As an apex predator in arid steppe,saker falcon plays a crucial role in maintaining ecosystem balance.Understanding their movement patterns concerning conspecific competition and prey availability is important for the...As an apex predator in arid steppe,saker falcon plays a crucial role in maintaining ecosystem balance.Understanding their movement patterns concerning conspecific competition and prey availability is important for their conservation.We aim to understand how movement pattern of breeding saker falcons relates to prey availability.Twelve adult sakers were tracked during the breeding seasons,using satellite transmitters.Throughout the breeding season,sakers exhibited territorial behavior,with minimal overlap in range use among neighboring conspecifics.Males occupied larger areas(mean=2,397 ha,median=1,221 ha),compared to females(mean=1,241 ha,median=554 ha),and it remained consistent throughout breeding season.Female home range size increased notably during a late nestling stage and post-fledging dependence periods,indicating release from brooding constraints.Notably,we found a negative relationship between male home range size and prey availability.In high rodent density areas,males occupied smaller areas(mean=1,135 ha,median=1,034 ha),contrasting with low rodent density areas(mean=6,815 ha,median=6,516 ha).However,no significant relationship was observed between female home range size and prey availability.We also noted instances of nest abandonment and early dispersal behavior in some females,potentially influenced by a handicapping effect of tagging.Our findings offer valuable insight into how prey availability shapes saker falcon space use and defines their spatial requirements for successful breeding.This knowledge is crucial for the conservation and management of globally endangered saker falcons,informing targeted habitat protection and resource management strategies.展开更多
Religious wildlife release is prevalent worldwide,especially in Asia countries.It is one of the anthropogenic pathways to cause biological inva-sions.Religious fish release is common on the Qinghai-Tibetan Plateau,yet...Religious wildlife release is prevalent worldwide,especially in Asia countries.It is one of the anthropogenic pathways to cause biological inva-sions.Religious fish release is common on the Qinghai-Tibetan Plateau,yet few studies have assessed the influences of religious fish release on local species.InYushu,a city on the Qinghai-Tibetan Plateau,we interviewedlocal people,conducted fish trap surveys in local rivers,and exam-ined the diet of Eurasian otters Lutra lutra using a fecal DNA metabarcoding approach.We found that fish release started at least in 1980-1990s in Yushu.Tibetan residents released fish in large amounts and released fish were usually exotic commercial fish purchased from market.Despite such long-term and intensive fish release activities,released fish were few in local rivers.On the other hand,Eurasian otters mainly prey on fish and released fish accounted for~20%of relative read abundance of prey DNA in otters'diet,indicating their high preference on released fish.Our study suggested that religious fish release may provide additional food resources for otters,whereas otters,as a top predator in local rivers,may deplete non-native fish once they were released and,therefore,reduce the probability of colonization of released fish,although further studies are required to assess otters'impact.Our study revealed otters'diet in Yushu,providing basic information for local otter management and conservation.Furthermore,it represents a case showing that native predators prey on religious released animals,implying a probable direction forcontrolling invasive species through nativepredator conservation.展开更多
In this paper, the dynamical behaviors of a modified Leslie-Gower predator-prey model incorporating fear effect and prey refuge are investigated. We delve into the construction of the model and its biological signific...In this paper, the dynamical behaviors of a modified Leslie-Gower predator-prey model incorporating fear effect and prey refuge are investigated. We delve into the construction of the model and its biological significance, with preliminary results encompassing positivity, boundedness, and persistence. The stability of the system’s boundary and positive equilibrium points is proven by calculating the real part of the eigenvalues of the Jacobian matrix. At the positive equilibrium point, we demonstrate that the system’s unique positive equilibrium is globally asymptotically stable by using the Dulac criterion. Furthermore, at this equilibrium point, we employ the Implicit Function Theorem to discuss how fear effects and prey refuges influence the population densities of both prey and predators. Finally, numerical simulations are conducted to validate the above-mentioned conclusions and explored the impact of Predator-taxis sensitivity αon dynamics of the system.展开更多
