Artifcial light at night(ALAN)is a common anthropogenic disturbance,which alters animal behavior.However,little is known about the impact of the spectral composition of ALAN and co-occurring predation risk on the beha...Artifcial light at night(ALAN)is a common anthropogenic disturbance,which alters animal behavior.However,little is known about the impact of the spectral composition of ALAN and co-occurring predation risk on the behavior of aquatic organisms.We experimentally investigated how ALAN of different spectra(cool white LED and HPS light)affects the behavior and foraging of Gammarus jazdzewskii(Amphipoda)on chironomid prey,both as a single stressor and in combination with an olfactory predation cue.Gammarids exposed to ALAN in the absence of predation cues consumed less,compared with darkness,mainly due to their lower activity.Moreover,gammarids showed a stronger response to LED light,spending more time in the shelter and increasing prey handling time in this treatment.The addition of predation cues did not enhance the negative impact of ALAN on the foraging success.Gammarids maintained similar consumption levels as in the ALAN treatment without predation cues and in darkness with predation cues.However,gammarids in LED light altered their behavior in response to predation threat:they decreased prey handling time and consumed prey faster,which may have compensated for the higher food demand in stressful conditions.They also tended to exhibit risky behavior,leaving the shelter and moving towards the lit area,presumably to escape and avoid the combined effects of light and predation cues.Therefore,when assessing the effects of ALAN on organisms,light quality and co-occurring biotic factors should be considered,as predator pressure is common in natural environments.展开更多
Tool use-once considered rare in insects-has been documented in a crafty predator.Researchers from China Agricultural University,and two institutions under the Chinese Academy of Sciences-the Xishuangbanna Tropical Bo...Tool use-once considered rare in insects-has been documented in a crafty predator.Researchers from China Agricultural University,and two institutions under the Chinese Academy of Sciences-the Xishuangbanna Tropical Botanical Garden(XTBG)and the Institute of Zoology-revealed that the assassin bug Pahabengkakia piliceps weaponizes resin from stingless bee nests to trick its prey.展开更多
Understanding how diet influences the breeding success of Saker Falcons (Falco cherrug) is key to assessing the role of food supply in population dynamics and informing conservation strategies. Through pellet analysis...Understanding how diet influences the breeding success of Saker Falcons (Falco cherrug) is key to assessing the role of food supply in population dynamics and informing conservation strategies. Through pellet analysis, we evaluated the influence of small mammal prey—present in 95% of pellets—on the reproductive performance of the sakers. In Mongolia, three species comprised 95% of the identified small mammals: Mongolian Gerbil (Meriones unguiculatus, 39%), Brandt's Vole (Lasiopodomys brandtii, 49%) and Daurian Pika (Ochotona dauurica, 7%). We found a strong positive association between the proportion of small mammals in the diet and key breeding parameters of sakers. Clutch size, fledged brood sizes, and nest success all increased with a mammal-rich diet. Earlier laying was also linked to higher small mammal intake and was independently associated with improved breeding outcomes. These findings highlight a critical role of small mammal prey in shaping the reproductive success of sakers. Conserving and restoring grassland habitats that support abundant prey populations is essential for sustaining saker populations and achieving long-term conservation goals.展开更多
Octopus minor is widely distributed along the northern coast of China. To date, there is little information on the prey selection process of this species. To understand this process, several experiments were carried o...Octopus minor is widely distributed along the northern coast of China. To date, there is little information on the prey selection process of this species. To understand this process, several experiments were carried out. Three types of bivalves, namely, Ruditapes philippinarum , Mactra chinensis , and Mytilus galloprovincialis , were used to observe the prey selection of O . minor and to analyze the potential causes of prey selection from three aspects: prey profi tability, adductor muscle tension and handling time. Under single-prey conditions, we found that the average (±SD) predation rates of O . minor on R . philippinarum , M . chinensis , and M . galloprovincialis were 1.73±0.50, 1.27±0.42, and 0.8±0.2/d, respectively. Under diff erent prey combinations, octopods actively selected one type of prey over the other(s), and the order of prey preference was R . philippinarum , followed by M . chinensis and lastly M. galloprovincialis . Furthermore, the shells of the consumed prey showed that O . minor only consumed bivalves by pulling them apart since there was no evidence of drill holes on the shells. The prey selection of O . minor was related to the prey profi tability and handling time;O . minor appeared to select preys with a higher profi tability and a shorter handling time. However, the diffi culty in opening the bivalve was not consistent with the prey preference of the octopods. These results suggest that O . minor prefers to consume R . philippinarum possibly due to a high profi tability and a short handling time that supports the optimum Foraging Theory.展开更多
