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Consistent habitat preference underpins the geographically divergent autumn migration of individual Mongolian common shelducks 被引量:4
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作者 Fanjuan MENG Xin WANG +5 位作者 Nyambayar BATBAYAR Tseveenmyadag NATSAGDORJ Batmunkh DAVAASUREN Iderbat DAMB Lei CAo Anthony DFox 《Current Zoology》 SCIE CAS CSCD 2020年第4期355-362,共8页
While many avian populations follow narrow,well-defined"migratory corridors,"individuals from other populations undertake highly divergent individual migration routes,using widely dispersed stopover sites en... While many avian populations follow narrow,well-defined"migratory corridors,"individuals from other populations undertake highly divergent individual migration routes,using widely dispersed stopover sites en route between breeding and wintering areas,although the reasons for these differences are rarely investigated.We combined individual GPS-tracked migration data from Mongolian-breeding common shelduck Tadorna tadorna and remote sensing datasets,to in-vestigate habitat selection at inland stopover sites used by these birds during dispersed autumn migration,to explain their divergent migration patterns.We used generalized linear mixed models to investigate population-level resource selection,and generalized linear models to investigate stopover-sit-level resource selection.The population-level model showed that water recurrence had the strongest positive effect on determining birds'occupancy at staging sites,while cultivated land and grassland land cover type had strongest negative effects;effects of other land cover types were negative but weaker,particularly effects of wwater seasonality and presence of a human foot-print,which were positive but weak or non-significant,respectively.Although stopover-site-level models showed variable resource selection patterns,the variance partitioning and cross-prediction AUC scores corroborated high inter-individual consistency in habitat selection at inland stopover sites during the dispersed autumn migration.These results suggest that the geographically wide-spread distribution(and generally rarity)of suitable habitats explained the spatially divergent autumn migrations of Mongolian breeding common shelduck,rather than the species showing flexible autumn staging habitat occupancy. 展开更多
关键词 common shelducks habitat selection individual variation resource selection function
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Effect of culture methods on individual variation in the growth of sea cucumber Apostichopus japonicus within a cohort and family 被引量:2
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作者 邱天龙 张立斌 +2 位作者 张涛 柏雨岑 杨红生 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 2014年第4期737-742,共6页
There is substantial individual variation in the growth rates of sea cucumber Apostiehopus japonicus individuals. This necessitates additional work to grade the seed stock and lengthens the production period. We evalu... There is substantial individual variation in the growth rates of sea cucumber Apostiehopus japonicus individuals. This necessitates additional work to grade the seed stock and lengthens the production period. We evaluated the influence of three culture methods (free-mixed, isolated-mixed, isolated-alone) on individual variation in growth and assessed the relationship between feeding, energy conversion efficiency, and individual growth variation in individually cultured sea cucumbers. Of the different culture methods, animals grew best when reared in the isolated-mixed treatment (i.e., size classes were held separately), though there was no difference in individual variation in growth between rearing treatment groups. The individual variation in growth was primarily attributed to genetic factors. The difference in food conversion efficiency caused by genetic differences among individuals was thought to be the origin of the variance. The level of individual growth variation may be altered by interactions among individuals and environmental heterogeneity. Our results suggest that, in addition to traditional seed grading, design of a new kind of substrate that changes the spatial distribution of sea cucumbers would effectively enhance growth and reduce individual variation in growth of sea cucumbers in culture. 展开更多
关键词 Apostichopusjaponicas individual growth variation culture methods family sea cucumber
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Individual variability in life-history traits drives population size stability 被引量:1
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作者 Ned A. DOCHTERMANN C. M. GIENGER 《Current Zoology》 SCIE CAS CSCD 2012年第2期358-362,共5页
Understanding how population sizes vary over time is a key aspect of ecological research. Unfortunately, our under- standing of population dynamics has historically been based on an assumption that individuals are ide... Understanding how population sizes vary over time is a key aspect of ecological research. Unfortunately, our under- standing of population dynamics has historically been based on an assumption that individuals are identical with homogenous life-history properties. This assumption is certainly false for most natural systems, raising the question of what role individual variation plays in the dynamics of populations. While there has been an increase of interest regarding the effects of within popula- tion variation on the dynamics of single populations, there has been little study of the effects of differences in within population variation on patterns observed across populations. We found that life-history differences (clutch size) among individuals ex- plained the majority of the variation observed in the degree to which population sizes of eastern fence lizards Sceloporus undula- tus fluctuated. This finding suggests that differences across populations cannot be understood without an examination of differences at the level of a system rather than at the level of the individual 展开更多
