查看更多>>摘要：Certain traits of recipient environments,such as the availability of limiting resources,strongly de-termine the establishment success and spread of non-native species.These limitations may be overcome through behavioral plasticity,allowing them to exploit alternative resources.Here,we show how a secondary cavity nester bird,the rose-ringed parakeet Psittacula krameri,innovates its nesting behavior as a response to the shortage of tree cavities for nesting in its invasive range in Tenerife(Canary Islands).We observed that some breeding pairs excavated their own nest cavities in palms,thus becoming primary cavity nester,whereas others occupied nests built with wood sticks by another invasive species,the monk parakeet Myiopsitta monachus.The use of these novel nesting strategies increased the number of breeding pairs by up to 52％over 6years,contri-buting to a 128.8％increase of the whole population.Innovative nests were located at greater heights above ground and were more aggregated around conspecifics but did not result in greater breeding success than natural cavities.Occupation of monk parakeet colonies by rose-ringed para-keets also benefited the former species through a protective-nesting association against nest pred-ators.Our results show how an invasive species innovate nesting behaviors and increase nest-site availability in the recipient environment,thus facilitating its population growth and invasion pro-cess.Potential behavioral innovations in other invasive rose-ringed parakeet populations may be overlooked,and should be considered for effective management plans.
查看更多>>摘要：Several Asian natricine snakes of the genus Rhabdophis feed on toads and sequester steroidal car-diac toxins known as bufadienolides(BDs)from them.A recent study revealed that species of the Rhabdophis nuchalis Group ingest lampyrine fireflies to sequester BDs.Although several species of fireflies are distributed in the habitat of the R.nuchalis Group,only lampyrine fireflies,which have BDs,are included in the diet of these snakes.Thus,we hypothesized that the R.nuchalis Group chemically distinguishes fireflies that have BDs from those that do not have BDs.We also predicted that the R.nuchalis Group detects BDs as the chemical cue of toxin source.To test these predictions,we conducted 3 behavioral experiments using Rhabdophis chiwen,which belongs to the R.nuchalis Group.In the first experiment,R.chiwen showed a moderate tongue flicking re-sponse to cinobufagin,a compound of BDs.On the other hand,the snake showed a higher re-sponse to the chemical stimuli of lampyrine fireflies(BD fireflies)than those of lucioline fireflies(non-BD fireflies).In the second experiment,in which we provided live BD and non-BD fireflies,the snake voluntarily consumed only the former.In the third,a Y-maze experiment,the snake tended to select the chemical trail of BD fireflies more frequently than that of non-BD fireflies.These results demonstrated that R.chiwen discriminates BD fireflies from non-BD fireflies,but the prediction that BDs are involved in this discrimination was not fully supported.To identify the proximate mechanisms of the recognition of novel toxic prey in the R.nuchalis Group,further investigation is necessary.
查看更多>>摘要：While theory suggests that at conception the sex ratio should be balanced(1∶1),this can be variable across space and time in wild populations.Currently,studies of the environmental factors that regulate adult sex ratio(ASR)in species with different life history traits are scarce.Using capture-recapture over a year,we analyzed the influence of habitat type(forest and nonforest)and season(rainy and dry)on variation in ASR,male aggregation and the trajectory movement of 2 dung bee-tle species with different life history traits:Deltochilum mexicanum(a hornless roller species)and Dichotomius satanas(a tunneler species with horns on its head and thorax).We found opposite tendencies.The D.mexicanum population tends to be female-biased,but the population of D.sata-nas tends to be predominantly male,and observed values were not related to habitat type or sea-son.However,the 95％confidence intervals estimated were highly variable between seasons de-pending on habitat.On examining the monthly variation in ASR for both habitats,we found that it depends on the species.In addition,male aggregation differed between species depending on habitat type and season,and species movement patterns were closely related to their habitat prefe-rences.Based on our results,we argue that comparative population studies of species with differ-ent life history traits are necessary to understand the variation in demographic parameters as well as its ecological and evolutionary implications in the face of spatial and climatic environmental variation.
