Animal species exhibit a wide range of coloration and patterns,which are under strong selection and often linked to individual quality,influencing mate choice,recognition,signaling,and interspecific interactions such ...Animal species exhibit a wide range of coloration and patterns,which are under strong selection and often linked to individual quality,influencing mate choice,recognition,signaling,and interspecific interactions such as predator avoidance.In amphibians,coloration can vary based on individual traits as well as environmental conditions,including the coloration of their environment.In this study,we described the dorsal coloration(body coloration reticulated by dark patches)in 676 Western spadefoot toads(Pelobates cultripes)from the French Atlantic coast,comparing color variations across different substrates.In addition,we assessed color change in 18 toads transferred between bright and dark substrates.We demonstrated that the dorsal coloration varies based on capture locations(beach vs.inland)and associated substrate types(bright vs.dark),suggesting background color matching.We showed more pronounced effects in females,which might reflect varying predation risks.Experimentally,we showed that individuals can rapidly adjust their coloration to match the substrate within 24 h.Rapid color changes in response to substrate type indicate significant pigmentation plasticity.Bright individuals from sandy substrates showed less dorsal background(body)color change than dark inland individuals,while patch coloration responded differently depending on the substrate of origin.These findings highlight the complex interactions between substrate type,sex,and pigmentation plasticity.These interactions have potential costs and benefits,which might be linked to melanin production,which warrant further investigation.展开更多
Snakes exhibit extraordinary ecological diversity and occupy a broad range of terrestrial,aquatic,and intermediate environments.Despite their widespread capacity for swimming,quantitative assessments of their aquatic ...Snakes exhibit extraordinary ecological diversity and occupy a broad range of terrestrial,aquatic,and intermediate environments.Despite their widespread capacity for swimming,quantitative assessments of their aquatic locomotion remain scarce.Furthermore,the roles of intraspecific variation in shaping swimming performance and kinematics have been largely overlooked,hindering robust interspecific comparisons.This study systematically investigated intraspecific and interspecific variation in 287individuals representing seven snake species along a terrestrial to aquatic continuum.Nine conventional swimming traits were quantified,including swimming speed and undulation characteristics such as frequency,wavelength,lateral velocities(head,body and tail) and amplitudes(head,body and tail).Undulation frequency and lateral velocity exhibited strong positive correlations with swimming speed,whereas wavelength showed a strong negative correlation.Semi-aquatic taxa attained the highest swimming speeds,while fully aquatic snakes displayed the lowest speeds.Intraspecific variation in swimming performance and kinematics was moderately reduced in aquatic species.Morphological traits,sex,and reproductive status significantly influenced both speed and kinematic profiles within species.Principal component analyses further revealed distinct kinematic domains among certain species(e.g.,no overlap between aspic viper and sea snakes),while others,such as the green whip snake,exhibited broad overlap with all taxa examined.These findings demonstrate that ecological specialization to aquatic habitats does not unilaterally dictate swimming speed or kinematic patterns.Moreover,conventional kinematic parameters alone are insufficient to study the evolutionary trajectories of aquatic locomotion in snakes.Integrating hydrodynamic,endurance capacity,and diving performance will be essential to better understand how natural selection has shaped locomotion in aquatic snakes.展开更多
Assessing the determinants of reproductive success is critical but often complicated because of complex interactions between parental traits and environmental conditions occurring during several stages of a reproducti...Assessing the determinants of reproductive success is critical but often complicated because of complex interactions between parental traits and environmental conditions occurring during several stages of a reproductive event.Here,we used a simplified ecological situation-an amphibian species lacking post-oviposition parental care-and a laboratory approach to investigate the relationships between parental(both maternal and paternal)phenotypes(body size and condition)and reproductive success(fecundity,egg size,embryonic and larval duration,larval and metamorphic morphology).We found significant effects of maternal phenotype on fecundity,hatching success,and tadpole size,as well as on the duration of larval development.Interestingly,and more surprisingly,we also found a potential contribution of the paternal phenotype occurring during early(embryonic development duration)offspring development.Although our study focused on life-history traits such as body size and development duration,additional mechanisms involving physiological costs of development may well mediate the relationships between parental phenotypes and offspring development.Future studies are required to decipher the mechanisms underlying our findings in order to clarify the mechanistic basis of the links between parental phenotypes and offspring development.展开更多
