Background: Resemblance to raptors such as hawks(Accipiter spp.) is considered to be an adaptive strategy of cuckoos(Cuculus spp.), which has evolved to protect cuckoos against host attacks. However, the effectiveness...Background: Resemblance to raptors such as hawks(Accipiter spp.) is considered to be an adaptive strategy of cuckoos(Cuculus spp.), which has evolved to protect cuckoos against host attacks. However, the effectiveness of the mimicry remains controversial, and is not yet fully studied for highly aggressive hosts.Methods: We evaluated the effectiveness of sparrowhawk(Accipiter nisus) mimicry by common cuckoos(Cuculus canorus) in oriental reed warblers(Acrocephaus orientalis), which are highly aggressive hosts. Using a both the single and the paired dummy experiment, defense behaviors and attack intensities of oriental reed warblers against common cuckoos, sparrowhawks and oriental turtle doves(Streptopelia orientalis) were assessed.Results: Oriental reed warblers exhibit strong nest defense behaviors, and such behaviors do not change with breeding stage(i.e., egg stage and nestling stage). Furthermore, assistance from conspecific helpers may increase attack intensities. However, they were deterred from mobbing overall by the presence of the hawk.Conclusions: Oriental reed warblers are able to distinguish cuckoos from harmless doves. However, they may be deterred from mobbing by the presence of the predatory hawk, suggesting hawk mimicry may be ineffective and does not reduce attacks of cuckoos by highly aggressive hosts.展开更多
Many birds join cooperative mobbing aggregations and collectively harass predators. Individuals participating in these ephemeral associations benefit by deterring the predator, but also incur energetic costs and incre...Many birds join cooperative mobbing aggregations and collectively harass predators. Individuals participating in these ephemeral associations benefit by deterring the predator, but also incur energetic costs and increased risk of predation. Ex- plaining the evolution of mobbing is challenging because individuals could prevail by selfishly seeking safety while allowing others to mob. An important step in understanding the evolution of mobbing is to identify factors affecting its expression. The ecological constraints model suggests that animals are more likely to cooperate under adverse environmental conditions, such as when local predation pressure is high. We tested this prediction by comparing the mobbing responses of several species of birds to the local abundance of their primary predator, the ferruginous pygmy-owl Glaucidium brasilianum. We used acoustic playback to elicit mobbing responses in environments where owls were common, uncommon, or rare. Stimuli were either the song of a fer- ruginous pygmy-owl or the mobbing calls of three of the owl＇s common prey species. During each playback, we characterized mobbing responses by noting the number of species and individuals that approached the loudspeaker, as well as the closest ap- proach by any bird. Mobbing responses to both stimuli were strong in locations where Ferruginous Pygmy-owls were common, intermediate where owls were uncommon, and weak where they were rare. This pattern persisted even after controlling for dif- ferences in species richness and composition among the three environments. Results support the ecological constraints model and provide strong evidence that intense predation pressure increases the expression of cooperative mobbing in tropical birds [Cur- rent Zoology 58 （5）： 781-790, 2012].展开更多
The aim of this article is to explore the psychology of abusive human behavior with special attention to gaslighting, defamation of character, mockery, bullying, and mobbing, based on the so-far published scientific l...The aim of this article is to explore the psychology of abusive human behavior with special attention to gaslighting, defamation of character, mockery, bullying, and mobbing, based on the so-far published scientific literature, and my own experience and observations. Abusive human behavior can have various forms, but the motivation is almost always the same: power and control over the victim. Psychological abuse, especially if longer lasting, can cause serious psychological and even physical damage to the victim. Society should be more aware of the detrimental effects of abusive human behavior in its variety of forms and be ready to offer adequate medical, psychological and legal help for the victim.展开更多
