The Comb-footed spider genera Theridion, Achaearanea and Anelosimus of Israel (Araneae: Theridiidae)

Israeli thendiid spiders of the genera Theridion, Achaearanea and Anelosimus have been revised. A relative richness in species is presented providing thereby updated information on the little known Mediterranean spider fauna. All type and non-type material previously described from the Middle East, deposited in several European collections has been re-examined, along with species from adjacent regions considered pertinent to the study undertaken. Altogether 21 species are recognized. Systematic, ecologic and all available zoogeographic information on taxa treated are discussed along with recent, pertaining literature. The presence of seven species formerly reported from Israel has been confirmed and the occurrence of another four species unknown hitherto from this region, has been proved. Some of these have never been adequately described or illustrated.
Ten new species are described: Theridion ochreolus, T. agaricographus, T hierwhonticus, T. jordanensis, T. negebensis, T. gekkonicus, T. dafnensis, T. vallisalinarum, T. pustiliferus and Anelosimus giladensis. The male of Theridion melanostictum is described for the first time. Keys, illustrations of diagnostic characters and records of distribution are provided for each species, all readily applicable also in adjacent countries. These may provide clues for better understanding of zoogeographic patterns of the Palearctic fauna, including those of the Old World Desert belt extending south and east of the Mediterranean region.     

中国银斑蛛属二新种(蜘蛛目:球蛛科)

记述了球蛛科银斑蛛属2新种:黄桑银斑蛛Argyrodes huangsangensis sp.nov. 和菱腹银斑蛛Argyrodes rhomboides sp.nov..并对环银斑蛛Argyrodes orbitus Zhu, 1988的雌蛛进行了补充描述.     

Spiders of the families Theridiidae, Tetragnathidae and Araneidae (Arachnida: Araneae) from Aldabra atoll

A total of 36 spider species of the families Theridiidae, Tetragnathidae and Araneidae are recorded from Aldabra atoll. Of these, 26 are described as new, together with one new subspecies. The taxonomy of the new species is discussed and, for comparative purposes, five other species not from Aldabra are illustrated. One new synonymy is established. Records for each species are given with, in some cases, notes on biology. The possible biological significance of the egg sac strings found in some species is considered. Finally, the biogeographical affinities of the Aldabra species are briefly discussed.     

Stabilizing selection maintains exuberant colour polymorphism in the spider Theridion californicum (Araneae, Theridiidae)

Genetically controlled colour polymorphisms provide a physical manifestation of the operation of selection and how this can vary according to the spatial or temporal arrangement of phenotypes, or their frequency in a population. Here, we examine the role of selection in shaping the exuberant colour polymorphism exhibited by the spider Theridion californicum. This species is part of a system in which several distantly related spiders in the same lineage, but living in very different geographical areas, exhibit remarkably convergent polymorphisms. These polymorphisms are characterized by allelic inheritance and the presence of a single common cryptic morph and, in the case of T. californicum and its congener the Hawaiian happy-face spider Theridion grallator, numerous rare patterned morphs. We compare population differentiation estimated from colour phenotypic data to differentiation at neutral amplified fragment length polymorphisms (AFLP) loci and demonstrate that the colour polymorphism appears to be maintained by balancing selection. We also examine the patterns of selection in the genome-wide sample of AFLP loci and compare approaches to detecting signatures of selection in this context. Our results have important implications regarding balancing selection, suggesting that selective agents can act in a similar manner across disparate taxa in globally disjunct locales resulting in parallel evolution of exuberant polymorphism.     

State-dependent prey type preferences of a kleptoparasitic spider Argyrodes flavescens (Araneae: Theridiidae)

Spiders from the theridiid genus Argyrodes exhibit considerable variation in foraging tactics. However, little is known about the conditions under which Argyrodes spiders switch foraging tactics. Argyrodes flavescens (Pickard-Cambridge) is commonly found in the webs of another spider Nephila pilipes (Fabricius) in Singapore. In this study, a series of prey-choice tests were conducted for A. flavescens , both in the presence and absence of N. pilipes , to investigate the state-dependent prey type preference of A. flavescens . It was found that, in the absence of N. pilipes , well-fed A. flavescens took houseflies more than fruit flies, but starved A. flavescens took more fruit flies than houseflies. Whether N. pilipes spiders were present or absent, both well-fed and starved A. flavescens preferred living prey and rarely took wrapped prey of any kind. When well fed, A. flavescens rarely took mealworms. However, when starved, A. flavescens tended to take freshly captured prey, and also tended to feed together with N. pilipes on a housefly or mealworm captured by N. pilipes . Whether A. flavescens were absent or present, both well-fed and starved N. pilipes took mealworm larvae more often than they took houseflies, and they never attacked fruit flies. This is the first study to show that Argyrodes spiders alter their foraging tactics depending on hunger level, prey type, or the presence of the host. In doing so, Argyrodes spiders may maximize their energy gain and minimize predation risk in different circumstances.     

