The Black-necked Crane (Grus nigricollis) is an endemic species of the Qinghai-Tibetan Plateau,with its population in Xinjiang largely found in the Kunlun and Altun mountain regions.A survey of the distribution,popula...The Black-necked Crane (Grus nigricollis) is an endemic species of the Qinghai-Tibetan Plateau,with its population in Xinjiang largely found in the Kunlun and Altun mountain regions.A survey of the distribution,population dynamics,flock size and behavior was conducted in Altun Mountain National Natural Reserve from September to November 2011.We investigated the size and distribution of its population in this area with a sample spot survey and by direct counting.We found Black-necked Cranes on the wetlands of Wuzunxiaoer,Yusup Aleksei,Yaziquan,Qimantag,Tula Ranch and elsewhere,where we recorded 126 individual birds of the species in Yixiekepati (37° 15′-37°23′N,90°11′-90°20′E,elevation 3903 m),the largest population we have observed in this area.In the reserve,the population consists of about 180-200 birds.Combined with previous records,we conclude that more than 260 Black-necked Cranes live in Xinjiang.Cranes gathered conspicuously in the middle of October where the highest number of birds appeared on 29 October.All of the cranes had migrated out of this area by 6 November.Time budgets and diurnal behavior rhythms of Blacknecked Cranes were observed in the Yixiekepati wetland at daylight (from 06:00 to 18:00).Foraging was the most prevalent type of behavior during the autumn period,accounting for 58.9％ of the diurnal time budget,followed by preening (13.2％),vigilance (9.5％),walking (8.2％),flying (3.5％),resting (3.4％),chirping (2.7％) and other types of behavior (0.6％).展开更多
We propose a solvable aggregation model to mimic the evolution of population A, asset B, and the quantifiable resource C in a society. In this system, the population and asset aggregates themselves grow through selfex...We propose a solvable aggregation model to mimic the evolution of population A, asset B, and the quantifiable resource C in a society. In this system, the population and asset aggregates themselves grow through selfexchanges with the rate kernels Kl（k,j） = K1kj and K2（h,j） = K2kj, respectively. The actions of the population and asset aggregations on the aggregation evolution of resource aggregates are described by the population-catalyzed monomer death of resource aggregates and asset-catalyzed monomer birth of resource aggregates with the rate kerne/s J1（k,j）=J1k and J2（k,j） = J2k, respectively. Meanwhile, the asset and resource aggregates conjunctly catalyze the monomer birth of population aggregates with the rate kernel I1 （k,i,j） = I1ki^μjη, and population and resource aggregates conjunctly catalyze the monomer birth of asset aggregates with the rate kernel /2（k, i, j） = I2ki^νj^η. The kinetic behaviors of species A, B, and C are investigated by means of the mean-field rate equation approach. The effects of the population-catalyzed death and asset-catalyzed birth on the evolution of resource aggregates based on the self-exchanges of population and asset appear in effective forms. The coefficients of the effective population-catalyzed death and the asset-catalyzed birth are expressed as J1e = J1/K1 and J2e= J2/K2, respectively. The aggregate size distribution of C species is found to be crucially dominated by the competition between the effective death and the effective birth. It satisfies the conventional scaling form, generalized scaling form, and modified scaling form in the cases of J1e〈J2e, J1e=J2e, and J1e〉J2e, respectively. Meanwhile, we also find the aggregate size distributions of populations and assets both fall into two distinct categories for different parameters μ,ν, and η： （i） When μ=ν=η=0 and μ=ν=η=1, the population and asset aggregates obey the generalized scaling forms; and （ii） When μ=ν=1,η=0, and μ=ν=η=1, the population and asset aggregates experience gelation transitions at finite times and the scaling forms break down.展开更多
We propose an aggregation evolution model of two-species （A- and B-species） aggregates to study the prevalent aggregation phenomena in social and economic systems. In this model, A- and B-species aggregates perform ...We propose an aggregation evolution model of two-species （A- and B-species） aggregates to study the prevalent aggregation phenomena in social and economic systems. In this model, A- and B-species aggregates perform self-exchange-driven growths with the exchange rate kernels K（k, l） = Kkl and L（k, l） = Lkl, respectively, and the two species aggregates perform self-birth processes with the rate kernels J1（k） = J1 k and J2（ k ） = J2k, and meanwhile the interaction between the aggregates of different species A and B causes a lose-lose scheme with the rate kernel H（k,l） = Hkl. Based on the mean-field theory, we investigated the evolution behaviors of the two species aggregates to study the competitions among above three aggregate evolution schemes on the distinct initial monomer concentrations A0 and B0 of the two species. The results show that the evolution behaviors of A- and B-species are crucially dominated by the competition between the two self-birth processes, and the initial monomer concentrations Ao and Bo play important roles, while the lose-lose scheme play important roles in some special cases.展开更多
