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1.
Narrow-clawed crayfish, Astacus leptodactylus is a native European freshwater crayfish species, also distributed in Croatian freshwater systems belonging to the Black Sea drainage. Its taxonomical status is still in the process of change and discussion, and the data on morphological, molecular, ecological and zoogeographical characteristics of this species are scarce. Therefore, comparative analyses of morphological characteristics were applied with the aim to contribute to the knowledge on the morphometrical and meristical characteristics of A. leptodactylus. Recent research proved that measurements of a large number of morphometrical characteristics, in combination with multivariate statistical analysis, could provide a good instrument for identification and differentiation between populations. In this research altogether 143 animals were analysed (121 from two Croatian populations and 22 from Armenia). 22 morphometrical characteristics and 4 meristical characteristics, per crayfish, were measured. It was found that males and females differ between populations in measured meristical and morphometrical characteristics. None of recorded meristical characteristics proved itself to be reliable characteristic for distinguishing populations. From measured morphometrical characteristics the most discriminant characteristics for separating males from different populations were those describing carapace shape and for females those that describe shape of the claws.  相似文献   

2.
Jasko DJ  Lein DH  Foote RH 《Theriogenology》1991,35(2):317-327
The within-stallion repeatability and effect of season on sperm movement characteristics, determined by computer-aided sperm analysis (CASA), were compared with those of other seminal characteristics. The computer-aided determinations of sperm movement were more repeatable than the seminal characteristics of gel-free volume and sperm cell concentration based on coefficients of variation obtained from the analysis of multiple ejaculates from the same stallions. A significant (P<0.05) seasonal effect on the computer-aided movement characteristic of mean sperm linearity was observed, with a reduction in sperm linearity in the winter months. The percentage of motile and progressively motile cells and mean sperm velocity determined by CASA also tended to be lower in the winter months. These changes in sperm movement characteristics paralleled changes in other seminal characteristics. The use of CASA may have value in the potential fertility evaluation of a stallion in that it can provide relatively precise quantification of sperm movement characteristics from the evaluation of only a few ejaculates. Some CASA derived sperm movement characteristics may be lower during the physiological nonbreeding season than during the breeding season.  相似文献   

3.
金针菇是著名的食、药两用真菌。以45份金针菇品种为试验材料,对21个性状进行分级与评价,对12个数量性状进行分级,并对其中10个数量性状的相关性和2个数量性状的不同测量部位的影响进行了研究。结果表明:所有性状均适合作为DUS(特异性、一致性和稳定性)测试性状,12个数量性状可分别划分为3–5级;10个数量性状至少与1个其他数量性状显著相关;菌柄由上往下逐渐变粗,不同品种变粗程度略有差异,测量菌柄直径时要求测量菌柄上部1/3处;子实体数量由下往上逐渐减少,不同品种减少程度略有差异,测量子实体数量时要求测量单瓶中长度在基部1/3以上的子实体个数;形态性状的聚类分析结果支持将"菌落:表面色素"、"菌盖:纵切面形状"和"菌盖:表面颜色"作为分组性状。  相似文献   

4.
Vocal characteristics of bill morphs of the African finch Pyrenestes ostrinus were investigated to see whether there were differences between the morphs that could potentially lead to assortative mating. Morphological differences between bill morphs are of a scale that could change resonance characteristics, with as a physical consequence, a change in acoustic characteristics. Song and variation in acoustic characteristics are very likely to be an important factor in mate choice. We analysed recordings of large and small-billed birds, and measured 11 acoustic characteristics focusing on frequency use and possibly correlated temporal features. In addition, we investigated in more detail the energy distribution within the frequency limits. We found no differences between bill morphs in acoustic characteristics of courtship song. Our findings contrast with other empirical studies which show an impact of the suprasyringeal vocal tract on song output. One possible explanation could be that the morphological changes affect resonance characteristics in multiple ways which do not operate in concert. Beside proximate aspects, we discuss the role of song and the bill polymorphism in the context of sympatric speciation.  相似文献   

5.
三叶木通茎藤及果实性状评价研究   总被引:4,自引:0,他引:4  
根据湖南、湖北两省野生三叶木通9个茎藤及果实性状的广义方差及主成分分析结果,探讨了三叶木通种源质量及优良品种茎藤、果实性状的选择重点。广义方差分析结果表明:湖北省鹤峰产地的野生三叶木通,9个茎藤及果实性状综合评价为最好,其次是湖北省宜昌、湖南省石门、永定、慈利产地的三叶木通。主成分分析结果表明:在三叶木通优良品种茎藤及果实性状选择中,果皮厚度、单果重、籽重、果皮重及茎藤纹理为第一主成分要素,为首选性状;果实容重、茎藤容重、茎藤色泽及果皮率为第二主成分要素,为比较重要的选择性状;适当注重较深茎藤色泽性状的选择,有可能尽量减少果实容重下降。所以,三叶木通茎藤及果实性状的选择,可以考虑3个主选性状:茎藤纹理及单果重为主体的果实性状、茎藤色泽性状和茎藤容重性状。  相似文献   

