fatty acid composition of croaker Protonibea diacanthus maw and perch L. niloticus maw. The results indicated that both maws were high protein sources and low in fat content. The dominant amino acids in both maws were glycine, proline, glutamic acid, alanine and arginine. These amino acids constituted 66.2% and 66.4% of the total amino acids in P. diacanthus and L. niloticus, respectively. The ratio of FAA: TAA(functional amino acids: total amino acids) in both maws were 0.69. This is a good explanation for why fish maws have been widely utilized as a traditional tonic and remedy in Asia. Except valine and histidine, all the essential amino acid contents in P. diacanthus were higher than in L. niloticus. Moreover, croaker P. diacanthus maw contained more AA and DHA than perch L. niloticus maw, showing a higher ratio of n-3 / n-6, which is more desirable.
基金Supported by the Special Fund of Chinese Government for Basic Scientific Research Operations in Commonweal Research Institute (Yellow Sea Fisheries Research Institute) (No. 2007-qn-12)the Strategic Research Grant of the Databases and Risk Analysis of POPs in Aquatic Products (No. 2005DIB4J049)the Standard System Research on Quality and Safety of Aquatic Products (No. 2004DEA70880)
文摘The persistence of malachite green (MG), and its metabolite leucomalachite green (LMG), in fish tissues is still unclear, leading to many trade disputes. In this research, we established and evaluated an HPLC method that could detect MG and LMG simultaneously, and then investigated the persistence of these two toxins in the tissues of juvenile perch (Lateolabrax japonicus) post sub-chronic MG exposure at 1.0 mg/L. Exposure lasted for 2 h everyday and was repeated six times. The perch were then placed in MG-free seawater for 100 d to eliminate the toxins. Results show that MG accumulated in the tissues, including the gills, liver, muscle, blood and viscera, and then was metabolized rapidly to LMG. The concentrations of these two toxins increased significantly with the accumulation process. In general, the highest concentrations of MG and LMG in all tissue exceeded 1 000 μg/kg, except for MG in the muscle. The order of accumulation levels (highest to lowest) of MG was gill>blood>liver>viscera>muscle, while that of LMG was liver>blood>gill>viscera>muscle. High levels of MG or LMG could persist for several hours but decreased rapidly during the elimination process. The concentration of LMG was much higher than that of MG during the experiment, especially in the gill, liver and blood. Therefore, the three tissues play important roles in toxin accumulation, biotransformation, and elimination. Although the MG and LMG concentrations in muscle were much lower than in other tissues, the content still exceeded the European minimum required performance limit (MRPL), even after 2 400 h (100 d) of elimination. This demonstrates that it is extremely difficult to eliminate MG and LMG from tissues of perch, and therefore use of these toxins is of concern to public health.
文摘Three continuous marine fish cell lines of FG (i.e., Flounder Gill) from flounder ( Paralichthys olivaceus) gill, SPH (i.e., Sea Perch Heart) from sea perch ( Lateolabrax japonicus ) heart and RSBF (i.e., Red Sea Bream Fin) from red sea bream ( Pagrosomus major ) fin, were characterized by lactate dehydrogenase (LDH) isozyme and morphological analysis. The LDH isozyme patterns of these three cell lines and their corresponding tissues of origin were investigated and compared. The results showed: (1) No difference was found in the LDH isozyme patterns of FG and flounder gill tissue. However, the LDH isozyme patterns of SPH and RSBF were significantly different from their corresponding tissues of origin; (2) LDH isozyme patterns of FG, SPH and RSBF were markedly different from each other and could serve as genetic markers for species identification and detection of cross contamination. Morphological change analysis of these three cell lines in comparison to their original tissues indicated that FG cells still appeared epithelioid without morphological transformation. However, morphological changes were found in SPH and RSBF compared to their original tissues. Therefore, the cellular morphology was still plastic in the relatively stable culture conditions, and it was possible that change of LDH patterns was related to morphological changes of fish cells in vitro .
文摘The technology of homology cloning and anchored PCR was used to clone the IL-1β gene from the Japanese sea perch （Lateolabrax iaponicus）. The full-length cDNA of sea perch IL-1β was 1 310 bp, including a 5＇ untranslated regiop （UTR） of 136 bp, a 3＇ UTR ot 430 bp, and an ORF of 774 bp encoding a polypeptide of 258 amino acids with an estimated molecular mass of 29.31 kDa. The searches for nucleotides and protein sequence similarities with the BLAST analysis indicated that the deduced amino acid sequence of sea perch IL-1β was homological to the IL-1β in other fish species and even the mammalian. Conserved signature sequences of the IL-1β gene family were found in the sea perch IL-1β deduced amino acid sequence. Temporal expressions of the IL-1β gene in LPS or iridovirus challenged group and in control group were measured by the semi-quantitative RT-PCR. The mRNA transcripts of IL-1β could be detected in head-kidney, spleen, liver, gill and heart of the healthy individuals, and the expression level of IL-1β in head-kidney, spleen and gill was higher than that in liver and heart, but it was hard to be detected in the brain. After being stimulated by the LPS or iridovirus, the IL-1β expression in most of examined tissues was up-regulated, and also could be detected in the brain. These results indicated that the expression of sea perch IL-1β was constitutive and could be up-regulated by immune effector stimulation. Therefore the sea perch IL-1β could play a critical role in the host-pathogen interaction.
