Brood parasitic birds lay eggs in the nests of other birds,and the parasitized hosts can reduce the cost of raising unrelated offspring through the recognition of parasitic eggs.Hosts can adopt vision-based cognitive ...Brood parasitic birds lay eggs in the nests of other birds,and the parasitized hosts can reduce the cost of raising unrelated offspring through the recognition of parasitic eggs.Hosts can adopt vision-based cognitive mechanisms to recognize foreign eggs by comparing the colors of foreign and host eggs.However,there is currently no uniform conclusion as to whether this comparison involves the single or multiple threshold decision rules.In this study,we tested both hypotheses by adding model eggs of different colors to the nests of Barn Swallows(Hirundo rustica)of two geographical populations breeding in Hainan and Heilongjiang Provinces in China.Results showed that Barn Swallows rejected more white model eggs(moderate mimetic to their own eggs)and blue model eggs(highly non-mimetic eggs with shorter reflectance spectrum)than red model eggs(highly nonmimetic eggs with longer reflectance spectrum).There was no difference in the rejection rate of model eggs between the two populations of Barn Swallows,and clutch size was not a factor affecting egg recognition.Our results are consistent with the single rejection threshold model.This study provides strong experimental evidence that the color of model eggs can has an important effect on egg recognition in Barn Swallows,opening up new avenues to uncover the evolution of cuckoo egg mimicry and explore the cognitive mechanisms underlying the visual recognition of foreign eggs by hosts.展开更多
Anthropogenic noise can affect a number of behavioral,physiological,and ecological aspects of animals from major taxonomic groups,raising serious conservation concerns.For example,noise pollution impacts communicative...Anthropogenic noise can affect a number of behavioral,physiological,and ecological aspects of animals from major taxonomic groups,raising serious conservation concerns.For example,noise pollution impacts communicative behavior and perception of signals,movements and distribution,as well as predator–prey interactions,such as hunting success or predator detection and predation risk assessment.We have carried out an experimental playback study,in which we investigated whether exposure to anthropogenic noise(sound of a tractor)distracts free-ranging barn swallows Hirundo rustica from paying attention to an approaching human“predator”(the“cognitive distraction”hypothesis),or whether noise leads to increased responsiveness to this“predator”(the“increased threat”hypothesis).The subjects were male barn swallows attending their breeding territories during the time when the females were incubating.We found that barn swallow males initiated fight at signifcantly greater distances to the approaching human“predator”in the noise treatment than during the quiet control trials.These results suggest that anthropogenic noise causes increased vigilance and reactivity rather than a distraction,enabling birds to avoid the“predator”more quickly.We further discuss the mechanism behind the increased alertness in response to noise and contrast the“increased threat”mechanism,usually tested in previous studies,with an alternative“cognitive sensitization”mechanism.展开更多
Behavioral responses to environmental change are the mechanisms that allow for rapid phenotypic change preventing temporary or permanent damage and hence preventing reductions in fitness. Extreme climatic events are b...Behavioral responses to environmental change are the mechanisms that allow for rapid phenotypic change preventing temporary or permanent damage and hence preventing reductions in fitness. Extreme climatic events are by definition rare, although they are predicted to increase in amplitude and frequency in the coming years. However, our current knowledge about behavioral responses to such extreme events is scarce. Here I analyze two examples of the effects of extreme weather events on behavior and life history： （1） A comparison of behavior and life history during extremely warm and extremely cold years relative to normal years; and （2） a comparison of behavior before and after the extremely early snowfall in fall 1974 when numerous birds died in the Alps during September-October. Behavioral and life history responses of barn swallows Hirundo rustica to extremely cold and extremely warm years were positively correlated, with particularly large effect sizes in cold years. Extreme mortality in barn swallows during fall migration 1974 in the Alps eliminated more than 40% of the breeding population across large areas in Central and Northern Europe, and this affected first arrival date, changes in timing and extent of reproduction and changes in degree of breeding sociality supposedly as a consequence of correlated responses to selection. Finally, I provide directions for research that will allow us to better understand behavior and life history changes in response to extreme climate change [Current Zoology 57 （3）： 351-362, 2011].展开更多
Microorganisms on and within organisms are ubiquitous and interactions with their hosts range from mutualistic over commensal, to pathogenic. We hypothesized that microorganisms might affect the ability of barn swallo...Microorganisms on and within organisms are ubiquitous and interactions with their hosts range from mutualistic over commensal, to pathogenic. We hypothesized that microorganisms might affect the ability of barn swallows Hirundo rustica to escape from potential predators, with positive associations between the abundance of microorganisms and escape ability implying mutualistic effects, while negative associations would imply antagonistic effects. We quantified escape behavior as the ability to avoid capture in a mist net and hence as a small number of recaptures. Because recapture probability may also depend on timing of reproduction and reproductive success, we also tested whether the association between recapture and microorganisms was mediated by an association between recapture and life history. We found intermediate to strong positive relationships between recapture probability and abundance of Bacillus megaterium, but not abundance of other bacteria or fungi. The abundance of B. megaterium was associated with an advance in laying date and an increase in reproductive success. However, these effects were independent of the number of recaptures. This interpretation is supported by the fact that there was no direct correlation between laying date and reproductive success on one hand and the number of recaptures on the other. These findings have implications not only for predator-prey interactions, but also for capture-mark-recapture analyses of vital rates such as survival and dispersal.展开更多
