蜘蛛飞航研究进展

种群扩散能够避免生物类群在同一栖息地中的资源竞争和同类相残, 促进基因流动, 具有重要的进化和生态意义。相比于昆虫的迁飞行为, 某些不具翅的节肢动物也能够借助细丝的作用而实现远距离扩散, 即飞航。蜘蛛为肉食性动物, 是陆地生态系统的重要组成部分, 在生态系统中防控害虫方面作用显著。飞航是蜘蛛的一种重要扩散方式, 在其物种形成、生态位分化及害虫防控等方面具有重要意义, 但有关其飞航扩散的报道较少。本文回顾了蜘蛛飞航的研究历程, 大致可分为三个阶段; 总结了其研究现状, 包括飞航蜘蛛的优势类群及特征、飞航过程中的三个环节(即起飞、空中航行和降落)及影响因子、两种飞航机制及四种相关模型、飞航蜘蛛采集和研究方法。同时基于过往研究, 指出了未来蜘蛛飞航研究的重点领域: 加强飞航蜘蛛类群鉴定工作, 继续深度挖掘飞航数据与环境因子间的关系, 探索蜘蛛飞航的全过程(包括起飞、空中航行和降落), 更加明确蜘蛛飞航作为一种扩散方式的意义。本综述将为蜘蛛飞航的知识普及、资源保护和利用等方面提供重要参考。     

An examination of the potential role of spider digestive proteases as a causative factor in spider bite necrosis

Tissue necrosis following spider bites is a widespread problem. In the continental United States, the brown recluse (Loxosceles reclusa), hobo spider (Tegenaria agrestis), garden spider (Argiope aurantia) and Chiracanthium species, among others, reportedly cause such lesions. The exact mechanism producing such lesions is controversial. There is evidence for both venom sphingomyelinase and spider digestive collagenases. We have examined the role of spider digestive proteases in spider bite necrosis. The digestive fluid of A. aurantia was assayed for its ability to cleave a variety of connective tissue proteins, including collagen. Having confirmed that the fluid has collagenases, the digestive fluid was injected into the skin of rabbits to observe whether it would cause necrotic lesions. It did not. The data do not support the suggestions that spider digestive collagenases have a primary role in spider bite necrosis.     

辽宁东部地区飞航蜘蛛的群落组成及特征

为了解辽宁东部地区飞航蜘蛛的群落组成及特点,于2009年5-9月,采用吸虫塔对辽宁岫岩地区的飞航蜘蛛进行了调查.共采集蜘蛛标本549头,隶属于14科.对飞航蜘蛛的群落组成、时间动态、体型大小、发育阶段及性别比例等进行了分析.结果表明:辽宁东部地区飞航蜘蛛多样性丰富,皿蛛科(58.29%)和园蛛科(11.84%)是该地区...     

蜘蛛毒素的研究进展及其相关应用

蜘蛛毒素含有多种化学成分,除毒性作用外这些物质对机体产生多重影响并具有多种活性。近年来,大量新的毒性组分不断被分离纯化,其结构和功能性作用被广泛深入研究,蜘蛛毒素成为了生物毒素领域新的研究热点。本文对蜘蛛毒素在离子通道作用机制方面的最新研究进展进行了阐述,同时还探讨了蜘蛛毒素在医学实践中新的应用和发展。     

Malignant arrhythmia in apical ballooning syndrome: risk factors and outcomes

Objectives

We sought to determine the frequency and outcomes with symptomatic arrhythmia in patients with apical ballooning syndrome (ABS).

Methods

A retrospective review of the Mayo Clinic Angiography database was conducted to identify patients who met the Mayo criteria for ABS. Patients with documented arrhythmias formed the study group, and 31 randomly selected patients with ABS but without arrhythmia formed the control group.