Sexual selection is widely viewed as playing a central role in haplochromine cichlid speciation. Hypothetically, once divergent mate preferences evolve among populations of these fishes, reproductive isolation follows...Sexual selection is widely viewed as playing a central role in haplochromine cichlid speciation. Hypothetically, once divergent mate preferences evolve among populations of these fishes, reproductive isolation follows and the populations begin to behave as different species. Various studies have examined patterns of assortative mating among species and sometimes populations, but few have examined variation in directional preferences, especially among populations of the same species. We investi- gated mate choice behavior in two populations of Labeotropheus fueUeborni, a Lake Malawi endemic. We test whether mating preferences between populations are based on the same traits and in the same direction as preferences within populations. We examine the potential contributions of two classes of trait, color patterns and behaviors, to reproductive isolation. When females chose between either two males of their own population, or two from another, female preferences were generally similar （for the female population） across the two contexts. Mate choice patterns differed between （female） populations for a measure of color, but only modestly for male behavior. In a separate experiment we simultaneously offered females a male of their own population and a male from a different population. In these trials, females consistently preferred males from their own population, which were also the males that displayed more frequently than their opponents, but not necessarily those with color traits suggested to be most attractive in the previous experiment. Thus directional preferences for chroma and related aspects of color may be important when females are presented with males of otherwise similar phenotypes, but may play little role in mediating assortative mating among populations with substantially different color patterns. A preference for male behavior could play some role in speciation if males preferentially court same-population females, as we have observed for the populations studied herein [Current Zoology 58 （3）： 475-483, 2012].展开更多
Phenotypic plasticity is often an adaptation of organisms to cope with temporally or spatially heter- ogenous landscapes. Like other adaptations, one would predict that different species, populations, or sexes might t...Phenotypic plasticity is often an adaptation of organisms to cope with temporally or spatially heter- ogenous landscapes. Like other adaptations, one would predict that different species, populations, or sexes might thus show some degree of parallel evolution of plasticity, in the form of parallel reaction norms, when exposed to analogous environmental gradients. Indeed, one might even ex- pect parallelism of plasticity to repeatedly evolve in multiple traits responding to the same gradi- ent, resulting in integrated parallelism of plasticity. In this study, we experimentally tested for paral- lel patterns of predator-mediated plasticity of size, shape, and behavior of 2 species and sexes of mosquitofish. Examination of behavioral trials indicated that the 2 species showed unique patterns of behavioral plasticity, whereas the 2 sexes in each species showed parallel responses. Fish shape showed parallel patterns of plasticity for both sexes and species, albeit males showed evidence of unique plasticity related to reproductive anatomy. Moreover, patterns of shape plasticity due to predator exposure were broadly parallel to what has been depicted for predator-mediated popula- tion divergence in other studies （slender bodies, expanded caudal regions, ventrally located eyes, and reduced male gonopodia）. We did not find evidence of phenotypic plasticity in fish size for ei- ther species or sex. Hence, our findings support broadly integrated parallelism of plasticity for sexes within species and less integrated parallelism for species. We interpret these findings with respect to their potential broader implications for the interacting roles of adaptation and constraint in the evolutionary origins of parallelism of plasticity in general.展开更多
