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1.
【目的】了解小头钩白蚁Ancistrotermes dimorphus Tsai et Chen的蚁巢结构、各品级在腔室中的分布和巢群个体数量,为有效防控该种白蚁提供科学依据。【方法】采用蚁巢定位和巢体结构解剖法研究蚁巢结构;采用统计法确定各品级在腔室中的分布和巢群个体数量。【结果】小头钩白蚁巢由腔室、菌圃、蚁路、王室、候飞室和分飞孔六部分组成;巢群个体数量为12 255~24 230头(含卵粒);卵、幼蚁、若蚁、工蚁、兵蚁和有翅成虫分散分布在蚁巢腔室中,并不集中于某一特定区域。【结论】小头钩白蚁巢属于极端分散类型,巢群个体数量较少。  相似文献   

2.
【目的】了解小头钩白蚁Ancistrotermes dimorphus Tsai et Chen的蚁巢结构、各品级在腔室中的分布和巢群个体数量,为有效防控该种白蚁提供科学依据。【方法】采用蚁巢定位和巢体结构解剖法研究蚁巢结构;采用统计法确定各品级在腔室中的分布和巢群个体数量。【结果】小头钩白蚁巢由腔室、菌圃、蚁路、王室、候飞室和分飞孔六部分组成;巢群个体数量为12 255~24 230头(含卵粒);卵、幼蚁、若蚁、工蚁、兵蚁和有翅成虫分散分布在蚁巢腔室中,并不集中于某一特定区域。【结论】小头钩白蚁巢属于极端分散类型,巢群个体数量较少。  相似文献   

3.
刘明花  张小晶  薛薇  陈娇玲  刘鹤  吴佳  苏晓红 《昆虫学报》2014,57(11):1328-1334
摘要: 【目的】为了探讨圆唇散白蚁Reticulitermes labralis补充生殖蚁对巢群稳定和发展的作用。【方法】对野外巢群进行调查研究, 及对婚飞成虫通过雌雄配对与补充生殖蚁隔离巢群进行人工饲养的对比研究。【结果】在野外巢群只发现1对原始蚁王蚁后, 而补充生殖蚁的数量最多可达到689头/巢。圆唇散白蚁有3种类型的补充生殖蚁, 即由工蚁转化来的无翅型补充生殖蚁、若蚁转化来的翅芽型补充生殖蚁和末龄若蚁羽化来的拟成虫型补充生殖蚁。实验室条件下婚飞配对群体和隔离群体建群1个月后的存活率分别为64%和96%。建巢初期婚飞配对群体的子代数目增长缓慢, 2个月时的群体数量为6.3±1.54, 10个月时的群体数量也仅为8.4±1.47; 而隔离建群补充生殖蚁2个月时的群体数量为52.4±6.44, 10个月时的群体数量为164.3±20.85, 都高于婚飞配对群体。 此外, 野外巢群的补充蚁后跟原始蚁后一样都具有发达的卵巢。【结论】在圆唇散白蚁中补充生殖蚁是白蚁巢群主要的繁殖力量, 也是建立新巢群的重要繁殖品级。  相似文献   

4.
为了解截头堆砂白蚁Cryptotermes domesticus(Haviland)群体中不同品级、不同虫态的雌雄性比,本文研究了该种白蚁自行配对室温条件下饲养4年巢龄的实验群体与采集的自然群体的各个品级和不同虫态的雌雄性比。结果表明:自行配对室温饲养4年巢龄群体与自然环境群体中原始繁殖蚁、幼蚁、若蚁、兵蚁都有雌雄之分,其中自行配对室温饲养群体的原始繁殖蚁雌雄比例为1:1,兵蚁雌雄比例为1:1.24,幼蚁和若蚁雌雄比例为1:1.46;自然环境群体原始繁殖蚁雌雄比例为1:1,兵蚁雌雄比例为1:1.15,幼蚁和若蚁雌雄比例为1:1.43。  相似文献   

