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The present study reports on the ultrastructure features of spermatozoa and spermatogenesis of several species of Dysderidae (Dysdera crocata, Dysdera erythrina, Dysdera ninnii, Harpactea arguta, Harpactea piligera, Dasumia taeniifera). Dysderid spiders are known to possess a peculiar sperm transfer form known as synspermia, characterized by fused spermatozoa surrounded by a secreted sheath. Until now the exact mode of formation of the synspermia is unknown. The present study demonstrates that the spermatids are connected via narrow cell bridges during the entire spermiogenesis as is usual, although in Dysderidae they do not separate at end of the spermiogenesis. Instead, they fuse completely within the testes shortly after the spermatid has coiled to get a spherical shape. The number of fusing sperm cells is different in the different observed species. The species of the genus Harpactea thus have synspermia consisting of two fused spermatozoa; whereas in the species of the genus Dysdera four sperm cells are fused and in D. taeniifera at least three spermatozoa are fused. In contrast with other known families with this peculiar form transfer of sperm, the synspermia in Dysderidae are mainly characterized by a conspicuous vesicular area which extends through the entire synspermium surrounding the cell organelles. Thus, all main cell components (e.g., nucleus, acrosomal vacuole, and axoneme) are covered by the vesicular membrane. The vesicular area seems to be functional and probably it is important during sperm activation in female genital system. Simultaneously to the extension of the vesicular area, the synspermium accumulates large amounts of glycogen. The glycogen is mainly located around the centriolar adjunct and along the axoneme accompanying the postcentriolar elongation of the nucleus. A further peculiar feature is the extremely elongated acrosomal vacuole, which seems to be synapomorphic trait for sperm cells of dysderids. Interestingly, spermatogenesis, including the fusion, exclusively occurs within the testes (in contrast to the formation of coenospermia). In the vas deferens only synspermia were found. The secreted sheath surrounding the spermatozoa is finally synthesized in the parts of the vasa deferentia, which are close to the genital opening where numerous vacuoles and microvilli are seen in the epithelial cells.  相似文献   

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1. Feeding behaviour of generalist and specialist predators is determined by a variety of trophic adaptations. Specialised prey‐capture adaptations allow specialists to catch relatively large prey on a regular basis. As a result, specialists might be adapted to exploit each item of prey more thoroughly than do generalists. 2. It was expected that obligatory specialist cursorial spiders would feed less frequently than generalists but for a longer time and, thus, that their foraging pause would be longer. First, the feeding frequencies of three generalist spider species (Cybaeodamus taim, Harpactea hombergi, Hersiliola sternbergsi) were compared with those three phylogenetically related specialist species: myrmecophagous Zodarion rubidum, and araneophagous Nops aff. variabilis and Palpimanus orientalis. 3. Generalists captured more prey, exploited each item of prey for a significantly shorter time, and had a shorter foraging pause than was the case for specialists. Generalists also gained significantly less relative amount of prey mass than did specialists. 4. Second, the study compared the prey DNA degradation rate in the gut of generalists and specialists by means of PCR. The degradation rate was not significantly different between specialists and generalists: the detectability half‐life was estimated to exist for 14.3 days after feeding. 5. This study shows that the feeding strategies of cursorial generalist and obligatory specialist spiders are different. Obligatory specialists have evolved a feeding strategy that is based on thorough exploitation of a few large prey, whereas generalists have evolved a strategy that is based on short exploitation of multiple small items of prey.  相似文献   