We consider the small value probability of supercritical continuous state branching processes with immigration. From Pinsky （1972） it is known that under regularity condition on the branching mechanism and immigrati...We consider the small value probability of supercritical continuous state branching processes with immigration. From Pinsky （1972） it is known that under regularity condition on the branching mechanism and immigration mechanism, the normalized population size converges to a non-degenerate finite and positive limit PV as t tends to infinity. We provide sharp estimate on asymptotic behavior of P（W≤ε〈） as ε→ 0＋ by studying the Laplace transform of W. Without immigration, we also give a simpler proof for the small value probability in the non-subordinator case via the prolific backbone decomposition.展开更多
基金supported by the National Natural Science Foundation of China(No.31272291,30970340)the Hong Kong Bird Watching Society China Conservation Fund and the Management Bureau of Altun Mountain Natural Reserve
文摘The Black-necked Crane (Grus nigricollis) is an endemic species of the Qinghai-Tibetan Plateau,with its population in Xinjiang largely found in the Kunlun and Altun mountain regions.A survey of the distribution,population dynamics,flock size and behavior was conducted in Altun Mountain National Natural Reserve from September to November 2011.We investigated the size and distribution of its population in this area with a sample spot survey and by direct counting.We found Black-necked Cranes on the wetlands of Wuzunxiaoer,Yusup Aleksei,Yaziquan,Qimantag,Tula Ranch and elsewhere,where we recorded 126 individual birds of the species in Yixiekepati (37° 15′-37°23′N,90°11′-90°20′E,elevation 3903 m),the largest population we have observed in this area.In the reserve,the population consists of about 180-200 birds.Combined with previous records,we conclude that more than 260 Black-necked Cranes live in Xinjiang.Cranes gathered conspicuously in the middle of October where the highest number of birds appeared on 29 October.All of the cranes had migrated out of this area by 6 November.Time budgets and diurnal behavior rhythms of Blacknecked Cranes were observed in the Yixiekepati wetland at daylight (from 06:00 to 18:00).Foraging was the most prevalent type of behavior during the autumn period,accounting for 58.9％ of the diurnal time budget,followed by preening (13.2％),vigilance (9.5％),walking (8.2％),flying (3.5％),resting (3.4％),chirping (2.7％) and other types of behavior (0.6％).
基金Supported by the National Natural Science Foundation of China under Grant Nos. 10775104, 10275048, and 10305009the Zhejiang Provincial Natural Science Foundation of China under Grant No. 102067
文摘We propose a solvable aggregation model to mimic the evolution of population A, asset B, and the quantifiable resource C in a society. In this system, the population and asset aggregates themselves grow through selfexchanges with the rate kernels Kl（k,j） = K1kj and K2（h,j） = K2kj, respectively. The actions of the population and asset aggregations on the aggregation evolution of resource aggregates are described by the population-catalyzed monomer death of resource aggregates and asset-catalyzed monomer birth of resource aggregates with the rate kerne/s J1（k,j）=J1k and J2（k,j） = J2k, respectively. Meanwhile, the asset and resource aggregates conjunctly catalyze the monomer birth of population aggregates with the rate kernel I1 （k,i,j） = I1ki^μjη, and population and resource aggregates conjunctly catalyze the monomer birth of asset aggregates with the rate kernel /2（k, i, j） = I2ki^νj^η. The kinetic behaviors of species A, B, and C are investigated by means of the mean-field rate equation approach. The effects of the population-catalyzed death and asset-catalyzed birth on the evolution of resource aggregates based on the self-exchanges of population and asset appear in effective forms. The coefficients of the effective population-catalyzed death and the asset-catalyzed birth are expressed as J1e = J1/K1 and J2e= J2/K2, respectively. The aggregate size distribution of C species is found to be crucially dominated by the competition between the effective death and the effective birth. It satisfies the conventional scaling form, generalized scaling form, and modified scaling form in the cases of J1e〈J2e, J1e=J2e, and J1e〉J2e, respectively. Meanwhile, we also find the aggregate size distributions of populations and assets both fall into two distinct categories for different parameters μ,ν, and η： （i） When μ=ν=η=0 and μ=ν=η=1, the population and asset aggregates obey the generalized scaling forms; and （ii） When μ=ν=1,η=0, and μ=ν=η=1, the population and asset aggregates experience gelation transitions at finite times and the scaling forms break down.