5.
【目的】研究圆唇散白蚁Reticulitermes labralis(Hsia)补充生殖蚁分化及发育过程中卵黄蛋白原(Vitellogenin,Vg)基因的表达、卵母细胞的发育以及子代品级分化。【方法】通过使用实时定量PCR(Real-time quantitative polymerase chain reaction)技术测定补充生殖蚁从分化到产卵的过程中Vg基因相对表达量的动态变化;采用组织染色的方法进行卵母细胞发育阶段的观察;对子代的数量及分化进行统计分析。【结果】补充生殖蚁发育过程中,Vg基因表达呈现先升高后降低的动态变化模式。在补充生殖蚁分化后的第10天开始形成具卵黄的卵母细胞,在20 d时具卵黄卵母细胞的数量达到最高值。第1个月至第3个月,补充生殖蚁的产卵数逐渐增加,分别为(2.45±1.43)、(7.68±2.53)和(12.10±7.09)粒。第3个月,巢内开始出现幼蚁,数量为(5.15±2.41)头;第10个月,巢群内有工蚁、前兵蚁和兵蚁的分化,分别为(17.03±2.28)、(1.45±0.31)和(0.79±0.18)头。【结论】在新建巢群中,若蚁的分化在工蚁和兵蚁分化之后。圆唇散白蚁若蚁在巢群需要的时候,可以在很短时间内转化为补充生殖蚁;Vg基因的表达水平与卵母细胞的卵黄形成相关,Vg基因表达量的增加启动了卵母细胞的卵黄摄取过程。虽然单个补充生殖蚁产卵量不如单个原始生殖蚁的多,但是在一个巢内补充生殖蚁总的产卵数目要远远超过原始生殖蚁,因为补充生殖蚁的数量比原始生殖蚁的数量多。因此补充生殖蚁对巢群稳定和发展具有重要作用。  相似文献   

6.
为了解截头堆砂白蚁Cryptotermes domesticus(Haviland)群体中不同品级、不同虫态的雌雄性比,本文研究了该种白蚁自行配对室温条件下饲养4年巢龄的实验群体与采集的自然群体的各个品级和不同虫态的雌雄性比.结果表明:自行配对室温饲养4年巢龄群体与自然环境群体中原始繁殖蚁、幼蚁、若蚁、兵蚁都有雌雄之分,其中自行配对室温饲养群体的原始繁殖蚁雌雄比例为1:1,兵蚁雌雄比例为1:1.24,幼蚁和若蚁雌雄比例为1:1.46;自然环境群体原始繁殖蚁雌雄比例为1:1,兵蚁雌雄比例为1:1.15,幼蚁和若蚁雌雄比例为1:1.43.  相似文献   

7.
黑翅土白蚁初期单腔巢群建立的观察   总被引:1,自引:1,他引:0  
经3年的室内配对饲养观察,黑翅土白蚁Odontotermes formosanus(Shiraki)初期单腔巢群的建立可划分为配对入土建巢、空巢产卵繁殖、单腔菌圃形成三个发育时期。脱翅成虫入土后4至10天开始产卵,第一批卵71至98粒,约在20天内产完,每天产2至6粒:胚胎发育期36至47天。工蚁是幼虫经3次蜕皮后分化出来的,幼蚁发育为兵蚁有一个前兵蚁龄期,是幼蚁经2次蜕皮后分化出来的。各龄幼蚁龄期约经历6至8天,前兵蚁龄期约经历11至12天。建巢3个半至4个月后出现菌圃。此外通过大量的野外解剖、观祭、测定,对初期单腔巢群的年龄以及巢群建立与环境条件的关系进行了研究。巢群出现副巢,发展为两个以上菌圃需经2—3年;缺乏Termitomyces a;buminosus(Berk.)Heim是影响菌圃形成、导致巢群死亡的主要原因。  相似文献   

