Predator dummies are usually used to explore the impact of predator features on the anti-predator behavior of birds.Previous studies have shown that the morphology and behavior of aerial predators can signal different...Predator dummies are usually used to explore the impact of predator features on the anti-predator behavior of birds.Previous studies have shown that the morphology and behavior of aerial predators can signal different threat levels to birds.However,whether subtle changes in ground predator dummies cause changes in the nest defense behavior of parent birds is unclear.In this study,we aimed to investigate whether Japanese Tits(Parus minor)exhibit different nest defense behaviors in response to experimentally manipulated variations in the appearance,posture,and size of virtual snake proxies(common nest predators).During the incubation period,we observed the nest defense behaviors of the parent tits against taxidermized Siberian Ratsnakes(Elaphe schrenckii)with varied characteristics and rubber-made model snakes.The tits exhibited more intense responses to taxidermized large(body length about 120 cm)coiled ratsnakes than to large coiled model snakes.They exhibited weaker responses to taxidermized small(body length about 20 cm)coiled ratsnakes than to taxidermized small sinusoidal ratsnakes.In addition,they exhibited more intense responses to taxidermized large coiled ratsnakes than to taxidermized small coiled ratsnakes,and more intense responses to taxidermized small sinusoidal ratsnakes than to large model snakes.However,there was no difference in the response of tits to taxidermized small sinusoidal ratsnakes and taxidermized large coiled ratsnakes,or to taxidermized small coiled ratsnakes and model snakes.Thus,the presence of scales,a sinusoidal posture,and a large body size of snake dummies can induce more intense behavioral responses in Japanese Tits.We suggested that Japanese Tits can discriminate subtle differences in ground predator dummies of nests and exhibit different nest defense behaviors.展开更多
Birds’behavioral response to brood parasitism can be influenced not only by evolution but also by context and individual experience.This could include nest sanitation,in which birds remove debris from their nests.Ult...Birds’behavioral response to brood parasitism can be influenced not only by evolution but also by context and individual experience.This could include nest sanitation,in which birds remove debris from their nests.Ultimately,nest sanitation behavior might be an evolutionary precursor to the rejection of parasitic eggs.Proximately,the context or experience of performing nest sanitation behavior might increase the detection or prime the removal of parasitic eggs,but evidence to date is limited.We tested incubation-stage nests of herring gulls Larus argentatus to ask whether nest sanitation increased parasitic egg rejection.In an initial set of 160 single-object experiments,small,red,blocky objects were usually rejected(18 of 20 nests),whereas life-sized,3D-printed herring gull eggs were not rejected whether red(0 of 20)or the olive-tan base color of herring gull eggs(0 of 20).Next,we simultaneously presented a red,3D-printed gull egg and a small,red block.These nests exhibited frequent nest sanitation(small,red block removed at 40 of 48 nests),but egg rejection remained uncommon(5 of those 40)and not significantly different from control nests(5 of 49)which received the parasitic egg but not the priming object.Thus,performance of nest sanitation did not shape individuals’responses to parasitism.Interestingly,parents were more likely to reject the parasitic egg when they were present as we approached the nest to add the experimental objects.Depending on the underlying mechanism,this could also be a case of experience creating variation in responses to parasitism.展开更多
Native animals are facing long-term coexistence with invasive plants worldwide,the impacts of which on animal behavior remain poorly known.Potential ecological traps could threaten native birds breeding in invasive pl...Native animals are facing long-term coexistence with invasive plants worldwide,the impacts of which on animal behavior remain poorly known.Potential ecological traps could threaten native birds breeding in invasive plant habitats,but behavioral strategies for birds to avoid such risks are few concerned.The invasion of Smooth Cordgrass(Spartina alterniflra) has seriously varied the vegetation landscape in the coastal wetlands of eastern China,and affected the habitat selection of native birds.Here,we investigated the nesting and breeding characteristics of a common native passerine,the Vinous-throated Parrotbill(Sinosuthora webbiana),in habitats dominated by native Common Reed(Phragmites australis) and exotic cordgrass.We found that parrotbills could complete their breeding cycle in cordgrass habitat.Most nest failure was attributed to predation in native habitat but tide inundation in cordgrass habitat.However,the nest success rate and daily survival rate(DSR) in cordgrass habitat were higher.Moreover,nest height was markedly higher in cordgrass habitat and was the most important influencing variable(positively correlated with the DSR).These results suggest that cordgrass habitat is a potential ecological trap due to the tide inundation,but some parrotbills seem to effectively avoid this risk by increasing nest height.Our study reveals that a native passerine changes its nesting behavior to accommodate invasive plant habitat and highlights that habitat changes caused by invasive plants may drive the adaptive evolution of native animal behavior.The limitation of these results must be acknowledged for the small sample size,and there is a need for a larger sample and long-term data for further verification.展开更多
