Urban green spaces and parks offer opportunities for retaining and increasing bird richness, diversity, and species abundance. However, urbanisation influences predator–prey interactions, leading to high predation ra...Urban green spaces and parks offer opportunities for retaining and increasing bird richness, diversity, and species abundance. However, urbanisation influences predator–prey interactions, leading to high predation rates in urban areas, in the UK notably through the presence of large populations of domestic cats and increased populations of synanthropic species, such as rats and squirrels. These high predation rates are assumed to be a significant cause of reproductive failure in birds. Some ecologists advocate for the use of buffer zones with reduced human influence to reduce potential hunting pressure in eco-sensitive areas. However, the buffer effect on predation rates of nesting birds in suburban areas is rarely investigated. In this study, we investigated how edge effects (how close nest sites are to housing) and nest height (i.e., ground vs. above-ground) affected nest predation rates in a suburban park using camera traps to monitor artificial nests containing quail eggs. Our hypothesis was that nests in the buffer area (<300 m inward from university boundary) and at low height would suffer higher predation rates than nests in the core area (>300 m from the university boundary) and at height, as the buffer zone effect, and ease of access to ground predators would result in higher predation rates. We found no significant effect of nest height in nest predation rates. However, contrary to our expectations, nests in the core zone suffered higher predation rates than those in the buffer zone, and corvids were responsible for almost half of the egg loss events. We speculate that this may be a consequence of higher levels of anthropogenic disturbance (e.g., pedestrians, dog walking, vehicles) adjacent to our buffer zone acting as a deterrent to avian nest predators. This work suggests that protecting urban sites from disturbance may not always act to support bird abundance.展开更多
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
[Objective] This study was conducted to explore the predation of Pardosa pseudoannulata and Pirata procurva_ on Plutela xylostela larvae. [Method] The quantities of P. xylostela larvae predated by the two spider speci...[Objective] This study was conducted to explore the predation of Pardosa pseudoannulata and Pirata procurva_ on Plutela xylostela larvae. [Method] The quantities of P. xylostela larvae predated by the two spider species at different temperatures and the quantities of P. xylostela larvae predated by P. pseudoannula-ta_in different volumes were analyzed. Based on three factors at five levels, the quadratic general regression rotation combination design was used to study the combined control effect of the two spider species on P. xylostela_larvae and the control effect of P. pseudoannulata on the larvae of P. xylostela and Spodoptera litura. [Result] The quantities of P. xylostela_ larvae predated by the two spider species increased first and then decreased with the increase of temperature, and the functional predation response of P. pseudoannulata and P. procurva_ on the fourth instar larvae of P. xylostela_fitted the Hol ing-Ⅱ model, and the Hol ing-Ⅲmodel could perfect the evaluation on the predation effect. Volume had great effect on the feeding of P. pseudoannulata. lnstantaneous attack ability （a’）, the time to handle one prey （Th） and predation function （a’/Th） in a smal er volume were al higher than that in a larger volume. The predation of the two spider species on P. xylostela_larvae was positively correlated with their densities. The overal effect of the three factors was： the density of P. xylostela＆gt;the density of P. procurva＆gt;the density of P. pseudoannulata. The densities of P. xylostela and S. litura larvae could affect the feeding amount of P. pseudoannulata. But there was no predation preference for P. pseudoannulata on the larvae of P. xylostela and S. litura. [Con-clusion] The results wil provide a reference for the evaluation of control effect of_P. xylostela_by P. pseudoannulata_and P. procurva in the field.展开更多
Predator–prey interactions are fundamental to understanding ecosystem stability and biodiversity.In this study,we propose and analyze a stochastic predator–prey model that incorporates two critical ecological factor...Predator–prey interactions are fundamental to understanding ecosystem stability and biodiversity.In this study,we propose and analyze a stochastic predator–prey model that incorporates two critical ecological factors:prey refuge and harvesting.The model also integrates disease transmission within the predator population,adding an important layer of realism.Using rigorous mathematical techniques,we demonstrate the existence and uniqueness of a global positive solution,thereby confirming the model's biological feasibility.We further derive sufficient conditions for two key ecological scenarios:stochastic permanence,which ensures the sustained co-existence of prey and predators over time,and extinction,where one or both populations decline to zero.The interplay between prey refuge and harvesting is thoroughly