8.
目的:调查和分析1993~2012年19年间住院的老年高血压患者的死亡原因及影响因素,为北京地区老年高血压防治中靶器官的保护和并发症的减少提供重要临床依据。方法:回顾性分析我院1993~2012年19年间住院死亡的2866例1〉60岁老年高血压患者,通过病历采集,收集性别、年龄、并发症及死亡原因等临床资料,按性别、年龄及高血压分期和危险程度将病人分组。采用卡方检验的方法比较各组病人的死亡原因。结果:①按疾病:与死亡相关性最高的疾病为心脏病1294例(45.15%),脑卒中985例(34.37%),肾功能衰竭340例(11.88%),感染性疾病131例(4.58%),恶性肿瘤116例(4.06%),心脏病是导致老年高血压患者死亡的首要原因;②按性别:男性占老年高血压死亡的53.31%,女性占46.69%,差异具有统计学意义(P〈0.01)。而心脏病(男性46.73%比女性43.35%]和脑卒中(男性37.04%比女性31.32%)均占据高血压死亡原因构成比的前两位;③按年龄:90岁以上高血压患者因心脏病(43.02%)、肾功能衰竭(20.54%)和感染(6.59%)死亡的比例低于其他各年龄组。因脑卒中死亡的比率低于60—69岁组(38.71%)和70~79岁组(33.37%)。因恶性肿瘤死亡的老年高血压患者在70~79岁组最高(4.80%);④按高血压分期和危险程度:I.Ⅱ期高血压患者因心脏病(49.70%)和恶性肿瘤(7.55%)死亡的比例高于Ⅲ期高血压患者(分别为43.78%和2.99%),而Ⅲ期高血压患者因脑卒中(35.84%)和肾功能衰竭(12.79%)死亡的比例高于I.Ⅱ期高血压患者(分别为29.45%和8.76%)。高危组的老年高血压患者因心脏病(38.15%)死亡的比例低于其他三组(低危组51.05%、中危组47.64%和极高危组47.38%),而其因肾功能衰竭(19.54%)死亡的比例则高于其他三组(低危组1.63%、中危组3.07%和极高危组11.69%),但中危组的老年高血压患者因脑卒中死亡的比例最高(42.69%)。结论:男性患者、60~79岁患者在老年高血压的根本死亡原因中所占的比率较高。不同的高血压分期和危险分层对根本死亡原因有不同的影响。  相似文献   

9.
<正> 在我国亚热带地区,家白蚁Coptotermes fo-rmosanus Shiraki是危害木、竹、塑料、橡胶,皮革、棉、麻、化纤等多种材料和产品最有代表性的白蚁种类,因此,它常被用来检验各种天然材料和加药材料的抗白蚁蛀蚀性能的实验群体。在自然条件下,家白蚁群体的品级组成有一定比例,兵蚁平均约占3%,可是在某些特殊情况下,例如某些主巢外围,王室附近或幼龄巢的白蚁,有时会出现兵蚁比例甚高现象。众所周知,兵蚁的食物靠工蚁饲喂,如果各实验群体中兵蚁所占百分比过高或不一致,对生物测定结果的正确性影响很大。本工作试验了家白蚁实验群体中不同工、兵蚁组成对取食和存活的影响,为制定材料抗白蚁蛀蚀的试验标准提供参考依据。  相似文献   

10.
流行性脑脊髓膜炎是由脑膜炎双球菌引起的化脓性脑膜炎,简称流脑。流脑的流行早在16世纪即被发现,至今已有悠久的历史了。我国的流脑发病情况为:全年以冬春季发病较多,每年自11月、12月开始上升,次年3月、4月达高峰,5月、6月开始下降,7~10月降至最低水平。2~4月的发病数占全年发病总数的60%~90%。任何年龄都可发病,以14岁以下年龄、尤其是7岁以下儿童发病率最高。脑膜炎双球菌隐藏于患或带菌的鼻咽分泌物中,主要通过咳嗽、打喷嚏、说话等由飞沫直接从空气传播,进入呼吸道而引起感染。  相似文献   

11.
 Sometimes a specific treatment is effective in one subgroup but not in another. An indicator allowing quantitative comparison of treatment effect in two subgroups would be useful in clinical medicine. We have developed such an indicator. It is obtained by calculations using Cox’s proportional hazard or logistic model with therapy, subgroup, and confounding explanatory variables. The parameter of the interaction between therapy and subgroup can be estimated and tested statistically. The exponential value of the interaction parameter is what we tentatively call the “hazard ratio ratio”, meaning the ratio between the treatment effects in two subgroups. The 95% confidence interval of the indicator can also be calculated. As a numerical example, the hazard ratio between the survival times of postoperative gastric cancer patients treated by adjuvant immunochemotherapy and patients without adjuvant immunochemotherapy in a subgroup with high serum glycosidically bound sialic acid (SA) level was lower than that in a low-SA subgroup using an estimate for hazard ratio ratio of less than 0.5 with statistical significance. We propose this indicator be used as a “responder/non-responder ratio” of therapy effect. Received: 11 April 1995 / Accepted: 5 September 1995  相似文献   

