In mammals,temporal and spatial variation in appendage sizes within and among species may be driven by variations in ambient temperature and allometric scaling.Here,we use two decades of morphological data on three ro...In mammals,temporal and spatial variation in appendage sizes within and among species may be driven by variations in ambient temperature and allometric scaling.Here,we use two decades of morphological data on three rodent species distributed across vast latitudinal gradients in China to estimate temporal and spatial trends of tail,hind-foot,and ear lengths.Further,we test 14 climate variables to identify the critical drivers of these trends and use structural equation modeling(SEM)to analyze whether the effects of climate variables on the appendage lengths are direct or indirect,via effects on body length.Relative to body length,and in contradiction to Allen’s rule,all appendage lengths remained unchanged over time and across space.By contrast,absolute appendage lengths increased in one species(Apodemus agrarius)over time and in two species(A.agrarius and Rattus norvegicus)across space;and most of the appendage lengths in the two species were associated with annual mean minimum temperature in the year preceding capture(PreAnnMinTemp).The SEM results suggest that PreAnnMinTemp affected absolute appendage lengths indirectly through body length.In addition,except for tail length in two species and both hind-foot and ear length in one species,absolute appendage lengths scaled allometrically with body length.These results suggest that the distinct temperature-appendage-length patterns among and within species arise from species-specific temperature sensitivities and appendage-specific ontogenetic rates and functions.展开更多
Background:Animals that live at higher latitudes/elevations would have a larger body size(Bergmann’s rule)and a smaller appendage size(Allen’s rule)for thermoregulatory reasons.According to the heat conservation hyp...Background:Animals that live at higher latitudes/elevations would have a larger body size(Bergmann’s rule)and a smaller appendage size(Allen’s rule)for thermoregulatory reasons.According to the heat conservation hypoth-esis,large body size and small appendage size help animals retain heat in the cold,while small body size and large appendage size help them dissipate heat in the warm.For animals living in seasonal climates,the need for conserving heat in the winter may tradeoff with the need for dissipating heat in the summer.In this study,we tested Bergmann’s rule and Allen’s rule in two widely-distributed passerine birds,the Oriental Magpie(Pica serica)and the Oriental Tit(Parus minor),across geographic and climatic gradients in China.Methods:We measured body size(body mass and wing length)and appendage size(bill length and tarsus length)of 165 Oriental Magpie and 410 Oriental Tit individuals collected from Chinese mainland.We used linear mixed-effect models to assess variation patterns of body size and appendage size along geographic and climatic gradients.Results:Oriental Magpies have a larger appendage size and Oriental Tits have a smaller body size in warmer environ-ments.Appendage size in Oriental Magpies and body size in Oriental Tits of both sexes were more closely related to the climates in winter than in summer.Minimum temperature of coldest month is the most important factor related to bill length and tarsus length of male Oriental Magpies,and wing length of male and female Oriental Tits.Bill length and tarsus length in female Oriental Magpies were related to the annual mean temperature and mean temperature of coldest quarter,respectively.Conclusions:In this study,Oriental Magpies and Oriental Tits followed Allen’s rule and Bergmann’rule respectively.Temperatures in the winter,rather than temperatures in the summer,drove morphological measurements in Oriental Magpies and Oriental Tits in Chinese mainland,demonstrating that the morphological measurements reflect selec-tion for heat conservation rather than for heat dissipation.展开更多
基金funded by the National Natural Science Foundation of China(grant no.32072438)supported by the Swiss National Science Foundation(grant no.31003A_182286).
文摘In mammals,temporal and spatial variation in appendage sizes within and among species may be driven by variations in ambient temperature and allometric scaling.Here,we use two decades of morphological data on three rodent species distributed across vast latitudinal gradients in China to estimate temporal and spatial trends of tail,hind-foot,and ear lengths.Further,we test 14 climate variables to identify the critical drivers of these trends and use structural equation modeling(SEM)to analyze whether the effects of climate variables on the appendage lengths are direct or indirect,via effects on body length.Relative to body length,and in contradiction to Allen’s rule,all appendage lengths remained unchanged over time and across space.By contrast,absolute appendage lengths increased in one species(Apodemus agrarius)over time and in two species(A.agrarius and Rattus norvegicus)across space;and most of the appendage lengths in the two species were associated with annual mean minimum temperature in the year preceding capture(PreAnnMinTemp).The SEM results suggest that PreAnnMinTemp affected absolute appendage lengths indirectly through body length.In addition,except for tail length in two species and both hind-foot and ear length in one species,absolute appendage lengths scaled allometrically with body length.These results suggest that the distinct temperature-appendage-length patterns among and within species arise from species-specific temperature sensitivities and appendage-specific ontogenetic rates and functions.
基金funded by Strategic Priority Research Program of the Chinese Academy of Sciences(XDA19050202)the National Natural Science Foundation of China(NSFC 31672299)Collaborative Innovation Center for Research and Development of Tibetan Agricultural and Animal Husbandry Resources
文摘Background:Animals that live at higher latitudes/elevations would have a larger body size(Bergmann’s rule)and a smaller appendage size(Allen’s rule)for thermoregulatory reasons.According to the heat conservation hypoth-esis,large body size and small appendage size help animals retain heat in the cold,while small body size and large appendage size help them dissipate heat in the warm.For animals living in seasonal climates,the need for conserving heat in the winter may tradeoff with the need for dissipating heat in the summer.In this study,we tested Bergmann’s rule and Allen’s rule in two widely-distributed passerine birds,the Oriental Magpie(Pica serica)and the Oriental Tit(Parus minor),across geographic and climatic gradients in China.Methods:We measured body size(body mass and wing length)and appendage size(bill length and tarsus length)of 165 Oriental Magpie and 410 Oriental Tit individuals collected from Chinese mainland.We used linear mixed-effect models to assess variation patterns of body size and appendage size along geographic and climatic gradients.Results:Oriental Magpies have a larger appendage size and Oriental Tits have a smaller body size in warmer environ-ments.Appendage size in Oriental Magpies and body size in Oriental Tits of both sexes were more closely related to the climates in winter than in summer.Minimum temperature of coldest month is the most important factor related to bill length and tarsus length of male Oriental Magpies,and wing length of male and female Oriental Tits.Bill length and tarsus length in female Oriental Magpies were related to the annual mean temperature and mean temperature of coldest quarter,respectively.Conclusions:In this study,Oriental Magpies and Oriental Tits followed Allen’s rule and Bergmann’rule respectively.Temperatures in the winter,rather than temperatures in the summer,drove morphological measurements in Oriental Magpies and Oriental Tits in Chinese mainland,demonstrating that the morphological measurements reflect selec-tion for heat conservation rather than for heat dissipation.
