Isoptera

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  • 文章类型: Journal Article
    自2007年以来,在肯尼亚的两个试验地点进行了一项长期实验,以评估有机和常规耕作系统对生产力的影响,盈利能力和可持续性。在这些试验期间,观察到大量白蚁(等翅目)的存在。白蚁是主要的大型土壤动物,在文献中,它们要么被描述为“害虫”,要么被描述为环境可持续性的重要指标。白蚁可以被管理以避免作物损害的程度,但是提高农业系统的可持续性是值得理解的。因此,在肯尼亚的长期实验中增加了一项关于白蚁的研究。研究的目的是量化有机(Org)和常规(Conv)农业系统在两个输入水平(低和高)对丰度的影响,发病率,白蚁的多样性和觅食活动。
    结果显示白蚁丰度较高,发病率,与Conv-High相比,组织中的活动和多样性高,Conv-Low和Org-Low。然而,每个系统中白蚁的存在也取决于土壤深度,试验地点和种植季节。在实验过程中,确定了九个不同的白蚁属,属于三个亚科:(i)巨蚁科(属:Allodontotermes,Ancistrotermes,Macrotermes,Microtermes,Odontotermes和Pseudocotermes),(ii)Termitinae(Amitermes和Cubitermes)和(iii)Nasuttiermitinae(Trinervitermes)。
    我们假设白蚁在不同的耕作系统中的存在可能会受到所应用的投入类型的影响,土壤水分含量和天敌的发生。我们的发现进一步表明,有机高输入系统吸引白蚁,这是一个重要的,而且往往是有益的,土壤动物的组成部分。这进一步增加了这种系统在提高肯尼亚可持续农业生产方面的潜力。
    A long-term experiment at two trial sites in Kenya has been on-going since 2007 to assess the effect of organic and conventional farming systems on productivity, profitability and sustainability. During these trials the presence of significant numbers of termites (Isoptera) was observed. Termites are major soil macrofauna and within literature they are either depict as \'pests\' or as important indicator for environmental sustainability. The extent by which termites may be managed to avoid crop damage, but improve sustainability of farming systems is worthwhile to understand. Therefore, a study on termites was added to the long-term experiments in Kenya. The objectives of the study were to quantify the effect of organic (Org) and conventional (Conv) farming systems at two input levels (low and high) on the abundance, incidence, diversity and foraging activities of termites.
    The results showed higher termite abundance, incidence, activity and diversity in Org-High compared to Conv-High, Conv-Low and Org-Low. However, the termite presence in each system was also dependent on soil depth, trial site and cropping season. During the experiment, nine different termite genera were identified, that belong to three subfamilies: (i) Macrotermitinae (genera: Allodontotermes, Ancistrotermes, Macrotermes, Microtermes, Odontotermes and Pseudocanthotermes), (ii) Termitinae (Amitermes and Cubitermes) and (iii) Nasutitiermitinae (Trinervitermes).
    We hypothesize that the presence of termites within the different farming systems might be influenced by the types of input applied, the soil moisture content and the occurrence of natural enemies. Our findings further demonstrate that the organic high input system attracts termites, which are an important, and often beneficial, component of soil fauna. This further increases the potential of such systems in enhancing sustainable agricultural production in Kenya.
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  • 文章类型: Journal Article
    白蚁是重要的生态系统工程师。然而,由于许多物种缺乏可靠的物种特异性形态特征,它们通常很难鉴定,这阻碍了生态研究。最近,与西非白蚁(西非白蚁分类学倡议)合作的白蚁学家召集了一个研讨会,目的是开始解决这个问题。最著名的西非白蚁分类学家反复测定相同的白蚁样本,发现了这个问题的巨大规模,因为只有不到10%的物种可以被明确地确定为物种水平。在研讨会结束时,深入的讨论和比较将识别成功率提高到约25%。然而,许多群体仍然存在问题,需要分子标记和条形码技术结合物种划界方法来帮助解决这些现有的分类学问题。根据本次研讨会的结果,我们建议采取协调一致的举措,在全球范围内解决白蚁分类学问题。我们相信,遵循类似结构化方法的区域分类学专门研讨会,重复测定相同的样品,将有助于克服白蚁分类学面临的困难。该计划还可以作为其他难以识别的分类学组的蓝图。
    Termites are important ecosystem engineers. Yet they are often difficult to identify due to the lack of reliable species-specific morphological traits for many species, which hampers ecological research. Recently, termitologists working with West African termites (West African Termite Taxonomy Initiative) convened for a workshop with the aim of beginning to address this problem. Repeated determination of the same termite samples by the most renowned taxonomists for West African termites identified the huge scale of the problem, as less than 10% of all species could be unambiguously determined to the species level. Intensive discussions and comparisons increased the identification success to around 25% at the end of the workshop. Yet many groups remained problematic and molecular markers and barcoding techniques combined with species delimitation approaches will be needed to help resolve these existing taxonomic problems. Based on the outcome of this workshop, we propose concerted initiatives to address termite taxonomy on a global scale. We are convinced that dedicated workshops on regional taxonomy that follow a similar structured approach, with repeated determination of the same sample, will help overcome the difficulties that termite taxonomy faces. This initiative can also serve as a blueprint for other taxonomical groups that are difficult to identify.