Predation is an important source of natural selection on prey species and has resulted in adaptations such as antipredator vocal signals,which can alert others to the presence of predators and solicit cooperative atta...Predation is an important source of natural selection on prey species and has resulted in adaptations such as antipredator vocal signals,which can alert others to the presence of predators and solicit cooperative attack.Although vocal alarm signals of birds have been well studied,they are poorly known in tropical African species.To address this lack of information,the antipredatory signals and responses of two lapwings(Wattled Lapwing Vanellus senegallus and Spur-winged Lapwing Vanellus spinosus)to potential predators were investigated using data collected from focal observation,distance measurements,focal recordings,and playback experiment.The lapwing calls elicited to predators were classified as alarm or mobbing calls based on whether the calls elicited alert behavior or attack from other lapwings.Discriminant linear analysis(DLA)was used to compare the time and frequency parameters of the call types measured in Raven PRO.Also,lapwings’responses to intruders,alert and start distance,time of day,and latency,as well as the effects of flock size and distance to cover were examined.About 48%of all calls was correctly classified by DLA.The best predictors of call type for the lapwings were maximum frequency and high frequency.Both alarm and mobbing calls were elicited by African Wattled Lapwings to dogs and humans.Mobbing calls were elicited to intruders by the Spur-winged Lapwings.Alert distance was positively associated with start distance,and differed between morning and evening in both lapwings.With scarce information from tropical Africa,this study put in perspective vocal and antipredator behavior of lapwing species in Africa.展开更多
Nest predation and avian brood parasitism are the main sources of nest failure in many passerine birds.Large predators threaten both brood and parents,whereas brood parasites pose only a danger to eggs or nestlings.Th...Nest predation and avian brood parasitism are the main sources of nest failure in many passerine birds.Large predators threaten both brood and parents,whereas brood parasites pose only a danger to eggs or nestlings.The fan-tailed gerygone Gerygone flavolateralis from New Caledonia is subjected to high rates of nest predation by the New Caledonian crow Corvus moneduloides(responsible for about 20-40%of predation)and moderate rates of brood parasitism by the shining bronze-cuckoo Chalcites lucidus(parasitizing about 18%of nests),which also depredates nests that are too advanced for parasitism(13%of nests).To test if fan-tailed gerygones are able to discriminate predators from brood parasites,we presented 3 bird models at active gerygone nests:a brood parasite/small nest predator(shining bronze-cuckoo),a large nest predator(crow),and a small non-native bird(common chaffinch Fringilla coelebs),which is unknown to the gerygone,as a control.We assessed the response of adult gerygones to the presentation of each model by measuring the minimum approach distance,number of alarm calls,number of attacks,and time to first nest visit after the presentation(latency).Adult gerygones often attacked the cuckoo,approached but never attacked the chaffinch and always avoided the crow.Latency was shorter after an attack response and during brooding,but similar among models.We did not find any link between the cuckoo model presentation and later ejection of cuckoo nestlings.We conclude that adult fan-tailed gerygones discriminate between different models and respond accordingly to the level of threat but do not show awareness of parasitism risk and increase of nestling ejection rates following exposure to the cuckoo model.展开更多
Mobbing behavior is an important and widespread antipredatory behavior. This is a well-known behavior especially in birds. There are many studies about mobbing in birds, and most of them use owls as a model of predato...Mobbing behavior is an important and widespread antipredatory behavior. This is a well-known behavior especially in birds. There are many studies about mobbing in birds, and most of them use owls as a model of predator. However it is not clear how mobbing works when a predator assume a role of a prey. In this paper we organize field observations, which were taken on records of mobbing behaviors performed by owls or by other animals against them. These observations were collected nearby four Brazilian cities in South-Eastern and Central Brazil： Joao Monlevade / MG, Sacramento / MG Baguari / MG and Cacu / GO. Events of mobbing behavior have always involved prey（s） and predator（s） thus, in this study we presents mobbing events which species of owl always were involved, and beside the owls, other animals like mammals or raptors. These records are important due to their infrequency and problems to be detected in natural field conditions. It is rare mobbing events when an owl assumes a role of a prey, and there are few studies that show the mobbing by the predator optics. The present data may contribute for elucidation of mobbing behavior intrinsic aspects.展开更多