Behavioral divergence among populations is common across taxonomic groups,still we know very little about anti-predator behaviors.Animal exposure to predation risk is variable in different ecological contexts.In addit...Behavioral divergence among populations is common across taxonomic groups,still we know very little about anti-predator behaviors.Animal exposure to predation risk is variable in different ecological contexts.In addition,reproduction value of animals in different geographical regions usually varies.In this study,we tested whether cinereous tits Parus cinereus in different populations exhibited nest defense behaviors similar to those of nest or adult predators and whether their nest defense behaviors showed geographical variation.By using field dummy experiments,we observed tits’nest defense behavior in nest predator common chipmunk Tamias sibiricus and red squirrel Sciurus vulgaris,adult predator Eurasian sparrowhawk Accipiter nisus and nonthreatening species Oriental turtle dove Streptopelia orientalis in the ZJ(44°N),DZ(31°N),and DLS(18°N)populations,respectively.The response scores varied significantly across the 4 dummies in ZJ-tits and DLS-tits but did not in DZ-tits.When facing the chipmunk,ZJ-tits showed the highest response score and DZ-tits showed the lowest response score.When facing the squirrel,ZJ-tits showed a higher response score than tits in the other 2 populations.However,tits among the 3 populations responded similarly to a sparrowhawk or dove with slight response behaviors.In addition,response scores to nest predators were positively correlated with brood size across the 3 populations,but no trend was found for sparrowhawks or doves.Our results indicated that the nest defense behaviors of cinereous tits have evolved in response to large-scale geographical variation in ecological contexts and reproduction value.展开更多
Increases in extreme environmental events are predicted to be major results of ongoing global climate change and may impact the persistence of species.We examined the effects of heat and cold waves during embryonic de...Increases in extreme environmental events are predicted to be major results of ongoing global climate change and may impact the persistence of species.We examined the effects of heat and cold waves during embryonic development of painted turtles(Chrysemys picta)in natural nests on the occurrence of abnormal shell morphologies in hatchlings.We found that nests exposed to extreme hot temperatures for>60 h produced more hatchlings with abnormalities than nests exposed to extreme hot temperatures for shorter periods,regardless of whether or not nesting females displayed abnormal morphologies.We observed no effect of extreme cold nest temperatures on the occurrence of hatchlings with abnormalities.Moreover,the frequency of nesting females with abnormal shell morphologies was approximately 2-fold lower than that of their offspring,suggesting that such abnormalities are negatively correlated with survival and fitness.Female turtles could potentially buffer their offspring from extreme heat by altering aspects of nesting behavior,such as choosing shadier nesting sites.We addressed this hypothesis by examining the effects of shade cover on extreme nest temperatures and the occurrence of hatchling abnormalities.While shade cover was negatively correlated with the occurrence of extreme hot nest temperatures,it was not significantly correlated with abnormalities.Therefore,female choice of shade cover does not appear to be a viable target for selection to reduce hatchling abnormalities.Our results suggest that increases in the frequency and intensity of heat waves associated with climate change might perturb developmental programs and thereby reduce the fitness of entire cohorts of turtles.展开更多
Vertebrate embryos require access to water;however,many species nest in terrestrial habitats that vary considerably in moisture content.Oviparous,non-avian reptiles have served as models to understand how environmenta...Vertebrate embryos require access to water;however,many species nest in terrestrial habitats that vary considerably in moisture content.Oviparous,non-avian reptiles have served as models to understand how environmental factors,like moisture availability,influence development because eggs are often exposed to prevailing environments in the absence of parental care.Though much research demonstrates the importance of water absorption by eggs,many ecological factors that influence moisture availability in natural nests have received little attention.For example,the type of substrate in which nests are constructed is understudied.We experimentally incubated eggs of the brown anole lizard(Anolis sagrei)in 2 naturally occurring nest substrates that were treated with varying amounts of water to determine how natural substrates influence development at different moisture concentrations.One substrate consisted of sand and crushed seashells and the other was mostly organic material(i.e.decayed plant material).Both are common nesting substrates at our field site.When controlling for water uptake by eggs,we found that egg survival and hatchling phenotypes were similar between substrates;however,embryos developed more quickly in the sand/shell substrate than the organic substrate,indicating substrate-specific effects on embryo physiology.These results demonstrate that different natural substrates can result in similar developmental outcomes if the water available to eggs is comparable;however,some aspects of development,like developmental rate,are affected by the type of substrate,independent of water availability.Further study is required to determine how natural substrates influence embryo physiology independent of water content.展开更多