The effects of the variability of individual prey locomotory performance on the vulnerability to predation are poorly understood,partly because individual performance is difficult to determine in natural habitats.To g...The effects of the variability of individual prey locomotory performance on the vulnerability to predation are poorly understood,partly because individual performance is difficult to determine in natural habitats.To gain insights into the role(s)of individual variation in predatory relationships,we study a convenient model system,the neotropical sandy beach gastropod Olivella semistriata and its main predator,the carnivorous snail Agaronia propatula.The largest size class of O.semistriata is known to be missing from A.propatula's spectrum of subdued prey,although the predator regularly captures much larger individuals of other taxa.To resolve this conundrum,we analyzed predation attempts in the wild.While A.propatula attacked O.semistriata of all sizes,large prey specimens usually escaped by'sculling',an accelerated,stepping mode of locomotion.Olivella semistriata performed sculling locomotion regardless of size,but sculling velocities determined in the natural environment increased strongly with size.Thus,growth in size as such does not establish a prey size refuge in which O.semistriata is safe from predation.Rather,a behaviorally mediated size refuge is created through the size-dependence of sculling performance.Taken together,this work presents a rare quantitative characterization in the natural habitat of the causal sequence from the size-dependence of individual performance,to the prey size-dependent outcome of predation attempts,to the size bias in the predator's prey spectrum.展开更多
According to one of the theses of optimal foraging theory,main prey species abundance in the hunting area is the main factor determining the diet and habitat choices of birds of prey.However other factors can also be ...According to one of the theses of optimal foraging theory,main prey species abundance in the hunting area is the main factor determining the diet and habitat choices of birds of prey.However other factors can also be important.The habitat structure influences the predators’diets as well.In this study we examined the influence of habitat structure on diet compositions of three species of birds:Long-eared Owl(Asio otus),Short-eared Owl(A.flammeus)and Common Kestrel(Falco tinnunculus).The study was carried out from 2007 to 2019 in a 48 km2area of the Crane’s Homeland Reserve,Moscow Region,Russia.The habitat structures of model species’hunting territories(ratio of different types of landscape elements)were classified in module"Semi-Automatic Classification Plugin"based on the QGIS.A boosted regression tree analysis identified that the share of the main prey species in the diet is primarily determined by the landscape structure of hunting territories.The largest share of Common Vole(Microtus arvalis)in birds’diet was determined by the shrubs area(15%of hunting area),the meadow area(75%),the habitat heterogeneity(70%)and the arable land area(5%).The same predictors determined the largest share of Root Vole(Microtus oeconomus):the shrubs area 25%,the meadow area 70%,and the arable land area 3%.The annual mean abundance of prey species did not determine their importance in the diet of birds of prey.Thus,the main prey abundance in the hunting area is not a determining factor for the formation of diet composition of birds of prey.展开更多
We formulate and analyze a predator-prey model followed by Leslie-Gower model in which the prey population is infected by disease. We assume that the disease can only spread over prey population. As a result prey popu...We formulate and analyze a predator-prey model followed by Leslie-Gower model in which the prey population is infected by disease. We assume that the disease can only spread over prey population. As a result prey population has been classified into two categories, namely susceptible prey, infected prey where as the predator population remains free from infection. To investigate the behaviour of prey population we incorporate prey refuge in this model. Since the prey refuge decreases the predation rate then it has an important effect in our predator-prey interaction model. We have discussed the existence of various equilibrium points and local stability analysis at those equilibrium points. We investigate the Hopf-bifurcation analysis about the interior equilibrium point by taking the rate of infection parameter and the prey refuge parameter as bifurcation parameters. The numerical analysis is carried out to support the analytical results and to discuss some interesting results that our model exhibits.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
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
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
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
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