Understanding the factors that facilitate the emergence of cooperation among organisms is central to the study of social evolution. Spotted hyenas Crocuta crocuta frequently cooperate to mob lions Panthera leo, approa...Understanding the factors that facilitate the emergence of cooperation among organisms is central to the study of social evolution. Spotted hyenas Crocuta crocuta frequently cooperate to mob lions Panthera leo, approaching the lions as a tightknit group while vocalizing loudly in an attempt to overwhelm them and drive them away. Whereas cooperative mobbing behavior has been well documented in birds and some mammals, to our knowledge it has never been described during interactions between 2 apex predators. Using a 27-year dataset, we characterize lion-hyena encoun- ters, assess rates of mobbing behavior observed during these interactions, and inquire whether mobbing results in successful acquisition of food. Lions and hyenas interacted most often at fresh kills, especially as prey size and the number of hyenas present increased. Possession of food at the beginning of an interaction positively affected retention of that food by each predator species. The presence of male lions increased the probability of an interspecific interaction but decreased the likelihood of hyenas obtaining or retaining possession of the food. Hyena mobbing rates were highest at fresh kills, but lower when adult male lions were present. The occurrence of mobbing was predicted by an increase in the number of hyenas present. Whether or not mobbing resulted in acquisition of food from lions was predicted by an increase in the number of mobs formed by the hyenas present, suggesting that cooperation among hyenas enhances their fitness.展开更多
Mobbing has been defined as a chronic asymmetric pattern of power relations and a consequent conflict transformed into a systematic discrimination or mistreatment at workplace which is expressed through unethical or a...Mobbing has been defined as a chronic asymmetric pattern of power relations and a consequent conflict transformed into a systematic discrimination or mistreatment at workplace which is expressed through unethical or aggressive communication （Leynman, 1996）. Mobbing occurs when an employee in the workplace is steadily subjected to aggressive behavior from more than one colleague or supervisor over a period of time, in a situation where the target finds it difficult to defend him/herself to escape this dire situation. Such a long term incivility tends to stigmatize the mobbed victim and may cause severe psychological trauma since （s）he is metaphorically in a straitjacket. In this double-bind and double-squeeze condition where （s）he can neither get out of the situation nor endure the ordeal, a positive outcome is unlikely. How do we differentiate mobbing from conflict in organizations and how are disputes converted into mobbing behavior, and if one may even do research on mobbing in a culture of＂organizational silence＂ and ＂obedience/submission＂ in a developing country will be the first theoretical research question. Whether systemic silence as a collective level phenomenon is not only an obstacle to healthy organizational communication and relationships, but also a serious barrier to development, participation and learning from malpractices is another relevant question. Most researches investigating the background of mobbing are based on either experiences of targets as victims or the critical cases including the perpetrators as mobber; Therefore, the findings are often at individual level and subjective. They are often ＂ex post facto＂ analysis of psychological dimensions （e.g., personality characteristics of mostly of mobbed victims and rarely of mobbers） or legal dimensions. There are few ＂ex ante＂ analyses of organizational culture dimensions so that preventive measures may be taken prior to any serious mobbing case is reported. This paper＇s objective is to approach mobbing as a展开更多
Two-dimensional(2D)MoB metal borides(MoB MBene)have attracted much attention due to their fascinating properties and functional applications.So far,work on the synthesis of 2D MoB nanosheets by acid or alkaline etchin...Two-dimensional(2D)MoB metal borides(MoB MBene)have attracted much attention due to their fascinating properties and functional applications.So far,work on the synthesis of 2D MoB nanosheets by acid or alkaline etching of MoAlB has not been very successful.It has been proposed that the 2D MoB MBene may be fabricated by chemical etching of a Mo_(2)AlB_(2) precursor,but further investigations were not performed possibly due to the difficult preparation of the metastable Mo_(2)AlB_(2) compound at high temperatures by