Results

Out of 105 patients identified with ABS, 6 (5.7%) women aged 69 +/- 9 years experienced significant arrhythmia (ventricular fibrillation, asystole), 2 patients died, and 1 required permanent pacemaker implantation. When compared with controls, the study group showed no significant difference with respect to ECG characteristics (QT, QRS duration or axis) except for R-R interval variability (see comments below) (30.6±6 vs 14.5±17 p = 0.0004), QTc, and P-R interval. Patients without arrhythmia were more likely to be on beta-blocker therapy than the study population (33% vs 80.6% p = 0.02).

Conclusion

Life-threatening arrhythmia is uncommon (5.7%) with ABS despite marked, structural abnormalities. When arrhythmias do occur, the outcome is poor. Prominent variability in R-R intervals appears to be predictive of significant arrhythmias in ABS. The role of beta-blocker therapy in preventing arrhythmia with ABS requires further investigation.     

Developmental strategies in an invasive spider: constraints and plasticity

1. Growth defines the major life‐history traits such as size, weight, and age at maturity that determine an organism's fitness. Different models have been developed to describe growth by means of geometric progressions (e.g. Dyar's rule). However, growth forced along a geometric trajectory might constrain a plastic response to variable environmental conditions (e.g. food availability). 2. The present study investigated growth patterns under varying food conditions in the bridge spider, Larinioides sclopetarius, an extremely successful species in colonising urban habitats. 3. In L. sclopetarius growth ratios of successive instars were not constant but decreased over development. Instead, these spiders' growth is well described by a developmental growth rate (weight gain per moult) and a growth coefficient (weight gain per development time), both of which are based on a geometric progression. All developmental parameters, including developmental growth rate and growth coefficient as well as the intermoult duration and the number of instars, highly depend on food availability in L. sclopetarius and thus show plasticity. 4. Our study shows that geometric growth patterns do not necessarily preclude plasticity and that the parameters of geometric growth are affected by developmental plasticity. We suggest that their high developmental plasticity may facilitate bridge spiders' success in invading urban habitats.     

Supercontraction forces in spider dragline silk depend on hydration rate

Spider dragline silk is a model biological polymer for biomimetic research due to its many desirable and unusual properties. ‘Supercontraction’ describes the dramatic shrinking of dragline silk fibers when wetted. In restrained silk fibers, supercontraction generates substantial stresses of 40–50 MPa above a critical humidity of 70% relative humidity (RH). This stress may maintain tension in webs under the weight of rain or dew and could be used in industry for robotics, sensor technology, and other applications. Our own findings indicate that supercontraction can generate stress over a much broader range than previously reported, from 10 to 140 MPa. Here we show that this variation in supercontraction stress depends upon the rate at which the environment reaches the critical level of humidity causing supercontraction. Slow humidity increase, over several minutes, leads to relatively low supercontraction stress, while fast humidity increase, over a few seconds, typically results in higher supercontraction stress. Slowly supercontracted fibers take up less water and differ in thermostability from rapidly supercontracted fibers, as shown by thermogravimetric analysis. This suggests that spider silk achieves different molecular configurations depending upon the speed at which supercontraction occurs. Ultimately, rate-dependent supercontraction may provide a mechanism to tailor the properties of silk or biomimetic fibers for various applications.     

Inheritance of sex ratio in the Kanzawa spider mite,Tetranychus kanzawai Kishida

Population Ecology - The frequency distributions in sex ratios of offspring from 4 fieldTetranychus kanzawai populations were examined. No significant difference was observed between average sex...     

The effect of food deprivation on aeronautic dispersal behaviour (ballooning) inErigone spp. spiders

Adult male and femaleErigone spp. (Araneae: Linyphiidae) spiders were kept without food for several days. Groups of spiders were tested for aeronautic dispersal behaviour (ballooning) in the laboratory. The validity of the assessment method was tested. In comparison with satiated spiders, the starved group exhibited an increased tendency to engage in aeronautic dispersal behaviour. A consistent trend for increased dispersal behaviour was detected in three independent experiments. Implications for spiders in agro-ecosystems are discussed briefly.     