Bird flight is a remarkable adaption that has allowed thousands of species to colonize all terrestrial habitats. A golden eagle has impressive flying abilities, such as hovering, perching, preying and attacking. To re...Bird flight is a remarkable adaption that has allowed thousands of species to colonize all terrestrial habitats. A golden eagle has impressive flying abilities, such as hovering, perching, preying and attacking. To reveal the flying abilities, avian geometry of a golden eagle was extracted based on noncontact surface measurements using a ROMBER three-dimensional laser scanner. Distributions of a camber line, thickness and a secondary feather line of the extracted point cloud were fitted using convenient analytical expressions. A traditional airfoil was established with the camber line and thickness, then a combined airfoil was constructed by combining the traditional airfoil with a secondary feather. Oscillations of an airfoil as well as rapid pitch up were simplified as a sine wave around the quarter chord axis. Thereafter, both steady and unsteady aerodynamic performances of the airfoil are computed, the influences of the secondary feather on the steady and unsteady aerodynamics were further studied.展开更多
A class of nonlinear predator prey reaction diffusion systems for singularly pe rturbed problems are considered.Under suitable conditions, by using theory of di fferential inequalities the existence and asymptotic be...A class of nonlinear predator prey reaction diffusion systems for singularly pe rturbed problems are considered.Under suitable conditions, by using theory of di fferential inequalities the existence and asymptotic behavior of solution for in itial boundary value problems are studied.展开更多
Abstract Deceptive antipredator defense mechanisms fall into three categories： depriving predators of knowledge of prey＇s presence, providing cues that deceive predators about prey handling, and dishonest signaling....Abstract Deceptive antipredator defense mechanisms fall into three categories： depriving predators of knowledge of prey＇s presence, providing cues that deceive predators about prey handling, and dishonest signaling. Deceptive defenses in terrestrial vertebrates include aspects of crypsis such as background matching and countershading, visual and acoustic Batesian mimicry, active defenses that make animals seem more difficult to handle such as increase in apparent size and threats, feigning injury and death, distractive behaviours, and aspects of flight. After reviewing these defenses, I attempt a preliminary evaluation of which aspects of antipredator deception are most widespread in amphibians, reptiles, mammals and birds展开更多
The pursuit problem is a well-known problem in computer science. In this problem, a group of predator agents attempt to capture a prey agent in an environment with various obstacle types, partial observation, and an i...The pursuit problem is a well-known problem in computer science. In this problem, a group of predator agents attempt to capture a prey agent in an environment with various obstacle types, partial observation, and an infinite grid-world. Predator agents are applied algorithms that use the univector field method to reach the prey agent, strategies for avoiding obstacles and strategies for cooperation between predator agents. Obstacle avoidance strategies are generalized and presented through strategies called hitting and following boundary(HFB); trapped and following shortest path(TFSP); and predicted and following shortest path(PFSP). In terms of cooperation, cooperation strategies are employed to more quickly reach and capture the prey agent. Experimental results are shown to illustrate the efficiency of the method in the pursuit problem.展开更多