The vast diversity of morphologies,body size,and lifestyles of snakes represents an important source of information that can be used to derive bio-inspired robots through a biology-push and pull process.An understandi...The vast diversity of morphologies,body size,and lifestyles of snakes represents an important source of information that can be used to derive bio-inspired robots through a biology-push and pull process.An understanding of the detailed kinematics of swimming snakes is a fundamental prerequisite to conceive and design bio-inspired aquatic snake robots.However,only limited information is available on the kinematics of swimming snake.Fast and accurate methods are needed to fill this knowledge gap.In the present paper,three existing methods were compared to test their capacity to characterize the kinematics of swimming snakes.(1)Marker tracking(Deftac),(2)Markerless pose estimation(DeepLabCut),and(3)Motion capture were considered.(4)We also designed and tested an automatic video processing method.All methods provided different albeit complementary data sets;they also involved different technical issues in terms of experimental conditions,snake manipulation,or processing resources.Marker tracking provided accurate data that can be used to calibrate other methods.Motion capture posed technical difficulties but can provide limited 3D data.Markerless pose estimation required deep learning(thus time)but was efficient to extract the data under various experimental conditions.Finally,automatic video processing was particularly efficient to extract a wide range of data useful for both biology and robotics but required a specific experimental setting.展开更多
Background:Collecting and studying live sperm is central to many important fields of biology.Yet,a simple method to collect live sperm is lacking in wild seabird species.Here,we describe a non?invasive method to colle...Background:Collecting and studying live sperm is central to many important fields of biology.Yet,a simple method to collect live sperm is lacking in wild seabird species.Here,we describe a non?invasive method to collect viable sperm samples based on a simple massage technique applied to male Black?legged Kittiwakes(Rissa tridactyla).Methods:We studied a colony breeding at Kongsfjorden,Svalbard and successfully obtained sperm samples from 32 males.With a subset of samples(n = 12 males),we compared the suitability of several extenders(0.9% NaCl,PBS,Earle's balance salt solution,Dulbecco's modified Eagle medium) in maintaining sperm alive long enough for analyses.With another 18 ejaculates,we conducted computer assisted sperm analyses using the CASA plugin for ImageJ.We provide details about the settings to be used for such analyses.Lastly,droplets from 20 ejaculates were smeared on glass slides and preserved with formalin to characterize sperm morphology in terms of total sperm length,sperm head length,midpiece length and flagellum length,and percentage of abnormal sperm.Results:With this method and under field conditions,we were able to obtain sufficient amounts of live sperm to assess traits related to sperm quality(e.g.sperm morphology,percentage of motile sperm,sperm velocity).We found that two extenders,Earle's balanced salt solution and Dulbecco modified Eagle's medium,yielded similarly good results.Additionally,we investigated whether specific behaviours were associated with successful sperm collection and whether sperm collection success depended on how long before laying sperm collection was attempted.Finally,we provide mean values for sperm morphology,sperm swimming ability and percentage of motile sperm,which may prove useful for future comparative analyses,and we report high levels of sperm abnormality and within?ejaculate variation in sperm morphology.Conclusions:We discuss the high percentage of abnormal sperm and high within?ejaculate variation in sperm morphology in light of sperm competition theory and conclude that these figures are likely due to relaxed post?cop?ulatory sexual selection,kittiwakes being strictly monogamous.Finally,we suggest that this method could be applied to other seabird species sharing similar ecology.展开更多
Herpes viruses are responsible for a variety of pathological effects in humans and in both wild and domestic animals. One mechanism that has been proposed to facilitate replication and activity of herpes viruses is ox...Herpes viruses are responsible for a variety of pathological effects in humans and in both wild and domestic animals. One mechanism that has been proposed to facilitate replication and activity of herpes viruses is oxidative stress （OS）. We used meta-analytical techniques to test the hypotheses that （1） herpes virus infection causes OS and （2） supplementation of antioxidants reduces virus load, indicating that replication is favoured by a state of OS. Results based on studies on mammals, including humans, and birds show that （1） OS is indeed increased by herpes virus infection across multiple tissues and species, （2） biomarkers of OS may change differently between tissues, and （3） the effect size does not differ among different virus strains. In addition, the increase of oxidative damage in blood （tissue commonly available in ecological studies） was similar to that in the tissues most sensitive to the herpes virus. Our results also show that administration of antioxidants re- duces virus yield, indicating that a condition of OS is favorable for the viral replication. In addition, some antioxidants may be more efficient than others in reducing herpes virus yield. Our results point to a potential mechanism linking herpes virus infection to individual health status.展开更多
基金Funding was provided by the CNRS,La Rochelle Université,the LPO,the Agence de l’Eau Adour-Garonne,the Conseil Départemental de la Charente-Maritime,the ANR PAMPAS(ANR-18-CE32-0006)the Beauval Nature association,the Contrat de plan Etat-région Econat and the Région Nouvelle Aquitaine(Projet d’Observatoire du Marais de Brouage-PSGAR CRNA 2025).