Forces in the spider orb web

Summary Pretensile forces were measured in individual threads of intact spider webs. In the orb web of Araneus diadematus forces decrease from mooring threads to frame threads and radii, a typical ratio being 1071. The smaller number of radii in the upper than in the lower half of the orb is paralleled by force ratios of 21 to 31. A similar difference between radii built first during web construction and radii added after completion of the frame underlines the importance of the former as part of the scaffolding. High tensions in the auxiliary spiral stabilize the radii in addition to providing a pathway for the spider when inserting the sticky spiral. Radial pretension (F) changes with spider mass (m). F/m is similar for different animals indicating an adaptation of radial forces to those resulting from spider mass. Several observations suggest tension control by the spider. When forced to anchor its web to thin flexible rods tension in the threads remains in the normal range. Tension values are similar in the webs of A. diadematus, Zygiella x-notata, Nuctenea umbratica, and Nephila clavipes indicating independence from details of web geometry. Only the mooring threads of Nephila show unusually large forces suggesting a narrower working range of tensions for the catching area than for the scaffolding.     

Predation of wild spider monkeys at La Macarena,Colombia

The killing of an adult male spider monkey (Ateles belzebuth ) by a jaguar (Panthera onca) and a predation attempt by a puma (Felis concolor) on an adult female spider monkey have been observed at the CIEM (Centro de Investigaciones Ecológicas La Macarena), La Macarena, Colombia. These incidents occurred directly in front of an observer, even though it is said that predation under direct observation on any type of primate rarely occurs. On the basis of a review of the literature, and the observations reported here, we suggest that jaguars and pumas are likely to be the only significant potential predators on adult spider monkeys, probably because of their large body size.     

崇明岛上沙地区蜘蛛种类及其动态分析

于2011年4月初到2013年10月底,在崇明岛上沙地区选择6个代表性区域,采用捕捉、扣管、扫网和陷阱法对蜘蛛种类进行系统调查和定点采集,共采集蜘蛛标本700头,初步鉴定出蜘蛛63种,隶属13科38属,另有8种鉴定到属。该地区蜘蛛优势种类是跳蛛科、肖蛸科、园蛛科、狼蛛科。文章介绍了蜘蛛种群年度消长规律,同时探讨了不同环境因子的变化对蜘蛛种群的影响,分析表明：蜘蛛种群密度与生境和农药的使用存在显著差异,蜘蛛适宜生存的温度在15℃～35℃,适易的相对湿度在65％-85％。     

江西宁都凌云山自然保护区蜘蛛资源初报

凌云山自然保护区位于江西省赣州市宁都县西北部边境,属雩山山脉中段。其地理坐标为东经115°50′16″-116°1′40″,北纬26°50′42″-27°2′11″,总面积11260hm^2。蜘蛛是农林生态系统害虫天敌的主要类群,也常作为生态系统稳定的指示生物。作者等人通过对凌云山自然保护区蜘蛛资源及区系分布进行野外调查、标本采集和分类鉴定等,发现该保护区有蜘蛛32科96属165种,其中,有5个江西新记录科,1个中国新记录种,29种江西新记录种和33未确定种。     

Analysis of the shoulder in brachiating spider monkeys.

Adult spider monkeys (Ateles geoffroyi and A. paniscus) were conditioned to brachiate on a rope mill (an arboreal analogue of a treadmill). The postures and excursions of the shoulder girdle were studied by cineradiography. These data, together with conventional cinematographic and anatomical studies, permit reassessment of some characteristic structural and functional features of the shoulder in brachiators. During the propulsive phase, the shoulder joint moves caudad from fifth cervical to seventh cervical levels; at the same time, the joint moves dorsad (from a frontal plane midway between the first thoracic vertebra and the manubrium, to a frontal plane through the spinous processes) and slightly mediad. Spider monkeys position the scapula principally on the dorsum of the thorax, in contrast to quadrupedal primates which maintain a more lateral position (even in suspended postures). During brachiation, the scapula rotates a total of 35°; most of this rotation (20°) occurs in the non-propulsive phase when the free arm is being elevated to secure a new handhold. The sigmoidal shape, twisting of proximal relative to distal ends, and elongation of the clavicle in spider monkeys and other brachiators appear to be related to the specialized positioning of the shoulder girdle on the dorsum of the thorax. Shoulder and elbow movements contribute to the efficiency of the swing in terms of the dynamics of a pendulum.     