Prey have evolved anti-predator defences that reduce or eliminate the risk of predation. Predators often reproduce at specific sites over many years causing permanent threats to local prey species. Such prey may respo...Prey have evolved anti-predator defences that reduce or eliminate the risk of predation. Predators often reproduce at specific sites over many years causing permanent threats to local prey species. Such prey may respond by moving elsewhere thereby reducing local population abundance, or they may stay put and adjust their behavior to the presence of predators. We tested these predictions by analyzing population abundance and anti-predator behavior within 100 m of and 500 m away from nests of sparrowhawks Accipiter nisus and goshawks A. gentilis for 80 species of birds. Population abundance of prey was reduced by 11% near goshawk nests and by 15% near sparrowhawk nests when compared with nearby control sites in similar habitats. Flight initiation distance （FID） of prey, estimated as the distance at which birds took flight when approached by a human, increased by 50% in the presence of hawk nests, providing evidence of adjustment of anti-predator behavior to prevailing risks of predation. Susceptibility to predation was estimated as log transformed abundance of the observed number of prey items obtained from prey remains collected around nests minus log transformed expected number of prey according to point counts of breeding birds. FID increased from 10 to 46 m with increasing susceptibility of prey species to predation by the goshawk and from 12 to 15 m with increasing susceptibility of prey species to predation by the sparrowhawk. These findings suggest that prey adjust their distribution and anti-predator behavior to the risk of predation.展开更多
Scorpion fauna of Mongolia, which are thus far poorly understood, were investigated country-wide during a China-Mongolia joint field survey from 2009 to 2012. Of the total 134 sites we surveyed, scorpions were found a...Scorpion fauna of Mongolia, which are thus far poorly understood, were investigated country-wide during a China-Mongolia joint field survey from 2009 to 2012. Of the total 134 sites we surveyed, scorpions were found at 10 sites in the southern Gobi regions, Umnugovi and Dornogovi Aimags （Provinces） of Mongolia. All scorpions collected from Mongolia belong to a single species, Mesobuthus eupeus mongolicus. Combining with its occurrence records in China, we assembled 98 presence data for M. eupeus mongolicus and predicted its geographical distribution using ecological niche modeling approach. This species occurs exclusively in the arid deserts and steppes, ranging from the west extreme of Junggar Basin （Xinjiang） to the Gobi deserts in North China and South Mongolia, with its distributional margins set by the Altai Mountains in the north, the Tian-Shan Mountains and the Qinghai-Tibet Plateau in the south, and the Loess Plateau in the east. We found that ecological niche models could accurately predict （AUC = 0.880 ± 0.016） geographic distribution of M. eupeus mongolicus. Our results show that climate is a reliable predictor for the geographic range of M. eupeus mongolicus, implying that climate might have exerted a dominant control over the natural occurrence of this species. A brief note on the ecology ofM. eupeus mongolicus was also provided,展开更多
Color polymorphisms have been traditionally attributed to apostatic selection.The perception of color depends on the visual system of the observer.Theoretical models predict that differently perceived degrees of consp...Color polymorphisms have been traditionally attributed to apostatic selection.The perception of color depends on the visual system of the observer.Theoretical models predict that differently perceived degrees of conspicuousness by two predator and prey species may cause the evolution of polymorphisms in the presence of anti-apostatic and apostatic selection.The spider Gasteracantha cancriformis(Araneidae)possesses several conspicuous color morphs.In orb-web spiders,the prey attraction hypothesis states that conspicuous colors are prey lures that increase spider foraging success via flower mimicry.Therefore,polymorphism could be maintained if each morph attracted a different prey species(multiple prey hypothesis)and each spider mimicked a different flower color(flower mimicry hypothesis).Conspicuous colors could be a warning signal to predators because of the spider's hard abdomen and spines.Multiple predators could perceive morphs differently and exert different degrees of selective pressures(multiple predator hypothesis).We explored these 3 hypotheses using reflectance data and color vision modeling to estimate the chromatic and achromatic contrast of G.cancriformis morphs as perceived by several potential prey and predator taxa.Our results revealed that individual taxa perceive the conspicuousness of morphs differently.Therefore,the multiple prey hypothesis and,in part,the multiple predator hypothesis may explain the evolution of color polymorphism in G.cancriformis,even in the presence of anti-apostatic selection.The flower mimicry hypothesis received support by color metrics,but not by color vision models.Other parameters not evaluated by color vision models could also affect the perception of morphs and influence morph survival and polymorphism stability.展开更多