The present study preliminarily examined the differences in maximum handling size, prey size and species selectivity of growth hormone transgenic and non-transgenic common carp Cyprinus carpio when foraging on four ga...The present study preliminarily examined the differences in maximum handling size, prey size and species selectivity of growth hormone transgenic and non-transgenic common carp Cyprinus carpio when foraging on four gastropods species( Bellamya aeruginosa, Radix auricularia, Parafossarulus sinensis and Alocinma longicornis) under laboratory conditions. In the maximum handling size trial, five fish from each age group(1-year-old and 2-year-old) and each genotype(transgenic and non-transgenic) of common carp were individually allowed to feed on B. aeruginosa with wide shell height range. The results showed that maximum handling size increased linearly with fish length, and there was no significant difference in maximum handling size between the two genotypes. In the size selection trial, three pairs of 2-year-old transgenic and non-transgenic carp were individually allowed to feed on three size groups of B. aeruginosa. The results show that the two genotypes of C. carpio favored the small-sized group over the large-sized group. In the species selection trial, three pairs of 2-year-old transgenic and non-transgenic carp were individually allowed to feed on thin-shelled B. aeruginosa and thick-shelled R. auricularia, and five pairs of 2-year-old transgenic and non-transgenic carp were individually allowed to feed on two gastropods species( P. sinensis and A. longicornis) with similar size and shell strength. The results showed that both genotypes preferred thin-shelled Radix auricularia rather than thick-shelled B. aeruginosa, but there were no significant difference in selectivity between the two genotypes when fed on P. sinensis and A. longicornis. The present study indicates that transgenic and non-transgenic C. carpio show similar selectivity of predation on the size-and species-limited gastropods. While this information may be useful for assessing the environmental risk of transgenic carp, it does not necessarily demonstrate that transgenic common carp might have lesser environmental impacts than non-transgenic carp.展开更多
Snakes often have specialized diets that undergo a shift from one prey type to another depending on the life stage of the snake. Crotalus viridis viridis （prairie rattlesnake） takes different prey at different life ...Snakes often have specialized diets that undergo a shift from one prey type to another depending on the life stage of the snake. Crotalus viridis viridis （prairie rattlesnake） takes different prey at different life stages, and neonates typically prey on ectotherms, while adults feed almost entirely on small endotherms. We hypothesized that elevated rates of tongue flicking to chemical stimuli should correlate with particular prey consumed, and that this response shifts from one prey type to another as in- dividuals age. To examine if an ontogenetic shift in response to chemical cues occurred, we recorded the rate of tongue flicking for 25 neonate, 20 subadult, and 20 adult （average SVL = 280.9, 552, 789.5 mm, respectively） wild-caught C. v. viridis to chemi- cal stimuli presented on a cotton-tipped applicator; water-soluble cues from two ectotherms （prairie lizard, Sceloporus undulatus, and house gecko, Hemidactylusfrenatus）, two endotherms （deer mouse, Peromyscus maniculatus and lab mouse, Mus musculus）, and water controls were used. Neonates tongue flicked significantly more to chemical cues of their common prey, S. undulatus, than to all other chemical cues; however, the response to this lizard＇s chemical cues decreased in adult rattlesnakes. Subadults tongue flicked with a higher rate of tongue flicking to both S. undulatus and P. maniculatus than to all other treatments, and adults tongue flicked significantly more to P. maniculatus than to all other chemical cues. In addition, all three sub-classes demonstrated a greater response for natural prey chemical cues over chemical stimuli of prey not encountered in the wild （M. musculus and H. frenatus）. This shift in chemosensory response correlated with the previously described ontogenetic shifts in C. v. viridis diet. Be-cause many vipers show a similar ontogenetic shift in diet and venom composition, we suggest that this shift in prey cue dis- crimination is likely a general phenomenon among viperid snakes.展开更多
This paper deals with the questio n of global stability of the positive locally asymptotically stable equilibrium in a class of predator\|prey system of Gause\|typ e with Holling Ⅲ functional response. The Dulac'...This paper deals with the questio n of global stability of the positive locally asymptotically stable equilibrium in a class of predator\|prey system of Gause\|typ e with Holling Ⅲ functional response. The Dulac's criterion is applied and lia punov functions are constructed to establish the global stability.展开更多
By using the continuation theorem of coincidence degree theory, sufficient conditions are obtained for the existence of positive periodic solutions of a delayed predator prey system with nonmonotonic functional respon...By using the continuation theorem of coincidence degree theory, sufficient conditions are obtained for the existence of positive periodic solutions of a delayed predator prey system with nonmonotonic functional response in a periodic environment.展开更多