文摘Animal species exhibit a wide range of coloration and patterns,which are under strong selection and often linked to individual quality,influencing mate choice,recognition,signaling,and interspecific interactions such as predator avoidance.In amphibians,coloration can vary based on individual traits as well as environmental conditions,including the coloration of their environment.In this study,we described the dorsal coloration(body coloration reticulated by dark patches)in 676 Western spadefoot toads(Pelobates cultripes)from the French Atlantic coast,comparing color variations across different substrates.In addition,we assessed color change in 18 toads transferred between bright and dark substrates.We demonstrated that the dorsal coloration varies based on capture locations(beach vs.inland)and associated substrate types(bright vs.dark),suggesting background color matching.We showed more pronounced effects in females,which might reflect varying predation risks.Experimentally,we showed that individuals can rapidly adjust their coloration to match the substrate within 24 h.Rapid color changes in response to substrate type indicate significant pigmentation plasticity.Bright individuals from sandy substrates showed less dorsal background(body)color change than dark inland individuals,while patch coloration responded differently depending on the substrate of origin.These findings highlight the complex interactions between substrate type,sex,and pigmentation plasticity.These interactions have potential costs and benefits,which might be linked to melanin production,which warrant further investigation.
基金supported by the French Government through the National Research Agency (ANR)part of the ANR DRAGON-2 Project (ANR-20-CE02-0010)。
文摘Snakes exhibit extraordinary ecological diversity and occupy a broad range of terrestrial,aquatic,and intermediate environments.Despite their widespread capacity for swimming,quantitative assessments of their aquatic locomotion remain scarce.Furthermore,the roles of intraspecific variation in shaping swimming performance and kinematics have been largely overlooked,hindering robust interspecific comparisons.This study systematically investigated intraspecific and interspecific variation in 287individuals representing seven snake species along a terrestrial to aquatic continuum.Nine conventional swimming traits were quantified,including swimming speed and undulation characteristics such as frequency,wavelength,lateral velocities(head,body and tail) and amplitudes(head,body and tail).Undulation frequency and lateral velocity exhibited strong positive correlations with swimming speed,whereas wavelength showed a strong negative correlation.Semi-aquatic taxa attained the highest swimming speeds,while fully aquatic snakes displayed the lowest speeds.Intraspecific variation in swimming performance and kinematics was moderately reduced in aquatic species.Morphological traits,sex,and reproductive status significantly influenced both speed and kinematic profiles within species.Principal component analyses further revealed distinct kinematic domains among certain species(e.g.,no overlap between aspic viper and sea snakes),while others,such as the green whip snake,exhibited broad overlap with all taxa examined.These findings demonstrate that ecological specialization to aquatic habitats does not unilaterally dictate swimming speed or kinematic patterns.Moreover,conventional kinematic parameters alone are insufficient to study the evolutionary trajectories of aquatic locomotion in snakes.Integrating hydrodynamic,endurance capacity,and diving performance will be essential to better understand how natural selection has shaped locomotion in aquatic snakes.
基金Funding was provided by the CNRS,the Agence de lʹEau Loire-Bretagne,the Agence de lʹEau Adour-Garonne,the Conseil Départemental des Deux-Sèvres,the Région Nouvelle-Aquitaine(Multistress 2017-1R20110,Aquastress 2018-1R20214,Amphitox 2019-1R20216)the ANSES(BiodiTox project 2019/1/031)the Plan dʹAction National ECOPHYTO(OFB-21-0941),and the CPER Econat.
文摘Assessing the determinants of reproductive success is critical but often complicated because of complex interactions between parental traits and environmental conditions occurring during several stages of a reproductive event.Here,we used a simplified ecological situation-an amphibian species lacking post-oviposition parental care-and a laboratory approach to investigate the relationships between parental(both maternal and paternal)phenotypes(body size and condition)and reproductive success(fecundity,egg size,embryonic and larval duration,larval and metamorphic morphology).We found significant effects of maternal phenotype on fecundity,hatching success,and tadpole size,as well as on the duration of larval development.Interestingly,and more surprisingly,we also found a potential contribution of the paternal phenotype occurring during early(embryonic development duration)offspring development.Although our study focused on life-history traits such as body size and development duration,additional mechanisms involving physiological costs of development may well mediate the relationships between parental phenotypes and offspring development.Future studies are required to decipher the mechanisms underlying our findings in order to clarify the mechanistic basis of the links between parental phenotypes and offspring development.
