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The inflorescences of Eleocharis elegans and Eleocharis sellowiana were investigated by dynamic headspace/GC–MS for the presence of volatiles. No floral volatile was detected in the inconspicuous inflorescences of E. sellowiana but various floral volatiles were produced by the showy inflorescences of E. elegans. The results are discussed in their ecological and evolutionary context.  相似文献   

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D. W. Snow 《Ibis》2003,145(3):546-546
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During a research project aimed at the study of the Culicinae fauna of Gabon and carried out in the National Park of La Lopé, we captured an unknown sandfly male specimen (genus Phlebotomus) by CDC miniature light trap belonging to a new species for Science. Furthermore, the originality of his genitalia does not allow us to include this species in one of the existing subgenus, thus in this paper we propose the creation of a new subgenus, as Phlebotomus (Legeromyia) multihamatus sp. nov., subg. nov. described from the National Park of La Lopé, through one male captured with CDC miniature light trap. A new species and a new subgenus of sandfly is characterised by a short style with three spines, a paramere wearing a basal hook as well as a basal pouch and the absence of basal lobe on the coxite. The originality of the genitalia of the male gives way to discussion about potential primary homologies between P. multihamatus sp. nov. and Phlebotomus (Abonnencius) fortunatarum, Phlebotomus (Anaphlebotomus) stantoni and Phlebotomus (Euphlebotomus) argentipes, which should be verified for future studies. The discovery of this new species in Gabon must encourage the study of sandflies in this country.  相似文献   

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Hymenopterans have become a model for the study of factors that govern sex allocation. In 1983, Seger proposed a model to study Sphecidae wasps with a strong prediction that sex ratio for univoltine wasps should be 1 : 1 (female : male), and for partially bivoltine species it should be male-biased. The present study investigates if Trypoxylon lactitarse (Saussure, 1867) is a univoltine or a bivoltine species and if Seger's model prediction fits the pattern of sex ratio found in this species. The study was carried out at Parque Municipal das Araucárias, in the municipality of Guarapuava, state of Paraná, southern Brazil, from December 2001 to December 2004. Nests of T. lactitarse were obtained using trap-nests drilled longitudinally to a depth to 80 mm with 7.0, 10.0 and 13.0 mm opening diameter. They were placed in a very heterogeneous site filled with araucaria forests, swamps and grasslands. Trypoxylon lactitarse showed two alternative life histories: either they pupated immediately and emerged as adults later in the same season (direct development), or they entered diapause, overwintering and pupating the following spring (delayed development). Its annual sex ratios were not significantly different from 1 : 1, and both sex ratio of overwintering and sex ratio of direct-developing wasps were also not significantly different from 1 : 1, in all years of this study. By examining these results, it was possible to conclude that although T. lactitarse is a multivoltine species, with four generations per year and two alternative life histories, its sex ratio did not support Seger's model.  相似文献   

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A male infant is described with unusual facial appearance, clubfeet, and moderate hydrocephalus internus without obvious deficiency in mental and physical development. Cytogenetic studies revealed a karyotype of 45,XY,--C,--D,+t(C;D). A chromosome 11 and a 13 are involved in the formation of the translocation chromosome. The long arm of chromosome 13 is linearly attached to the end of the long arm of chromosome 11 (tandem translocation). Chromosome material of the distal part of the long arm of chromosome 11, as well as the short arm plus the centromere of chromosome 13 seem to have been lost.  相似文献   

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The nematode Drilomermis leioderma n. gen., n. sp. (Merrnithidae) is described from larvae of Cybister fimbriolatus (Say) (Dytiscidae: Coleoptera) in Louisiana. Diagnostic characters of the genus Drilomermis are: medium-sized nematodes with the cuticle appearing smooth (lacking cross fibers) under the light microscope, six cephalic papillae, without mouth papillae, six hypodermal cords at midbody, 2 extremely long spicules (longer than 10 times body width at anus) which are separate and parallel (not twisted), an S-shaped vagina, medium-sized amphids located near head papillae, and postparasitic juvenile with a tail appendage. D. leioderma possesses a ventrally displaced mouth, very long vagina, and male genital papillae arranged in 3 double rows in the vicinity of the cloacal opening. Even when containing multiple parasites, about 40% of the hosts sulwived emergence of the memithids and lived several more days. In nature, some of these hosts may be able to continue their development, which is unusual since most mermithid-parasitized hosts die soon after the nematode emerges.  相似文献   

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Abstract Here we use amplified fragment length polymorphism (AFLP) to assess genetic differentiation of Helicoverpa armigera and H. assulta . The results indicated that both species-specific fingerprints and cluster analysis showed the ability of AFLP technique to discriminate the two sibling species; among a total 1963 AFLP markers amplified from nine primer combinations: 777 (39.6%) were H. armigera -specific, 602 (30.7%) were H. assulta -specific, and 584 (29.7%) were common bands. The mean number of H. armigera -specific bands was significantly more than that of H. assulta -specific bands for nine primer combinations ( P < 0.05); the intraspecific distance of H. armigera and H. assulta was 0.123 0 and 0.110 7 respectively, and the interspecific distance was 0.178 3. In addition, the percentage of polymorphic loci and estimated average heterozygosity were used to estimate genetic diversity of the two species. This study therefore demonstrates that AFLP analysis is a sensitive and reliable technique to study genetic differentiation and genetic relationships between species and provides sufficient molecular markers for future linkage map construction, location and eventual cloning of genes involved in traits differentiation.  相似文献   

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Intraspecific diversification of the wildcat (Felis silvestris), including the European wildcat (F. s. silvestris), the Asian wildcat (F. s. ornata) and the African wildcat (F. s. lybica), was examined based on 39 cranial morphology variables. The samples of free‐ranging cats originated from Britain, Europe, Central Asia and southern Africa, consisting of both nominal wildcat specimens (referred to henceforth as ‘wildcats’) and nominal non‐wildcat specimens (‘non‐wildcats’) based on museum labels. The skull morphology of ‘wildcats’ from Britain and Europe is clearly different from that of ‘wildcats’ of Central Asia and southern Africa. The latter are characterized especially by their proportionately larger cheek teeth. On the basis of principal component, discriminant function and canonical variate analyses, the skull morphology of British ‘non‐wildcats’ is less distinct than is that of British ‘wildcats’ from the skull morphologies of ‘wildcats’ of Central Asia and southern Africa. On the other hand, the skull morphology of southern African ‘non‐wildcats’ is as distinct from those of ‘wildcats’ of Britain and Europe as is that of southern African ‘wildcats’. We suggest that the evolution of the modern wildcat probably consisted of at least three different distribution expansions punctuated by two differentiation events: the exodus from Europe during the late Pleistocene, coinciding with the emergence of the steppe wildcat lineage (phenotype of Asian–African wildcat), followed by its rapid range expansion in the Old World. The second differentiation event was the emergence of the domestic cat followed by its subsequent colonization of the entire world with human assistance. Considering the recent evolutionary history of, and morphological divergence in, the wildcat, preventing hybridization between the European wildcat and the domestic cat is a high conservation priority. © 2004 The Linnean Society of London, Biological Journal of the Linnean Society, 2004, 83 , 47–63.  相似文献   

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