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The males of invertebrates from a few phyla, including arthropods, have been reported to practise traumatic insemination (TI; i.e. injecting sperm by using the copulatory organ to penetrate the female''s body wall). As all previously reported arthropod examples have been insects, there is considerable interest in whether TI might have evolved independently in other arthropods. The research reported here demonstrates the first case of TI in the arthropod subphylum Chelicerata, in particular how the genital morphology and mating behaviour of Harpactea sadistica (Řezáč 2008), a spider from Israel, has become adapted specifically for reproduction based on TI. Males have needle-like intromittent organs and females have atrophied spermathecae. In other spiders, eggs are fertilized simultaneously with oviposition, but the eggs of H. sadistica are fertilized in the ovaries (internal fertilization) and develop as embryos before being laid. Sperm-storage organs of phylogenetically basal groups to H. sadistica provide males with last male sperm priority and allow removal of sperm by males that mate later, suggesting that TI might have evolved as an adaptive strategy to circumvent an unfavourable structure of the sperm-storage organs, allowing the first male to mate with paternity advantage. Understanding the functional significance of TI gives us insight into factors underlying the evolution of the genital and sperm-storage morphology in spiders.  相似文献   

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Female Harpactea lepida possess a single genital opening leading into a diverticulum. This diverticulum shows no secretory layer. It continues posteriorly into a receptaculum which is associated with gland cells. In the two already described dysderids, Dysdera crocata and D. erythrina, the bilobed spermatheca lies anteriorly to the diverticulum. Gland cells are associated with the spermatheca and the diverticulum. In H. lepida, the sclerotized genital structures lie dorsally to the diverticulum and consist of a posterior and an anterior part. The posterior part shows a lamella extending laterally to sclerites functioning as muscle attachments. The anterior part has two roundish structures. A hollow stalk-like sclerite functioning as muscle attachment extends towards anterior. The posterior and the anterior part of the sclerotized genital structures fit together. A narrow uterine valve connecting the uterus externus with the diverticulum forms between them. It may be opened by muscles as also suggested for D. erythrina. In H. lepida, spermatozoa embedded in secretion are found in the diverticulum and the receptaculum. There is no evidence that they are stored under different conditions like in D. erythrina. Additional spermatozoa are found in the uterus externus of H. lepida which could be an indication for internal fertilization. Spermatogenesis occurs in cysts in the testes of male H. lepida. In the vasa deferentia, the ductus ejaculatorius and the palpal bulb, the spermatozoa are embedded in homogenous secretion. The palpal bulb has a distal extension bearing a crown-like structure. The embolus is situated at the base of the extension. In memoriam of Konrad Thaler.  相似文献   

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A new species and two new Chinese records in the genus Ulocladium from soil are reported. New species is Ulocladium leve, and the new records are U. alternariae and U. consortiale. Latin diagnosis of the new species is presented. Holotype specimen (dried culture) of the new species and dried cultures of two new records are deposited in the Herbarium of Shandong Agricultural University: Plant Pathology (HSAUP).  相似文献   

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Three new species of the mycophagous aleocharine genus Gyrophaena Mannerheim are described in Korea. The types and paratypes of the new species are designated. Illustrations of the diagnostic characters and habitus photographs of new species are provided with a key to Korean species of Gyrophaena.  相似文献   

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The 125 species of the satyrid butterfly tribe Pronophilini known from the three Andean Cordilleras of Colombia are listed, together with two species whose Colombian status is doubtful. The biological, ecological and biogeographical features of the tribe are described, using the listed species as examples. The features include restriction to moist conditions at high altitudes, endemism in the Cordilleras and in areas and on slopes within them, allopatric speciation and subspeciation, parapatric distributions of related species up the altitude gradients, intraspecific variation and polymorphism and apparent mimicry. The criteria used for classifying the taxa and assessing their relationships are discussed. Seventeen new species, three new subspecies and one new form are described. At the species level, 11 new synonymies are established, two synonymies are rejected, the status of 15 other taxa is revised, and 23 new combinations are made. At the generic level, two new synonymies are established, and one genus is resurrected.  相似文献   

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Knížek M 《ZooKeys》2010,(56):191-206
Fivenew species of the genus Triotemnus from Morocco and Yemen are described. Triotemnus is a new genus of Scolytinae for the Yemen region. External morphology of the new species and all morphologically related species of the genus were studied. While the new species from Morocco are morphologically similar to the known species from the corresponding region, all three newly described species from Yemen, mainly two of them living in Socotra, are morphologically very different from all other known species of the genus. Geographical distribution and the probability of endemicity are discussed.  相似文献   