Prey use reliable public information in order to assess local habitat condirions such as predation risks, competitive interactions, and foraging opportunities (Dall et al. 2005), allowing for context appropriate behav...Prey use reliable public information in order to assess local habitat condirions such as predation risks, competitive interactions, and foraging opportunities (Dall et al. 2005), allowing for context appropriate behavioral decisions. However, public information can often differ widely in reliability (Feyten and Brown 2018), increasing the potential costs associated with behavioral decision making (Dall et al. 2005). The reliability of public information is expected to decrease with in creased un certainty of environmental conditio ns (Koops 2004;Dall et al. 2005), where ecological uncertainty is the ambiguity about the current state of the environment due to imperfect or incomplete information (Dall et al. 2005;Munoz and Blumstein 2012;Feyten and Brown 2018).展开更多
Support vector machine(SVM)has a good application prospect for speech recognition problems;still optimum parameter selection is a vital issue for it.To improve the learning ability of SVM,a method for searching the op...Support vector machine(SVM)has a good application prospect for speech recognition problems;still optimum parameter selection is a vital issue for it.To improve the learning ability of SVM,a method for searching the optimal parameters based on integration of predator prey optimization(PPO)and Hooke-Jeeves method has been proposed.In PPO technique,population consists of prey and predator particles.The prey particles search the optimum solution and predator always attacks the global best prey particle.The solution obtained by PPO is further improved by applying Hooke-Jeeves method.Proposed method is applied to recognize isolated words in a Hindi speech database and also to recognize words in a benchmark database TI-20 in clean and noisy environment.A recognition rate of 81.5%for Hindi database and 92.2%for TI-20 database has been achieved using proposed technique.展开更多
Sexual size dimorphism （SSD） is a general phenomenon in lizards, and can evolve through sexual selection or natural selection. But natural selection, which was thought to operate mainly through reducing the competit...Sexual size dimorphism （SSD） is a general phenomenon in lizards, and can evolve through sexual selection or natural selection. But natural selection, which was thought to operate mainly through reducing the competition be- tween the two sexes （niche divergence hypothesis）, gave rise to a lot of controversy. We tested the niche divergence hypothesis in the toad-headed lizard Phrynocephalus przewalskii by comparing diet composition and prey sizes between males and females. The species was found to be sexual dimorphic, with males having relatively larger snout-vent length, head width, head length, and tail length, while females have relatively larger abdomen length. Based on analysis of 93 studied stomachs, a total of 1359 prey items were identified. The most common prey items were formicid, lygaeid and tenebrionid. The two sexes did not differ in the relative proportions of prey size categories they consumed and the dietary overlap based on prey species was high （O = 0.989）. In addition, the meal size, the volume or any maximal dimension of the largest prey item in the stomach was not explained by the sexes. According to our results, food niche divergence might not play an important role in the SSD evolution ofP. przewalskii.展开更多
Nowadays,the usage of socialmedia platforms is rapidly increasing,and rumours or false information are also rising,especially among Arab nations.This false information is harmful to society and individuals.Blocking an...Nowadays,the usage of socialmedia platforms is rapidly increasing,and rumours or false information are also rising,especially among Arab nations.This false information is harmful to society and individuals.Blocking and detecting the spread of fake news in Arabic becomes critical.Several artificial intelligence(AI)methods,including contemporary transformer techniques,BERT,were used to detect fake news.Thus,fake news in Arabic is identified by utilizing AI approaches.This article develops a new hunterprey optimization with hybrid deep learning-based fake news detection(HPOHDL-FND)model on the Arabic corpus.The HPOHDL-FND technique undergoes extensive data pre-processing steps to transform the input data into a useful format.Besides,the HPOHDL-FND technique utilizes long-term memory with a recurrent neural network(LSTM-RNN)model for fake news detection and classification.Finally,hunter prey optimization(HPO)algorithm is exploited for optimal modification of the hyperparameters related to the LSTM-RNN model.The performance validation of the HPOHDL-FND technique is tested using two Arabic datasets.The outcomes exemplified better performance over the other existing techniques with maximum accuracy of 96.57%and 93.53%on Covid19Fakes and satirical datasets,respectively.展开更多