6.
Being a highly industrialized country with one of the highest male lung cancer mortality rates in Europe, Belgium is an interesting study area for lung cancer research. This study investigates geographical patterns in lung cancer mortality in Belgium. More specifically it probes into the contribution of individual as well as area-level characteristics to (sub-district patterns in) lung cancer mortality. Data from the 2001 census linked to register data from 2001–2011 are used, selecting all Belgian inhabitants aged 65+ at time of the census. Individual characteristics include education, housing status and home ownership. Urbanicity, unemployment rate, the percentage employed in mining and the percentage employed in other high-risk industries are included as sub-district characteristics. Regional variation in lung cancer mortality at sub-district level is estimated using directly age-standardized mortality rates. The association between lung cancer mortality and individual and area characteristics, and their impact on the variation of sub-district level is estimated using multilevel Poisson models. Significant sub-district variations in lung cancer mortality are observed. Individual characteristics explain a small share of this variation, while a large share is explained by sub-district characteristics. Individuals with a low socioeconomic status experience a higher lung cancer mortality risk. Among women, an association with lung cancer mortality is found for the sub-district characteristics urbanicity and unemployment rate, while for men lung cancer mortality was associated with the percentage employed in mining. Not just individual characteristics, but also area characteristics are thus important determinants of (regional differences in) lung cancer mortality.  相似文献   

7.
The level of the brain permanent potential as a physiological criterion of the functional interhemisphere asymmetry, as well as immunological and biochemical characteristics of peripheral blood in patients with systemic rheumatic diseases were studied. It was found that the distribution of the characteristics of immune response in patients with different types of interhemisphere asymmetry. Significant differences were observed for average values of biochemical and immunological characteristics, their dispersions, as well as for the structure of relationships between the type of the interhemisphere asymmetry and immunobiochemical characteristics.  相似文献   

8.
Mucous glycoproteins of teleostean fish: a comparative histochemical study   总被引:1,自引:0,他引:1  
Synopsis To examine the hypothesis that the histochemical characteristics of teleostean mucus reflect functional characteristics, mucous cells were studied in four related and behaviourally similar species of fish (Family Belontidae). Histochemical characteristics were determined with Alcian Blue at both pH 2.6 and pH 1.0 followed by the periodic acid-Schiff technique. It was found that the four species differed in glycoprotein type as well as in number of mucus-containing cells. The differences are ciscussed in regard to functional characteristics and environmental influence.  相似文献   

9.
Studies have linked variation in feeding and foraging success to variation in survival and reproductive success, which makes exploring influences on feeding invaluable. In the current study, we quantified energy contents of foods consumed by wild golden lion tamarins (Leontopithecus rosalia, GLT) and feeding behaviors of 34 GLT from March 1998 to March 1999. Our objective was to test predictions regarding effects of characteristics of the 1) individual, 2) group, 3) environment, and 4) other behaviors on 3 feeding behaviors: feeding on plant matter, searching for prey, and feeding on prey. We hypothesized that environmental characteristics, e.g., resource availability, in addition to group characteristics e.g., group size, would influence feeding on plant matter, because several individuals in a group often consume fruit in the same fruit tree. We hypothesized that environmental characteristics and individual characteristics, e.g., age, would influence searching for and consuming prey because the individual often searches for and consumes prey while it is alone at a substrate. We used SAS mixed models to determine the relative influence of these characteristics on the feeding behaviors. We found that group characteristics more significantly influenced feeding on plant matter, while individual characteristics more significantly influenced searching for prey. The results emphasize the distinctly different influences of individual and group characteristics on feeding. That influences other than competition may affect feeding on plant matter warrants further exploration. An erratum to this article can be found at  相似文献   