基金sponsored by National Natural Science Foundation of China(No.32271560 to H.W.,32001094 to J.Y.)Natural Science Foundation of Jilin Province,China(No.20230101160JC to L.J.)+1 种基金the Open Project of Ministry of Education Key Laboratory for Ecology of Tropical Islands,Hainan Normal University,China(No.HNSF-OP-202301 to J.Y.)the Fundamental Research Funds for the Central Universities(No.2412022ZD019 to J.Y.)。
文摘Predator dummies are usually used to explore the impact of predator features on the anti-predator behavior of birds.Previous studies have shown that the morphology and behavior of aerial predators can signal different threat levels to birds.However,whether subtle changes in ground predator dummies cause changes in the nest defense behavior of parent birds is unclear.In this study,we aimed to investigate whether Japanese Tits(Parus minor)exhibit different nest defense behaviors in response to experimentally manipulated variations in the appearance,posture,and size of virtual snake proxies(common nest predators).During the incubation period,we observed the nest defense behaviors of the parent tits against taxidermized Siberian Ratsnakes(Elaphe schrenckii)with varied characteristics and rubber-made model snakes.The tits exhibited more intense responses to taxidermized large(body length about 120 cm)coiled ratsnakes than to large coiled model snakes.They exhibited weaker responses to taxidermized small(body length about 20 cm)coiled ratsnakes than to taxidermized small sinusoidal ratsnakes.In addition,they exhibited more intense responses to taxidermized large coiled ratsnakes than to taxidermized small coiled ratsnakes,and more intense responses to taxidermized small sinusoidal ratsnakes than to large model snakes.However,there was no difference in the response of tits to taxidermized small sinusoidal ratsnakes and taxidermized large coiled ratsnakes,or to taxidermized small coiled ratsnakes and model snakes.Thus,the presence of scales,a sinusoidal posture,and a large body size of snake dummies can induce more intense behavioral responses in Japanese Tits.We suggested that Japanese Tits can discriminate subtle differences in ground predator dummies of nests and exhibit different nest defense behaviors.
基金supported by funds from the Arthur Vining Davis Foundation.
文摘Birds’behavioral response to brood parasitism can be influenced not only by evolution but also by context and individual experience.This could include nest sanitation,in which birds remove debris from their nests.Ultimately,nest sanitation behavior might be an evolutionary precursor to the rejection of parasitic eggs.Proximately,the context or experience of performing nest sanitation behavior might increase the detection or prime the removal of parasitic eggs,but evidence to date is limited.We tested incubation-stage nests of herring gulls Larus argentatus to ask whether nest sanitation increased parasitic egg rejection.In an initial set of 160 single-object experiments,small,red,blocky objects were usually rejected(18 of 20 nests),whereas life-sized,3D-printed herring gull eggs were not rejected whether red(0 of 20)or the olive-tan base color of herring gull eggs(0 of 20).Next,we simultaneously presented a red,3D-printed gull egg and a small,red block.These nests exhibited frequent nest sanitation(small,red block removed at 40 of 48 nests),but egg rejection remained uncommon(5 of those 40)and not significantly different from control nests(5 of 49)which received the parasitic egg but not the priming object.Thus,performance of nest sanitation did not shape individuals’responses to parasitism.Interestingly,parents were more likely to reject the parasitic egg when they were present as we approached the nest to add the experimental objects.Depending on the underlying mechanism,this could also be a case of experience creating variation in responses to parasitism.
基金the National Natural Science Foundation of China(32171526,32201267)Natural Science Foundation of Anhui Province(2208085QC71)the Key University Science Research Project of Anhui Province(KJ2020A0085,KJ2021A0128).
文摘Native animals are facing long-term coexistence with invasive plants worldwide,the impacts of which on animal behavior remain poorly known.Potential ecological traps could threaten native birds breeding in invasive plant habitats,but behavioral strategies for birds to avoid such risks are few concerned.The invasion of Smooth Cordgrass(Spartina alterniflra) has seriously varied the vegetation landscape in the coastal wetlands of eastern China,and affected the habitat selection of native birds.Here,we investigated the nesting and breeding characteristics of a common native passerine,the Vinous-throated Parrotbill(Sinosuthora webbiana),in habitats dominated by native Common Reed(Phragmites australis) and exotic cordgrass.We found that parrotbills could complete their breeding cycle in cordgrass habitat.Most nest failure was attributed to predation in native habitat but tide inundation in cordgrass habitat.However,the nest success rate and daily survival rate(DSR) in cordgrass habitat were higher.Moreover,nest height was markedly higher in cordgrass habitat and was the most important influencing variable(positively correlated with the DSR).These results suggest that cordgrass habitat is a potential ecological trap due to the tide inundation,but some parrotbills seem to effectively avoid this risk by increasing nest height.Our study reveals that a native passerine changes its nesting behavior to accommodate invasive plant habitat and highlights that habitat changes caused by invasive plants may drive the adaptive evolution of native animal behavior.The limitation of these results must be acknowledged for the small sample size,and there is a need for a larger sample and long-term data for further verification.