Fish behavior can be altered by contaminants. There is an extensive literature on laboratory behavioral assays, with many chemicals impairing feeding or predator avoidance. However, there is not extensive work on fish...Fish behavior can be altered by contaminants. There is an extensive literature on laboratory behavioral assays, with many chemicals impairing feeding or predator avoidance. However, there is not extensive work on fishes that live in contami- nated environments. Therefore, we then review our recent research on feeding and trophic relations of populations from contami- nated estuaries compared with relatively unpolluted sites. The mummichog Fundulus heteroclitus, is a non-migratory fish; those from more contaminated areas are poor predators and slower to capture active prey （grass shrimp, Palaemonetes pugio）. In the field, they consume much detritus and sediment, which is not nutritious. They are less active than fish from cleaner sites and more vulnerable to predation. They have altered thyroid glands and neurotransmitter levels, which may underlie altered behaviors Fish from the reference site kept in tanks with sediment and food from the polluted site showed bioaccumulation and reduced prey capture after two months, although fish from the polluted site did not show significant improvement when maintained in a clean environment. Poor nutrition and predator avoidance may be responsible for their being smaller and having a shorter life span than reference fish. Bluefish Pomatomus saltatrix, are a marine species in which the young-of-the-year spend their first summer in es- tuaries. We found bioaccumulation of contaminants and reduced activity, schooling, and feeding in young-of-the-year bluefish from a relatively unpolluted site that were fed prey fish from a contaminated site. They also had altered thyroid glands and neuro- transmitter levels. Many field-caught specimens had empty stomachs, which is rare in this species. In the fall, when they migrate back out to the ocean, they are smaller, slower, and more likely to starve or to be eaten than those that spent their summer in cleaner estuaries [Current Zoology 58 （1）： 9-20, 2012].展开更多
Feeding strategies of an organism depend on the multimodal sensory processing that most efficiently integrates available visual,chemosensory,and/or mechanoreceptive cues as part of their environmental adaptation.The b...Feeding strategies of an organism depend on the multimodal sensory processing that most efficiently integrates available visual,chemosensory,and/or mechanoreceptive cues as part of their environmental adaptation.The blind cavefish morph of Astyanax mexicanus has developed sensory-dependent behaviors to find food more efficiently than their eyed,surface-morph counterparts while in darkness.In the absence of light,adult cavefish have evolved enhanced behaviors,such as vibration attraction behavior(VAB),and changes in feeding angle.Here,we identified evolved differences in cavefish larval prey capture(LPC)behavior.In the dark,LPC is more efficient in cavefish than in surface fish.Furthermore,different cave populations express laterality in their LPC and strike towards prey preferentially located on their left or right sides.This suggests the occurrence,to some extent,of divergent LPC evolution among cave populations.While LPC can be triggered exclusively by a vibration stimulus in both surface and cavefish,we provide evidence that LPC is,at least partially,a multimodal sensory process different from adult VAB.We also found that a lack of food may exacerbate the laterality of LPC.Thus,we proposed a mathematical model for explaining laterality based on a balance between:(1)enlarged range of foraging field(behavioral or perceptive)due to asymmetry,(2)food abundance,and(3)disadvantages caused by laterality(unequal lateral hydrodynamic resistance when swimming,allocation of resources for the brain and receptors,and predator escape).展开更多
基金funded by and undertaken on behalf of the Environment Agency Abu Dhabi(EAD)under a memorandum of understanding with Mongolia’s Ministry of Environment and Green Development(MEGD)supported by the National Natural Science Foundation of China(31930013,32361133559)+1 种基金the Third Xinjiang Scientifc Expedition Program(grant no.2022xjkk0801)the CASTWAS President’s Fellowship Programme(BB).
文摘As an apex predator in arid steppe,saker falcon plays a crucial role in maintaining ecosystem balance.Understanding their movement patterns concerning conspecific competition and prey availability is important for their conservation.We aim to understand how movement pattern of breeding saker falcons relates to prey availability.Twelve adult sakers were tracked during the breeding seasons,using satellite transmitters.Throughout the breeding season,sakers exhibited territorial behavior,with minimal overlap in range use among neighboring conspecifics.Males occupied larger areas(mean=2,397 ha,median=1,221 ha),compared to females(mean=1,241 ha,median=554 ha),and it remained consistent throughout breeding season.Female home range size increased notably during a late nestling stage and post-fledging dependence periods,indicating release from brooding constraints.Notably,we found a negative relationship between male home range size and prey availability.In high rodent density areas,males occupied smaller areas(mean=1,135 ha,median=1,034 ha),contrasting with low rodent density areas(mean=6,815 ha,median=6,516 ha).However,no significant relationship was observed between female home range size and prey availability.We also noted instances of nest abandonment and early dispersal behavior in some females,potentially influenced by a handicapping effect of tagging.Our findings offer valuable insight into how prey availability shapes saker falcon space use and defines their spatial requirements for successful breeding.This knowledge is crucial for the conservation and management of globally endangered saker falcons,informing targeted habitat protection and resource management strategies.
