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Agroecosystems are altered systems whose soil structure has changed affecting the dynamics of soil organisms. This paper aims at evaluation of the effects of garlic farming practices on phenology, richness, abundance, composition and diversity of soil-dwelling Cunaxidae. Ten pilot plots in Guanajuato State were sampled from August 2002 to July 2005, every month, 8 months per year. Ten soil samples (1 kg) were taken from each plot and extracted in Berlese-Tullgren funnels. A total of 108 cunaxids were found, belonging to 11 species. Neocunaxoides andrei was the most abundant, and Cunaxa evansi and Armascirus sp. were least abundant. Relative abundance was highest after harvesting and during plant growth, and lowest during planting. Dactyloscirus nicobarensis and D. candylus were present from planting to harvesting. According to Sörensen’s similarity coefficient between cultivation stages, Cunaxidae communities were similar during plant growth and harvesting, sharing 80 % of the species. The highest abundance and diversity were found in 2004, during and after harvesting. Cunaxid species increased over 100 % from planting to the harvesting phase, suggesting that they play an important role in the soil agrosystems food web. Species composition and diversity in cunaxid communities present in garlic crop fields varied with agricultural phase, but little change was observed among the years studied. All species found in this study are new records for the state of Guanajuato and for the garlic crop fields.  相似文献
2.
A new species of Pseudachorutes is described and illustrated from Nicaragua. Pseudachorutes nicasp. n. is very easy to distinguish from other members of this genus from Central America, because its chaetotaxy consists of macro and microsetae and a postantennal organ with multiple vesicles (close to 20).  相似文献
3.
In order to assess the phylogenetic structure of the springtail genus Palmanura, as well as to test the monophyly of the tribe Sensillanurini (Neanuridae: Neanurinae), a data matrix of morphological (chaetotactic and other) characters of members of this group was assembled and analysed in the light of Wagner parsimony. The data matrix included all the known members of the Neotropical genus Palmanura, plus representatives of Sensillanura and Americanura. Although not all the clades obtained were highly supported by bootstrap resampling, some structures were relatively constant under different approaches. Alternative analyses (unordered and ordered character states, rescaled weighting procedure) were applied. While alternative solutions were obtained, a number of structures were shared by the results irrespective of the method used. On this basis, the results suggest that some further reassessment is required to confirm formally the monophyly of the tribe Sensillanurini. The genera Palmanura and Americanura are mutually poly/paraphyletic; we thus suggest that Palmanura should be considered as a synonym of Americanura, although some character reassessment and more varied outgroup species may be necessary before a formal generic redefinition can be proposed. Finally, a comparison of the performance of the characters under Wagner parsimony analysis indicated that differences in the characters’ retention indexes are due not to the topological (tagmal) position of the traits involved, but to character coding: the characters describing quantitative features (generally numbers of setae) generally performed worse than other types of characters under parsimony. An updated list of the known members of the Sensillanurini (Collembola: Neanuridae: Neanurinae) is presented.
© The Willi Hennig Society 2009.  相似文献
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