solid-state reactions.Here,we report on the successful synthesis of the Mo_(2)AlB_(2) compound and 2D MoB nanosheets by the deintercalation of Al from MoAlB through a ZnCl_(2) molten salt etching approach at relatively low temperatures.The influence of etching temperature,etching time,and starting mixtures on the formation of desirable phases have been investigated.A pure Mo_(2)AlB_(2) compound was synthesized at temperatures below 600℃,while the 2D MoB MBene nanosheets were obtained at 700℃through the molten salt etching of MoAlB.In addition,the present work further confirms that the MoB MBene can be prepared by etching the as-synthesized Mo_(2)AlB_(2) precursor in LiF–HCl solution.Our work demonstrates that the molten salt etching is an effective method to prepare 2D MoB MBene.展开更多
基金supported by the National Natural Science Foundation of China(Nos.31672303 to CY,31472013 and 31772453 to WL)
文摘Background: Resemblance to raptors such as hawks(Accipiter spp.) is considered to be an adaptive strategy of cuckoos(Cuculus spp.), which has evolved to protect cuckoos against host attacks. However, the effectiveness of the mimicry remains controversial, and is not yet fully studied for highly aggressive hosts.Methods: We evaluated the effectiveness of sparrowhawk(Accipiter nisus) mimicry by common cuckoos(Cuculus canorus) in oriental reed warblers(Acrocephaus orientalis), which are highly aggressive hosts. Using a both the single and the paired dummy experiment, defense behaviors and attack intensities of oriental reed warblers against common cuckoos, sparrowhawks and oriental turtle doves(Streptopelia orientalis) were assessed.Results: Oriental reed warblers exhibit strong nest defense behaviors, and such behaviors do not change with breeding stage(i.e., egg stage and nestling stage). Furthermore, assistance from conspecific helpers may increase attack intensities. However, they were deterred from mobbing overall by the presence of the hawk.Conclusions: Oriental reed warblers are able to distinguish cuckoos from harmless doves. However, they may be deterred from mobbing by the presence of the predatory hawk, suggesting hawk mimicry may be ineffective and does not reduce attacks of cuckoos by highly aggressive hosts.
文摘Many birds join cooperative mobbing aggregations and collectively harass predators. Individuals participating in these ephemeral associations benefit by deterring the predator, but also incur energetic costs and increased risk of predation. Ex- plaining the evolution of mobbing is challenging because individuals could prevail by selfishly seeking safety while allowing others to mob. An important step in understanding the evolution of mobbing is to identify factors affecting its expression. The ecological constraints model suggests that animals are more likely to cooperate under adverse environmental conditions, such as when local predation pressure is high. We tested this prediction by comparing the mobbing responses of several species of birds to the local abundance of their primary predator, the ferruginous pygmy-owl Glaucidium brasilianum. We used acoustic playback to elicit mobbing responses in environments where owls were common, uncommon, or rare. Stimuli were either the song of a fer- ruginous pygmy-owl or the mobbing calls of three of the owl＇s common prey species. During each playback, we characterized mobbing responses by noting the number of species and individuals that approached the loudspeaker, as well as the closest ap- proach by any bird. Mobbing responses to both stimuli were strong in locations where Ferruginous Pygmy-owls were common, intermediate where owls were uncommon, and weak where they were rare. This pattern persisted even after controlling for dif- ferences in species richness and composition among the three environments. Results support the ecological constraints model and provide strong evidence that intense predation pressure increases the expression of cooperative mobbing in tropical birds [Cur- rent Zoology 58 （5）： 781-790, 2012].
文摘The aim of this article is to explore the psychology of abusive human behavior with special attention to gaslighting, defamation of character, mockery, bullying, and mobbing, based on the so-far published scientific literature, and my own experience and observations. Abusive human behavior can have various forms, but the motivation is almost always the same: power and control over the victim. Psychological abuse, especially if longer lasting, can cause serious psychological and even physical damage to the victim. Society should be more aware of the detrimental effects of abusive human behavior in its variety of forms and be ready to offer adequate medical, psychological and legal help for the victim.
基金funding(No.217)from the A.P.Leventis Foundation Scholarship(to F.R.J).