基金supported by the National Natural Science Foundation of China(31900372)One Yangtze River Project of the Huatai Securities,and the State Key Laboratory of Biocontrol(Sun Yat-sen University).
文摘Religious wildlife release is prevalent worldwide,especially in Asia countries.It is one of the anthropogenic pathways to cause biological inva-sions.Religious fish release is common on the Qinghai-Tibetan Plateau,yet few studies have assessed the influences of religious fish release on local species.InYushu,a city on the Qinghai-Tibetan Plateau,we interviewedlocal people,conducted fish trap surveys in local rivers,and exam-ined the diet of Eurasian otters Lutra lutra using a fecal DNA metabarcoding approach.We found that fish release started at least in 1980-1990s in Yushu.Tibetan residents released fish in large amounts and released fish were usually exotic commercial fish purchased from market.Despite such long-term and intensive fish release activities,released fish were few in local rivers.On the other hand,Eurasian otters mainly prey on fish and released fish accounted for~20%of relative read abundance of prey DNA in otters'diet,indicating their high preference on released fish.Our study suggested that religious fish release may provide additional food resources for otters,whereas otters,as a top predator in local rivers,may deplete non-native fish once they were released and,therefore,reduce the probability of colonization of released fish,although further studies are required to assess otters'impact.Our study revealed otters'diet in Yushu,providing basic information for local otter management and conservation.Furthermore,it represents a case showing that native predators prey on religious released animals,implying a probable direction forcontrolling invasive species through nativepredator conservation.
文摘In this paper, the dynamical behaviors of a modified Leslie-Gower predator-prey model incorporating fear effect and prey refuge are investigated. We delve into the construction of the model and its biological significance, with preliminary results encompassing positivity, boundedness, and persistence. The stability of the system’s boundary and positive equilibrium points is proven by calculating the real part of the eigenvalues of the Jacobian matrix. At the positive equilibrium point, we demonstrate that the system’s unique positive equilibrium is globally asymptotically stable by using the Dulac criterion. Furthermore, at this equilibrium point, we employ the Implicit Function Theorem to discuss how fear effects and prey refuges influence the population densities of both prey and predators. Finally, numerical simulations are conducted to validate the above-mentioned conclusions and explored the impact of Predator-taxis sensitivity αon dynamics of the system.
文摘The effects of the variability of individual prey locomotory performance on the vulnerability to predation are poorly understood,partly because individual performance is difficult to determine in natural habitats.To gain insights into the role(s)of individual variation in predatory relationships,we study a convenient model system,the neotropical sandy beach gastropod Olivella semistriata and its main predator,the carnivorous snail Agaronia propatula.The largest size class of O.semistriata is known to be missing from A.propatula's spectrum of subdued prey,although the predator regularly captures much larger individuals of other taxa.To resolve this conundrum,we analyzed predation attempts in the wild.While A.propatula attacked O.semistriata of all sizes,large prey specimens usually escaped by'sculling',an accelerated,stepping mode of locomotion.Olivella semistriata performed sculling locomotion regardless of size,but sculling velocities determined in the natural environment increased strongly with size.Thus,growth in size as such does not establish a prey size refuge in which O.semistriata is safe from predation.Rather,a behaviorally mediated size refuge is created through the size-dependence of sculling performance.Taken together,this work presents a rare quantitative characterization in the natural habitat of the causal sequence from the size-dependence of individual performance,to the prey size-dependent outcome of predation attempts,to the size bias in the predator's prey spectrum.
文摘According to one of the theses of optimal foraging theory,main prey species abundance in the hunting area is the main factor determining the diet and habitat choices of birds of prey.However other factors can also be important.The habitat structure influences the predators’diets as well.In this study we examined the influence of habitat structure on diet compositions of three species of birds:Long-eared Owl(Asio otus),Short-eared Owl(A.flammeus)and Common Kestrel(Falco tinnunculus).The study was carried out from 2007 to 2019 in a 48 km2area of the Crane’s Homeland Reserve,Moscow Region,Russia.The habitat structures of model species’hunting territories(ratio of different types of landscape elements)were classified in module"Semi-Automatic Classification Plugin"based on the QGIS.A boosted regression tree analysis identified that the share of the main prey species in the diet is primarily determined by the landscape structure of hunting territories.The largest share of Common Vole(Microtus arvalis)in birds’diet was determined by the shrubs area(15%of hunting area),the meadow area(75%),the habitat heterogeneity(70%)and the arable land area(5%).The same predictors determined the largest share of Root Vole(Microtus oeconomus):the shrubs area 25%,the meadow area 70%,and the arable land area 3%.The annual mean abundance of prey species did not determine their importance in the diet of birds of prey.Thus,the main prey abundance in the hunting area is not a determining factor for the formation of diet composition of birds of prey.