In this paper, food habits of the wolf (Canis lupus) was determined in Inner Monolia, using scat analysis. Results indicated that ungulates were the staple food items(frequency 53.8%, relative biomass 85.2%). In the s...In this paper, food habits of the wolf (Canis lupus) was determined in Inner Monolia, using scat analysis. Results indicated that ungulates were the staple food items(frequency 53.8%, relative biomass 85.2%). In the scats, animals was 40.3% by the frequency of occurrence, and 75.7% by the relative biomass. Compared with the food habits of wolves in Heilongjiang Province, wolves showed a different pattern in prey selection in this ergion. In this study, we estimated the relative biomass of food items, and amount of each prey ingested by a wolf, based on a linear regression equation, y=2.76+0.02x(r=0.997), which was obtained in the feeding trials, It is suggerted that wolves are opportunistic predator. Some suggestions for wolf conservation and management were disussed.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
文摘Artifcial light at night(ALAN)is a common anthropogenic disturbance,which alters animal behavior.However,little is known about the impact of the spectral composition of ALAN and co-occurring predation risk on the behavior of aquatic organisms.We experimentally investigated how ALAN of different spectra(cool white LED and HPS light)affects the behavior and foraging of Gammarus jazdzewskii(Amphipoda)on chironomid prey,both as a single stressor and in combination with an olfactory predation cue.Gammarids exposed to ALAN in the absence of predation cues consumed less,compared with darkness,mainly due to their lower activity.Moreover,gammarids showed a stronger response to LED light,spending more time in the shelter and increasing prey handling time in this treatment.The addition of predation cues did not enhance the negative impact of ALAN on the foraging success.Gammarids maintained similar consumption levels as in the ALAN treatment without predation cues and in darkness with predation cues.However,gammarids in LED light altered their behavior in response to predation threat:they decreased prey handling time and consumed prey faster,which may have compensated for the higher food demand in stressful conditions.They also tended to exhibit risky behavior,leaving the shelter and moving towards the lit area,presumably to escape and avoid the combined effects of light and predation cues.Therefore,when assessing the effects of ALAN on organisms,light quality and co-occurring biotic factors should be considered,as predator pressure is common in natural environments.
文摘Tool use-once considered rare in insects-has been documented in a crafty predator.Researchers from China Agricultural University,and two institutions under the Chinese Academy of Sciences-the Xishuangbanna Tropical Botanical Garden(XTBG)and the Institute of Zoology-revealed that the assassin bug Pahabengkakia piliceps weaponizes resin from stingless bee nests to trick its prey.
基金supported by the National Natural Science Foundation of China (32125005, 32361133559)the Institute of Zoology,Chinese Academy of Sciences (2023IOZ0104)+2 种基金the Third Xinjiang Scientific Expedition Program (Grant No. 2022xjkk0800)the CAS-TWAS President’s Fellowship programme (BB)The Environment Agency Abu Dhabi (EAD) funded the project under a MOU with Mongolia’s Ministry of Environment and Green Development (MEGD)
文摘Understanding how diet influences the breeding success of Saker Falcons (Falco cherrug) is key to assessing the role of food supply in population dynamics and informing conservation strategies. Through pellet analysis, we evaluated the influence of small mammal prey—present in 95% of pellets—on the reproductive performance of the sakers. In Mongolia, three species comprised 95% of the identified small mammals: Mongolian Gerbil (Meriones unguiculatus, 39%), Brandt's Vole (Lasiopodomys brandtii, 49%) and Daurian Pika (Ochotona dauurica, 7%). We found a strong positive association between the proportion of small mammals in the diet and key breeding parameters of sakers. Clutch size, fledged brood sizes, and nest success all increased with a mammal-rich diet. Earlier laying was also linked to higher small mammal intake and was independently associated with improved breeding outcomes. These findings highlight a critical role of small mammal prey in shaping the reproductive success of sakers. Conserving and restoring grassland habitats that support abundant prey populations is essential for sustaining saker populations and achieving long-term conservation goals.