文摘Predation is an important source of natural selection on prey species and has resulted in adaptations such as antipredator vocal signals,which can alert others to the presence of predators and solicit cooperative attack.Although vocal alarm signals of birds have been well studied,they are poorly known in tropical African species.To address this lack of information,the antipredatory signals and responses of two lapwings(Wattled Lapwing Vanellus senegallus and Spur-winged Lapwing Vanellus spinosus)to potential predators were investigated using data collected from focal observation,distance measurements,focal recordings,and playback experiment.The lapwing calls elicited to predators were classified as alarm or mobbing calls based on whether the calls elicited alert behavior or attack from other lapwings.Discriminant linear analysis(DLA)was used to compare the time and frequency parameters of the call types measured in Raven PRO.Also,lapwings’responses to intruders,alert and start distance,time of day,and latency,as well as the effects of flock size and distance to cover were examined.About 48%of all calls was correctly classified by DLA.The best predictors of call type for the lapwings were maximum frequency and high frequency.Both alarm and mobbing calls were elicited by African Wattled Lapwings to dogs and humans.Mobbing calls were elicited to intruders by the Spur-winged Lapwings.Alert distance was positively associated with start distance,and differed between morning and evening in both lapwings.With scarce information from tropical Africa,this study put in perspective vocal and antipredator behavior of lapwing species in Africa.
基金This study was funded by the National Science Centre,Poland,NCN 2016/23/B/NZ8/03082.
文摘Nest predation and avian brood parasitism are the main sources of nest failure in many passerine birds.Large predators threaten both brood and parents,whereas brood parasites pose only a danger to eggs or nestlings.The fan-tailed gerygone Gerygone flavolateralis from New Caledonia is subjected to high rates of nest predation by the New Caledonian crow Corvus moneduloides(responsible for about 20-40%of predation)and moderate rates of brood parasitism by the shining bronze-cuckoo Chalcites lucidus(parasitizing about 18%of nests),which also depredates nests that are too advanced for parasitism(13%of nests).To test if fan-tailed gerygones are able to discriminate predators from brood parasites,we presented 3 bird models at active gerygone nests:a brood parasite/small nest predator(shining bronze-cuckoo),a large nest predator(crow),and a small non-native bird(common chaffinch Fringilla coelebs),which is unknown to the gerygone,as a control.We assessed the response of adult gerygones to the presentation of each model by measuring the minimum approach distance,number of alarm calls,number of attacks,and time to first nest visit after the presentation(latency).Adult gerygones often attacked the cuckoo,approached but never attacked the chaffinch and always avoided the crow.Latency was shorter after an attack response and during brooding,but similar among models.We did not find any link between the cuckoo model presentation and later ejection of cuckoo nestlings.We conclude that adult fan-tailed gerygones discriminate between different models and respond accordingly to the level of threat but do not show awareness of parasitism risk and increase of nestling ejection rates following exposure to the cuckoo model.
文摘Mobbing behavior is an important and widespread antipredatory behavior. This is a well-known behavior especially in birds. There are many studies about mobbing in birds, and most of them use owls as a model of predator. However it is not clear how mobbing works when a predator assume a role of a prey. In this paper we organize field observations, which were taken on records of mobbing behaviors performed by owls or by other animals against them. These observations were collected nearby four Brazilian cities in South-Eastern and Central Brazil： Joao Monlevade / MG, Sacramento / MG Baguari / MG and Cacu / GO. Events of mobbing behavior have always involved prey（s） and predator（s） thus, in this study we presents mobbing events which species of owl always were involved, and beside the owls, other animals like mammals or raptors. These records are important due to their infrequency and problems to be detected in natural field conditions. It is rare mobbing events when an owl assumes a role of a prey, and there are few studies that show the mobbing by the predator optics. The present data may contribute for elucidation of mobbing behavior intrinsic aspects.