关键词 individual variation Population size variability Ecological stability Demographic stochasticity Demographic heterogeneity Sceloporus undulatus
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Colonies of ants allocate exploratory individuals to where they are ecologically needed
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作者 Max Madrzyk Noa Pinter-Wollman 《Current Zoology》 SCIE CAS CSCD 2023年第5期585-591,共7页
Individual differences in behavior have large consequences for the way in which ecology impacts fitness.Individuals differ in how they explore their environment and how exploratory behavior benefits them.In group-livi... Individual differences in behavior have large consequences for the way in which ecology impacts fitness.Individuals differ in how they explore their environment and how exploratory behavior benefits them.In group-living animals,behavioral heterogeneity can be beneficial because different individuals perform different tasks.For example,exploratory individuals may discover new food sources and recruit group members to exploit the food,while less exploratory individuals forgo the risks of exploration.Here we ask how individual variation in exploratory behavior affects the ability of Argentine ant Linepithema humile colonies to(1)locate novel food sources,(2)exploit known food resources,and(3)respond to disruptions while foraging.To address these questions,we conducted field experiments on L.humile foraging trails in which we manipulated food availability near and at the foraging trails and disrupted the foraging trails.We sampled individuals based on their response to the perturbations in the field and tested their exploratory behavior in the lab.We found that exploratory individuals benefit the colony by locating novel foods and increasing resource exploitation,but they do not play an important role in the recovery of a foraging trail after disruption.Thus,the benefits of behavioral heterogeneity to the group,specifically in exploratory behavior,differ across ecological contexts. 展开更多
关键词 exploration FORAGING individual variation novel resources RECRUITMENT RESILIENCE
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Individual variation in ballooning dispersal by black widow spiderlings: The effects of family and social rearing
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作者 J. Chadwick JOHNSON Rebecca HALPIN Dale STEVENS II Annika VANNAN Jesse LAM Katie BRATSCH 《Current Zoology》 SCIE CAS CSCD 2015年第3期520-528,共9页
Individual behavioral variation is ubiquitous across taxa and important to understand if we wish to fully use beha- vioral data to understand the ecology and evolution of organisms. Only recently have studies of indiv... Individual behavioral variation is ubiquitous across taxa and important to understand if we wish to fully use beha- vioral data to understand the ecology and evolution of organisms. Only recently have studies of individual variation in dispersal behavior become a focus of research. A better understanding of individual variation in dispersal behavior is likely to improve our understanding of population dynamics. In particular, the dynamics of critically small populations (endangered species) and large populations (pest species) may be driven by unique dispersal variants. Here we documented individual variation in the ballooning dispersal behavior of Western black widow spiderlings Latrodectus hesperus, an urban pest species found in superabundant in- festations throughout cities of the desert Southwest USA. We found a great deal of family-level variation in ballooning dispersal, and this variation was highly consistent (repeatable) across time. Maternal egg investment was a poor predictor of this ballooning dispersal. Instead, we show that spiderlings reared in isolation are significantly slower to disperse than spiderlings raised in a more natural setting surrounded by full siblings. Thus, our study examines a widespread but poorly understood dispersal behavior (ballooning), and suggests urban pest population dynamics are likely driven by the interaction of variation in individuals, families and social environments 展开更多
关键词 individual variation Dispersal Spiders BALLOONING Social rearing
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Discovery of an Internasal Bone in Hynobius maoershanensis(Urodela:Hynobiidae) 被引量:2
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作者 Jianli XIONG Xiuying LIU Xiaomao ZENG 《Asian Herpetological Research》 SCIE 2011年第2期87-90,共4页
Internasal bones have generally been recorded in teleostean and tetrapod fossils, being absent in most extant vertebrates. Presently, there has been one case of the internasal bone discovered in a living salamander, P... Internasal bones have generally been recorded in teleostean and tetrapod fossils, being absent in most extant vertebrates. Presently, there has been one case of the internasal bone discovered in a living salamander, Pseudohynobius puxiongensis (Caudata: Hynobiidae). The second case discovered in living salamanders is reported in this article, which is present in one of five specimens ofHynobius maoershanensis, a species endemic to China. This case is again regarded as individual variation. Thus, the presence of an "internasal bone" may represent intraspecific variation and is thus a misleading taxonomic character. 展开更多
关键词 SALAMANDER intemasal bone SKULL ANATOMY individual variation
