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51.
双重标准差法在昆虫科阶元分类学上的应用 总被引:1,自引:0,他引:1
在科分类阶元上对半翅目、鳞翅目和鞘翅目8个科的23种昆虫图像中提取的昆虫面积、周长等11项数学形态特征进行了双重标准差法分析,以评估该方法在昆虫科阶元分类上的应用有效性。结果表明,在科的阶元上11项特征可靠性大小依次为: (似圆度、偏心率、 圆形性>(横轴长、形状参数、叶状性>(面积、周长、球状性> (纵轴长、亮斑数)。科的亲缘关系远近结果显示: 蝽科和缘蝽科关系较近>丽金龟科、天牛科与鳃金龟科关系较近>夜蛾科、大蚕蛾科和粉蝶科关系较近。所得结果与统计假设检验分析所得结果非常相似。 相似文献
52.
Z. Zheng Adrian Khoo Douglas Fambrough Jr. Luis Garza Ronald Booker 《Development genes and evolution》1999,209(8):460-472
Antibodies were used to examine the expression patterns of Antennapedia (Antp), Ultrabithorax (Ubx), Ubx and abdominal-A combined(Ubx/abd-A),and Distalless (Dll) in the embryos of the moth Manduca sexta. We found that the spatial and temporal pattern of Antp expression in Manduca was correlated with the anterior migration of two patches of epithelium that include the anterior-most tracheal pits, and
with the development of functional spiracles. Ubx expression showed an intricate pattern which suggests complex regulation
during development. Throughout Manduca embryogenesis the expression of Ubx/Abd-A and Dll was similar to that reported for other insects. However, there was no apparent
reduction in Ubx/Abd-A expression in the Manduca abdominal proleg primordia that expressed Dll. The expression of these four proteins was also examined in embryosof the Manduca homozygous homeotic mutant Octopod (Octo). The Octo mutation results in the transformation of A1 and A2 in the anterior direction, with homeotic legs appearing on A1 and occasionally
A2. Our results suggest that in Octo animals there is a reduction in the level of Ubx protein expression throughout its domain. Based on homeotic gene expression
in wild-type and mutant Manduca and in other insects, we discuss potential roles of homeotic genes in insect morphological evolution.
Received: 21 September 1998 / Accepted: 5 March 1999 相似文献
53.
Arctic shrubs have a strong potential for climate and environmental reconstructions in the chronically understudied regions of the high northern latitudes. The climate dynamics of these regions are important to understand because of large-scale feedbacks to the global climate system. However, little is known about other factors influencing shrub ring growth, possibly obscuring their climate signal. For example, as of yet we are not able to differentiate between herbivory or climatically induced growth depressions. Here, we use one of the most common Arctic shrubs, Alnus viridis as a test case to address this question. We sampled Alnus in Kobbefjord, Greenland, measured shrub-ring width and cell wall thickness and built site chronologies of each parameter. We analysed climate-growth relationships, tested their stability over time and employed a pointer-year analysis to detect growth depressions. We employed bootstrapped transfer function stability tests (BTFS) to assess the suitability of our shrub chronologies for climate reconstruction. Correlations with climate data showed strong significantly positive and stable correlations between summer temperature and ring-width with the exception of the recent decade. A climate reconstruction model failed stability tests, when the complete period of record was used for calibration and verification. Wood anatomy analysis uncovered the occurrence of unusual cell structure (very thin cell walls) in the exceptionally narrow ring of 2004, a recorded insect outbreak year in other parts of Greenland. When excluding the affected ring and a recovery period, the reconstruction model passed all tests, suggesting that the unusual 2004 ring was not climate driven, but rather the result of an insect attack. When combining anatomical analysis with traditional ring-width measurements, we move a step further in potentially distinguishing small rings caused by insect attacks from small rings formed in climatically challenging years. While this study does not provide unambiguous evidence, it does provide potential useful methodological combinations to enable more robust climate reconstructions in areas where climatic records are extremely sparse. 相似文献
54.
Hiroshi Takeda 《Population Ecology》1979,21(1):120-134
The distribution pattern of ten species of Collembola was studied during the four years period from July 1971 to May 1975 in a pine forest soil. The distribution patterns were analysed for two scales of distribution, i. e., the distribution over the plot of 10×10 m2 and the micro-distribution within a block sample consisting of 36 contigious units each 2×2 cm2 in area, by applying the -m regression method. The fundamental pattern which appeared was quite similar for the species examined and individuals were aggregated in response to the heterogeneity of habitat conditions. The causes of aggregations were discussed with regard to some environmental factors. The relative abundances of 10 species within the collembolan community was examined in relation to the habitat utilization and the relative abundance was not related to the degree of aggregation but rather to the area occupied by individuals. This suggests that the more numerically abundant species tend to occupy broader micro-habitat. Biological meaning of aggregation was discussed in connection with the population biology and community organization of collembola. 相似文献
55.