examined to understand their combined impact on population dynamics.All theoretical results are validated by detailed numerical simulations,highlighting the applicability of the model to real-world ecological systems.From the simulation results,we observed that with an adequate level of prey refuge and predator harvesting,the susceptible predator and prey coexist with extensive oscillations,while the infected predator population was moving towards extinction.In addition,we have investigated the effect of disease transmission on system dynamics.Our results show that,as the transmission rate of disease increases,the susceptible predator approaches extinction,whereas,on the other hand,when it declines,the susceptible predator shows robust oscillations while the infected approaches extinction.In both cases,the prey population demonstrates robust stability due to the prey refuge.Our findings show that the management of harvesting and the prey refuge can be effective ecological tactics for disease control and species protection under stochastic environmental effects.展开更多
To address the critical challenge of risk perception and assessment for autonomous vehicles in dynamic interactive envi-ronments,this study proposes a semi-supervised spatiotemporal interaction risk cognition network ...To address the critical challenge of risk perception and assessment for autonomous vehicles in dynamic interactive envi-ronments,this study proposes a semi-supervised spatiotemporal interaction risk cognition network with attention mecha-nism(SS-SIRCN),inspired by the behavioral adaptation patterns of biological groups under external threats.First,by thoroughly analyzing the dynamic interaction characteristics exhibited by typical biological collectives when exposed to risk,the study reveals the underlying patterns of trajectory changes influenced by external danger.Then,an attention-based spatiotemporal risk cognition network is designed to establish a mapping between driving behavior features and potential driving risks.Finally,a semi-supervised learning framework is employed to enable risk assessment for autono-mous vehicles using only a small amount of labeled data.Experimental results on real-world vehicle trajectory datasets demonstrate that the proposed method achieves a risk prediction accuracy of 90.76%,outperforming other baseline models in performance.展开更多
This paper proposes a new stochastic optimizer called the Colony Predation Algorithm(CPA)based on the corporate predation of animals in nature.CPA utilizes a mathematical mapping following the strategies used by anima...This paper proposes a new stochastic optimizer called the Colony Predation Algorithm(CPA)based on the corporate predation of animals in nature.CPA utilizes a mathematical mapping following the strategies used by animal hunting groups,such as dispersing prey,encircling prey,supporting the most likely successful hunter,and seeking another target.Moreover,the proposed CPA introduces new features of a unique mathematical model that uses a success rate to adjust the strategy and simulate hunting animals'selective abandonment behavior.This paper also presents a new way to deal with cross-border situations,whereby the optimal position value of a cross-border situation replaces the cross-border value to improve the algorithm's exploitation ability.The proposed CPA was compared with state-of-the-art metaheuristics on a comprehensive set of benchmark functions for performance verification and on five classical engineering design problems to evaluate the algorithm's efficacy in optimizing engineering problems.The results show that the proposed algorithm exhibits competitive,superior performance in different search landscapes over the other algorithms.Moreover,the source code of the CPA will be publicly available after publication.展开更多
The importance of predation risk as a key driver of evolutionary change is exemplified by the Northern Range in Trinidad, where research on guppies living in multiple parallel streams has pro- vided invaluable insight...The importance of predation risk as a key driver of evolutionary change is exemplified by the Northern Range in Trinidad, where research on guppies living in multiple parallel streams has pro- vided invaluable insights into the process of evolution by natural selection. Although Trinidadian guppies are now a textbook example of evolution in action, studies have generally categorized predation as a dichotomous variable, representing high or low risk. Yet, ecologists appreciate that community structure and the attendant predation risk vary substantially over space and time. Here, we use data from a longitudinal study of fish assemblages at 16 different sites in the Northern Range to quantify temporal and spatial variation in predation risk. Specifically we ask： 1） Is there evidence for a gradient in predation risk？ 2） Does the ranking of sites （by risk） change with the defi- nition of the predator community （in terms of species composition and abundance currency）, and 3） Are site rankings consistent over time？ We find compelling evidence that sites lie along a contin- uum of risk. However, site rankings along this gradient depend on how predation is quantified in terms of the species considered to be predators and the abundance currency is used. Nonetheless, for a given categorization and currency, rankings are relatively consistent over time. Our study sug- gests that consideration of predation gradients will lead to a more nuanced understanding of the role of predation risk in behavioral and evolutionary ecology. It also emphasizes the need to justify and report the definition of predation risk being used.展开更多