The spider genus Enoplognatha (Araneae: Theridiidae) in Israel

Israeli theridiid spiders of the genus Enoplognatha are revised. Five species, four of them new, each represented by the two sexes, are recognized, and their affinities with similar species from adjacent regions are discussed. All species previously described from this region have been re-examined. The occurrence of E. mandibularis , formerly reported from Israel, has been confirmed, while the record of E. ovata has proved erroneous. A key to the species is provided.     

Evolution of Social Behavior in Spiders (Araneae; Eresidae and Theridiidae)

Whereas most spiders are asocial, species in eight familiesare known to live all their life in communities and are thus"permanent-social." Their special attributes are: tolerance,interattraction, and cooperation. These peculiarities must havebeen achieved step by step several times independently. Periodic-socialspiders have been studied as a link between asocial and permanent-socialspiders. In two families—the cribellate Eresidae and ecribellateTheridiidae—different steps of periodic sociality havebeen discovered, from brood-care to feeding by regurgitation.The comparative study of the phylogeny of social behavior inboth families uncovers remarkable convergences of patterns fromasocial to permanent-social via periodical-social species ofspiders.     

Chromosome Mapping of Dragline Silk Genes in the Genomes of Widow Spiders (Araneae,Theridiidae)

With its incredible strength and toughness, spider dragline silk is widely lauded for its impressive material properties. Dragline silk is composed of two structural proteins, MaSp1 and MaSp2, which are encoded by members of the spidroin gene family. While previous studies have characterized the genes that encode the constituent proteins of spider silks, nothing is known about the physical location of these genes. We determined karyotypes and sex chromosome organization for the widow spiders, Latrodectus hesperus and L. geometricus (Araneae, Theridiidae). We then used fluorescence in situ hybridization to map the genomic locations of the genes for the silk proteins that compose the remarkable spider dragline. These genes included three loci for the MaSp1 protein and the single locus for the MaSp2 protein. In addition, we mapped a MaSp1 pseudogene. All the MaSp1 gene copies and pseudogene localized to a single chromosomal region while MaSp2 was located on a different chromosome of L. hesperus. Using probes derived from L. hesperus, we comparatively mapped all three MaSp1 loci to a single region of a L. geometricus chromosome. As with L. hesperus, MaSp2 was found on a separate L. geometricus chromosome, thus again unlinked to the MaSp1 loci. These results indicate orthology of the corresponding chromosomal regions in the two widow genomes. Moreover, the occurrence of multiple MaSp1 loci in a conserved gene cluster across species suggests that MaSp1 proliferated by tandem duplication in a common ancestor of L. geometricus and L. hesperus. Unequal crossover events during recombination could have given rise to the gene copies and could also maintain sequence similarity among gene copies over time. Further comparative mapping with taxa of increasing divergence from Latrodectus will pinpoint when the MaSp1 duplication events occurred and the phylogenetic distribution of silk gene linkage patterns.     

Spiders of the genus Lachesana and a new storenoid genus from Israel (Araneae: Zodariidae)

Zodariid spiders of two genera in Israel are revised. The genus Lachesana is represented by two species. Only one male of these was ever depicted while the females of both and their hitherto unknown retreats were never described. Pax gen. nov. has been erected to accommodate five species, some of which have formerly been placed in Slorena, Selamia or Habronestes . Diagnostic characters of the West Mediterranean Selamia and the Australian Habronestes are newly illustrated. No drawings of Pax libani and P. islamita were ever published; the male of the latter is described here for the first time. Pax palmonii sp. nov. and P. engediensis sp. nov. are described and affinities of all taxa are discussed. Illustrations, records of distribution and keys to the species are provided.     

