首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 31 毫秒
1.
The locust genus Schistocerca (Stål) has a transatlantic disjunction, which has been controversial for more than a century. Among 50 species within the genus, only one species, the desert locust (S. gregaria Forskål), occurs in the Old World, and the rest occur in the New World. Earlier taxonomists suggested that the desert locust is a migrant from America, but this view was strongly challenged when a large swarm of the desert locust successfully crossed the Atlantic Ocean from West Africa to the West Indies in 1988. The currently accepted view, supported by this incident, is that the New World species are descendants of a gregaria-like ancestor, and the desert locust would be ancestral to the rest of the genus. However, there is surprisingly little evidence to support this view other than the 1988 swarm. I present the most comprehensive phylogenetic study that suggests that the desert locust originated from the New World, contrary to the accepted view. I also present a hypothesis about how the ancestral Schistocerca might have colonized the New World in the first place in light of phylogenetic relationships with other cyrtacanthacridine genera.  相似文献   

2.
The biology of the veliid bug M. d. atrolineata, its predatory behavior, and the effects of plural hunting were studied to evaluate its role as a predator of the brown planthopper Nilaparvata lugens in the Philippines. The probability of planthoppers falling onto the water surface and provision of habitat continuity was measured by a sticky trap placed at the base of rice hills in a greenhouse and in paddy fields. The developmental period of immature stages combined was 21 days. If given prey, females laid 25 eggs on the average during an adult life span of 18 days. Starved adults could survive for only 3–5 days. The functional response to prey density was sigmoid, and the maximum number of prey killed was 7 per day. Prey feeding was completed in 12–36 min. The percentage of successful prey attacks averaged 5–8%, decreasing with higher (and larger) developmental. stages of prey, but adult prey were found the soonest. Plural hunting increased the probability of capturing prey by as much as 2.5 times that by individual hunting. Late-instar nymphs, which may be more active, fell from rice hills in a greenhouse more than early-instar nymphs, and the number falling increased with density. In the field the percentage of planthoppers falling to the water in 1 day varied considerably, from 1% for nymphs in one field to 67% for adults in another field. On the basis of work described above and given the high density of veliid predators in flooded paddy fields of tropical Asia, M. d. atrolineata is considered one of the most important natural enemies of the brown planthopper.  相似文献   

3.
4.
The present work reports on a neuroanatomical study of the butterfly Pararge aegeria (Lepidoptera : Satyridae) focusing on the lamina ganglionaris underlying two different regions of the retina of the compound eye: the dorsal rim area and the large dorsal region. No differences between both lamina regions, concerning the structure of the cartridges and the morphology of the identified neurons, could be detected. After passing the basement membrane, the visual cell axons are organized in retinotopic bundles (pseudocartridges), in which the axons of the 9 visual cells (V1 and 5, D2, 4, 6, 8, H3 and 7, B9) are arranged in the same way as in the retina. In the pseudocartridge there are no synaptic contacts. Before entering the lamina cartridge, the bundles rotate 90 °. The cartridges are joined by the fibres of 4 monopolar cells (L1, L2, L3 and L4), which could be identified and located inside the lamina cartridges in serial EM-sections. Golgi impregnations revealed the morphology of these fibres. Thus, the regional specialization of the retina (dorsal rim area and large dorsal region) does not seem to be reflected at the level of the first visual neuropil. Additionally, the cartridges of both lamina regions were investigated qualitatively for synaptic contacts among fibres. In addition to monadic chemical synapses and multiple contact synapses with presynaptic ribbons, cell contacts are also facilitated by invaginations and bridges. These cellular interactions and their functional implications are discussed.  相似文献   

5.
6.
The fine structure of the reproductive accessory gland of the parthenogenetic thrips Heliothrips haemorrhoidalis (Thysanoptera : Thripidae) is reported. It consists of an apical bulb and a fine gland duct. The former consists of an epithelium with secretory and duct-forming cells surrounding a large gland lumen lined with a thin cuticle and filled with dense secretion. Spent secretory cells degenerate and are eliminated from the epithelium. The gland duct is characterized by an irregular, branched lumen surrounded by a very flat epithelium. A valve controls the opening of the duct lumen. The proximal gland duct runs through a cuticular papilla that opens between the dorsal ovipositor valves. The secretions may serve for ovipositor valve lubrication and possibly to protect laid eggs. Observations of serial sections through the vagina exclude the presence of a spermatheca in this species.  相似文献   

7.
Pharyngodon medinae García-Calvente, 1948 (Nematoda: Pharyngodonidae) is redescribed from Podarcis pityusensis (Bosca, 1883) (Sauria: Lacertidae) of the Balearic Islands (Spain) and confirmed as a member of the genus Skrjabinodon Inglis, 1968. A systematic review of S. medinae and closely related species is also given. Parathelandros canariensis is referred to Skrjabinodon as a new combination and Parathelandros Magzoub et al., 1980 is dismissed as a junior homonym of Parathelandros Baylis, 1930.  相似文献   