Since its 2018 invasion of eastern Asia,the fall armyworm Spodoptera frugiperda(Lepidoptera:Noctuidae)has become a key pest in local maize production.Though pesticides have been widely used to mitigate the initial S.f...Since its 2018 invasion of eastern Asia,the fall armyworm Spodoptera frugiperda(Lepidoptera:Noctuidae)has become a key pest in local maize production.Though pesticides have been widely used to mitigate the initial S.frugiperda attack,biological control is receiving ample attention as a desirable,environmentally-sound alternative to chemical control.Hoverflies(Diptera:Syrphidae)are abundant natural enemies in Chinese maize fields and have been observed to consume S.frugiperda larvae.In this study,we use laboratory assays to study the two-way interaction between immature stages of S.frugiperda and the endemic syrphid Eupeodes corollae.To mimic natural conditions,assays were performed in the presence of fresh maize leaves.Those 2 nd or 3 rd instar larvae of E.corollae preyed on 1 st and 2 nd instar S.frugiperda larvae with a Holling type III response,consuming a respective theoretical maximum of 43.48 and 83.33 larvae over a 24-h period.Conversely,once S.frugiperda larvae reached 3 rd instar,they exhibited aggressive behavior and equally preyed on syrphid larvae with a Holling type III response.Those 5 th and 6 th instar larvae of S.frugiperda consumed a respective 16.39-19.23,6.02-19.61 and 6.76-8.26 of 1 st,2 nd and 3 rd instar E.corollae larvae per day.Though our results await field-level validation,S.frugiperda agonistic(i.e.,defensive)and consumptive behavior towards resident natural enemies such as E.corollae possibly degrades biotic resistance and raises its invasion potential.Our findings shine new light on the interaction between lepidopteran herbivores and their natural enemies,and can help advance the development of conservation biological control and other integrated pest management(IPM)strategies against S.frugiperda in China and abroad.展开更多
Alien species are one of the most serious threats to the decline and extinction of native amphibian populations. In this study, we examined the predation of invasive Western Mosquitofish Gambusia affinis on the eggs, ...Alien species are one of the most serious threats to the decline and extinction of native amphibian populations. In this study, we examined the predation of invasive Western Mosquitofish Gambusia affinis on the eggs, embryos, and tadpoles of Duttaphrynus melanostictus and Pelophylax nigromaculatus in south China. Our results suggested that the survival of eggs and embryos remaining in the egg capsules of P. nigromaculatus and D. melanostictus was significantly higher than those removed from the egg capsule at 12-h intervals within 72 h in the presence of G. affinis. The survival of P. nigromaculatus eggs and embryos without egg capsules was significantly lower than those of D. melanostictus without egg capsules. The survival of P. nigromaculatus eggs and embryos with egg capsules was significantly higher than those of D. melanostictus with egg capsules from 24 h to 72 h except for 12 h. The survival of D. melanostictus tadpoles was significantly higher than that of P. nigromaculatus tadpoles in the presence of G. affinis. The survival of Gosner stage 26 tadpoles of P. nigromaculatus was significantly higher than that of Gosner stage 30 tadpoles from 12 h to 60 h, but there were no significant differences at 72 h. In contrast, the survival of Gosner stage 26 tadpoles of D. melanostictus was significantly lower than that of Gosner stage 30 tadpoles within 72 h, recording every 12 h. The increasing temperature caused a significant increase in predation by G. affinis on P. nigromaculatus eggs and embryos. The outer jelly capsule surrounding anurans eggs might serve as a mechanical defense against predation by G. affinis due to its large diameter, relatively stationary state and unpalatability. The differences in the vulnerability of P. nigromaculatus and D. melanostictus embryos and tadpoles to G. affinis probably due to differences in the unpalatability, black skin and activity. Based on the magnitude of predation by G. affinis on the eggs, embryos and tadpoles of these two species and the combined impact of temperature, we might speculate that invasive G. affinis and global warming would have more detrimental impacts on population viability of P. nigromaculatus than D. melanostictus in China.展开更多