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Seasonal waterbird population changes in Lashihai Lake in northwest Yunnan, China 被引量:3
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作者 LIAO Jun-tao YE Hui +1 位作者 HUANG Ting-fa PENG Gui-hong 《Journal of Mountain Science》 SCIE CSCD 2017年第9期1852-1862,共11页
We studied the waterbird population at Lashihai Lake, Yunnan Province, China, which is a Ramsar Site(Wetland of International Importance), to determine seasonal variation in the species composition and size of the wat... We studied the waterbird population at Lashihai Lake, Yunnan Province, China, which is a Ramsar Site(Wetland of International Importance), to determine seasonal variation in the species composition and size of the waterbird population. The study was conducted at five selected spots along Lashihai Lake at the same time each week from August 2011 to September 2013. In total, 62 waterbird species were recorded, of which 38.71%, 35.48%, 16.13%, and 9.68% were winter migrants, passage visitors, residents, and summer migrants, respectively. We found important seasonal changes in waterbird species composition and population size. Waterbird species richness was highest from September to the following April, with the total species numbers peaking in December. Total individual numbers peaked twice from late November to early December and mid-to-late February. However, waterbird species and individual numbers were comparatively lower from May to August. The change in species composition was determined by the arrival and departure dynamics of winter migrants and passage visitors. Winter migrants primarily caused the periodic changes in population size. Of concern,species and overall waterbird numbers seemed to be lower than the numbers in historical records. The decline of waterbird numbers implies that environmental changes caused by the implementation of the dam upstream of Lashihai Lake may have had adverse effects on this waterbird population. This study confirms the existence of major seasonal changes in species composition and size of the waterbird population at Lashihai Lake. Furthermore, the findings demonstrate that this wetland is of high conservation importance for waterbirds using the Central Asian–Indian and Asian–Pacific migratory routes. 展开更多
关键词 Seasonal variation Species number individual number Waterbird population
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Quantitative volumetric analysis of the optic radiation in the normal human brain using diffusion tensor magnetic resonance imaging-based tractography
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作者 Dong-Hoon Lee Ji-Won Park Cheol-Pyo Hong 《Neural Regeneration Research》 SCIE CAS CSCD 2014年第3期280-284,共5页
To attain the volumetric information of the optic radiation in normal human brains, we per- formed diffusion tensor imaging examination in 13 healthy volunteers. Simultaneously, we used a brain normalization method to... To attain the volumetric information of the optic radiation in normal human brains, we per- formed diffusion tensor imaging examination in 13 healthy volunteers. Simultaneously, we used a brain normalization method to reduce individual brain variation and increase the accuracy of volumetric information analysis. In addition, tractography-based group mapping method was also used to investigate the probability and distribution of the optic radiation pathways. Our results showed that the measured optic radiation fiber tract volume was a range of about 0.16% and that the fractional anisotropy value was about 0.53. Moreover, the optic radiation probability fiber pathway that was determined with diffusion tensor tractography-based group mapping was able to detect the location relatively accurately. We believe that our methods and results are help- ful in the study of optic radiation fiber tract information. 展开更多
关键词 nerve regeneration optic radiation diffusion tensor imaging diffusion tensor tractogra-phy magnetic resonance imaging volumetric analysis probability map group mapping visualiza-tion individual variation neural regeneration
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Color variation in signal crayfish Pacifastacus leniusculus
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作者 Roberto SACCHI Stefania CANCIAN +2 位作者 Daniela GHIA Gianluca FEA Alan COLADONATO 《Current Zoology》 SCIE CAS CSCD 2021年第1期35-43,共9页
External coloration in animals depends on the interaction of several different factors including the genetics and epigenetics processes that underlie the color expression,the mechanisms of color perception,and the gen... External coloration in animals depends on the interaction of several different factors including the genetics and epigenetics processes that underlie the color expression,the mechanisms of color perception,and the general mechanisms controlling color evolution and function.Among all,camouflages from predators and conspicuousness are of particular interest because pose animal to choose between opposite adjustment in coloration.The external coloration of crustaceans is mainly due to the accumulation of carotenoids in the exoskeleton and the epidermal layer,and the trade-off between camouflage and communication had led to a variety of responses,involving signal partitioning,spectral sensibility,changing coloration,or signaling behavior.Here,we used digital images to explore intrapopulation variability of the external coloration of Pacifastacus leniusculus among body regions within an individual and between sexes.We found that 1)ventral coloration of claws are more saturated and brilliant than upper parts,2)males express a more saturated and brightness coloration than females,especially on the lower portion of claws,3)color intensity and brightness increases with size differently in different body regions,and 4)brightness is more variable in males than in females.All the above patterns support the hypothesis that color in this species could be the result of a compromise between camouflage from predators and conspicuousness for communication.The results of this study suggest that carotenoid might have something to do with intraspecific communication and perform more complex functions than that of a simple pigment. 展开更多