8.
During 2009–2011, mosquitoes were captured in CDC miniature light traps using CO2 (dry ice) at six sites in the Lower Dyje River Basin (Czech Republic). Other methods of capture — sweeping from vegetation and collection of larvae and pupae from ponds — were also used for more precise diagnostics. Thirty mosquito species of six genera were confirmed. A total of 415,218 females were captured. Most frequently found were the outbreak species Aedes vexans (56.52% of all mosquitoes collected) and Ae. sticticus (16.40%). Among other flood species, Ae. rossicus (5.17%), Ae. cantans and Ae. annulipes (2.44% of all females collected), and Ae. cinereus s. l. (1.11%) were especially abundant. Females of Ae. cataphylla were captured in spring (0.31%) and Ae. intrudens was numerous only at one site. Among the other species, Culex pipiens s. l. (6.61%) and Cx. modestus (8.87%) were abundant. Anopheles maculipennis s. l. (1.01%), An. claviger (0.43%), An. plumbeus (0.08%), An. hyrcanus (0.08%), Coquillettidia richiardii (0.52%) and Culiseta annulata (0.18%) were also detected. Sparsely occurring were Ae. excrucians, Ae. flavescens, Ae. caspius and Ae. geniculatus. Captured only very sporadically were Ae. communis, Ae. leucomelas, Ae. dorsalis, Ae. rusticus, Cx. martinii, Cx. territans, Cs. morsitans and Uranotaenia unguiculata.  相似文献   

9.
Myrmecia dispar (Clark) is found in the drier inland areas of New South Wales and southern Queensland in Australia. Its nests, which are situated adjacent to trees, have a distinctive structure of simple architecture. The composition of the colonies varies seasonally with little or no brood production during the colder months. Colony founding probably takes place in March, April, and/or May. Several myrmecophiles are found in nests ofM. dispar, and some of these are present in relatively large numbers.  相似文献   

10.
The synthesis of a peptide-PEG-oligonucleotide chimera is compared when starting from the peptide or from the oligonucleotide sequence.  相似文献   

11.
The wing louse genus Lunaceps, is the most speciose chewing louse (Phthiraptera) genus inhabiting sandpipers (Charadriiformes: Calidrinae) and is known from almost all sandpiper species. The hosts follow specific flyways from the Arctic breeding grounds to wintering locations in the southern hemisphere, and often form large mixed-species flocks during migration and wintering. We estimated a phylogeny of Lunaceps based on three mitochondrial loci, supporting monophyly of the genus but revealing extensive paraphyly at the species level. We also evaluated the relative importance of flyway differentiation (same host species having different lice along different flyways) and flyway homogenisation (different host species having the same lice along the same flyway). We found that while the lice of smaller sandpipers and stints show some evidence of flyway homogenisation, those of larger sandpipers do not. No investigated host species migrating along more than one flyway showed any evidence of flyway differentiation. The host-parasite associations within Lunaceps are in no case monophyletic, rejecting strict cospeciation.  相似文献   

12.
The Coccinellidae (ladybirds) is a highly speciose family of the Coleoptera. Ladybirds are well known because of their use as biocontrol agents, and are the subject of many ecological studies. However, little is known about phylogenetic relationships of the Coccinellidae, and a precise evolutionary framework is needed for the family. This paper provides the first phylogenetic reconstruction of the relationships within the Coccinellidae based on analysis of five genes: the 18S and 28S rRNA nuclear genes and the mitochondrial 12S, 16S rRNA and cytochrome oxidase subunit I (COI) genes. The phylogenetic relationships of 67 terminal taxa, representative of all the subfamilies of the Coccinellidae (61 species, 37 genera), and relevant outgroups, were reconstructed using multiple approaches, including Bayesian inference with partitioning strategies. The recovered phylogenies are congruent and show that the Coccinellinae is monophyletic but the Coccidulinae, Epilachninae, Scymninae and Chilocorinae are paraphyletic. The tribe Chilocorini is identified as the sister-group of the Coccinellinae for the first time.  相似文献   