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  • 文章类型: Journal Article
    社会性昆虫是有希望的衰老研究新模型。在单一殖民地中,存在几个数量级的寿命差异,只能在不同物种之间的其他地方找到。再现女王(和,在白蚁中,也是国王)可以活几十年,而无菌工人通常只有几周的寿命。我们研究了一种高度社交的昆虫在野外的衰老,白蚁巨蚁,这是繁殖者和工人之间最明显的寿命差异之一。我们表明,基因表达模式在年轻人和老年人之间几乎没有差异,暗示微不足道的衰老。相比之下,老主要工人有许多与转座因子(TEs)相关的基因上调,这会导致衰老。引人注目的是,来自PIWI相互作用RNA(piRNA)途径的基因,通常已知会使多细胞动物的种系中的TE沉默,仅在老主要工人中下调,而在生殖系统中没有下调。动物种系中常见的piRNA防御的持续上调可以解释白蚁繁殖体的长寿命,暗示社会进化过程中种系防御的体细胞协同作用。这提出了超有机体概念所设想的惊人的种系/体细胞类比:殖民地的繁殖体和工人反映了多细胞动物的种系和体细胞,分别。我们的结果为一次性体衰老理论提供了支持。
    Social insects are promising new models in aging research. Within single colonies, longevity differences of several magnitudes exist that can be found elsewhere only between different species. Reproducing queens (and, in termites, also kings) can live for several decades, whereas sterile workers often have a lifespan of a few weeks only. We studied aging in the wild in a highly social insect, the termite Macrotermes bellicosus, which has one of the most pronounced longevity differences between reproductives and workers. We show that gene-expression patterns differed little between young and old reproductives, implying negligible aging. By contrast, old major workers had many genes up-regulated that are related to transposable elements (TEs), which can cause aging. Strikingly, genes from the PIWI-interacting RNA (piRNA) pathway, which are generally known to silence TEs in the germline of multicellular animals, were down-regulated only in old major workers but not in reproductives. Continued up-regulation of the piRNA defense commonly found in the germline of animals can explain the long life of termite reproductives, implying somatic cooption of germline defense during social evolution. This presents a striking germline/soma analogy as envisioned by the superorganism concept: the reproductives and workers of a colony reflect the germline and soma of multicellular animals, respectively. Our results provide support for the disposable soma theory of aging.
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  • 文章类型: Journal Article
    动物宿主通常对微生物共生体及其功能具有很强的特异性。共生关系通过贡献几种原核代谢能力,增强了大多数真核生物的有限代谢网络。比如产甲烷,化学性自体萎缩,氮同化,等。这篇综述将研究确定细菌对某些动物群体的“保真度”的特征(例如,木食昆虫,例如白蚁和蟑螂)在世代和整个进化过程中。以木材为食的白蚁和蟑螂的后肠细菌属于几种门,包括变形杆菌,尤其是Deltaproteobacteria,拟杆菌,Firmicutes,放线菌,螺旋体,Verrucomicrobia,和放线菌,由16SrRNA检测。白蚁在其肠道微生物共生体的辅助下有效地以多种类型的木质纤维素为食。尽管宿主(白蚁和蟑螂)之间的群落结构不同,随着特定细菌分类群相对丰度的变化,细菌群落的组成可以至少部分反映宿主的进化,因为微生物群可能来自共同祖先的微生物群。因此,宿主系统发育以外的因素,例如饮食可能对塑造细菌群落结构有很大的影响。
    Animal hosts typically have strong specificity for microbial symbionts and their functions. The symbiotic relationships have enhanced the limited metabolic networks of most eukaryotes by contributing several prokaryotic metabolic capabilities, such as methanogenesis, chemolithoautotrophy, nitrogen assimilation, etc. This review will examine the characteristics that determine bacterial \"fidelity\" to certain groups of animals (e.g., xylophagous insects, such as termites and cockroaches) over generations and throughout evolution. The hindgut bacteria of wood-feeding termites and cockroaches belong to several phyla, including Proteobacteria, especially Deltaproteobacteria, Bacteroidetes, Firmicutes, Actinomycetes, Spirochetes, Verrucomicrobia, and Actinobacteria, as detected by 16S rRNA. Termites effectively feed on many types of lignocelluloses assisted by their gut microbial symbionts. Although the community structures differ between the hosts (termites and cockroaches), with changes in the relative abundances of particular bacterial taxa, the composition of the bacterial community could reflect at least in part the host evolution in that the microbiota may derive from the microbiota of a common ancestor. Therefore, factors other than host phylogeny, such as diet could have had strong influence in shaping the bacterial community structure.