基金Supported by the Fundamental Research Funds for the Central Universities(No.201822022)the Key Development Plan of Shandong Province(No.2016GSF115014)
文摘Octopus minor is widely distributed along the northern coast of China. To date, there is little information on the prey selection process of this species. To understand this process, several experiments were carried out. Three types of bivalves, namely, Ruditapes philippinarum , Mactra chinensis , and Mytilus galloprovincialis , were used to observe the prey selection of O . minor and to analyze the potential causes of prey selection from three aspects: prey profi tability, adductor muscle tension and handling time. Under single-prey conditions, we found that the average (±SD) predation rates of O . minor on R . philippinarum , M . chinensis , and M . galloprovincialis were 1.73±0.50, 1.27±0.42, and 0.8±0.2/d, respectively. Under diff erent prey combinations, octopods actively selected one type of prey over the other(s), and the order of prey preference was R . philippinarum , followed by M . chinensis and lastly M. galloprovincialis . Furthermore, the shells of the consumed prey showed that O . minor only consumed bivalves by pulling them apart since there was no evidence of drill holes on the shells. The prey selection of O . minor was related to the prey profi tability and handling time;O . minor appeared to select preys with a higher profi tability and a shorter handling time. However, the diffi culty in opening the bivalve was not consistent with the prey preference of the octopods. These results suggest that O . minor prefers to consume R . philippinarum possibly due to a high profi tability and a short handling time that supports the optimum Foraging Theory.
文摘Bird flight is a remarkable adaption that has allowed thousands of species to colonize all terrestrial habitats. A golden eagle has impressive flying abilities, such as hovering, perching, preying and attacking. To reveal the flying abilities, avian geometry of a golden eagle was extracted based on noncontact surface measurements using a ROMBER three-dimensional laser scanner. Distributions of a camber line, thickness and a secondary feather line of the extracted point cloud were fitted using convenient analytical expressions. A traditional airfoil was established with the camber line and thickness, then a combined airfoil was constructed by combining the traditional airfoil with a secondary feather. Oscillations of an airfoil as well as rapid pitch up were simplified as a sine wave around the quarter chord axis. Thereafter, both steady and unsteady aerodynamic performances of the airfoil are computed, the influences of the secondary feather on the steady and unsteady aerodynamics were further studied.
基金Supported by important study project of the National Natural Science Foundation of China(9 0 2 1 1 0 0 4 ) and by the"Hundred Talents'Project"of Chinese Academy of Sciences
文摘A class of nonlinear predator prey reaction diffusion systems for singularly pe rturbed problems are considered.Under suitable conditions, by using theory of di fferential inequalities the existence and asymptotic behavior of solution for in itial boundary value problems are studied.
文摘Abstract Deceptive antipredator defense mechanisms fall into three categories： depriving predators of knowledge of prey＇s presence, providing cues that deceive predators about prey handling, and dishonest signaling. Deceptive defenses in terrestrial vertebrates include aspects of crypsis such as background matching and countershading, visual and acoustic Batesian mimicry, active defenses that make animals seem more difficult to handle such as increase in apparent size and threats, feigning injury and death, distractive behaviours, and aspects of flight. After reviewing these defenses, I attempt a preliminary evaluation of which aspects of antipredator deception are most widespread in amphibians, reptiles, mammals and birds
基金the Basic Science Research Program through the National Research Foundation of Korea (NRF-2014R1A1A2057735)the Kyung Hee University in 2016 [KHU-20160601]
文摘The pursuit problem is a well-known problem in computer science. In this problem, a group of predator agents attempt to capture a prey agent in an environment with various obstacle types, partial observation, and an infinite grid-world. Predator agents are applied algorithms that use the univector field method to reach the prey agent, strategies for avoiding obstacles and strategies for cooperation between predator agents. Obstacle avoidance strategies are generalized and presented through strategies called hitting and following boundary(HFB); trapped and following shortest path(TFSP); and predicted and following shortest path(PFSP). In terms of cooperation, cooperation strategies are employed to more quickly reach and capture the prey agent. Experimental results are shown to illustrate the efficiency of the method in the pursuit problem.