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57.
Bhanupriya Madarampalli Gerald F.M. Watts Paul M. Panipinto Hung N. Nguygen Michael B. Brenner Erika H. Noss 《生物化学与生物物理学报:疾病的分子基础》2019,1865(6):1516-1524
Cadherins are homophilic cell-to-cell adhesion molecules that help cells respond to environmental changes. Newly formed cadherin junctions are associated with increased cell phosphorylation, but the pathways driving this signaling response are largely unknown. Since cadherins have no intrinsic signaling activity, this phosphorylation must occur through interactions with other signaling molecules. We previously reported that cadherin-11 engagement activates joint synovial fibroblasts, promoting inflammatory and degradative pathways important in rheumatoid arthritis (RA) pathogenesis. Our objective in this study was to discover interacting partners that mediate cadherin-11 signaling. Protein array screening showed that cadherin-11 extracellular binding domains linked to an Fc domain (cad11Fc) induced platelet-derived growth factor (PDGFR)-α phosphorylation in synovial fibroblasts and glioblastoma cells. PDGFRs are growth factor receptor tyrosine kinases that promote cell proliferation, survival, and migration in mesodermally derived cells. Increased PDGFR activity is implicated in RA pathology and associates with poor prognosis in several cancers, including sarcoma and glioblastoma. PDGFRα activation by cadherin-11 signaling promoted fibroblast proliferation, a signaling pathway independent from cadherin-11-stimulated IL-6 or matrix metalloproteinase (MMP)-3 release. PDGFRα phosphorylation mediated most of the cad11Fc-induced phosphatidyl-3-kinase (PI3K)/Akt activation, but only part of the mitogen-activated protein kinase (MAPK) response. PDGFRα-dependent signaling did not require cell cadherin-11 expression. Rather, cad11Fc immunoprecipitated PDGFRα, indicating a direct interaction between cadherin-11 and PDGFRα extracellular domains. This study is the first to report an interaction between cadherin-11 and PDGFRα and adds to our growing understanding that cadherin-growth factor receptor interactions help balance the interplay between tissue growth and adhesion. 相似文献
58.
《Fungal Ecology》2019
For entomopathogenic fungi (EPF), it may be particularly advantageous to manipulate host behavior in order to increase conspecific encounters that facilitate transmission of conidia. To achieve this, some EPF apparently alter the chemical communication and signaling of insect sexual behavior, but there are very few documented examples. Here, we identify and discuss the few known examples and propose two categories of EPF-induced alterations in insect sexual behavior. First, EPF may induce changes in how healthy conspecifics of the opposite sex perceive and respond to the infected individual via chemical or visual cues, which promote the display of sexual behaviors towards the infected individual. Second, EPF may directly change sexual behavior of the infected individual to promote conspecific encounters. We conclude that the scarcity of observed examples is likely caused by the difficulty of detecting subtle changes in insect sexual behavior, but also because manipulation of host sexual behavior is a trait primarily present in understudied host-specific EPF. 相似文献
59.
Rudi C. Swart Michael J. Samways James S. Pryke Francois Roets 《Ecological Entomology》2020,45(2):333-344
1. The present study tested the hypothesis that tree context (natural, semi-natural or planted) and contrast (height of surrounding vegetation) affect tree physiological characters (leaf size, nutrient content, and stress-related factors), and also alter the arthropod biodiversity patterns either directly or indirectly. 2. Arthropods were collected from tree canopies using chemical fogging from the ecologically important South African native tree Podocarpus elongatus. 3. Low contrast trees had significantly larger leaves than those in high contrast environments and harboured an overall higher richness, abundance, and biomass of arthropods, although this was guild-dependent. 4. Trees in natural contexts had less foliar δ13C, suffered less from artificial nitrogen enrichment, and harboured significantly higher herbivore and predator arthropod richness and unique assemblages, compared with planted trees. 5. Semi-natural trees supported natural levels of arthropod richness, although these were mostly generalist species. 6. Tree context and contrast can therefore dictate associated biota at multiple trophic levels and native trees may fail to maintain natural biodiversity in transformed landscapes. 相似文献
60.
R. Rajagopal 《Indian journal of microbiology》2009,49(2):114-119
Insects are amongst the most successful of animals, both in terms of diversity and in colonizing all ecological niches. Recent
studies have highlighted the benefi ciary roles that bacteria play in the success and establishment of insects. By adopting
techniques like 16S rRNA sequencing we are now in a position to understand the diversity of bacteria present in insect guts.
It has been shown that some of these bacteria, like Wolbachia and Cardinium are involved in manipulating insect populations and distorting their sex ratio. Attempts have been made to culture these
bacteria in insect cell lines, as they are recalcitrant to culture under normal microbiological conditions. The diversity
of bacteria associated with insects and the functional role played by them in the insect is discussed below. 相似文献