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  • 文章类型: Journal Article
    Termite (Blattodea: Termitoidae) assemblages have important ecological functions and vary in structure between habitats, but have not been studied in lower subtropical forests. To examine whether differences in the richness and relative abundance of termite species and functional groups occur in lower subtropical regions, termite assemblages were sampled in Dinghushan Biosphere Reserve, China, among pine forest, pine and broad-leaved mixed forest (mixed forest), and monsoon evergreen broad-leaved forest (monsoon forest). The dominant functional group was wood-feeding termites (family Termitidae), and the mixed forest hosted the greatest richness and relative abundance. Soil-feeding termites were absent from the lower subtropical system, while humus-feeding termites were sporadically distributed in mixed forest and monsoon forest. The species richness and functional group abundance of termites in our site may be linked to the forest succession. Altitude, soil temperature, air temperature, surface air relative humidity, and litter depth were significant influences on species and functional group diversity.
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  • 文章类型: Journal Article
    Species boundaries are traditionally inferred using morphological characters, although morphology sometimes fails to correctly delineate species. To overcome this limitation, researchers have widely taken advantage of alternative methods such as DNA barcoding or analysis of cuticular hydrocarbons (CHs) profiles, but rarely use them simultaneously in an iterative taxonomic approach. Here, we follow such an approach using morphology, DNA barcoding and CHs profiles to precisely discriminate species of soldierless termites, a diversified clade constituting about one-third of the Neotropical termite species richness, but poorly resolved taxonomically due to the paucity of useful characters. We sampled soldierless termites in various forest types of the Nouragues Nature Reserve, French Guiana. Our results show that morphological species determination generally matches DNA barcoding, which only suggests the existence of three cryptic species in the 31 morphological species. Among them, Longustitermes manni is the only species whose splitting is corroborated by ecological data, other widely distributed species being supported by DNA barcoding. On the contrary, although CHs profiles provide a certain taxonomic signal, they often suggest inconsistent groupings which are not supported by other methods. Overall, our data support DNA barcoding and morphology as two efficient methods to distinguish soldierless termite species.
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  • 文章类型: Journal Article
    BACKGROUND: The molecular operational taxonomic unit (MOTU) has recently been applied to microbial and microscopic animal biodiversity surveys. However, in many cases, some of the MOTUs cannot be definitively tied to any of the taxonomic groups in current databases. To surmount these limitations, the concept of \"reverse taxonomy\" has been proposed, i.e. to primarily list the MOTUs with morphological information, and then identify and/or describe them at genus/species level using subsamples or by re-isolating the target organisms. Nevertheless, the application of \"reverse taxonomy\" has not been sufficiently evaluated. Therefore, the practical applicability of \"reverse taxonomy\" is tested using termite-associated nematodes as a model system for phoretic/parasitic organisms which have high habitat specificity and a potential handle (their termite host species) for re-isolation attempts.
    METHODS: Forty-eight species (from 298 colonies) of termites collected from the American tropics and subtropics were examined for their nematode associates using the reverse taxonomy method and culturing attempts (morphological identification and further sequencing efforts). The survey yielded 51 sequence types ( =  MOTUs) belonging to 19 tentatively identified genera. Within these, four were identified based on molecular data with preliminary morphological observation, and an additional seven were identified or characterized from successful culturing, leaving eight genera unidentified.
    CONCLUSIONS: That 1/3 of the genera were not successfully identified suggests deficiencies in the depth of available sequences in the database and biological characters, i.e. usually isolated as phoretic/parasitic stages which are not available for morphological identification, and too many undiscovered lineages of nematodes. Although there still is the issue of culturability of nematodes, culturing attempts could help to make reverse taxonomy methods more effective. However, expansion of the database, i.e., production of more DNA barcodes tied to biological information by finding and characterizing additional new and known lineages, is necessary for analyzing functional diversity.
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  • 文章类型: Journal Article
    Termite mounds are abundant components of Tummalapalle area of uranium mineralization of Cuddapah District of Andhra Pradesh, India. The systematic research has been carried out on the application of termite mound sampling to mineral exploration in this region. The distribution of chemical elements Cu, Pb, Zn, Ni, Co, Cr, Li, Rb, Sr, Ba, and U were studied both in termite soils and adjacent surface soils. Uranium accumulations were noticed in seven termite mounds ranging from 10 to 36 ppm. A biogeochemical parameter called \"Biological Absorption Coefficient\" of the termite mounds indicated the termite affected soils contained huge amounts of chemical elements than the adjacent soils.
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  • 文章类型: Case Reports
    Acute otalgia during childhood is one of the most common complaints in general ENT practice. It may occur as a result of acute otitis externa, otitis media or a foreign body. Animate foreign body in the ear canal or in the middle ear usually results in otalgia and hearing loss. We present a rare case of a living mature termite in the middle ear of a 9-year-old girl complaining of intermittent attacks of otalgia associated with a loud cracking sound in the left ear. In this case, a small perforation of the tympanic membrane without a history of previous trauma, infection, or evidence of a foreign body in the external ear raises a suspicion. A careful, time-consumed microscopic examination could show the living creature in the middle ear. Immediate immobilization and removal of the living foreign body are imperative. In conclusion, tympanic membrane perforation and intermittent severe otalgia without history of otitis may lead to a suspicion of any insects in the middle ear.
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