文摘Prey have evolved anti-predator defences that reduce or eliminate the risk of predation. Predators often reproduce at specific sites over many years causing permanent threats to local prey species. Such prey may respond by moving elsewhere thereby reducing local population abundance, or they may stay put and adjust their behavior to the presence of predators. We tested these predictions by analyzing population abundance and anti-predator behavior within 100 m of and 500 m away from nests of sparrowhawks Accipiter nisus and goshawks A. gentilis for 80 species of birds. Population abundance of prey was reduced by 11% near goshawk nests and by 15% near sparrowhawk nests when compared with nearby control sites in similar habitats. Flight initiation distance （FID） of prey, estimated as the distance at which birds took flight when approached by a human, increased by 50% in the presence of hawk nests, providing evidence of adjustment of anti-predator behavior to prevailing risks of predation. Susceptibility to predation was estimated as log transformed abundance of the observed number of prey items obtained from prey remains collected around nests minus log transformed expected number of prey according to point counts of breeding birds. FID increased from 10 to 46 m with increasing susceptibility of prey species to predation by the goshawk and from 12 to 15 m with increasing susceptibility of prey species to predation by the sparrowhawk. These findings suggest that prey adjust their distribution and anti-predator behavior to the risk of predation.
基金supported by the National Natural Science Foundation of China(31000951)the External Cooperation Program of BIC,Chinese Academy of Sciences(GJHZ201311,GJHZ1023)
文摘Scorpion fauna of Mongolia, which are thus far poorly understood, were investigated country-wide during a China-Mongolia joint field survey from 2009 to 2012. Of the total 134 sites we surveyed, scorpions were found at 10 sites in the southern Gobi regions, Umnugovi and Dornogovi Aimags （Provinces） of Mongolia. All scorpions collected from Mongolia belong to a single species, Mesobuthus eupeus mongolicus. Combining with its occurrence records in China, we assembled 98 presence data for M. eupeus mongolicus and predicted its geographical distribution using ecological niche modeling approach. This species occurs exclusively in the arid deserts and steppes, ranging from the west extreme of Junggar Basin （Xinjiang） to the Gobi deserts in North China and South Mongolia, with its distributional margins set by the Altai Mountains in the north, the Tian-Shan Mountains and the Qinghai-Tibet Plateau in the south, and the Loess Plateau in the east. We found that ecological niche models could accurately predict （AUC = 0.880 ± 0.016） geographic distribution of M. eupeus mongolicus. Our results show that climate is a reliable predictor for the geographic range of M. eupeus mongolicus, implying that climate might have exerted a dominant control over the natural occurrence of this species. A brief note on the ecology ofM. eupeus mongolicus was also provided,
文摘Color polymorphisms have been traditionally attributed to apostatic selection.The perception of color depends on the visual system of the observer.Theoretical models predict that differently perceived degrees of conspicuousness by two predator and prey species may cause the evolution of polymorphisms in the presence of anti-apostatic and apostatic selection.The spider Gasteracantha cancriformis(Araneidae)possesses several conspicuous color morphs.In orb-web spiders,the prey attraction hypothesis states that conspicuous colors are prey lures that increase spider foraging success via flower mimicry.Therefore,polymorphism could be maintained if each morph attracted a different prey species(multiple prey hypothesis)and each spider mimicked a different flower color(flower mimicry hypothesis).Conspicuous colors could be a warning signal to predators because of the spider's hard abdomen and spines.Multiple predators could perceive morphs differently and exert different degrees of selective pressures(multiple predator hypothesis).We explored these 3 hypotheses using reflectance data and color vision modeling to estimate the chromatic and achromatic contrast of G.cancriformis morphs as perceived by several potential prey and predator taxa.Our results revealed that individual taxa perceive the conspicuousness of morphs differently.Therefore,the multiple prey hypothesis and,in part,the multiple predator hypothesis may explain the evolution of color polymorphism in G.cancriformis,even in the presence of anti-apostatic selection.The flower mimicry hypothesis received support by color metrics,but not by color vision models.Other parameters not evaluated by color vision models could also affect the perception of morphs and influence morph survival and polymorphism stability.
文摘Prey use reliable public information in order to assess local habitat condirions such as predation risks, competitive interactions, and foraging opportunities (Dall et al. 2005), allowing for context appropriate behavioral decisions. However, public information can often differ widely in reliability (Feyten and Brown 2018), increasing the potential costs associated with behavioral decision making (Dall et al. 2005). The reliability of public information is expected to decrease with in creased un certainty of environmental conditio ns (Koops 2004;Dall et al. 2005), where ecological uncertainty is the ambiguity about the current state of the environment due to imperfect or incomplete information (Dall et al. 2005;Munoz and Blumstein 2012;Feyten and Brown 2018).
