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D. N. Alstad 《Oecologia》1987,71(4):525-531
Summary The dimensions of net meshes constructed by hydropsychid Trichoptera vary both within and between species. Despite these catchnet differences, the diets of most Hydropsychidae studied in Utah streams were statistically indistinguishable. There was no relationship between the size of available resources and catchnet construction among species assemblages inhabiting 10 different localities. A particle-size model of caddis communities, suggesting that taxa feed selectively on particle sizes corresponding to the dimension of catchnet meshes, is not supported by these data.Diatom concentration increased regularly with downstream passage in two different drainages. The identity and number of coexisting hydropsychid species and the size of their catchnets were strongly correlated with diatom concentration. Taxa with large catchnet mesh were the only residents at sites where diatom concentration was very low; as resource concentration increased downstream, species with successively smaller mesh joined the coexisting guild. Together, the broad dietary similarities and distributional pattern from Utah streams suggest that resource concentration, rather than particle size, is the basis of community organization among the hydropsychid Trichoptera.  相似文献   

3.
According to the results of a bioacoustic analysis of the mating calls recorded at the northern end of Lake Skutari, Yugoslavia, this region is inhabited by three water frog phenotypes: Rana ridibunda, R. lessonae and hybrids of these two species. The mating call of R. ridibunda consists of an average of 3.55 pulse groups at all water temperatures. Other parameters of the call, however, are greatly influenced by temperature. The conclusion that the second phenotype is the species R. lessonae was based on the characteristics of the mating call. At a water temperature of 20°C, a call consists of 29 pulse groups repeated at a rate of 24 Hz. Analysis revealed almost complete agreement between this mating call and those of Central and Eastern European R. lessonae. The systematic implications of this finding are discussed. The mating calls of the hybrids of R. ridibunda and R. lessonae are intermediate between those of the parents.  相似文献   

4.
Numbers of species and genera,endemic genera,extant primitive genera,relationship and distribution patterns of presently living Chenopodiaceae(two subfamilies,12 tribes,and 118 genera)are analyzed and compared for eight distributional areas,namely central Asia,Europe,the Mediterranean region,Africa,North America,South America, Australia and East Asia. The Central Asia,where the number of genera and diversity of taxa are greater than in other areas,appears to be the center of distribution of extant Chenopodiaceae.North America and Australia are two secondary centers of distribution. Eurasia has 11 tribes out of the 12,a total of 70 genera of extant chenopodiaceous plants,and it contains the most primitive genera of every tribe. Archiatriplex of Atripliceae,Hablitzia of Hablitzeae,Corispermum of Corispermeae,Camphorosma of Camphorosmaea,Kalidium of Salicornieae,Polecnemum of Polycnemeae,Alexandra of Suaedeae,and Nanophyton of Salsoleae,are all found in Eurasia,The Beteae is an Eurasian endemic tribe,demonstrating the antiquity of the Chenopodiaceae flora of Eurasia.Hence,Eurasia is likely the place of origin of chenopodiaceous plants. The presence of chenopodiaceous plants is correlated with an arid climate.During the Cretaceous Period,most places of the continent of Eurasia were occupied by the ancient precursor to the Mediterranean,the Tethys Sea.At that time the area of the Tethys Sea had a dry and warm climate.Therefore,primitive Chenopodiaceae were likely present on the beaches of this ancient land.This arid climatic condition resulted in differentiation of the tribes Chenopodieae,Atripliceae,Comphorosmeae,Salicornieae,etc.,the main primitive tribes of the subfamily Cyclolobeae. Then following continental drift and the Laurasian and Gondwanan disintegration, the Chenopodiaceae were brought to every continent to propagate and develop, and experience the vicissitudes of climates, forming the main characteristics and distribution patterns of recent continental floras. The tribes Atripliceae, Chenopodieae, Camphorosmeae, and Salicornieae of recent Chenopodiaceae in Eurasia, North America, South America, southern Africa, and Australia all became strongly differentiated. However, Australia and South America, have no genera of Spirolobeae except for a few maritime Suaeda species. The Salsoleae and Suaedeae have not arrived in Australia and South America, which indicates that the subfamily Spirolobeae developed in Eurasia after Australia separated from the ancient South America-Africa continent, and South America had left Africa. The endemic tribe of North America, the tribe Sarcobateae, has a origin different from the tribes Salsoleae and Suaedeae of the subfamily Spirolobeae. Sarcobateae flowers diverged into unisexuality and absence of bractlets. Clearly they originated in North America after North America had left the Eurasian continent. North America and southern Africa have a few species of Salsola, but none of them have become very much differentiated or developed, so they must have arrived through overland migration across ancient continental connections. India has no southern African Chenopodiaceae floristic components except for a few maritime taxa, which shows that when the Indian subcontinent left Africa in the Triassic period, the Chenopodiaceae had not yet developed in Africa. Therefore, the early Cretaceous Period about 120 million years ago, when the ancient Gondwanan and Laurasian continents disintegrated, could have been the time of origin of Chenopodiaceae plants.The Chinese flora of Chenopodiaceae is a part of Chenopodiaceae flora of central Asia. Cornulaca alaschnica was discovered from Gansu, China, showing that the Chinese Chenopodiaceae flora certainly has contact with the Mediterranean Chenopodiaceae flora. The contact of southeastern China with the Australia Chenopodiaceae flora, however, is very weak.  相似文献   