文摘Predation is thought to be one of the main structuring forces in animal communities. However, se- lective predation is often measured on isolated traits in response to a single predatory species, but only rarely are selective forces on several traits quantified or even compared between different predators naturally occurring in the same system. In the present study, we therefore measured be- havioral and morphological traits in young-of-the-year Eurasian perch Perca fluviatilis and com- pared their selective values in response to the 2 most common predators, adult perch and pike Esox lucius. Using mixed effects models and model averaging to analyze our data, we quantified and compared the selectivity of the 2 predators on the different morphological and behavioral traits. We found that selection on the behavioral traits was higher than on morphological traits and perch predators preyed overall more selectively than pike predators. Pike tended to positively se- lect shallow bodied and nonvigilant individuals （i.e. individuals not performing predator inspec- tion）. In contrast, perch predators selected mainly for bolder juvenile perch （i.e. individuals spend- ing more time in the open, more active）, which was most important. Our results are to the best of our knowledge the first that analyzed behavioral and morphological adaptations of juvenile perch facing 2 different predation strategies. We found that relative specific predation intensity for the di- vergent traits differed between the predators, providing some additional ideas why juvenile perch display such a high degree of phenotypic plasticity.
文摘Background:For all vertebrates in general,a concerted effort to move beyond single season research is vital to improve our understanding of species ecology.Knowledge of habitat use and selection by Eurasian Bullfinches(Pyrrhula pyrrhula)is limited with regard to the non-breeding season.To date,research on the habitat of the Iberian subspecies iberiae consists of very general descriptions.In relation to space use,only broad features are available for the entire distribution range of Eurasian Bullfinches,including Iberia.Methods:In this study,seasonal preferences regarding habitat and space in a population of Eurasian Bullfinches are examined for the first time in the Iberian Peninsula,through direct observation during a six-year period.The essential habitat components,substrate selection and perch height were assessed.Results:Hedgerows were the key essential habitat component for bullfinches during all seasons.Nevertheless,small poplar plantations became increasingly important from winter to summer-autumn.Bullfinches perched mostly in shrubs/trees throughout the year,but there were significant seasonal changes in substrate use,ground and herbs being of considerable importance during spring-summer.Throughout the year,over half of the records corresponded to feeding,reaching almost 90%in winter.Generally,bullfinches perched noticeably lower while feeding.Male bullfinches perched markedly higher than females,notably singing males in spring-summer.Juveniles perched at a height not much lower than that of males.In all seasons,males tended to feed at greater heights than females.Bullfinches of different ages and sexes were seen bathing in all seasons except winter.Conclusions:Hedgerow habitat in general appeared to be valuable for bullfinches throughout the year.In summer and autumn,they selected sites with an abundance of food and shade,as well as shelter,a much-needed requirement for fledglings and moulting individuals.There was usually a close link between the most used and most consumed plant species in each season.Males appeared to assume a more important role in vigilance,and often they accompanied dependent young in June and July.Bullfinch conservation strategies should consider seasonal demand for habitat and space.
文摘Fish size and harvest density generally exhibit a negative relationship in pond culture, but the influence that pond substrate type can have on this relationship is not well understood. To evaluate the influence of pond substrate type on yellow perch (<i></span><i><span style="font-family:Verdana;">Perca flavescens</span></i><span style="font-family:Verdana;"></i></span><span style="font-family:Verdana;">), harvest density (number/hectare) was linearly regressed against individual fingerling size (grams) for lined (n = 48) and earthen (n = 40) substrate ponds that were treated similarly in terms of organic fertilizer use and the number of days in the pond over 12 culture seasons at Blue Dog Lake State Hatchery, South Dakota, USA. Harvest density explained 45 and 39% of the variation in yellow perch size in lined and earthen-substrate ponds (all <i></span><i><span style="font-family:Verdana;">P</span></i><span style="font-family:Verdana;"></i></span><span style="font-family:Verdana;"> < 0.01). Comparison of regression lines indicated that fingerling size decreased as harvest density increased at a similar rate in both pond types (slope comparison, <i></span><i><span style="font-family:Verdana;">P</span></i><span style="font-family:Verdana;"></i></span><span style="font-family:Verdana;"> = 0.62);however, fingerling size was significantly larger in lined ponds regardless of density that varied from near 0 to 700,000 per hectare (y-intercept comparison, <i></span><i><span style="font-family:Verdana;">P</span></i><span style="font-family:Verdana;"></i></span><span style="font-family:Verdana;"> < 0.01). At the same harvest density, lined ponds will tend to produce larger yellow perch fingerlings compared to earthen ponds when similar organic fertilizers are used.