文摘Understanding the factors that facilitate the emergence of cooperation among organisms is central to the study of social evolution. Spotted hyenas Crocuta crocuta frequently cooperate to mob lions Panthera leo, approaching the lions as a tightknit group while vocalizing loudly in an attempt to overwhelm them and drive them away. Whereas cooperative mobbing behavior has been well documented in birds and some mammals, to our knowledge it has never been described during interactions between 2 apex predators. Using a 27-year dataset, we characterize lion-hyena encoun- ters, assess rates of mobbing behavior observed during these interactions, and inquire whether mobbing results in successful acquisition of food. Lions and hyenas interacted most often at fresh kills, especially as prey size and the number of hyenas present increased. Possession of food at the beginning of an interaction positively affected retention of that food by each predator species. The presence of male lions increased the probability of an interspecific interaction but decreased the likelihood of hyenas obtaining or retaining possession of the food. Hyena mobbing rates were highest at fresh kills, but lower when adult male lions were present. The occurrence of mobbing was predicted by an increase in the number of hyenas present. Whether or not mobbing resulted in acquisition of food from lions was predicted by an increase in the number of mobs formed by the hyenas present, suggesting that cooperation among hyenas enhances their fitness.
文摘Mobbing has been defined as a chronic asymmetric pattern of power relations and a consequent conflict transformed into a systematic discrimination or mistreatment at workplace which is expressed through unethical or aggressive communication （Leynman, 1996）. Mobbing occurs when an employee in the workplace is steadily subjected to aggressive behavior from more than one colleague or supervisor over a period of time, in a situation where the target finds it difficult to defend him/herself to escape this dire situation. Such a long term incivility tends to stigmatize the mobbed victim and may cause severe psychological trauma since （s）he is metaphorically in a straitjacket. In this double-bind and double-squeeze condition where （s）he can neither get out of the situation nor endure the ordeal, a positive outcome is unlikely. How do we differentiate mobbing from conflict in organizations and how are disputes converted into mobbing behavior, and if one may even do research on mobbing in a culture of＂organizational silence＂ and ＂obedience/submission＂ in a developing country will be the first theoretical research question. Whether systemic silence as a collective level phenomenon is not only an obstacle to healthy organizational communication and relationships, but also a serious barrier to development, participation and learning from malpractices is another relevant question. Most researches investigating the background of mobbing are based on either experiences of targets as victims or the critical cases including the perpetrators as mobber; Therefore, the findings are often at individual level and subjective. They are often ＂ex post facto＂ analysis of psychological dimensions （e.g., personality characteristics of mostly of mobbed victims and rarely of mobbers） or legal dimensions. There are few ＂ex ante＂ analyses of organizational culture dimensions so that preventive measures may be taken prior to any serious mobbing case is reported. This paper＇s objective is to approach mobbing as a
基金supported by the Fundamental Research Funds for the Central Universities(Grant No.2022YJS088)the National Natural Science Foundation of China(Grant No.52275171).
文摘Two-dimensional(2D)MoB metal borides(MoB MBene)have attracted much attention due to their fascinating properties and functional applications.So far,work on the synthesis of 2D MoB nanosheets by acid or alkaline etching of MoAlB has not been very successful.It has been proposed that the 2D MoB MBene may be fabricated by chemical etching of a Mo_(2)AlB_(2) precursor,but further investigations were not performed possibly due to the difficult preparation of the metastable Mo_(2)AlB_(2) compound at high temperatures by solid-state reactions.Here,we report on the successful synthesis of the Mo_(2)AlB_(2) compound and 2D MoB nanosheets by the deintercalation of Al from MoAlB through a ZnCl_(2) molten salt etching approach at relatively low temperatures.The influence of etching temperature,etching time,and starting mixtures on the formation of desirable phases have been investigated.A pure Mo_(2)AlB_(2) compound was synthesized at temperatures below 600℃,while the 2D MoB MBene nanosheets were obtained at 700℃through the molten salt etching of MoAlB.In addition,the present work further confirms that the MoB MBene can be prepared by etching the as-synthesized Mo_(2)AlB_(2) precursor in LiF–HCl solution.Our work demonstrates that the molten salt etching is an effective method to prepare 2D MoB MBene.