5.
藜科植物的起源、分化和地理分布   总被引:27,自引:0,他引:27  
全球藜科植物共约130属1500余种,广泛分布于欧亚大陆、南北美洲、非洲和大洋洲的半干旱及盐碱地区。它基本上是一个温带科,对亚热带和寒温带也有一定的适应性。本文分析了该科包含的1l族的系统位置和分布式样,以及各个属的分布区,提出中亚区是现存藜科植物的分布中心,原始的藜科植物在古地中海的东岸即华夏陆台(或中国的西南部)发生,然后向干旱的古地中海沿岸迁移、分化,产生了环胚亚科主要族的原始类群;起源的时间可能在白垩纪初,冈瓦纳古陆和劳亚古陆进一步解体的时期。文章对其迁移途径及现代分布式样形成的原因进行了讨论。  相似文献   

6.
Cupressaceae and Taxodiaceae have recently been merged under the earlier name Cupressaceae s.I. by many authors, as the two families are similar in a number of morpho logical characters. Sciadopitys S. et Z., which has often been treated as a morphologically isolated member of the Taxodiaceae, has recently been considered as a monotypic family, Sciadopityaceae. The Cupressaceae s.s. may be reorganized into two subfamilies. The Cu pressoideae is composed of genera with the uppermost cone-scales infertile and can be divided into four tribes: Cnpresseae, including Cupressus, X Cupressocyparis, Charnaecyparis and Fokeinia;Thujopsideae, including Thuja, Thujopsis and Platycladusl Junipereae, including Juniperus and Microbiota; and Tetraclineae, including Calocedrus and Tetraclinis. The Callitroideae is composed of genera with the uppermost cone-scales fertile and can be divided into three tribes: Actinostrobeae, including Actinostrobus, Callitris, Fitzroya and Neocallitropsis; Widdringtoneae, including Pilgerodendron, Diselma and Widdringtonia ; Libocedreae, including Libocedrus, Papuacedrus and Austrocedrus. Five geographical distribution patterns are recognized in the 21 genera of Cupressaceae. (a) One genus, X Cupressocyparis, is a natural hybrid derived from selections in England; (b) Two genera, Cupressus and Juniperus, are distributed in Africa, Europe, Asia and North America; (c) Three genera, Thuja, Chamaecyparis, and Calocedrus, are disjnnctly distributed in Eastem Asia and North America; (d) Five genera, Actinostrobus, Callitris, Libocedrus, Papuacedrus and Widdringtonia, have limited distribution; and (e) The other 10 genera, which are monotypic, are restricted to narrow areas except Plotycladus. Three centers of genera diversity are identified in the Cupressaceae, i. e Eastern Asia with nine genera, southwestern North America with five genera, and Australia and its adjacent islands in the east with six genera, including New Zealand,. Tasmania, New Caledonia, and New Guinea. Other important areas are western Mediterranean with three genera and Chile and Argentinawith three genera.  相似文献   