There are many situations in which the ability of animals to distinguish between two similar looking objects can have significant selective consequences. For example, the objects that require discrimination may be edi...There are many situations in which the ability of animals to distinguish between two similar looking objects can have significant selective consequences. For example, the objects that require discrimination may be edible versus defended prey, predators versus non-predators, or mates of varying quality. Working from the premise that there are situations in which discrimi- nation may be more or less successful, we hypothesized that individuals find it more difficult to distinguish between stimuli when they encounter them sequentially rather than simultaneously. Our study has wide biological and psychological implications from the perspective of signal perception, signal evolution, and discrimination, and could apply to any system where individuals are making relative judgments or choices between two or more stimuli or signals. While this is a general principle that might seem intuitive, it has not been experimentally tested in this context, and is often not considered in the design of models or experiments, or in the interpretation of a wide range of studies. Our study is different from previous studies in psychology in that a） the level of similarity of stimuli are gradually varied to obtain selection gradients, and b） we discuss the implications of our study for specific areas in ecology, such as the level of perfection of mimicry in predator-prey systems. Our experiments provide evidence that it is indeed more difficult to distinguish between stimuli - and to learn to distinguish between stimuli - when they are encountered sequentially rather than simultaneously, even if the intervening time interval is short .展开更多
Sensory drive predicts that the conditions under which signaling takes place have large effects on signals, sensory systems, and behavior. The coupling of an ecological genetics approach with sen sory drive has been f...Sensory drive predicts that the conditions under which signaling takes place have large effects on signals, sensory systems, and behavior. The coupling of an ecological genetics approach with sen sory drive has been fruitful. An ecological genetics approach compares populations that experi ence different environments and asks whether population differences are adaptive and are the result of genetic and/or environmental variation. The multifaceted effects of signaling environ ments are wellexemplified by the bluefin killifish. In this system, males with blue anal fins are abundant in tanninstained swamps that lack UV/blue light but are absent in clear springs where UV/blue light is abundant. Past work indicates that lighting environments shape genetic and envir onmental variation in color patterns, visual systems, and behavior. Less is known about the select ive forces creating the across population correlations between UV/blue light and the abundance of blue males. Here, we present three new experiments that investigate the roles of lighting environ ments on male competition, female mate choice, and predation. We found strong effects of lighting environments on male competition where blue males were more likely to emerge as dominant in teastained water than in clear water. Our preliminary study on predation indicated that blue males may be less susceptible to predation in teastained water than in clear water. However, there was little evidence for female preferences favoring blue males. The resulting pattern is one where the effects of lighting environments on genetic variation and phenotypic plasticity match the direction of selection and favor the expression of blue males in swamps.展开更多
文摘Urban green spaces and parks offer opportunities for retaining and increasing bird richness, diversity, and species abundance. However, urbanisation influences predator–prey interactions, leading to high predation rates in urban areas, in the UK notably through the presence of large populations of domestic cats and increased populations of synanthropic species, such as rats and squirrels. These high predation rates are assumed to be a significant cause of reproductive failure in birds. Some ecologists advocate for the use of buffer zones with reduced human influence to reduce potential hunting pressure in eco-sensitive areas. However, the buffer effect on predation rates of nesting birds in suburban areas is rarely investigated. In this study, we investigated how edge effects (how close nest sites are to housing) and nest height (i.e., ground vs. above-ground) affected nest predation rates in a suburban park using camera traps to monitor artificial nests containing quail eggs. Our hypothesis was that nests in the buffer area (<300 m inward from university boundary) and at low height would suffer higher predation rates than nests in the core area (>300 m from the university boundary) and at height, as the buffer zone effect, and ease of access to ground predators would result in higher predation rates. We found no significant effect of nest height in nest predation rates. However, contrary to our expectations, nests in the core zone suffered higher predation rates than those in the buffer zone, and corvids were responsible for almost half of the egg loss events. We speculate that this may be a consequence of higher levels of anthropogenic disturbance (e.g., pedestrians, dog walking, vehicles) adjacent to our buffer zone acting as a deterrent to avian nest predators. This work suggests that protecting urban sites from disturbance may not always act to support bird abundance.
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.
