To avoid unnecessary energy expenditures in territorial defense,many species(e.g.,insects,amphibians,birds,and mammals)have developed the capability to distinguish between different intruder types using visual,acousti...To avoid unnecessary energy expenditures in territorial defense,many species(e.g.,insects,amphibians,birds,and mammals)have developed the capability to distinguish between different intruder types using visual,acoustic,and/or chemical signals.Determining the mechanism used for intruder recognition is key to understanding the dynamics of territorial behaviors.In birds that use vocalizations for territorial defense,the frequency and duration of vocalizations or the familiarity with the intruder may be the main mechanism used for intruder recognition.Here,we conducted a playback experiment with territorial White-eared Ground-sparrows(Melozone leucotis),to analyze if territorial pairs recognize intruders using frequency and duration characteristics(a bird’s response is based on how structurally similar the intruders’duets are to their own)or by familiarity with the intruders(neighbors vs.non-neighbors).We focused on duets because this species uses duets exclusively for territorial defense.We broadcasted a duet from a territorial neighbor,two duets from non-neighbors(with different frequency and duration characteristics),and a duet from a control species in 39 territorial pair from three populations.During playback we measured five behavioral responses:latency of the first vocalization,latency of the approach to the speaker,time spent close the speaker(within 5 m),number of individuals that approached the speaker,and the number of vocalizations.We found that territorial White-eared Ground-sparrow pairs responded stronger to neighbors than non-neighbors,and this response is not influenced by duet duration or frequency characteristics.This result suggests that neighbors represent a greater territorial threat for White-eared Ground-sparrows than non-neighbors.Further work is necessary to understand how common this observation is for tropical species that defend small territories year-round.展开更多
The recent Xi-Modi informal meeting was a step toward deepening mutual trust When Indian troops trespassed into China’s Donglang area last June,it was almost impossible to imagine that several months later Indian Pri...The recent Xi-Modi informal meeting was a step toward deepening mutual trust When Indian troops trespassed into China’s Donglang area last June,it was almost impossible to imagine that several months later Indian Prime Minister Narendra Modi would be having a one-on-one meeting with Chinese展开更多
遵循导师利盖蒂(GyrgyLigeti,1923～2006)的教导,陈晓勇(1955～)始终避免进入一般概念的中国音乐或西方先锋派阵营。其音乐致力于探究单个声音的无限可能性。在作品《为小提琴和筝而作的二重奏》(Duet for Violinand Zheng,1989年)中,...遵循导师利盖蒂(GyrgyLigeti,1923～2006)的教导,陈晓勇(1955～)始终避免进入一般概念的中国音乐或西方先锋派阵营。其音乐致力于探究单个声音的无限可能性。在作品《为小提琴和筝而作的二重奏》(Duet for Violinand Zheng,1989年)中,作曲家使用了微分音调音,并着眼于碰撞性音响和特殊调音体系的内在回响。《逸》(Evapora,为小型室内乐队而作,1996年),体现了他对和谐及非和谐融合(harmonic/non-harmonic fusion)的并置的兴趣。他以极为简洁的方式和高度个性化的音乐语汇,揭示出一个包含有不同调音体系、调式、音响相互碰撞的多元世界,同时抓住了不同文化要素相互作用产生的张力与整合。展开更多
基金provided by the Vicerrectoria de Investigacion Universidad de Costa Rica through the project numbers B9123,B9469,and C1085。
文摘To avoid unnecessary energy expenditures in territorial defense,many species(e.g.,insects,amphibians,birds,and mammals)have developed the capability to distinguish between different intruder types using visual,acoustic,and/or chemical signals.Determining the mechanism used for intruder recognition is key to understanding the dynamics of territorial behaviors.In birds that use vocalizations for territorial defense,the frequency and duration of vocalizations or the familiarity with the intruder may be the main mechanism used for intruder recognition.Here,we conducted a playback experiment with territorial White-eared Ground-sparrows(Melozone leucotis),to analyze if territorial pairs recognize intruders using frequency and duration characteristics(a bird’s response is based on how structurally similar the intruders’duets are to their own)or by familiarity with the intruders(neighbors vs.non-neighbors).We focused on duets because this species uses duets exclusively for territorial defense.We broadcasted a duet from a territorial neighbor,two duets from non-neighbors(with different frequency and duration characteristics),and a duet from a control species in 39 territorial pair from three populations.During playback we measured five behavioral responses:latency of the first vocalization,latency of the approach to the speaker,time spent close the speaker(within 5 m),number of individuals that approached the speaker,and the number of vocalizations.We found that territorial White-eared Ground-sparrow pairs responded stronger to neighbors than non-neighbors,and this response is not influenced by duet duration or frequency characteristics.This result suggests that neighbors represent a greater territorial threat for White-eared Ground-sparrows than non-neighbors.Further work is necessary to understand how common this observation is for tropical species that defend small territories year-round.
文摘The recent Xi-Modi informal meeting was a step toward deepening mutual trust When Indian troops trespassed into China’s Donglang area last June,it was almost impossible to imagine that several months later Indian Prime Minister Narendra Modi would be having a one-on-one meeting with Chinese
文摘遵循导师利盖蒂(GyrgyLigeti,1923～2006)的教导,陈晓勇(1955～)始终避免进入一般概念的中国音乐或西方先锋派阵营。其音乐致力于探究单个声音的无限可能性。在作品《为小提琴和筝而作的二重奏》(Duet for Violinand Zheng,1989年)中,作曲家使用了微分音调音,并着眼于碰撞性音响和特殊调音体系的内在回响。《逸》(Evapora,为小型室内乐队而作,1996年),体现了他对和谐及非和谐融合(harmonic/non-harmonic fusion)的并置的兴趣。他以极为简洁的方式和高度个性化的音乐语汇,揭示出一个包含有不同调音体系、调式、音响相互碰撞的多元世界,同时抓住了不同文化要素相互作用产生的张力与整合。