7.
毛宗铮   《广西植物》1989,9(1):1-11
我国银杉自1955年发现以来,陆续发现了它的新分布,至今已知在四省、区7个分布区的30多个分布点上,自然生长着银杉3200余株。它们是:广西花坪林区(越城岭南部)6个点有银杉1040抹,其中高5米以上的68株,1~5米的49株,1米以下的923株,最高21.1米,最大胸径83厘米;广西大瑶山4个点有银杉143株,其中高10米以上的94株,1~3米的3株,1米以下的46株,最高30米,最大胸径79.2厘米;湖南罗汉洞(越城岭北部)2个点有银杉58株,5米以上的有45株,最高18米,最大胸径43厘米;湖南罗霄山脉八面山有银杉707株,高1米以上的334株,最高24米,最大胸径46厘米;四川南川金佛山(大娄山东段北部)6个点有银杉527株,其中成年树400余株,最高17米,最大胸径50厘米;百枝山有银杉52株,最高8米,最大胸径27厘米;贵州道真沙河林区(大娄山东段南部)3处12个点有银杉729株,其中高5米以上的105株,2~5米的209株,1~2米的111株,1米以下的304株,最高18.8米,最大胸径48厘米;贵州桐梓白菁有银杉10株,高4~5米的2株,1~3米的6株,1米以下的2株。 银杉分布区范围自北纬24°5′~29°13′14″,东经107°10′~113°40′。其垂直分布自海拔940~1840米,金佛山银杉分布最高,为1600~1840米;罗汉洞银杉分布最低,为940~1060米。分布区内,年均温8.2°~17℃,绝对最低温  相似文献   

8.
柏科分类和分布:亚科,族和属   总被引:4,自引:0,他引:4  
柏科Cupressaceae和杉科Taxodiaceae有许多相似之处,近年来不少分类学家主张把两科合并成广义的柏科。原杉科中的金松属Sciadopitys与两科其他属的差异较大,被提升为单种科Sciadopity-aceae。本文根据球果可育种鳞的位置把柏科(狭义)分为2亚科,即上部种鳞不可育的柏木亚科Cupres-soideae和上部种鳞可育的澳洲柏亚科Callitroideae。综合其他形态学和解剖学证据,柏木亚科又分4族,即柏木族Cupresseae(包括:柏术属Cupressus、杂交柏属×Cupressocyparis、扁柏属Chamaecyparis和福建柏属Fokeinia)、侧柏族Thujopsideae(包括:崖柏属Thuja、罗汉柏属Thujopsis和侧柏属Platycladus)、圆柏族Junipereae(包括:圆柏属Juniperus和海参威柏属Microbiota)以及香漆柏族Tetraclineae(包括:翠柏属Calocedrus和香漆柏属Tetraclinis)。澳洲柏亚科又分3族,即澳洲柏族Actinostrobeae(包括:西澳柏属Actinostuobus、澳洲柏属Callitris、智利柏属Fitzroya和杉叶柏属Neocallitropsis)、南非柏族Widdring-toneae(包括:白智利柏属Pilgerodendron、塔斯曼柏属Diselma和南非柏属Widdringtonia)以及甜柏族Libocedreae(包括:甜柏属Libocedrus、巴布亚柏属Papuacedrus和南美柏属Austrocedrus)。柏科21个属的地理分布可划分为5种类型,即:(  相似文献   