基金Supported by the Science and Technology Innovation Program of Chinese Academy of Agricultural Sciences(ASTIP-IBFC09)Technical System of Vegetable Industry of Hunan Province+1 种基金National Natural Science Foundation of China(31501653)Earmarked fund for Modern Agro-industry Technology Research System of China(CARS-19-E09)~~
文摘[Objective] This study was conducted to explore the predation of Pardosa pseudoannulata and Pirata procurva_ on Plutela xylostela larvae. [Method] The quantities of P. xylostela larvae predated by the two spider species at different temperatures and the quantities of P. xylostela larvae predated by P. pseudoannula-ta_in different volumes were analyzed. Based on three factors at five levels, the quadratic general regression rotation combination design was used to study the combined control effect of the two spider species on P. xylostela_larvae and the control effect of P. pseudoannulata on the larvae of P. xylostela and Spodoptera litura. [Result] The quantities of P. xylostela_ larvae predated by the two spider species increased first and then decreased with the increase of temperature, and the functional predation response of P. pseudoannulata and P. procurva_ on the fourth instar larvae of P. xylostela_fitted the Hol ing-Ⅱ model, and the Hol ing-Ⅲmodel could perfect the evaluation on the predation effect. Volume had great effect on the feeding of P. pseudoannulata. lnstantaneous attack ability （a’）, the time to handle one prey （Th） and predation function （a’/Th） in a smal er volume were al higher than that in a larger volume. The predation of the two spider species on P. xylostela_larvae was positively correlated with their densities. The overal effect of the three factors was： the density of P. xylostela＆gt;the density of P. procurva＆gt;the density of P. pseudoannulata. The densities of P. xylostela and S. litura larvae could affect the feeding amount of P. pseudoannulata. But there was no predation preference for P. pseudoannulata on the larvae of P. xylostela and S. litura. [Con-clusion] The results wil provide a reference for the evaluation of control effect of_P. xylostela_by P. pseudoannulata_and P. procurva in the field.
基金supported by the National Natural Science Foundation of China(Grant No.32271554)the Guangdong Basic and Applied Basic Research Foundation(Grant No.2023A1515011501)。
文摘Predator–prey interactions are fundamental to understanding ecosystem stability and biodiversity.In this study,we propose and analyze a stochastic predator–prey model that incorporates two critical ecological factors:prey refuge and harvesting.The model also integrates disease transmission within the predator population,adding an important layer of realism.Using rigorous mathematical techniques,we demonstrate the existence and uniqueness of a global positive solution,thereby confirming the model's biological feasibility.We further derive sufficient conditions for two key ecological scenarios:stochastic permanence,which ensures the sustained co-existence of prey and predators over time,and extinction,where one or both populations decline to zero.The interplay between prey refuge and harvesting is thoroughly examined to understand their combined impact on population dynamics.All theoretical results are validated by detailed numerical simulations,highlighting the applicability of the model to real-world ecological systems.From the simulation results,we observed that with an adequate level of prey refuge and predator harvesting,the susceptible predator and prey coexist with extensive oscillations,while the infected predator population was moving towards extinction.In addition,we have investigated the effect of disease transmission on system dynamics.Our results show that,as the transmission rate of disease increases,the susceptible predator approaches extinction,whereas,on the other hand,when it declines,the susceptible predator shows robust oscillations while the infected approaches extinction.In both cases,the prey population demonstrates robust stability due to the prey refuge.Our findings show that the management of harvesting and the prey refuge can be effective ecological tactics for disease control and species protection under stochastic environmental effects.
基金the Jilin Provincial Department of Science and Technology Youth Science and Technology Talent Cultivation Project(20250602051RC)Fundamental Research Funds for the Central Universities(2025-JCXK-19)National Natural Science Foundation of China under Grant 52272417.
文摘To address the critical challenge of risk perception and assessment for autonomous vehicles in dynamic interactive envi-ronments,this study proposes a semi-supervised spatiotemporal interaction risk cognition network with attention mecha-nism(SS-SIRCN),inspired by the behavioral adaptation patterns of biological groups under external threats.First,by thoroughly analyzing the dynamic interaction characteristics exhibited by typical biological collectives when exposed to risk,the study reveals the underlying patterns of trajectory changes influenced by external danger.Then,an attention-based spatiotemporal risk cognition network is designed to establish a mapping between driving behavior features and potential driving risks.Finally,a semi-supervised learning framework is employed to enable risk assessment for autono-mous vehicles using only a small amount of labeled data.Experimental results on real-world vehicle trajectory datasets demonstrate that the proposed method achieves a risk prediction accuracy of 90.76%,outperforming other baseline models in performance.