文摘We formulate and analyze a predator-prey model followed by Leslie-Gower model in which the prey population is infected by disease. We assume that the disease can only spread over prey population. As a result prey population has been classified into two categories, namely susceptible prey, infected prey where as the predator population remains free from infection. To investigate the behaviour of prey population we incorporate prey refuge in this model. Since the prey refuge decreases the predation rate then it has an important effect in our predator-prey interaction model. We have discussed the existence of various equilibrium points and local stability analysis at those equilibrium points. We investigate the Hopf-bifurcation analysis about the interior equilibrium point by taking the rate of infection parameter and the prey refuge parameter as bifurcation parameters. The numerical analysis is carried out to support the analytical results and to discuss some interesting results that our model exhibits.
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.
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.
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.
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.
基金Supported by the National Natural Science Foundation of China(Nos.31200423,30970553)the National Special Research Fund for Non-Profit Sector(Agriculture)(No.201203081)the National Key Technology R&D Program of China(No.2015BAD13B02)
文摘The present study preliminarily examined the differences in maximum handling size, prey size and species selectivity of growth hormone transgenic and non-transgenic common carp Cyprinus carpio when foraging on four gastropods species( Bellamya aeruginosa, Radix auricularia, Parafossarulus sinensis and Alocinma longicornis) under laboratory conditions. In the maximum handling size trial, five fish from each age group(1-year-old and 2-year-old) and each genotype(transgenic and non-transgenic) of common carp were individually allowed to feed on B. aeruginosa with wide shell height range. The results showed that maximum handling size increased linearly with fish length, and there was no significant difference in maximum handling size between the two genotypes. In the size selection trial, three pairs of 2-year-old transgenic and non-transgenic carp were individually allowed to feed on three size groups of B. aeruginosa. The results show that the two genotypes of C. carpio favored the small-sized group over the large-sized group. In the species selection trial, three pairs of 2-year-old transgenic and non-transgenic carp were individually allowed to feed on thin-shelled B. aeruginosa and thick-shelled R. auricularia, and five pairs of 2-year-old transgenic and non-transgenic carp were individually allowed to feed on two gastropods species( P. sinensis and A. longicornis) with similar size and shell strength. The results showed that both genotypes preferred thin-shelled Radix auricularia rather than thick-shelled B. aeruginosa, but there were no significant difference in selectivity between the two genotypes when fed on P. sinensis and A. longicornis. The present study indicates that transgenic and non-transgenic C. carpio show similar selectivity of predation on the size-and species-limited gastropods. While this information may be useful for assessing the environmental risk of transgenic carp, it does not necessarily demonstrate that transgenic common carp might have lesser environmental impacts than non-transgenic carp.
文摘Snakes often have specialized diets that undergo a shift from one prey type to another depending on the life stage of the snake. Crotalus viridis viridis （prairie rattlesnake） takes different prey at different life stages, and neonates typically prey on ectotherms, while adults feed almost entirely on small endotherms. We hypothesized that elevated rates of tongue flicking to chemical stimuli should correlate with particular prey consumed, and that this response shifts from one prey type to another as in- dividuals age. To examine if an ontogenetic shift in response to chemical cues occurred, we recorded the rate of tongue flicking for 25 neonate, 20 subadult, and 20 adult （average SVL = 280.9, 552, 789.5 mm, respectively） wild-caught C. v. viridis to chemi- cal stimuli presented on a cotton-tipped applicator; water-soluble cues from two ectotherms （prairie lizard, Sceloporus undulatus, and house gecko, Hemidactylusfrenatus）, two endotherms （deer mouse, Peromyscus maniculatus and lab mouse, Mus musculus）, and water controls were used. Neonates tongue flicked significantly more to chemical cues of their common prey, S. undulatus, than to all other chemical cues; however, the response to this lizard＇s chemical cues decreased in adult rattlesnakes. Subadults tongue flicked with a higher rate of tongue flicking to both S. undulatus and P. maniculatus than to all other treatments, and adults tongue flicked significantly more to P. maniculatus than to all other chemical cues. In addition, all three sub-classes demonstrated a greater response for natural prey chemical cues over chemical stimuli of prey not encountered in the wild （M. musculus and H. frenatus）. This shift in chemosensory response correlated with the previously described ontogenetic shifts in C. v. viridis diet. Be-cause many vipers show a similar ontogenetic shift in diet and venom composition, we suggest that this shift in prey cue dis- crimination is likely a general phenomenon among viperid snakes.