10.
Animal signal characteristics vary at multiple levels, and this variation can be related to the selective forces acting on signal structure. However, the effectiveness of selection acting on any one signal type may depend on selective forces acting on the same characteristics in other signal types, particularly if the signals share a common physical production mechanism. In anurans, signal variability has been related to the potential for various forms of selection by female choice on the characteristics of male advertisement calls. The significance of variability in the characteristics of another vocalization type, the aggressive call, is less well understood. In the present stiudy, within‐ and between‐male variability was measured in several characteristics of both advertisement and aggressive calls in the treefrog Dendropsophus ebraccatus. Many characteristics of both call types were repeatable within males. Fine‐temporal and spectral characteristics generally had low variation within males, whereas gross‐temporal characteristics were more variable. Unexpectedly, there were strong correlations between both measures of variability and mean values of the call characteristics of advertisement and aggressive calls. Thus, despite potentially conflicting selection pressures acting on advertisement and aggressive calls, the characteristics of individuals' calls were consistent across these two signal types. The potential forces responsible for consistency across call types are discussed, including morphological constraints and behavioural syndromes that act across different signalling contexts. In general, it is argued that measurements of variability made across multiple signal types, as in the present study, can provide important insights into the evolution of signal structure in organisms with complex signal repertoires. © 2013 The Linnean Society of London, Biological Journal of the Linnean Society, 2013, 109 , 131–145.  相似文献   

11.
中国西南部明纹花鼠三个亚种的分化   总被引:1,自引:0,他引:1  
明纹花鼠是东南亚地区的特有种,在中国有3亚种(阿萨姆亚种、滇西亚种、滇南亚种),分布于藏东南、云南西南部和南部。以往主要根据外部形态特征进行分类。为探讨3亚种头骨性状的差异,在测量15个陛状的基础上,运用统计分析软件SPSS 11.0对其可测量性状进行多变量分析。结果及推测如下:①明纹花鼠3个亚种的地位是确定的。②在头骨15个性状中,两两亚种之间具有显著差异的性状:阿萨姆亚种与滇西亚种有8个(枕鼻长、吻宽、颤宽、眶间宽、后头宽、鼻骨宽、下齿列、下颌骨高);阿萨姆亚种与滇西亚种有7个(颅全长、枕鼻长、颧宽、眶间宽、后头宽、下颌高、下颌骨高);滇西亚种与滇南亚种有4个(吻宽、后头宽、鼻骨宽、下颌高)。③滇南亚种与滇西亚种之间的亲缘关系近:于两者各自与阿萨姆亚种之间的亲缘关系。  相似文献   

12.
本文对蟋蟀科Grylidae棺头蟋属Loxoblemmus6种常见种类的鸣声特征进行了较为系统的分析研究。从其频域特征和时域特征上明显地显示了种间差异,并将其鸣声特征用于分类。  相似文献   

13.
蟋蟀常见鸣声类型的比较研究(直翅目:蟋蟀总科)   总被引:7,自引:0,他引:7  
对蟋蟀的3类常见鸣声(召唤声、求偶声、争斗声)进行了分析比较,同种3类鸣声在频域特征和时域特征上存在差异,但也有一些相似的特征;3类鸣声中,召唤声在分类研究上更有应用价值。  相似文献   

14.
Teeth are one of the most important materials for anthropological studies because they are likely to be preserved in ancient remains.While the frequencies of dental characteristics can provide clues to the phylogeny of populations,genetic studies at the individual level can further reveal the biological mechanisms and evolutionary context of dental characteristics.In this study,by analyzing 38 dental characteristics of 242 Xinjiang Uyghur individuals,we found that(i)the dental characteristics of the Uyghurs showed evidence of admixture between European and East Asian populations.The admixture proportions were in line with those previously reported in population genetic studies;(ii)the Xinjiang Uyghur dental characteristics formed three clusters in pairwise correlation analysis.One of the main clusters consisted of characteristics including incisor shoveling,double shoveling and mesial ridge;and(iii)all the characteristics in this cluster were significantly correlated with the genetic variant EDARV370A.The extracted composite phenotypic factor was also significantly associated with EDARV370A,which explained 18%of the total phenotypic variance.This indicated a pleiotropic effect,i.e.,the same genetic factor affects a number of dental characteristics at the same time.Our results confirmed that EDARV370A,a genetic variant that first originated in East Asia about 30000 years ago,played an important role in incisor shoveling in East Asia.This finding suggested that incisor shoveling in modern humans in East Asia is likely to have appeared after the late Pleistocene.  相似文献   

15.
Studies have linked variation in feeding and foraging success to variation in survival and reproductive success, which makes exploring influences on feeding invaluable. In the current study, we quantified energy contents of foods consumed by wild golden lion tamarins (Leontopithecus rosalia, GLT) and feeding behaviors of 34 GLT from March 1998 to March 1999. Our objective was to test predictions regarding effects of characteristics of the 1) individual, 2) group, 3) environment, and 4) other behaviors on 3 feeding behaviors: feeding on plant matter, searching for prey, and feeding on prey. We hypothesized that environmental characteristics, e.g., resource availability, in addition to group characteristics e.g., group size, would influence feeding on plant matter, because several individuals in a group often consume fruit in the same fruit tree. We hypothesized that environmental characteristics and individual characteristics, e.g., age, would influence searching for and consuming prey because the individual often searches for and consumes prey while it is alone at a substrate. We used SAS mixed models to determine the relative influence of these characteristics on the feeding behaviors. We found that group characteristics more significantly influenced feeding on plant matter, while individual characteristics more significantly influenced searching for prey. The results emphasize the distinctly different influences of individual and group characteristics on feeding. That influences other than competition may affect feeding on plant matter warrants further exploration.  相似文献   