基金This research was supported by the National Natural Science Foundation of China(62076185,U1809209).
文摘This paper proposes a new stochastic optimizer called the Colony Predation Algorithm(CPA)based on the corporate predation of animals in nature.CPA utilizes a mathematical mapping following the strategies used by animal hunting groups,such as dispersing prey,encircling prey,supporting the most likely successful hunter,and seeking another target.Moreover,the proposed CPA introduces new features of a unique mathematical model that uses a success rate to adjust the strategy and simulate hunting animals'selective abandonment behavior.This paper also presents a new way to deal with cross-border situations,whereby the optimal position value of a cross-border situation replaces the cross-border value to improve the algorithm's exploitation ability.The proposed CPA was compared with state-of-the-art metaheuristics on a comprehensive set of benchmark functions for performance verification and on five classical engineering design problems to evaluate the algorithm's efficacy in optimizing engineering problems.The results show that the proposed algorithm exhibits competitive,superior performance in different search landscapes over the other algorithms.Moreover,the source code of the CPA will be publicly available after publication.
文摘The importance of predation risk as a key driver of evolutionary change is exemplified by the Northern Range in Trinidad, where research on guppies living in multiple parallel streams has pro- vided invaluable insights into the process of evolution by natural selection. Although Trinidadian guppies are now a textbook example of evolution in action, studies have generally categorized predation as a dichotomous variable, representing high or low risk. Yet, ecologists appreciate that community structure and the attendant predation risk vary substantially over space and time. Here, we use data from a longitudinal study of fish assemblages at 16 different sites in the Northern Range to quantify temporal and spatial variation in predation risk. Specifically we ask： 1） Is there evidence for a gradient in predation risk？ 2） Does the ranking of sites （by risk） change with the defi- nition of the predator community （in terms of species composition and abundance currency）, and 3） Are site rankings consistent over time？ We find compelling evidence that sites lie along a contin- uum of risk. However, site rankings along this gradient depend on how predation is quantified in terms of the species considered to be predators and the abundance currency is used. Nonetheless, for a given categorization and currency, rankings are relatively consistent over time. Our study sug- gests that consideration of predation gradients will lead to a more nuanced understanding of the role of predation risk in behavioral and evolutionary ecology. It also emphasizes the need to justify and report the definition of predation risk being used.
基金supported by the earmarked fund for China Agriculture Research System(CARS-15-19)。
文摘Since its 2018 invasion of eastern Asia,the fall armyworm Spodoptera frugiperda(Lepidoptera:Noctuidae)has become a key pest in local maize production.Though pesticides have been widely used to mitigate the initial S.frugiperda attack,biological control is receiving ample attention as a desirable,environmentally-sound alternative to chemical control.Hoverflies(Diptera:Syrphidae)are abundant natural enemies in Chinese maize fields and have been observed to consume S.frugiperda larvae.In this study,we use laboratory assays to study the two-way interaction between immature stages of S.frugiperda and the endemic syrphid Eupeodes corollae.To mimic natural conditions,assays were performed in the presence of fresh maize leaves.Those 2 nd or 3 rd instar larvae of E.corollae preyed on 1 st and 2 nd instar S.frugiperda larvae with a Holling type III response,consuming a respective theoretical maximum of 43.48 and 83.33 larvae over a 24-h period.Conversely,once S.frugiperda larvae reached 3 rd instar,they exhibited aggressive behavior and equally preyed on syrphid larvae with a Holling type III response.Those 5 th and 6 th instar larvae of S.frugiperda consumed a respective 16.39-19.23,6.02-19.61 and 6.76-8.26 of 1 st,2 nd and 3 rd instar E.corollae larvae per day.Though our results await field-level validation,S.frugiperda agonistic(i.e.,defensive)and consumptive behavior towards resident natural enemies such as E.corollae possibly degrades biotic resistance and raises its invasion potential.Our findings shine new light on the interaction between lepidopteran herbivores and their natural enemies,and can help advance the development of conservation biological control and other integrated pest management(IPM)strategies against S.frugiperda in China and abroad.