9.
The activity of transglutaminase was characterized in the rat brain. In adults, comparable levels of transglutaminase activity are present in all brain regions examined. The activity is present in all subcellular fractions, as studied by differential centrifugation, but the soluble fraction contains the highest specific activity. The endogenous activity (enzyme activity assayed in the absence of the exogenous substrate casein) is very low in all subcellular fractions, except in the synaptosomal fraction where its highest levels are about 40-60% of the activity assayed in the presence of casein. Furthermore, enzyme activity is present on the external surface of synaptosomes. In the soluble fraction, maximal activity can be detected between pH values of 9 and 10 when assayed in the presence of 5 mM CaCl2 (with half-maximal activity requiring 0.75 mM CaCl2) and 0.4 mM putrescine (with an apparent Km for putrescine of 0.1 mM). The activity can be partially inhibited by ZnCl2 (with an IC50 of 4.5 mM) and by AlCl3 (with an IC50 of 5.1 mM). In the cerebellum, where the full span of neuronal development can be studied after birth, the highest specific activity is observed just after birth, thereafter the activity starts to decline and by 14 days, after a reduction of about 65%, it reaches levels observed throughout life.  相似文献   

10.
广州地区淡水水体尿素的分布特征   总被引:2,自引:0,他引:2  
近年来,随着农业的发展,化学肥料尿素的使用量逐年攀升,由于土壤中氮肥的流失,导致水体中尿素含量偏高,对浮游植物的生长繁殖起到了重要的作用。于2007年8月~2008年7月对广州市区、从化市、花都区和增城区四个地区的具有代表性的河涌、河流、人工湖和水库等47个样点的尿素含量进行了一年的监测。结果表明,这四个地区河涌、河流、人工湖和水库都不同程度的受到了尿素的污染,其中广州市区尿素污染最严重,其次是花都区和增城区,污染最轻的是从化市;从水体类型来看,人工湖和大多数水库尿素污染较轻,而人口居住较密集地区和农田附近的河涌和河流污染较严重,可能与人类活动和农业生产关系较大。  相似文献   

11.
12.
滇金丝猴(Rhinopithecus bieti)属于世界珍稀灵长类动物,对它的研究报道仅限于分类地位(彭鸿绶等,1962;彭燕章等,1985;陈服官等,1981)、形态解剖(陈宜峰,1981;彭燕章等,1983;张耀平等,1983)、地理分布及生活习性(李致祥等,1981;木文伟等,1982)等。其分布、数量以及进化地位、生态学等方面的资料甚少。1985年笔者在白马雪山自然保护区对滇金丝猴的数量、分布及种群结构进行了观察。  相似文献   

13.
Bruno Massa 《ZooKeys》2015,(472):77-102
The results of the study of many specimens preserved in different European museums are reported. The tribe Terpnistrini Brunner von Wattenwyl, 1878 is resurrected. The distribution of the following species is enhanced: Pardalota asymmetrica Karsch, 1896, Diogena denticulata Chopard, 1954, Diogena fausta (Burmeister, 1838), Plangiopsis adeps Karsch, 1896, Poreuomena sanghensis Massa, 2013 and Tylopsis continua (Walker, 1869). Further, for their peculiar characteristics, two African representatives of the American genus Symmetropleura Brunner von Wattenwyl, 1878 are included in two new genera: Symmetrokarschia africana (Brunner von Wattenwyl, 1878), comb. n. and Symmetroraggea dirempta (Karsch, 1889), comb. n. A new genus and species from the Democratic Republic of Congo, Angustithorax spiniger gen. n., sp. n., and a new genus and species from Tanzania, Arostratum oblitum gen. n., sp. n. are described. Finally Melidia claudiae sp. n. and Atlasacris brevipennis sp. n. are described and compared with related species.  相似文献   