查看更多>>摘要：Large carrion is inhabited by highly variable and interactive communities of insects.Positive inter-actions in carrion insect communities have been recently the focus in carrion ecology.In contrast,competition between carrion insects is rather undervalued.Here we provide evidence that blow flies(Calliphoridae)and Necrodes beetles(Silphidae),dominant decomposers of large carcasses in terrestrial habitats,compete over carrion.By reanalyzing the results from 90 pig carcasses,we demonstrated that the contribution of the flies and the beetles to the decay was negatively related.The greater part of the large carrion pool was monopolized by blowflies,whereas Necrodes beetles abundantly colonized carcasses,on which blow flies were less effective as decomposers.In behav-ioral assays,we found that adult beetles killed 4 times more frequently feeding than postfeeding third instar larvae of the flies,with the large decrease in the killing frequency after the larvae reached the age of early third instar.Therefore,adult Necrodes beetles preferentially killed the lar-vae that were before or in their peak feeding.The study provides evidence that the interaction be-tween blow flies and Necrodes beetles is a combination of indirect exploitative effects of the flies and direct interference effects of the beetles(the mixed competition).
Felipe MONTALVAHector PAVéSDiego PéREZ-VENEGASKarin G BARRIENTOS E...
657-666页
查看更多>>摘要：Interspecific interactions are key drivers of individual and population-level fitness in a wide range of animals.However,in marine ecosystems,it is relatively unknown which biotic and abiotic fac-tors impact behavioral interactions between competing species.We assessed the impact of wea-ther,marine productivity,and population structure on the behavioral agonistic interactions be-tween South American fur seals(SAFSs),Arctocephalus australis,and South American sea lions(SASLs),Otaria byronia,in a breeding colony of SAFS.We hypothesized that agonistic interactions between SAFSs and SASLs respond to biotic and abiotic factors such as SAFS population struc-ture,marine productivity,and weather.We found that SASL and SAFS interactions almost always resulted in negative impacts on the social structure or reproductive success of the SAFS colony.SASL adult males initiated stampedes of SAFS and/or abducted and predated SAFS pups.Adult SAFS males abundance and severe weather events were negatively correlated with agonistic inter-actions between species.However,proxies for lower marine productivity such as higher sea sur-face temperature and lower catches of demerso-pelagic fish were the most important predictors of more frequent agonistic interactions between SAFS and SASL.Under the current scenario of de-cline in marine biomass due to global climate change and overfishing,agonistic interactions be-tween competing marine predators could increase and exacerbate the negative impacts of environ-mental change in these species.
查看更多>>摘要：The behavioral video recordings of the gray-backed shrike Lanius tephronotus revealed that parent birds eat the feces produced by their nestlings."Parental nutrition hypothesis"attributes the origin of this behavior to nutrition-recovery and cost-saving,respectively.However,the presence of us-able nutrients in the nestlings'feces is unknown because of traditional technology.In this study,we analyzed all the metabolites and the variations in the diversity and content of microbes in the feces of gray-backed shrike nestlings.We aimed to report the changes in microbes and metabolites with the age of nestlings and point out that the parent birds that eat the feces may gain potential nutrition benefits.The results showed that the relative abundances of Proteobacteria,Firmicutes,and Bacteroidota,changed significantly when the nestlings were 6 days old.The relative abundan-ces of 6 probiotics,which are involved in digestion,metabolism,and immunity-related physiologic-al functions,decreased in the nestlings'feces gradually with age;therefore,these probiotics may be obtained by parent birds upon ingestion of the feces of young nestlings.Among the metabolites that were detected,20 were lipids and some had a role in anti-parasitic functions and wound heal-ing;however,their relative contents decreased with age.These beneficial substances in the nest-lings'feces may stimulate the parents to swallow the feces.Moreover,there were many aromatic metabolites in the newly hatched nestlings'feces,but the content of bitter metabolites increased as they grew up.Therefore,our results are in accordance with the nutritional hypothesis.
查看更多>>摘要：Rapid learning in the young of most endothermic animals can be expected to be favored by natural selection because early independence reduces the period of vulnerability.Cases of comparatively slow juvenile development continue,therefore,to attract scientific attention.In most species of birds,including raptors,the young depend on their parents for some time after fledging for the pro-visioning of food and for protection while they learn to become nutritionally and otherwise inde-pendent.Among raptors,post-fledging dependence periods that exceed 6 months are exclusive to the largest species and these have reproductive cycles that exceed 12 months.By contrast,young of the medium-sized grey falcon Falco hypoleucos have been reported in close company with their parents up to 12 months after fledging,that is,at a time when the adults are expected to breed again.We investigated the occurrence and characteristics of prolonged adult-juvenile association relative to other falcons and similar-sized raptors.We found that the behavioral development of grey falcon young is extremely delayed,and that they even depend nutritionally on their parents for up to 12 months after fledging.We suggest that these 2 distinctive features are,ultimately,adaptations of the grey falcon to its extreme environment,Australia's arid and semi-arid zone,one of the hottest environments in the world.