基金supported by the National Natural Science Foundation of China(no.32001094 to J.Y.,31770419 and 31971402 to H.W.,and 31772453 and 31970427 to W.L.).
文摘Behavioral divergence among populations is common across taxonomic groups,still we know very little about anti-predator behaviors.Animal exposure to predation risk is variable in different ecological contexts.In addition,reproduction value of animals in different geographical regions usually varies.In this study,we tested whether cinereous tits Parus cinereus in different populations exhibited nest defense behaviors similar to those of nest or adult predators and whether their nest defense behaviors showed geographical variation.By using field dummy experiments,we observed tits’nest defense behavior in nest predator common chipmunk Tamias sibiricus and red squirrel Sciurus vulgaris,adult predator Eurasian sparrowhawk Accipiter nisus and nonthreatening species Oriental turtle dove Streptopelia orientalis in the ZJ(44°N),DZ(31°N),and DLS(18°N)populations,respectively.The response scores varied significantly across the 4 dummies in ZJ-tits and DLS-tits but did not in DZ-tits.When facing the chipmunk,ZJ-tits showed the highest response score and DZ-tits showed the lowest response score.When facing the squirrel,ZJ-tits showed a higher response score than tits in the other 2 populations.However,tits among the 3 populations responded similarly to a sparrowhawk or dove with slight response behaviors.In addition,response scores to nest predators were positively correlated with brood size across the 3 populations,but no trend was found for sparrowhawks or doves.Our results indicated that the nest defense behaviors of cinereous tits have evolved in response to large-scale geographical variation in ecological contexts and reproduction value.
基金supported by National Science Foundation grant LTREB DEB-0089680 to F.J.Janzensupported by a United States EPA STAR fellowship+1 种基金supported by NSF LTREB DEB-0640932 to F.J.Janzensupported by the Iowa State University Program for Women in Science and Engineering.
文摘Increases in extreme environmental events are predicted to be major results of ongoing global climate change and may impact the persistence of species.We examined the effects of heat and cold waves during embryonic development of painted turtles(Chrysemys picta)in natural nests on the occurrence of abnormal shell morphologies in hatchlings.We found that nests exposed to extreme hot temperatures for>60 h produced more hatchlings with abnormalities than nests exposed to extreme hot temperatures for shorter periods,regardless of whether or not nesting females displayed abnormal morphologies.We observed no effect of extreme cold nest temperatures on the occurrence of hatchlings with abnormalities.Moreover,the frequency of nesting females with abnormal shell morphologies was approximately 2-fold lower than that of their offspring,suggesting that such abnormalities are negatively correlated with survival and fitness.Female turtles could potentially buffer their offspring from extreme heat by altering aspects of nesting behavior,such as choosing shadier nesting sites.We addressed this hypothesis by examining the effects of shade cover on extreme nest temperatures and the occurrence of hatchling abnormalities.While shade cover was negatively correlated with the occurrence of extreme hot nest temperatures,it was not significantly correlated with abnormalities.Therefore,female choice of shade cover does not appear to be a viable target for selection to reduce hatchling abnormalities.Our results suggest that increases in the frequency and intensity of heat waves associated with climate change might perturb developmental programs and thereby reduce the fitness of entire cohorts of turtles.
基金The research was approved by Auburn University IACUC(protocol 2019-3465)This study was supported by funds from Auburn University.J.M.H.was supported by the National Science Foundation(NSF DEB-1942145 to DAW)during the preparation of this manuscript.
文摘Vertebrate embryos require access to water;however,many species nest in terrestrial habitats that vary considerably in moisture content.Oviparous,non-avian reptiles have served as models to understand how environmental factors,like moisture availability,influence development because eggs are often exposed to prevailing environments in the absence of parental care.Though much research demonstrates the importance of water absorption by eggs,many ecological factors that influence moisture availability in natural nests have received little attention.For example,the type of substrate in which nests are constructed is understudied.We experimentally incubated eggs of the brown anole lizard(Anolis sagrei)in 2 naturally occurring nest substrates that were treated with varying amounts of water to determine how natural substrates influence development at different moisture concentrations.One substrate consisted of sand and crushed seashells and the other was mostly organic material(i.e.decayed plant material).Both are common nesting substrates at our field site.When controlling for water uptake by eggs,we found that egg survival and hatchling phenotypes were similar between substrates;however,embryos developed more quickly in the sand/shell substrate than the organic substrate,indicating substrate-specific effects on embryo physiology.These results demonstrate that different natural substrates can result in similar developmental outcomes if the water available to eggs is comparable;however,some aspects of development,like developmental rate,are affected by the type of substrate,independent of water availability.Further study is required to determine how natural substrates influence embryo physiology independent of water content.