基金funded by grants from the National Natural Science Foundation of China(31270443,31500329)the Science Foundation of Zhejiang Provincial Committee of Education(Y201534237)the Scientific Research Foundation of Ph.D.,Lishui University(QD1423)
文摘Alien species are one of the most serious threats to the decline and extinction of native amphibian populations. In this study, we examined the predation of invasive Western Mosquitofish Gambusia affinis on the eggs, embryos, and tadpoles of Duttaphrynus melanostictus and Pelophylax nigromaculatus in south China. Our results suggested that the survival of eggs and embryos remaining in the egg capsules of P. nigromaculatus and D. melanostictus was significantly higher than those removed from the egg capsule at 12-h intervals within 72 h in the presence of G. affinis. The survival of P. nigromaculatus eggs and embryos without egg capsules was significantly lower than those of D. melanostictus without egg capsules. The survival of P. nigromaculatus eggs and embryos with egg capsules was significantly higher than those of D. melanostictus with egg capsules from 24 h to 72 h except for 12 h. The survival of D. melanostictus tadpoles was significantly higher than that of P. nigromaculatus tadpoles in the presence of G. affinis. The survival of Gosner stage 26 tadpoles of P. nigromaculatus was significantly higher than that of Gosner stage 30 tadpoles from 12 h to 60 h, but there were no significant differences at 72 h. In contrast, the survival of Gosner stage 26 tadpoles of D. melanostictus was significantly lower than that of Gosner stage 30 tadpoles within 72 h, recording every 12 h. The increasing temperature caused a significant increase in predation by G. affinis on P. nigromaculatus eggs and embryos. The outer jelly capsule surrounding anurans eggs might serve as a mechanical defense against predation by G. affinis due to its large diameter, relatively stationary state and unpalatability. The differences in the vulnerability of P. nigromaculatus and D. melanostictus embryos and tadpoles to G. affinis probably due to differences in the unpalatability, black skin and activity. Based on the magnitude of predation by G. affinis on the eggs, embryos and tadpoles of these two species and the combined impact of temperature, we might speculate that invasive G. affinis and global warming would have more detrimental impacts on population viability of P. nigromaculatus than D. melanostictus in China.
文摘There are many situations in which the ability of animals to distinguish between two similar looking objects can have significant selective consequences. For example, the objects that require discrimination may be edible versus defended prey, predators versus non-predators, or mates of varying quality. Working from the premise that there are situations in which discrimi- nation may be more or less successful, we hypothesized that individuals find it more difficult to distinguish between stimuli when they encounter them sequentially rather than simultaneously. Our study has wide biological and psychological implications from the perspective of signal perception, signal evolution, and discrimination, and could apply to any system where individuals are making relative judgments or choices between two or more stimuli or signals. While this is a general principle that might seem intuitive, it has not been experimentally tested in this context, and is often not considered in the design of models or experiments, or in the interpretation of a wide range of studies. Our study is different from previous studies in psychology in that a） the level of similarity of stimuli are gradually varied to obtain selection gradients, and b） we discuss the implications of our study for specific areas in ecology, such as the level of perfection of mimicry in predator-prey systems. Our experiments provide evidence that it is indeed more difficult to distinguish between stimuli - and to learn to distinguish between stimuli - when they are encountered sequentially rather than simultaneously, even if the intervening time interval is short .
文摘Sensory drive predicts that the conditions under which signaling takes place have large effects on signals, sensory systems, and behavior. The coupling of an ecological genetics approach with sen sory drive has been fruitful. An ecological genetics approach compares populations that experi ence different environments and asks whether population differences are adaptive and are the result of genetic and/or environmental variation. The multifaceted effects of signaling environ ments are wellexemplified by the bluefin killifish. In this system, males with blue anal fins are abundant in tanninstained swamps that lack UV/blue light but are absent in clear springs where UV/blue light is abundant. Past work indicates that lighting environments shape genetic and envir onmental variation in color patterns, visual systems, and behavior. Less is known about the select ive forces creating the across population correlations between UV/blue light and the abundance of blue males. Here, we present three new experiments that investigate the roles of lighting environ ments on male competition, female mate choice, and predation. We found strong effects of lighting environments on male competition where blue males were more likely to emerge as dominant in teastained water than in clear water. Our preliminary study on predation indicated that blue males may be less susceptible to predation in teastained water than in clear water. However, there was little evidence for female preferences favoring blue males. The resulting pattern is one where the effects of lighting environments on genetic variation and phenotypic plasticity match the direction of selection and favor the expression of blue males in swamps.
