Mixed-species flocks of birds are distributed world-wide and can be especially dominant in temperate forests during the non-breeding season and in tropical rainforests year-round.We review from a community ecology per...Mixed-species flocks of birds are distributed world-wide and can be especially dominant in temperate forests during the non-breeding season and in tropical rainforests year-round.We review from a community ecology perspective what is known about the structure and organization of flocks,emphasizing that flocking species tend to be those particularly vulnerable to predation,and flocks tend to be led by species that are able to act as sources of information about predators for other species.Studies on how flocks respond to fragmentation and land-use intensification continue to accumulate,but the question of whether the flock phenomenon makes species more vulnerable to anthropogenic change remains unclear.We review the literature on flocks in East Asia and demonstrate there is a good foundation of knowledge on which to build.We then outline potentially fruitful future directions,focusing on studies that can investigate how dependent species are on each other in flocks,and how such interdependencies might affect avian habitat selection in the different types of human-modified environments of this region.展开更多
Although the Neotropical territorially dominant arboreal ant Azteca chartifex Forel is very aggressive towards any intruder,its populous colonies tolerate the close presence of the fierce polistine wasp Polybia reject...Although the Neotropical territorially dominant arboreal ant Azteca chartifex Forel is very aggressive towards any intruder,its populous colonies tolerate the close presence of the fierce polistine wasp Polybia rejecta(F.).In French Guiana,83.33%of the 48 P.rejecta nests recorded were found side by side with those of A.chartifex.This nesting association results in mutual protection from predators(i.e.,the wasps protected from army ants;the ants protected from birds).We conducted field studies,laboratorybased behavioral experiments and chemical analyses to elucidate the mechanisms allowing the persistence of this association.Due to differences in the cuticular profiles of the two species,we eliminated the possibility of chemical mimicry.Also,analyses of the carton nests did not reveal traces of marking on the envelopes.Because ant forager flows were not perturbed by extracts from the wasps’Dufour’s and venom glands,we rejected any hypothetical action of repulsive chemicals.Nevertheless,we noted that the wasps"scraped"the surface of the upper part of their nest envelope using their mandibles,likely removing the ants'scent trails,and an experiment showed that ant foragers were perturbed by the removal of their scent trails.This leads us to use the term"erasure hypothesis."Thus,this nesting association persists thanks to a relative tolerance by the ants towards wasp presence and the behavior of the wasps that allows them to"contain"their associated ants through the elimination of their scent trails,direct attacks,"wing-buzzing"behavior and ejecting the ants.展开更多
基金the 1000 Plan Recruitment Program of Global Experts of the People’s Republic of Chinathe Special Talent Recruitment Program of Guangxi University for support
文摘Mixed-species flocks of birds are distributed world-wide and can be especially dominant in temperate forests during the non-breeding season and in tropical rainforests year-round.We review from a community ecology perspective what is known about the structure and organization of flocks,emphasizing that flocking species tend to be those particularly vulnerable to predation,and flocks tend to be led by species that are able to act as sources of information about predators for other species.Studies on how flocks respond to fragmentation and land-use intensification continue to accumulate,but the question of whether the flock phenomenon makes species more vulnerable to anthropogenic change remains unclear.We review the literature on flocks in East Asia and demonstrate there is a good foundation of knowledge on which to build.We then outline potentially fruitful future directions,focusing on studies that can investigate how dependent species are on each other in flocks,and how such interdependencies might affect avian habitat selection in the different types of human-modified environments of this region.
基金this study was provided by an“Investissement d’Avenir”grant managed by the French Agence Nationale de la Recherche(CEBA,ref.ANR-10-LABX-25-01).
文摘Although the Neotropical territorially dominant arboreal ant Azteca chartifex Forel is very aggressive towards any intruder,its populous colonies tolerate the close presence of the fierce polistine wasp Polybia rejecta(F.).In French Guiana,83.33%of the 48 P.rejecta nests recorded were found side by side with those of A.chartifex.This nesting association results in mutual protection from predators(i.e.,the wasps protected from army ants;the ants protected from birds).We conducted field studies,laboratorybased behavioral experiments and chemical analyses to elucidate the mechanisms allowing the persistence of this association.Due to differences in the cuticular profiles of the two species,we eliminated the possibility of chemical mimicry.Also,analyses of the carton nests did not reveal traces of marking on the envelopes.Because ant forager flows were not perturbed by extracts from the wasps’Dufour’s and venom glands,we rejected any hypothetical action of repulsive chemicals.Nevertheless,we noted that the wasps"scraped"the surface of the upper part of their nest envelope using their mandibles,likely removing the ants'scent trails,and an experiment showed that ant foragers were perturbed by the removal of their scent trails.This leads us to use the term"erasure hypothesis."Thus,this nesting association persists thanks to a relative tolerance by the ants towards wasp presence and the behavior of the wasps that allows them to"contain"their associated ants through the elimination of their scent trails,direct attacks,"wing-buzzing"behavior and ejecting the ants.