14.
The classification and the relationships among the genera of Chinese Triticeae were studied based on morphological characters with reference to geographical distribution and habitat conditions. The spike of Triticeae might have been derived from a panicled inflorescence like that in the Bromeae through a racemose inflorescence like the one in the Brachypodieae. There might be three evolutionary lines in the tribe. 1. Pedicels of the panicled inflorescence have become short and bracts decreased in size, which has resulted in a panicled spike with indefinite spikelets or false solitary spikelets at each node of rachis. The middle ribes of both glumes and lemmas and rachilla are not in a single plane. 2. A simple spike with usual solitary spikelets at each node of rachis has been derived from the raceme. The middle ribe of both glumes and lemmas and rachilla are in a single plane. 3. A cymose spike with 3-spikelets at each node of rachis has evolved from the cymose panicle. The glume on the central spikelet is behind the lemma, while those on the lateral spikelets are on lateral sides of the lemmas. From what we have described above Triticeae may be divided into three subtribes: Elyminae, Triticinae and Hordeinae. Then according to the morphological characters of glume, lemma and other organs as well as the habitats and distribution, the native and introduced triticeous plants are classified into 13 genera (Leymus, Elymus, Roegneria, Elytrigia, Aegilops, Triticum, Agropyron, Eremopyrum, Secale, Haynaldia, Psathyrostachys, Hordeum and Hystrix) and their relationships are also discussed meanwhile.  相似文献   

15.
《Journal of Asia》2021,24(3):764-771
Members of the genus Wolbachia are a group of Rickettsia-like, intracellular, maternally inherited bacterial endosymbionts that infect a diverse range of insects and cause reproductive changes in their hosts. Although Wolbachia’s role in many insects has been extensively studied, only a little of their effects on host’s reproduction and their infection frequencies were reported in Lepidopteran which is one of the most diverse insects. Here, we present the first systematic survey of the Wolbachia infection status in different species of moths from three different geographic regions of Thailand, which was carried out during January to December in 2019 with the screening of 1,235 specimens in total of 58 moth species from 13 families. Specimens were collected from Khao Yai National Park (the Central and the Northeast regions), and Kaeng Krachan National Park (the West region). Infections of Wolbachia were screened by using polymerase chain reaction with 16S rRNA, ftsZ and wsp gene primers which the results indicated high rates of Wolbachia infection in moth populations from Thailand. Wolbachia was found in all different geographically populations in total of 625 individuals in total of 28 moth species from 9 families, including 144 individuals (46 males and 98 females) from the Central, 156 individuals (49 males and 107 females) from the Northeast, and 325 individuals (114 males and 211 females) from the West. The highest infection rate was 90.47% in the West populations and the average infection rate was 61.90%. The detection of Wolbachia in different moth populations from all regions was identical when all primers were used to screen for Wolbachia. The relative densities of Wolbachia within each individual were determined using quantitative real-time PCR and the result showed that there was a low Wolbachia infection density in these moth populations. These findings indicated that Wolbachia are distributed throughout the moth populations from Thailand.  相似文献   

16.
Synopsis Catch records from the Hawai'i Cooperative Shark Research and Control Program, which operated in Hawai'i from 1967–1969, were examined and data on the Galapagos shark,Carcharhinus galapagensis were analyzed. A total of 304 Galapagos sharks was caught, predominantly with longlines. More female sharks were caught than males, and the catch was skewed geographically. On the island of O'ahu the highest catch rates occurred along the north and south coasts. High catch rates also occurred near points of land, where longshore currents converge. Average depth of capture was greater for juveniles (45.1 m) and mature males (60.2 m), than for subadults (38.8 m) and mature female sharks (34.2 m). Males appear to reach maturity between 205 and 239 cm total length, and females between 215 and 245 cm. Litter size ranged from 4 to 16 pups, with an average of 8.7. In Hawaiian waters Galapagos sharks are born at just over 80 cm total length. Mating and parturition apparently occur early in the year, and gestation is estimated to be about 12 months. Stomach contents consisted mainly of teleosts and benthic prey, and ontogenetic changes in diet occurred as sharks increased in size. Sharks consumed a smaller proportion of teleosts and more elasmobranchs with increasing size. Dietary diversity also increased with increasing size of shark.  相似文献   