12.
Odds ratios approximate risk ratios when the outcome under consideration is rare but can diverge substantially from risk ratios when the outcome is common. In this paper, we derive optimal analytic conversions of odds ratios and hazard ratios to risk ratios that are minimax for the bias ratio when outcome probabilities are specified to fall in any fixed interval. The results for hazard ratios are derived under a proportional hazard assumption for the exposure. For outcome probabilities specified to lie in symmetric intervals centered around 0.5, it is shown that the square-root transformation of the odds ratio is the optimal minimax conversion for the risk ratio. General results for any nonsymmetric interval are given both for odds ratio and for hazard ratio conversions. The results are principally useful when odds ratios or hazard ratios are reported in papers, and the reader does not have access to the data or to information about the overall outcome prevalence.  相似文献   

13.
14.
《Biomarkers》2013,18(3):216-222
The objective of this study was to clarify whether the neutrophil-lymphocyte ratio (NLR) and the platelet-lymphocyte ratio (PLR) are significant prognostic markers in patients with resectable colorectal cancer (CRC). A total of 200 patients who underwent curative resection for CRC were enrolled. The NLR and PLR were positively correlated (p?<?0.001). Both the NLR and PLR were shown to be good prognostic biomarkers of overall survival (OS) (p?=?0.002 and p?=?0.001, respectively). The PLR was an independent prognostic factor of OS based on multivariate analysis (hazard ratio, 1.971; 95% confidence interval, 1.102–3.335; p?=?0.021).  相似文献   

15.
Sequences for multiple protein-coding genes are now commonly available from several, often closely related species. These data sets offer intriguing opportunities to test hypotheses regarding whether different types of genes evolve under different selective pressures. Although maximum likelihood (ML) models of codon substitution that are suitable for such analyses have been developed, little is known about the statistical properties of these tests. We use a previously developed fixed-sites model and computer simulations to examine the accuracy and power of the likelihood ratio test (LRT) in comparing the nonsynonymous-to-synonymous substitution rate ratio (=dN/dS) between two genes. Our results show that the LRT applied to fixed-sites models may be inaccurate in some cases when setting significance thresholds using a 2 approximation. Instead, we use a parametric bootstrap to describe the distribution of the LRT statistic for fixed-sites models and examine the power of the test as a function of sampling variables and properties of the genes under study. We find that the power of the test is high (>80%) even when sampling few taxa (e.g., six species) if sequences are sufficiently diverged and the test is largely unaffected by the tree topology used to simulate data. Our simulations show fixed-sites models are suitable for comparing substitution parameters among genes evolving under even strong evolutionary constraint ( 0.05), although relative rate differences of 25% or less may be difficult to detect.Reviewing Editor: Dr. Rosmus Nielsen  相似文献   

16.
Summary Reproductive success is divided into two phases: preemergent (the number of viable seeds that enter the ambient environment) and postemergent (the percentage of progeny that survive to reproduce). We studied preemergent reproductive success (PERS) in flowering plants by measuring the fruit/flower (Fr/Fl) ratio and the seed/ovule (S/O) ratio in a number of species of outcrossing and inbreeding plants, where PERS=the product of (Fr/Fl) and (S/O). In order to determine the influence of the ambient environment (including resource availability) we studied pairs of outcrossing and inbreeding species occurring in the same habitat. Among outcrossing species PERS averaged about 22%, whereas in inbreeding species the average was approximately 90%. The progeny/zygote (P/Z) ratio was studied in hand-pollinated populations in Epilobium angustifolium (a strongly outcrossing species) from populations in Oregon and Utah, by direct observation of embryogenesis at twoday intervals throughout the course of seed development. The P/Z ratio in both populations averaged near 30%, and the developing embryos showed a surprising array of abnormalities that resulted in embryo death. During early development >95% of the ovules had normally developing globular embryos, but beginning with differentiation (cotyledon formation) about 70% of the original globular embryos aborted during the course of embryogenesis and seed development. The clustering of developmental lethals during peroids of major differentiation events parallels the animal model of development. We found little evidence that PERS was limited by the ambient environment (including resource availability), pollination, or factors associated with the inbreeding habit. Instead, PERS was found to be inextricably linked to outcrossing plants, whose breeding systems promote genetic variability. The high incidence of developmental lethals in E. angustifolium and the resulting low P/Z ratio (ca. 30%) is attributed to genetic load (any lethal mutation or allelic combination) possibly working in combination with developmental selection (interovarian competition among genetically diverse embryos). Examples of maternally controlled, fixed patterns of ovule abortion with respect to position or number are discussed. However, we found no need to employ female choice as a hypothesis to explain our results for the extensive, seemingly random patterns of embryo abortion in E. angustifolium and other outcrossing species. A more parsimonious, mechanistic explanation based on genetic load-developmental selection is sufficient to account for the differential survivorship of embryos. Likewise, the traditional concept of a positive growth regulator feedback system based on the number of surviving ovules in an ovary can account for subsequent fruit survivorship.  相似文献   