文摘Plinian pumice fall from the Holocene eruption of Mount Mazama in the Cascade volcanic arc is an unconfined, perched aquifer in south-central Oregon. The pumice aquifer provides near-surface groundwater storage that maintains biologically diverse wetland environments. Wetland environments reflect post-eruption disruption of the once uniform pumice blanket by fluvial and lacustrine processes operating within the template of the pre-eruption landscape. In the 8.6 km<sup>2</sup> Round Meadow watershed the pumice aquifer interacts with a seasonally flooded meadow, fen, springs, and perennial stream. The laterally uniform, isotropic pumice aquifer is disrupted by flat-bottomed ephemeral stream valleys that drain to the seasonally flooded meadow. Surface water levels in the seasonally flooded meadow are controlled by a knickpoint developed on bedrock. The underlying aquifer is confined by a layer of glass-rich diatomaceous silt grading upward to organic-rich silt. Here, the aquifer is comprised of remnants of the pumice deposit, lag sand, and reworked pumice. The water level in the confined aquifer is maintained by recharge from the unconfined pumice aquifer following flow pathways beneath ephemeral stream valleys. The fen is developed on a down-thrown block of welded tuff and pre-eruption diatomaceous silt. Water levels in the fen are sensitive to inter-annual variations in precipitation. Low discharge, low temperature (5.0°C to 6.5°C), and low conductivity (30 to 50 μS/cm) springs appear to be fracture controlled and rising through welded tuff. Spring discharge and seepage through pumice from the welded tuff support perennial flow in the creek that also carries discharge from the seasonally flooded meadow when water levels are high enough to cross the knickpoint.
基金Financial support was provided by CONACYT,through the project“Importancia del JB Benjamin Francis Johnston y otrasareas verdes urbanas para las aves en los Mochis,Sinaloa,durante laepoca migratoria y reproductiva del 2021”(Fondo FORDECYT-PRONACES).
文摘The simultaneous study of demography and behavior might provide a more comprehensive understanding about animal responses to anthropogenic disturbances.The White-winged Dove(Zenaida asiatica)is a frequent dweller of urban and agricultural habitats in North America,Central America,and the Caribbean.Still,research on the species is heavily biased to the USA.We analyzed the response of the species to human disturbances during winter across an urban-agricultural landscape in northwestern Mexico through a demographic and behavioral approach.We modeled the effect of disturbance types(pedestrians,cars,pavement and building cover)on the density of the species.Also,we investigated if surveillance behavior varied across the landscape by estimating and comparing perching proportion among land uses(urban grey areas,urban green areas,cropfields,shrublands).We did not detect the species within cropfields,possibly because food resources were not available for the dove during winter in this land use.Pavement cover limited species’density,as it might reduce the surface of the preferred feeding substrates of the dove.Pedestrians and building cover increased the density of the species,as they might provide food and shelter for the dove,respectively.Surveillance behavior peaked in urban grey areas,whereas it dropped in urban green areas.Differences on threat levels,threat type,and protective cover among land uses might in-fluence such behavioral pattern.Our approach contributes to the knowledge of the species and demonstrates that both demographic and behavioral cues provide complementary evidence for analyzing the impact of human disturbances on animals.
文摘New born hatchlings of Calotes versicolor were reared in terrarium having narrow or wide perches for a period of 4-month and their snout vent length（SVL）, tail, fore and hindlimb lengths were measured at monthly intervals. Limb postures（closer to the body or spread away from the body） were also recorded. The sprint speed was recorded in two and four-month old lizards on a 1 m long race track providing 45° or 60° slope. In both the groups, SVL and tail lengths were comparable but the limb lengths and their growth rates were significantly greater in lizards of wider perch group. The lizards reared with narrow perches positioned their limbs closer to the body; while those reared on wider perches spread their limbs away from their body. Further, the latter exhibited significantly higher sprint speed regardless of the slope of the race track over those of narrow perch group. Sprint speeds of lizards in both groups were correlated with the limb sizes. The study showed that the lizards reared on narrow or wide perches exhibited divergent adaptive responses（phenotypic plasticity） by developing longer or shorter limbs and corresponding changes in their sprint speeds. These findings support the idea that availability of perch structure during early development evokes adaptive plasticity in the limb development and associated locomotory performance in arboreal lizards like C. versicolor.