基金Agence Nationale de la recherche(Grant no.ANR-20-CE02-0010).
文摘The vast diversity of morphologies,body size,and lifestyles of snakes represents an important source of information that can be used to derive bio-inspired robots through a biology-push and pull process.An understanding of the detailed kinematics of swimming snakes is a fundamental prerequisite to conceive and design bio-inspired aquatic snake robots.However,only limited information is available on the kinematics of swimming snake.Fast and accurate methods are needed to fill this knowledge gap.In the present paper,three existing methods were compared to test their capacity to characterize the kinematics of swimming snakes.(1)Marker tracking(Deftac),(2)Markerless pose estimation(DeepLabCut),and(3)Motion capture were considered.(4)We also designed and tested an automatic video processing method.All methods provided different albeit complementary data sets;they also involved different technical issues in terms of experimental conditions,snake manipulation,or processing resources.Marker tracking provided accurate data that can be used to calibrate other methods.Motion capture posed technical difficulties but can provide limited 3D data.Markerless pose estimation required deep learning(thus time)but was efficient to extract the data under various experimental conditions.Finally,automatic video processing was particularly efficient to extract a wide range of data useful for both biology and robotics but required a specific experimental setting.
基金supported by the Institut Polaire Fran?ais,IPEV project 330 to OCPB was funded by an Arctic Field Grant(No.256934)from the Research Council of Norway+1 种基金by a Ph.D grant from University of La RochelleFH was financially supported by a grant from the Swiss National Science Foundation(No.PP00P3_139011)
文摘Background:Collecting and studying live sperm is central to many important fields of biology.Yet,a simple method to collect live sperm is lacking in wild seabird species.Here,we describe a non?invasive method to collect viable sperm samples based on a simple massage technique applied to male Black?legged Kittiwakes(Rissa tridactyla).Methods:We studied a colony breeding at Kongsfjorden,Svalbard and successfully obtained sperm samples from 32 males.With a subset of samples(n = 12 males),we compared the suitability of several extenders(0.9% NaCl,PBS,Earle's balance salt solution,Dulbecco's modified Eagle medium) in maintaining sperm alive long enough for analyses.With another 18 ejaculates,we conducted computer assisted sperm analyses using the CASA plugin for ImageJ.We provide details about the settings to be used for such analyses.Lastly,droplets from 20 ejaculates were smeared on glass slides and preserved with formalin to characterize sperm morphology in terms of total sperm length,sperm head length,midpiece length and flagellum length,and percentage of abnormal sperm.Results:With this method and under field conditions,we were able to obtain sufficient amounts of live sperm to assess traits related to sperm quality(e.g.sperm morphology,percentage of motile sperm,sperm velocity).We found that two extenders,Earle's balanced salt solution and Dulbecco modified Eagle's medium,yielded similarly good results.Additionally,we investigated whether specific behaviours were associated with successful sperm collection and whether sperm collection success depended on how long before laying sperm collection was attempted.Finally,we provide mean values for sperm morphology,sperm swimming ability and percentage of motile sperm,which may prove useful for future comparative analyses,and we report high levels of sperm abnormality and within?ejaculate variation in sperm morphology.Conclusions:We discuss the high percentage of abnormal sperm and high within?ejaculate variation in sperm morphology in light of sperm competition theory and conclude that these figures are likely due to relaxed post?cop?ulatory sexual selection,kittiwakes being strictly monogamous.Finally,we suggest that this method could be applied to other seabird species sharing similar ecology.
文摘Herpes viruses are responsible for a variety of pathological effects in humans and in both wild and domestic animals. One mechanism that has been proposed to facilitate replication and activity of herpes viruses is oxidative stress （OS）. We used meta-analytical techniques to test the hypotheses that （1） herpes virus infection causes OS and （2） supplementation of antioxidants reduces virus load, indicating that replication is favoured by a state of OS. Results based on studies on mammals, including humans, and birds show that （1） OS is indeed increased by herpes virus infection across multiple tissues and species, （2） biomarkers of OS may change differently between tissues, and （3） the effect size does not differ among different virus strains. In addition, the increase of oxidative damage in blood （tissue commonly available in ecological studies） was similar to that in the tissues most sensitive to the herpes virus. Our results also show that administration of antioxidants re- duces virus yield, indicating that a condition of OS is favorable for the viral replication. In addition, some antioxidants may be more efficient than others in reducing herpes virus yield. Our results point to a potential mechanism linking herpes virus infection to individual health status.