基金Supported by National Natural Science Foundation of China under Grant Nos.10875086 and 10775104
文摘We propose an aggregation evolution model of two-species （A- and B-species） aggregates to study the prevalent aggregation phenomena in social and economic systems. In this model, A- and B-species aggregates perform self-exchange-driven growths with the exchange rate kernels K（k, l） = Kkl and L（k, l） = Lkl, respectively, and the two species aggregates perform self-birth processes with the rate kernels J1（k） = J1 k and J2（ k ） = J2k, and meanwhile the interaction between the aggregates of different species A and B causes a lose-lose scheme with the rate kernel H（k,l） = Hkl. Based on the mean-field theory, we investigated the evolution behaviors of the two species aggregates to study the competitions among above three aggregate evolution schemes on the distinct initial monomer concentrations A0 and B0 of the two species. The results show that the evolution behaviors of A- and B-species are crucially dominated by the competition between the two self-birth processes, and the initial monomer concentrations Ao and Bo play important roles, while the lose-lose scheme play important roles in some special cases.
文摘Sexual selection is widely viewed as playing a central role in haplochromine cichlid speciation. Hypothetically, once divergent mate preferences evolve among populations of these fishes, reproductive isolation follows and the populations begin to behave as different species. Various studies have examined patterns of assortative mating among species and sometimes populations, but few have examined variation in directional preferences, especially among populations of the same species. We investi- gated mate choice behavior in two populations of Labeotropheus fueUeborni, a Lake Malawi endemic. We test whether mating preferences between populations are based on the same traits and in the same direction as preferences within populations. We examine the potential contributions of two classes of trait, color patterns and behaviors, to reproductive isolation. When females chose between either two males of their own population, or two from another, female preferences were generally similar （for the female population） across the two contexts. Mate choice patterns differed between （female） populations for a measure of color, but only modestly for male behavior. In a separate experiment we simultaneously offered females a male of their own population and a male from a different population. In these trials, females consistently preferred males from their own population, which were also the males that displayed more frequently than their opponents, but not necessarily those with color traits suggested to be most attractive in the previous experiment. Thus directional preferences for chroma and related aspects of color may be important when females are presented with males of otherwise similar phenotypes, but may play little role in mediating assortative mating among populations with substantially different color patterns. A preference for male behavior could play some role in speciation if males preferentially court same-population females, as we have observed for the populations studied herein [Current Zoology 58 （3）： 475-483, 2012].
文摘Phenotypic plasticity is often an adaptation of organisms to cope with temporally or spatially heter- ogenous landscapes. Like other adaptations, one would predict that different species, populations, or sexes might thus show some degree of parallel evolution of plasticity, in the form of parallel reaction norms, when exposed to analogous environmental gradients. Indeed, one might even ex- pect parallelism of plasticity to repeatedly evolve in multiple traits responding to the same gradi- ent, resulting in integrated parallelism of plasticity. In this study, we experimentally tested for paral- lel patterns of predator-mediated plasticity of size, shape, and behavior of 2 species and sexes of mosquitofish. Examination of behavioral trials indicated that the 2 species showed unique patterns of behavioral plasticity, whereas the 2 sexes in each species showed parallel responses. Fish shape showed parallel patterns of plasticity for both sexes and species, albeit males showed evidence of unique plasticity related to reproductive anatomy. Moreover, patterns of shape plasticity due to predator exposure were broadly parallel to what has been depicted for predator-mediated popula- tion divergence in other studies （slender bodies, expanded caudal regions, ventrally located eyes, and reduced male gonopodia）. We did not find evidence of phenotypic plasticity in fish size for ei- ther species or sex. Hence, our findings support broadly integrated parallelism of plasticity for sexes within species and less integrated parallelism for species. We interpret these findings with respect to their potential broader implications for the interacting roles of adaptation and constraint in the evolutionary origins of parallelism of plasticity in general.
基金supported by National Science Foundation of US (Grant Nos. DMS-0805929 and DMS-1106938)National Natural Science Foundation of China (Grant Nos. 10928103,10971003 and 11128101)+1 种基金Specialized Research Fund for the Doctoral Program of Higher Education of Chinathe Fundamental Research Funds for the Central Universities
文摘We consider the small value probability of supercritical continuous state branching processes with immigration. From Pinsky （1972） it is known that under regularity condition on the branching mechanism and immigration mechanism, the normalized population size converges to a non-degenerate finite and positive limit PV as t tends to infinity. We provide sharp estimate on asymptotic behavior of P（W≤ε〈） as ε→ 0＋ by studying the Laplace transform of W. Without immigration, we also give a simpler proof for the small value probability in the non-subordinator case via the prolific backbone decomposition.