17.
江西发现绵枣儿多倍体复合体多细胞型混合居群   总被引:3,自引:0,他引:3  
对来自江西省新干县三湖镇绵枣儿(Scilla scilloides)多倍体复合体两个居群263个植株进行了细胞学调查,发现4个整倍体细胞型,即BB、BBB、BBBB和ABBB。其中BBBB和ABBB为大陆上首次记录。至此在东亚大陆上已经发现该多倍体复合体12个整倍体细胞型中的9个。这表明东亚大陆也是该复合体细胞型分化的重要地区之一。此地出现ABBB和BBB,而未出现ABB以及非整倍体可能是说明自第四纪以来BB细胞型在大陆和朝鲜半岛的分布区正在收缩;大陆上AABB已经接近消失;而大陆、朝鲜半岛和济州岛(韩国)的BB和AABB混合居群只是残遗。大陆与日本列岛居群细胞型组成的相似性可能暗示着它们的某种历史关系,但是并不能支持日本分布的绵枣儿是从中国引入的“史前归化”植物。  相似文献   

18.
ABSTRACT

Euathlus

Ausserer, 1875 is a South American genus of spiders of the family Theraphosidae known from Chile and Argentina. Three new species from Argentina: Euathlus mauryi sp. n. (from San Juan province), Euathlus grismadoi sp. n. (from La Rioja province), and Euathlus pampa sp. n. (from Salta province) are described here. New records of the previous species Euathlus diamante and Euathlus tenebrarum are contributed. The distribution of these new species expands the geographical distribution of the genus along the Andean hills, with Salta province as the northernmost record of the genus. A key is provided for identification of Euathlus species as well as a map with all the records in Argentina.  相似文献   

19.
金粟兰科的起源,演化及其分布   总被引:9,自引:3,他引:6  
本文利用形态解剖,孢粉学及化石资料,讨论了金粟兰科的系统;并对其起源,演化和现代分布格局形成等问题做了合理推测,主要结果如下:(1)Sarcandra和Chloranthus的亲缘关系最接近,而Ascarina和Hedyosmum的系统位置最靠近。Sarcandra是金粟兰科中最原始的属,而Hedyosmum则是最进化的属。(2)金粟兰科可能于白垩纪最早期起源于木质部无导管的,具简单两性虫媒花的祖  相似文献   

20.
In the present study described the impact of water quality on the Asian clam, Corbicula fluminea, distribution in man – made Pergau Lake was carried out. Recently, Pergau Lake was gazette as state park and any activities related to fishery and agricultural were not allowed in the park. Subsequently, the nearby lake community was affected as many of them earn a living by carrying fisheries activity in the lake especially harvesting Asian clam. 10 sampling sites were selected in the lake to monitor water quality and Asian clam distribution. Water parameters data were also subjected to cluster analysis by using Ward’s method with squared Euclidean distances as a measure of similarity and a dendrogram was successfully generated. The water quality of the lake is under good condition and suitable to carry fishery activities by referred to Malaysia National Water Quality Standards (NWQS). The dendrogram revealed that the sampling sites can be divided into 2 clusters where Location 1 alone in its own cluster. Another cluster possesses 2 sub-clusters where Location 2 and 3 shared similar sub cluster. Another sub-cluster has two groups namely Location 5, 6 and 8 in one group whereas Location 4, 7, 9 and 10 shared similar group. The findings of the present study showed most of sampled Asian clam in Pergau Lake was semi mature indicating highly exploitation of Asian clam in the Lake. Furthermore, there were no correlation was detected between the population of Asian clam and water quality of the lake. Hence, we suggest that seasonal harvesting Asian clam should be implemented in order to conserve the population of Asian clam in the lake at the mean time the community to continue earn a living through carrying fishery activities in the lake.  相似文献   

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