查看更多>>摘要：Human activities involving noise emission can affect wild animals.European mink was exposed to road noise and human voice playbacks to analyze how sound intensity level and duration of both noises altered the time that individuals were active and if their fecal cortisol metabolite(FCM)levels varied.A Hierarchical Analysis Cluster was performed to establish 2 mink groups with respect to both noise source type:short duration/low intensity(SL)and long duration/high intensity(LH).We performed general linear mixed models to evaluate the variation in locomotor activity duration(s)and FCM(nanogram per gram)levels,respectively.The results showed both road noise and human voices decreased locomotor activity duration in SL more sharply compared with LH,and human voices were the triggers that induced the most pronounced response to both exposure con-ditions.FCM(ng/g)levels increased in SL compared with LH during road noise while the opposite happened during human voices.Differences based on sex and age of individuals were observed.In conclusion,noise characteristics given by the sound type determined the variations in locomotor activity duration while noise exposure level determined the variations in FCM(ng/g)levels.Attention should be paid to noisy activities(e.g.,recreational activities for visitors in protected nat-ural areas)and loud groups of people to conserve wildlife,especially noise sensitive species.
查看更多>>摘要：Distress calls,as a type of alarm call,play important roles in expressing bodily condition and convey-ing information concerning predation threats.In this study,we examined the communication via dis-tress calls in parent-offspring and inter-offspring interactions.First,we used playback of chick dis-tress calls of 2 sympatric breeders,the vinous-throated parrotbill Sinosuthora webbiana and the oriental reed warbler Acrocephalus orientalis,to the adults/chicks of these 2 species,respectively,and measured the responses of conspecifics or heterospecifics.The playback-to-chicks experiment showed that both species ofchicks reduced the number of begging calls and begging duration time as a response to conspecific/heterospecific distress calls compared with natural begging and back-ground noise controls.However,reed warbler chicks also reduced beak opening frequency in the re-sponse to conspecific distress calls compared with other playback stimuli.Second,the results of the playback-to-adults experiment showed that reed warbler adults could eavesdrop on distress calls of conspecific neighbors and sympatric heterospecifics.Furthermore,the nest-leaving behavior of reed warblers did not differ significantly when they heard the distress calls of conspecifics or parrotbills.Finally,reed warbler adults responded to heterospecific distress calls more quickly than to conspecif-ic distress calls,and parrotbill adults presented the same response.Our results supported the warn-kin hypothesis and show that chick distress calls play an important role in conveying risk and the con-dition of chicks to enhance individual fitness.In addition,we also found that eavesdropping on dis-tress calls is a congenital behavior that begins in the chick stage.
Robert PATCHETTPatrick STYLESJoanna ROBINs KINGAlexander N.G.KIRSCHEL...
708-715页
查看更多>>摘要：One possible hypothesis for the function of post-fledging dispersal is to locate a suitable future breeding area.This post-fledging period may be particularly important in migratory species because they have a limited period to gather information prior to autumn migration,and in protandrous spe-cies,males must quickly acquire a territory after returning from spring migration to maximize their fitness.Here we use color-ring resightings to investigate how the post-fledging dispersal movements of the Cyprus wheatear Oenanthe cypriaca,a small migratory passerine,relate to their first breeding territory the following year when they return from migration.We found that males established first breeding territories that were significantly closer to their post-fledging location than to their natal sites or to post-fledging locations of other conspecifics,but these patterns were not apparent in females.Our findings suggest that familiarity with potential breeding sites may be important for juveniles of migratory species,particularly for the sex that acquires and advertises breeding territo-ries.Exploratory dispersal prior to a migrant's first autumn migration may contribute toward its breeding success the following year,further highlighting the importance of early seasonal breeding on fitness and population dynamics more generally.
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