17.
The allometric equation, y=gxh, was applied monthly to the relationships between two different dimensions of tree seedlings of hinoki cypress (Chamaecyparis obtusa) during a course of self-thinning from April 1990 to March 1991 to detect differences in biomass allocation among individuals. As the h-value in the allometry of crown length and seedling height was greater than unity for all seasons, crown ratio became greater as seedling height increased. Leaf weight ratio increased with increasing seedling size because the h-value in the allometry of leaf dry weight and whole seedling dry weight was greater than unity in every month. Therefore, smaller seedlings are disadvantageous to photosynthetic production by leaves. In contrast, the leaf area ratio was constant irrespective of seedling size because the h-value in the allometry of leaf area and whole seedling dry weight was nearly equal to unity in most seasons. In addition, because the h-value in the allometry of leaf area and leaf dry weight was less than unity in all seasons, specific leaf area decreased with an increase in leaf dry weight, indicating that smaller seedlings adapt to low light environments by possessing shade leaves. Root weight ratio decreased with increasing seedling size because the h-value in the allometry of root dry weight and whole seedling dry weight was less than unity in most seasons.  相似文献   

18.
Offspring allocation in structured populations with dimorphic males   总被引:2,自引:0,他引:2  
Summary Many fig wasp species have dimorphic males. These males often mate in different localities; one typically disperses before mating whereas the other does not disperse. In 1979 a model was developed for offspring allocation in dimorphic fig wasps, but it assumed that females only lay a single egg per fig. This assumption is not realistic and precludes any effects local mate competition (LMC) may exert on morph abundance. I develop a model without these restrictions and show that the optimal proportions of each morph is determined by two parameters. Firstly, the proportion of the non-dispersing morph is affected by the mean number of females that oviposit in a patch. This effect is due to the negative correlation between LMC between brothers and the number of females that oviposit in a patch. Secondly, the proportions of both male morphs correlate with the expected proportion of females which will mate with each morph. The separation of the two parameters generalizes the model to any other species which is spatially structured and which has two male morphs or even two alternative mating strategies. A comparison of two models shows that parent—offspring conflict involving morph ratios will not have far reaching consequences. I test these models using the 1979 model's data and both models accurately predict the variation in morph ratios in six species of dimorphic fig wasps.  相似文献   

19.
Many studies suggest that in 10-25% of cases of Alzheimer's, the most common dementia in our society, can be prevented with the elimination of some risk factors. Barnes and Yaffe found that one-third of Alzheimer's cases are attributable to depression, but in the scientific literature it is not clear if it has a real causal effect on the development of dementia. The purpose of this study is to analyse the scientific evidence on the hypothesis that depression increases the risk of developing dementia.A systematic review and a meta-analysis were performed on the scientific literature published up until the present day, searching articles that were published between 1990 and 2014. Ten of the studies found met the selection criteria –similar to a) size and characteristics of the sample (origin, age…), b) process of gathering data c) method of studying the relationship (within and/or between group comparison), and d) statistical analysis of the results– and the previously established quality.The value of odds ratio varied from 1.72 to 3.59, and the hazard ratio from 1,72 to 5.44. This indicates that the subjects with a history of depression have a higher risk of developing dementia than others who did not suffer depression.  相似文献   

20.
舞毒蛾核型多角体病毒亚致死剂量对舞毒蛾幼虫的影响   总被引:4,自引:0,他引:4  
丁翠  马可 《昆虫学报》1993,36(3):272-276
用舞毒蛾核型多角体病毒亚致死剂量1.3X104-1.3X106多角体/毫升对舞毒蛾(Lymantri dispar)五龄雌雄幼虫分别进行感染后发现,除获得死亡率的不同外,存活个体化蛹数及雌雄比例亦发生变化。雌雄比例倾向于雄性。电镜照片显示在雌性幼虫中被侵染的组织包括脂肪、气管基底膜、腹神经节、胸腺、卵巢及大脑,而胸腺、卵巢和大脑被核型多角体病毒感染的报道很少。使用免疫金颗粒标记技术测得细胞核中的舞毒蛾核型多角体病毒与其抗体间具有强烈的亲和性。  相似文献   

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