基金supported by the National Natural Science Foundation of China(Nos.31970427 and 32270526 to W.L.)。
文摘Brood parasitic birds lay eggs in the nests of other birds,and the parasitized hosts can reduce the cost of raising unrelated offspring through the recognition of parasitic eggs.Hosts can adopt vision-based cognitive mechanisms to recognize foreign eggs by comparing the colors of foreign and host eggs.However,there is currently no uniform conclusion as to whether this comparison involves the single or multiple threshold decision rules.In this study,we tested both hypotheses by adding model eggs of different colors to the nests of Barn Swallows(Hirundo rustica)of two geographical populations breeding in Hainan and Heilongjiang Provinces in China.Results showed that Barn Swallows rejected more white model eggs(moderate mimetic to their own eggs)and blue model eggs(highly non-mimetic eggs with shorter reflectance spectrum)than red model eggs(highly nonmimetic eggs with longer reflectance spectrum).There was no difference in the rejection rate of model eggs between the two populations of Barn Swallows,and clutch size was not a factor affecting egg recognition.Our results are consistent with the single rejection threshold model.This study provides strong experimental evidence that the color of model eggs can has an important effect on egg recognition in Barn Swallows,opening up new avenues to uncover the evolution of cuckoo egg mimicry and explore the cognitive mechanisms underlying the visual recognition of foreign eggs by hosts.
基金This study was supported by the Cardinal Stefan Wyszyhski University in Warsaw(grant to P.M.).
文摘Anthropogenic noise can affect a number of behavioral,physiological,and ecological aspects of animals from major taxonomic groups,raising serious conservation concerns.For example,noise pollution impacts communicative behavior and perception of signals,movements and distribution,as well as predator–prey interactions,such as hunting success or predator detection and predation risk assessment.We have carried out an experimental playback study,in which we investigated whether exposure to anthropogenic noise(sound of a tractor)distracts free-ranging barn swallows Hirundo rustica from paying attention to an approaching human“predator”(the“cognitive distraction”hypothesis),or whether noise leads to increased responsiveness to this“predator”(the“increased threat”hypothesis).The subjects were male barn swallows attending their breeding territories during the time when the females were incubating.We found that barn swallow males initiated fight at signifcantly greater distances to the approaching human“predator”in the noise treatment than during the quiet control trials.These results suggest that anthropogenic noise causes increased vigilance and reactivity rather than a distraction,enabling birds to avoid the“predator”more quickly.We further discuss the mechanism behind the increased alertness in response to noise and contrast the“increased threat”mechanism,usually tested in previous studies,with an alternative“cognitive sensitization”mechanism.
文摘Behavioral responses to environmental change are the mechanisms that allow for rapid phenotypic change preventing temporary or permanent damage and hence preventing reductions in fitness. Extreme climatic events are by definition rare, although they are predicted to increase in amplitude and frequency in the coming years. However, our current knowledge about behavioral responses to such extreme events is scarce. Here I analyze two examples of the effects of extreme weather events on behavior and life history： （1） A comparison of behavior and life history during extremely warm and extremely cold years relative to normal years; and （2） a comparison of behavior before and after the extremely early snowfall in fall 1974 when numerous birds died in the Alps during September-October. Behavioral and life history responses of barn swallows Hirundo rustica to extremely cold and extremely warm years were positively correlated, with particularly large effect sizes in cold years. Extreme mortality in barn swallows during fall migration 1974 in the Alps eliminated more than 40% of the breeding population across large areas in Central and Northern Europe, and this affected first arrival date, changes in timing and extent of reproduction and changes in degree of breeding sociality supposedly as a consequence of correlated responses to selection. Finally, I provide directions for research that will allow us to better understand behavior and life history changes in response to extreme climate change [Current Zoology 57 （3）： 351-362, 2011].
文摘Microorganisms on and within organisms are ubiquitous and interactions with their hosts range from mutualistic over commensal, to pathogenic. We hypothesized that microorganisms might affect the ability of barn swallows Hirundo rustica to escape from potential predators, with positive associations between the abundance of microorganisms and escape ability implying mutualistic effects, while negative associations would imply antagonistic effects. We quantified escape behavior as the ability to avoid capture in a mist net and hence as a small number of recaptures. Because recapture probability may also depend on timing of reproduction and reproductive success, we also tested whether the association between recapture and microorganisms was mediated by an association between recapture and life history. We found intermediate to strong positive relationships between recapture probability and abundance of Bacillus megaterium, but not abundance of other bacteria or fungi. The abundance of B. megaterium was associated with an advance in laying date and an increase in reproductive success. However, these effects were independent of the number of recaptures. This interpretation is supported by the fact that there was no direct correlation between laying date and reproductive success on one hand and the number of recaptures on the other. These findings have implications not only for predator-prey interactions, but also for capture-mark-recapture analyses of vital rates such as survival and dispersal.