13.
The genus Echiniscus C.A.S. Schultze, 1840, one of the earliest established and speciose tardigrade genera, has been hypothesized to be polyphyletic. Moreover, the presence or absence of trunk appendages, the type of cuticular sculpturing and body colour have been argued to hold taxonomic significance at the genus level in Echiniscus-line taxa. Here, by combining morphological and genetic analyses, we demonstrate that the so-called “arctomys group”, i.e. Echiniscus spp. lacking trunk appendages, comprises numerous separate evolutionary lineages within the family Echiniscidae. As a result, we erect five new echiniscid genera: Barbaria gen. nov. , presumably of Neotropical (Gondwanan) origin, previously classified as the Echiniscus bigranulatus group; the pantropical and subtropical Kristenseniscus gen. nov. (the tessellatus group), characterized by a peculiar subdivision of dorsal plates; Claxtonia gen. nov. (the wendti group), with large and evident endocuticular pillars in the form of polygons; Nebularmis gen. nov. (the reticulatus group), with an elusive dorsal sculpturing; and Viridiscus gen. nov. (the viridis group), with body colour ranging from light green through brownish to even almost black. Additionally, we briefly address appendaged Echiniscus s.s. and divide the genus into several groups based on dorsal plate sculpturing and suggest that these could also represent separate supraspecific entities.  相似文献   

14.
15.
Three new Annitella species (Trichoptera, Limnephilidae, Chaetopterygini) from the Iberian Peninsula, Annitella amelia sp.n. (Portugal), A. cabeza sp.n. (Spain) and A. lalomba sp.n. (Spain) are described. Psilopteryx (Acropsilopteryx) esparraguera Schmid, 1952 and Psilopteryx sanabriensis Gonzales and Otero, 1985 are transferred to the genus Annitella. Brief decriptions and illustrations of these species and of the related species A. pyrenaea (Navás, 1930) are given. A sketch map of the distribution of the Annitella species in the Iberian Peninsula is included.  相似文献   

16.
17.
The taxonomy of marsupials from the late Paleogene of North America (Chadronian to Arikareean North American land mammal ages: late Eocene–late Oligocene) is reviewed based on new and previously undescribed fossil material as well as reevaluation of previously described material. Two families are recognized, the Herpetotheriidae and Peradectidae. Nine species of herpetotheriids are recognized within two genera: Herpetotherium Cope, 1873a and Copedelphys Korth, 1994, including one new species, H. tabrumi. The greatest diversity of herpetotheriids was in the Chadronian (four species). By the late Arikareean, only a single species is recognized. The range of Copedelphys is extended into the early Whitneyan (previously limited to Chadronian–Orellan). Among species of Herpetotherium, the ranges of two species have been extended: H. valens (Lambe, 1908) from the Chadronian is reported from the Orellan, and H. marsupium (Troxell, 1923) from the Uintan and Duchesnean is reported from the early Chadronian. The range of H. merriami (Stock and Furlong, 1922), previously only known from the Arikareean of Oregon, is expanded geographically eastward to Montana. Within the Peradectidae only three species are recognized: Peradectes cf. californicus (Stock, 1936) and Didelphidectes pumilis Hough, 1961 from the Chadronian, and Nanodelphys hunti (Cope, 1873b) from the Orellan to early Arikareean. Specimens previously identified as an unnamed new species of Nanodelphys from the Whitneyan and Arikareean are referred here to N. hunti.  相似文献   

18.
Fine structure of the midgut and degeneration of the midgut epithelium of the scorpionfly Sinopanorpa tincta (Navás) adults were investigated using light microscopy and scanning and transmission electron microscopy. The results show that the tubular midgut lacks gastric caeca and is composed of an outer longitudinal and an inner circular muscle layer, a basal lamina, an epithelium and a lumen from the outside to inside. A peritrophic membrane was not found in the lumen. A mass of nodules was observed on the surface of the basal lamina. Three types of cells were recognized in the epithelium: digestive, secretory, and regenerative cells. The digestive cells contain irregular-shaped infoldings in the basal membrane and two types of microvilli in the apical membrane. The secretory cells are characterized by irregular shape and large quantities of secretory granules in the basal cytoplasm. The regenerative cells are triangular in shape and distributed only in the nodules. The epithelial cells are degenerated through programmed cell-death mechanisms (apoptosis and necrosis). The type, function, and degeneration of the epithelial cells of the midgut are briefly discussed.  相似文献   

19.
Genetically tractable organisms with relatively simple nervous systems offer a realistic platform to understand how and where memories are formed and stored in defined neural circuits. Recent work in Drosophila provides promise that this analysis may soon reach the resolution of identifiable synapses.  相似文献   

20.
(1) Clematis taiwaniana Hayata, C. grata Wall. var. ryukiuensis Tamura, C . sikkimensis (Hook. f. & Thoms. ) Drumm. ex Burkill, C. connata DC. var. bipinnata M. Y. Fang, C. kilungensis W. T. Wang & M. Y. Fang etc. are reduced to synonymy. (2) New classifications for sect. Tubulosae Decne., C. siamensis Drumm. & Craib and C. connata DC. are proposed. (3) 3 series, 3 species and 4 varieties are described as new. (4) 6 new combinations and 3 newranks are made.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号