Spidroins from the Brazilian spider Nephilengys cruentata (Araneae: Nephilidae)

Spiders produce up to six different kinds of silk, each one for a specific biological function. Spider silks are also known for their unique mechanical properties. The possibility of producing new materials with similar properties motivated research on these silk proteins (spidroins). Using expression sequence tags, we identified four spidroins produced by major ampullate, minor ampullate, flagelliform and tubuliform silk glands from the Brazilian spider Nephilengys cruentata (Araneae: Nephilidae). The new protein sequences showed substantial similarity to other spidroins previously described, with high content of alanine and glycine due to the presence of the highly repetitive motifs (polyAla, (GA)_n, (GGX)_n, (GPGGX)_n). Similarities among sequences were also observed between the different spidroins with the exception of tubuliform spidroin, which presents a unique complex amino acid sequence with high amounts of serine and low amounts of glycine.     

Embryonic expression patterns of Wnt genes in the RTA-clade spider Cupiennius salei

Spiders represent widely used model organisms for chelicerate and even arthropod development and evolution. Wnt genes are important and evolutionary conserved factors that control and regulate numerous developmental processes. Recent studies comprehensively investigated the complement and expression of spider Wnt genes revealing conserved as well as diverged aspects of their expression and thus (likely) function among different groups of spiders representing Mygalomorphae (tarantulas), and both main groups of Araneae (true spiders) (Haplogynae/Synspermiata and Entelegynae). The allegedly most modern/derived group of entelegyne spiders is represented by the RTA-clade of which no comprehensive data on Wnt expression were available prior to this study. Here, we investigated the embryonic expression of all Wnt genes of the RTA-clade spider Cupiennius salei. We found that most of the Wnt expression patterns are conserved between Cupiennius and other spiders, especially more basally branching species. Surprisingly, most differences in Wnt gene expression are seen in the common model spider Parasteatoda tepidariorum (a non-RTA clade entelegyne species). These results show that data and conclusions drawn from research on one member of a group of animals (or any other organism) cannot necessarily be extrapolated to the group as a whole, and instead highlight the need for comprehensive taxon sampling.     

Lattice deformation and thermal stability of crystals in spider silk

The X-ray diffraction of dragline silks, produced by Nephila and Cyrtophora spiders, were measured by synchrotron radiation in their original states or in situ during stretching and heating. Nephila pilipes spiders construct a two-dimensional orb web that must be rebuilt in one or 2 days, but Cyrtophora spiders form a three-dimensional tent web that can exist for several weeks in a tropical forest. Diffraction patterns of N. pilipes and Cyrtophora draglines resemble each other. Crystals of two kinds are identified in these draglines; one is aligned parallel to the silk direction and another is less oriented. The less oriented crystal in Cyrtophora dragline is aligned better than that in N. pilipes dragline, which generates about three times stronger diffract intensity. Crystals in N. pilipes and C. moluccensis dragline silks have remarkable thermal stability. Equatorial reflections remain undiminished until 350 and 450 °C for N. pilipes and C. moluccensis, respectively. In contrast, the meridional reflections S and (0 0 2), which are parallel to the silk thread, disappear at a temperature less than 100 °C for C. moluccensis but remain for Nephila up to 100 °C. Meridional reflections S and (0 0 2) shift to a smaller angle during stretching, whereas equatorial reflections remain constant in a range 1.0–1.3 times the original length. The position of the S reflection shifts rapidly in the first 10% of elongation from the original length but remains constant during subsequent stretching, whereas the (0 0 2) reflection shifts rapidly during the first 5% elongation from the original length and continues to shift subsequently. In contrast, the features of N. pilipes dragline alter insignificantly during stretching. Examination of the composition of amino acids of the draglines of N. pilipes and C. moluccensis indicates that a dragline of N. pilipes contains more glycine, but much less alanine, than that of C. moluccensis.