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《Mycoscience》2014,55(3):196-212
The Longibrachiatum Clade of the genus Trichoderma in Japan was examined, among which two new species and three new records are herewith reported. The new species, T. tsugarense and T. kunigamense were isolated from a bed log (cultivation of Lentinula edodes) and volcanic ash soil, respectively. These species are distinguished from closely related species by growth and morphological characteristics and in phylogenetic analysis. Additional species new to Japan were T. ghanense, T. parareesei and T. sinense. The significance of their distribution is discussed. Most species of the Longibrachiatum Clade are tropical rather than temperate in distribution. Their in vitro optimum growth tends to be >35 °C but the optimum temperature for some Japanese species was lower. Some species are endophytes of temperate plant species, some of which are endemic in Japan.  相似文献   

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A total of 36 spider species of the families Theridiidae, Tetragnathidae and Araneidae are recorded from Aldabra atoll. Of these, 26 are described as new, together with one new subspecies. The taxonomy of the new species is discussed and, for comparative purposes, five other species not from Aldabra are illustrated. One new synonymy is established. Records for each species are given with, in some cases, notes on biology. The possible biological significance of the egg sac strings found in some species is considered. Finally, the biogeographical affinities of the Aldabra species are briefly discussed.  相似文献   

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秦岭鸡皮衣科地衣的初步研究   总被引:4,自引:2,他引:2  
对采自陕西秦岭地区的鸡皮衣科Pertusariaceae地衣进行了形态学、解剖学、化学研究,鉴定出该科地衣3属23种,其中肉疣衣属Ochrolechia8种,鸡皮衣属Pertusaria14种,果疣衣属varicellaria1种。拟苍白肉疣衣Ochrolechiapseudopallescens和类斑点鸡皮衣Pertusariamultipunctoides为中国新记录种。  相似文献   

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茎点霉和叶点霉两属的新种及国内新记录种   总被引:1,自引:0,他引:1  
本文对采自东北地区的115份茎点霉(Phoma)和叶点霉(Phyllosticta)的标本进行分类研究,有新种2个和国内新记录种9个。新种是木瓜生叶点霉(Phyllosticta chaenomelesicola L.Yu et Bai)和草玉铃生叶点霉(Phyllosticta convallaricola L.Yu et Bai)。新种有拉丁文和汉文描述及图。对新记录种作了简要介绍。模式标本保存于沈阳农业大学植保系真菌标本室(HMSAU)。  相似文献   

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本文从形态学、解剖学、化学等方面对采自中国西北地区的树花属Ramalina地衣进行了研究,鉴定出该属地衣18种,其中簇树花R.chihuahuana和平树花R.complanata为中国新记录种,西北地区新记录种有12个。  相似文献   

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The 36 species of the tribe Pronophilini known from the Cordillera de Merida, the main Andean mountain range in Venezuela, are listed, together with three others probably erroneously described or labelled as from the range. The general ecological characteristics of the tribe are described, using the Merida species as examples. These include its restriction to high altitudes, endemism in mountain 'islands', species partitioning up the altitude gradient, mimicry within the tribe, and seasonality. The evolutionary relationships of the 16 endemic species are analyzed. Two new genera, six new species, two new subspecies and one new form are described. Three new synonymies are established, three new combinations made, new status is given to two taxa and the status of one taxon is revised.  相似文献   

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东亚粗叶木属(茜草科)植物纪要   总被引:2,自引:2,他引:2  
朱华 《云南植物研究》1998,20(2):149-159
修订了东亚茜草科粗叶木属植物,新归并11个种名及2个变种名,建立1个新变种,3个新组合变种和1个新等级亚种。报道2个中国分布新记录种。讨论了一些易于混淆种的界限,以及探讨了一些种的植物地理意义。  相似文献   

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