16.
Questionnaires were distributed in 3308 families divided into two groups: group 1 with no cases of acute intestinal infections and group 2 where such cases were registered. Information contained in the questionnaires was processes by means of computers bzsm-6. The analysis of the data on the occurrence of characteristics indicating the quality of water supply and water consumption (25 characteristics), sewage and sanitation (12 characteristics), living conditions (19 characteristics) showed that the living conditions of the families in group 2 were worse than those of the families in group 1. The occurrence of these characteristics in the families of patients with acute intestinal infections and in the families of carriers were mostly the same, and the existing differences in such characteristics as "fishing", "use of water from ponds for house-hold purposes" proved to be nonessential. The population of the city was divided into four risk groups with regard to the possibility of contacting infection, depending on the conditions of water supply, water consumption and sewage in different housing areas: the group registered as stable on account of sanitary and hygienic conditions, the groups of usual, increased and maximum risk.  相似文献   

17.
Sexual selection through female mate choice for genetic characteristics has been suggested to be an important evolutionary force maintaining genetic variation in animal populations. However, the genetic targets of female mate choice are not clearly identified and whether female mate choice is based on neutral genetic characteristics or on particular functional loci remains an open question. Here, we investigated the genetic targets of female mate choice in Alpine marmots (Marmota marmota), a socially monogamous mammal where extra‐pair paternity (EPP) occurs. We used 16 microsatellites to describe neutral genetic characteristics and two MHC loci belonging to MHC class I and II as functional genetic characteristics. Our results reveal that (1) neutral and MHC genetic characteristics convey different information in this species, (2) social pairs show a higher MHC class II dissimilarity than expected under random mate choice, and (3) the occurrence of EPP increases when social pairs present a high neutral genetic similarity or dissimilarity but also when they present low MHC class II dissimilarity. Thus, female mate choice is based on both neutral and MHC genetic characteristics, and the genetic characteristics targeted seem to be context dependent (i.e., the genes involved in social mate choice and genetic mate choice differ). We emphasize the need for empirical studies of mate choice in the wild using both neutral and MHC genetic characteristics because whether neutral and functional genetic characteristics convey similar information is not universal.  相似文献   

18.
This study uses an ecological perspective to explore the unique associations of maternal personal characteristics, parenting behaviors, and adolescents' own characteristics to posttraumatic distress and symptoms of arousal, avoidance, and intrusions, in 97 early adolescents and mothers from the Washington, DC, area to the events of September 11, 2001. Maternal characteristics and/or adolescents' perceptions of parenting behaviors were uniquely related to adolescents' responses, controlling for adolescents' own characteristics. Maternal responses and parenting behaviors play key roles in adolescents' continuing responses to the traumatic events of September 11.  相似文献   

19.
为明确喀斯特森林植物叶片功能性状对土壤特性的响应,采用样地与样线相结合的方法调查茂兰喀斯特森林的木本植物群落,计算不同地形木本植物叶片加权平均性状值,运用单因素方差分析和冗余分析不同地形植物叶片功能性状的差异及其与土壤特性的关系。结果表明, 在生长型(常绿、落叶)和群落水平上,植物叶片功能性状在不同地形间存在显著差异(P<0.05),其中叶面积最为敏感,对生境的响应明显,常绿植物的叶厚度大于落叶植物,比叶面积则相反,而叶绿素含量差异不显著(P>0.05)。不同地形间土壤特性差异显著(P<0.05),漏斗地形土壤的田间持水量、毛管孔隙度、全氮含量、全磷含量及有机质含量较高,土壤肥力最佳,槽谷和阴坡次之,而阳坡地段土壤相对贫瘠。不同地形植物叶片功能性状与土壤特性间具有相关性,但不同地形土壤特性对叶片功能性状变异的解释率不同,影响植物叶片功能性状的主要土壤特性为有机质含量、全氮含量、全磷含量、田间持水量和土壤容重。茂兰喀斯特森林不同地形植物叶片功能性状和土壤特性的差异较大,随着土壤特性的改变,叶片功能性状的响应特征不同,这有利于林区物种共存及生物多样性维持。  相似文献   

20.
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