Molecular insights into the phylogenetic structure of the spider genus Theridion (Araneae, Theridiidae) and the origin of the Hawaiian Theridion-like fauna

The Hawaiian happy face spider ( Theridion grallator Simon, 1900), named for a remarkable abdominal colour pattern resembling a smiling face, has served as a model organism for understanding the generation of genetic diversity. Theridion grallator is one of 11 endemic Hawaiian species of the genus reported to date. Asserting the origin of island endemics informs on the evolutionary context of diversification, and how diversity has arisen on the islands. Studies on the genus Theridion in Hawaii, as elsewhere, have long been hampered by its large size (> 600 species) and poor definition. Here we report results of phylogenetic analyses based on DNA sequences of five genes conducted on five diverse species of Hawaiian Theridion , along with the most intensive sampling of Theridiinae analysed to date. Results indicate that the Hawaiian Islands were colonised by two independent Theridiinae lineages, one of which originated in the Americas. Both lineages have undergone local diversification in the archipelago and have convergently evolved similar bizarre morphs. Our findings confirm para- or polyphyletic status of the largest Theridiinae genera: Theridion , Achaearanea and Chrysso . Convergent simplification of the palpal organ has occurred in the Hawaiian Islands and in two continental lineages. The results confirm the convergent evolution of social behaviour and web structure, both already documented within the Theridiidae. Greater understanding of phylogenetic relationships within the Theridiinae is key to understanding of behavioural and morphological evolution in this highly diverse group.     

中国肥腹蛛属一新种记述(蜘蛛目:球蛛科)

2008～2010年在宁夏六盘山国家级自然保护区进行无脊椎动物科学考察,采集到蜘蛛目球蛛科Theridi-idae蜘蛛标本3370余头,经鉴定共有13属。发现肥腹蛛属Steatoda一新种,命名为彭阳肥腹蛛Steatoda pengyangensissp.nov.。模式标本保存于河北大学博物馆。     

Venom of Latrodectus mactans from Chile (Araneae, Theridiidae): effect on smooth muscle

The venoms of Latrodectus sp. have been reported to induce contraction probably mediated by adrenergic and cholinergic transmitters. We have demonstrated that the venom of Chilean Latrodectus mactans contains neurotoxins that induce a contraction partially independent of transmitters release. Transmembrane mobility of Na+ and Ca2+ ions and more specifically, the increase of cytoplasmic calcium concentration are responsible for tonic contraction in smooth muscle. Calcium may enter the cell by several ways, such as the voltage-dependent Ca2+ L-type channels and the Na+/Ca2+ exchanger. This study aimed to examine the participation of this exchanger in the tonic contraction of smooth muscle in vas deferent of rat induced by the venom of the Chilean spider L. mactans. Blockers of Na+ channels (amiloride) and Ca2+ L-type channels (nifedipine), and a stimulator of the exchanger (modified Tyrode, Na+ 80 mM) were used. Simultaneously, variations of the cytoplasmic concentration of Ca2+ were registered by microfluorimetry (Fura-2 indicator) in the presence of nifedipine. In presence of amiloride, dose-dependent inhibition of venom-induced contraction was observed, suggesting the participation of voltage-dependent Ca2+ L-type channels. The contraction was only partially inhibited by nifedipine and the Ca2+ cytoplasmic concentration increased, as assessed by the microfluorimetric registration. Finally, the venom-induced contraction increased in the presence of modified Tyrode, probably due to the action of the Na+/Ca2+ exchanger. Taken together, our results support the idea that the Na+/Ca2+ exchanger is active and may be, at least in part, responsible for the contraction induced by the venom of Chilean L. mactans.     

Spiders of the genera Pachygnatha,Dyschiriognatha and Glenognatha (Araneae,Tetragnathidae), with a revision of the Afrotropical species*

Pachygnatha kiwuana Strand, P. leleupi Lawrence, P. longipes Simon. P. mucronata Tullgren, P. palmqvisti Tullgren, P. ruanda Strand and Dyschiriognatha argyrostilba (O.-P. Cambridge, 1876) (junior synonym: D. atlantica Holm, 1969) are redescribed. Puchygnutha hexutrucheutu, P. zuppu, P. procincta, P. okuensis, P. utromurginata, P. jansseni, P., goedeli, P. opdmwrdiue and Glenognatha smilodon, all species collected during the Belgian Cameroon expeditions, arc described as new. A key for all Afrotropical species is presented.     