基金Supported by the National Natural Science Foundation of China(195 310 70 )
文摘This paper deals with the questio n of global stability of the positive locally asymptotically stable equilibrium in a class of predator\|prey system of Gause\|typ e with Holling Ⅲ functional response. The Dulac's criterion is applied and lia punov functions are constructed to establish the global stability.
文摘By using the continuation theorem of coincidence degree theory, sufficient conditions are obtained for the existence of positive periodic solutions of a delayed predator prey system with nonmonotonic functional response in a periodic environment.
文摘Fish behavior can be altered by contaminants. There is an extensive literature on laboratory behavioral assays, with many chemicals impairing feeding or predator avoidance. However, there is not extensive work on fishes that live in contami- nated environments. Therefore, we then review our recent research on feeding and trophic relations of populations from contami- nated estuaries compared with relatively unpolluted sites. The mummichog Fundulus heteroclitus, is a non-migratory fish; those from more contaminated areas are poor predators and slower to capture active prey （grass shrimp, Palaemonetes pugio）. In the field, they consume much detritus and sediment, which is not nutritious. They are less active than fish from cleaner sites and more vulnerable to predation. They have altered thyroid glands and neurotransmitter levels, which may underlie altered behaviors Fish from the reference site kept in tanks with sediment and food from the polluted site showed bioaccumulation and reduced prey capture after two months, although fish from the polluted site did not show significant improvement when maintained in a clean environment. Poor nutrition and predator avoidance may be responsible for their being smaller and having a shorter life span than reference fish. Bluefish Pomatomus saltatrix, are a marine species in which the young-of-the-year spend their first summer in es- tuaries. We found bioaccumulation of contaminants and reduced activity, schooling, and feeding in young-of-the-year bluefish from a relatively unpolluted site that were fed prey fish from a contaminated site. They also had altered thyroid glands and neuro- transmitter levels. Many field-caught specimens had empty stomachs, which is rare in this species. In the fall, when they migrate back out to the ocean, they are smaller, slower, and more likely to starve or to be eaten than those that spent their summer in cleaner estuaries [Current Zoology 58 （1）： 9-20, 2012].
基金funded by German Sumbre at the Institut de Biologie de l’ENS (IBENS), CNRS, FranceSylvie Rétaux at the Paris-Saclay Institute of Neuroscience, CNRSUniversity Paris-Saclay, France
文摘Feeding strategies of an organism depend on the multimodal sensory processing that most efficiently integrates available visual,chemosensory,and/or mechanoreceptive cues as part of their environmental adaptation.The blind cavefish morph of Astyanax mexicanus has developed sensory-dependent behaviors to find food more efficiently than their eyed,surface-morph counterparts while in darkness.In the absence of light,adult cavefish have evolved enhanced behaviors,such as vibration attraction behavior(VAB),and changes in feeding angle.Here,we identified evolved differences in cavefish larval prey capture(LPC)behavior.In the dark,LPC is more efficient in cavefish than in surface fish.Furthermore,different cave populations express laterality in their LPC and strike towards prey preferentially located on their left or right sides.This suggests the occurrence,to some extent,of divergent LPC evolution among cave populations.While LPC can be triggered exclusively by a vibration stimulus in both surface and cavefish,we provide evidence that LPC is,at least partially,a multimodal sensory process different from adult VAB.We also found that a lack of food may exacerbate the laterality of LPC.Thus,we proposed a mathematical model for explaining laterality based on a balance between:(1)enlarged range of foraging field(behavioral or perceptive)due to asymmetry,(2)food abundance,and(3)disadvantages caused by laterality(unequal lateral hydrodynamic resistance when swimming,allocation of resources for the brain and receptors,and predator escape).