文摘Support vector machine(SVM)has a good application prospect for speech recognition problems;still optimum parameter selection is a vital issue for it.To improve the learning ability of SVM,a method for searching the optimal parameters based on integration of predator prey optimization(PPO)and Hooke-Jeeves method has been proposed.In PPO technique,population consists of prey and predator particles.The prey particles search the optimum solution and predator always attacks the global best prey particle.The solution obtained by PPO is further improved by applying Hooke-Jeeves method.Proposed method is applied to recognize isolated words in a Hindi speech database and also to recognize words in a benchmark database TI-20 in clean and noisy environment.A recognition rate of 81.5%for Hindi database and 92.2%for TI-20 database has been achieved using proposed technique.
基金founded by the National Natural Science Foundation of China (31200287)the Fundamental Research Funds for the Central Universities (lzujbky-2012-114)
文摘Sexual size dimorphism （SSD） is a general phenomenon in lizards, and can evolve through sexual selection or natural selection. But natural selection, which was thought to operate mainly through reducing the competition be- tween the two sexes （niche divergence hypothesis）, gave rise to a lot of controversy. We tested the niche divergence hypothesis in the toad-headed lizard Phrynocephalus przewalskii by comparing diet composition and prey sizes between males and females. The species was found to be sexual dimorphic, with males having relatively larger snout-vent length, head width, head length, and tail length, while females have relatively larger abdomen length. Based on analysis of 93 studied stomachs, a total of 1359 prey items were identified. The most common prey items were formicid, lygaeid and tenebrionid. The two sexes did not differ in the relative proportions of prey size categories they consumed and the dietary overlap based on prey species was high （O = 0.989）. In addition, the meal size, the volume or any maximal dimension of the largest prey item in the stomach was not explained by the sexes. According to our results, food niche divergence might not play an important role in the SSD evolution ofP. przewalskii.
基金The authors extend their appreciation to the Deanship of Scientific Research at King Khalid University for funding this work through Small Groups Project under Grant Number(120/43)Princess Nourah bint Abdulrahman University Researchers Supporting Project Number(PNURSP2022R281)Princess Nourah bint Abdulrahman University,Riyadh,Saudi Arabia.The authors would like to thank the Deanship of Scientific Research at Umm Al-Qura University for supporting this work by Grant Code:(22UQU4331004DSR32).
文摘Nowadays,the usage of socialmedia platforms is rapidly increasing,and rumours or false information are also rising,especially among Arab nations.This false information is harmful to society and individuals.Blocking and detecting the spread of fake news in Arabic becomes critical.Several artificial intelligence(AI)methods,including contemporary transformer techniques,BERT,were used to detect fake news.Thus,fake news in Arabic is identified by utilizing AI approaches.This article develops a new hunterprey optimization with hybrid deep learning-based fake news detection(HPOHDL-FND)model on the Arabic corpus.The HPOHDL-FND technique undergoes extensive data pre-processing steps to transform the input data into a useful format.Besides,the HPOHDL-FND technique utilizes long-term memory with a recurrent neural network(LSTM-RNN)model for fake news detection and classification.Finally,hunter prey optimization(HPO)algorithm is exploited for optimal modification of the hyperparameters related to the LSTM-RNN model.The performance validation of the HPOHDL-FND technique is tested using two Arabic datasets.The outcomes exemplified better performance over the other existing techniques with maximum accuracy of 96.57%and 93.53%on Covid19Fakes and satirical datasets,respectively.
文摘In this paper, food habits of the wolf (Canis lupus) was determined in Inner Monolia, using scat analysis. Results indicated that ungulates were the staple food items(frequency 53.8%, relative biomass 85.2%). In the scats, animals was 40.3% by the frequency of occurrence, and 75.7% by the relative biomass. Compared with the food habits of wolves in Heilongjiang Province, wolves showed a different pattern in prey selection in this ergion. In this study, we estimated the relative biomass of food items, and amount of each prey ingested by a wolf, based on a linear regression equation, y=2.76+0.02x(r=0.997), which was obtained in the feeding trials, It is suggerted that wolves are opportunistic predator. Some suggestions for wolf conservation and management were disussed.
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.