关键词 CRAYFISH external coloration HSV individual variation sexual dimorphism
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Populations with individual variation in dispersal in heterogeneous environments: Dynamics and competition with simply diffusing populations 被引量:1
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作者 Robert Stephen Cantrell Chris Cosner Xiao Yu 《Science China Mathematics》 SCIE CSCD 2020年第3期441-464,共24页
We consider a model for a population in a heterogeneous environment, with logistic-type local population dynamics, under the assumption that individuals can switch between two different nonzero rates of diffusion. Suc... We consider a model for a population in a heterogeneous environment, with logistic-type local population dynamics, under the assumption that individuals can switch between two different nonzero rates of diffusion. Such switching behavior has been observed in some natural systems. We study how environmental heterogeneity and the rates of switching and diffusion affect the persistence of the population. The reactiondiffusion systems in the models can be cooperative at some population densities and competitive at others. The results extend our previous work on similar models in homogeneous environments. We also consider competition between two populations that are ecologically identical, but where one population diffuses at a fixed rate and the other switches between two different diffusion rates. The motivation for that is to gain insight into when switching might be advantageous versus diffusing at a fixed rate. This is a variation on the classical results for ecologically identical competitors with differing fixed diffusion rates, where it is well known that "the slower diffuser wins". 展开更多
关键词 REACTION-DIFFUSION ecology and evolutionary biology population dynamics animal behavior individual variation in dispersal evolution of dispersal
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CONFIDENCE INDEX AND ORAL PROFICIENCY
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作者 李晓陆 《Chinese Journal of Applied Linguistics》 2006年第4期11-14,20+127,共6页
Many researchers confirm that confidence factor plays a significant role in oral English training. However, lack of reliable evaluation methods renders teachers impotent in measuring individual confidence variation. T... Many researchers confirm that confidence factor plays a significant role in oral English training. However, lack of reliable evaluation methods renders teachers impotent in measuring individual confidence variation. They can do little more than form a rough impression on the basis of students' test scores and their personality traits, which proves deceptive and misleading. This paper introduces the notion of confidence index as an evaluation criterion, and empirical investigation reveals the wide variation in individual confidence index. Finally this paper explores the correlation between confidence factor and proficiency. 展开更多
关键词 confidence index individual variation oral proficiency correlation analysis
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Molecular and functional characterization of a candidate sex pheromone receptor OR1 in Spodoptera fitura 被引量:7
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作者 Qin-Hui Zhang Zhong-Nan Wu +1 位作者 Jing-Jiang Zhou Yong-Jun Du 《Insect Science》 SCIE CAS CSCD 2017年第4期543-558,共16页
Olfaction is primarily mediated by highly specified olfactory receptors (ORs). Here, we cloned and identified an olfactory receptor, named SlituOR1 (Genbank no. JN835269), from Spodoptera litura and found evidence... Olfaction is primarily mediated by highly specified olfactory receptors (ORs). Here, we cloned and identified an olfactory receptor, named SlituOR1 (Genbank no. JN835269), from Spodoptera litura and found evidence that it is a candidate pheromone receptor. It exhibited male-biased expression in the antennae, where it was localized at the base of sensilla trichoidea, the antennal sensilla mainly responsive to pheromones in moths. Conserved orthologues of this receptor, found among known pheromone receptors within the Lepidoptera, and SlituOR1 were placed among a clade of candidate pheromone re- ceptors in a phylogeny tree of insect OR gene sequences. SlituOR1 showed differential expression in S. litura populations attracted to traps baited with different ratios of the two sex pheromone components (9Z,11E)-tetradecadienyl acetate (Z9E11-14:OAc) and (9Z,12E)-tetradecadienyl acetate (Z9E12-14:OAc). Knocking down of SlituOR1 by RNA interference reduced the electroantennogram (EAG) response to Z9E11-14:OAc, and this result is consistent with the field trapping experiment. We infer that variation in transcrip- tion levels of olfactory receptors may modulate sex pheromone perception in male moths and could provide some of the flexibility required to maintain the functionality of com- munication with females when a population is adapting to a new niche and reproductive isolation becomes an advantage. 展开更多
关键词 electroantennogram (EAG) individual variation in situ hybridization ol-factory receptor (9Z 11E)-tetradecadienyl acetate (9Z 12E)-tetradecadienyl acetate RNAINTERFERENCE
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