Postembryonic development of the spider Enoplognatha ovata (Clerck) (Araneae:Theridiidae)

The postembryonic development of the three colour varieties of Enoplognatha ovata (CI.) was studied in the field and in the laboratory for two generations. Native and European spiders of this species were compared. Estimates of the number and duration of each stage were obtained from laboratory mating studies and verified by field studies. Males and females matured after five instars. Males matured faster than females but did not live as long. Each instar was characterized by several measurable parameters. All varieties over-winter in the second instar. Sexes could be easily separated at the fourth instar by comparing the ratio of the tarsal to patellar width of the pedipalps. Sexual dimorphism occurs at maturation ecdysis. Filial and mating studies indicate that the three colour varieties belong to a single species.     

海南岛菜萨蛛属2新种（蜘蛛目：球蛛科）

作者在进行中国海南岛及西沙群岛无脊椎动物资源调查研究时,发现了蜘蛛目球蛛科莱萨蛛属2新种,命名为半月莱萨蛛Lasaeola lunata sp．nov．和锥莱萨蛛Lasaeola fastigata sp．nov．。所有标本均保存在河北大学生命科学学院。文中测量单位为mm。     

Spiders of the genus Cupiennius Simon 1891 (Araneae,Ctenidae)

Summary Cupiennius salei (Ctenidae) is a tropical wandering spider which lives in close association with a particular type of plant (see companion paper). These plants are the channels through which the spiders receive and emit various types of vibrations. We measured the vibrations the spiders are typically exposed to when they sit on their dwelling plants (banana plant, bromeliad) in their natural biotope in Central America. In addition a laboratory analysis was carried out to get an approximate idea of the complex vibration-propagating properties of the dwelling plants, taking a banana plant as an example. (1) Types of vibrations (Figs. 1–4). Despite variability in detail there are characteristic differences in spectral composition between the vibrations of various abiotic and biotic origins: (a) Vibrations due to wind are very low frequency phenomena. Their frequency spectra are conspicuously narrow with prominent peaks close to or, more often, below 10 Hz. Vibrations due to raindrops show maximal acceleration values at ca. 1000 Hz. Their frequency band at-20 dB extends up to ca. 250 Hz where-as that of the vibrations due to wind extends to only ca. 50 Hz. (b) The frequency spectra of prey vibrations such as those generated by a running cockroach are typically broad-banded and contain high frequencies; they have largest peaks mostly between ca. 400 and 900 Hz. Their-20 dB frequency bands usually extend from a few Hz to ca. 900 Hz. Some potential prey animals such as grass-hoppers seem to be vibrocryptic; they walk by the spider as if unnoticed. Their cautious gait leads to only weak vibrations at very low frequencies resembling the background noise due to wind. Courtship signals are composed maily of low frequencies, intermediate between background noise and prey vibrations (male: prominent peaks at ca. 75 Hz and ca. 115 Hz; female: dominant frequencies between ca. 20 Hz and ca. 50 Hz). The male signal is composed of syllables and differs from all other vibrations studied here by being temporally highly ordered. A comparison with previous electrophysiological studies suggests that the high pass characteristics of the vibration receptors enhance the signal-to-(abiotic)-noise ratio and that the vibration-sensitive interneurons so far examined and found to have band pass characteristics are tuned to the frequencies found in the vibrations of biotic origin. (2) Signal propagation (Fig. 5). In terms of frequency-dependent attenuation of vibrations the banana plant is well suited for transmitting the above signals. Average attenuation values are ca. 0.35 dB/cm. Together with known data on vibration receptor sensitivity this explains the range of courtship signals of more than 1 m observed in behavioral studies. Attenuation in the plant is neither a monotonic function of frequency nor of distance from the signal source.     

蜘蛛抗逆能力的研究

本文对隐蛛科的白斑隐蛛;狼蛛科的拟环纹豹蛛、星豹蛛、真水狼蛛、细毛水狼蛛;卷叶蛛科的猫卷叶蛛;栅蛛科的栓栅蛛;球蛛科的温室希蛛;皿蛛科的草间钻头蛛、难波小黑蛛、隆背微蛛、花腹盖蛛;园蛛科的黄斑园蛛;管巢蛛科的棕管巢蛛;蟹蛛科的三突花蛛;跳蛛科的吉蚁蛛等10科共16种蜘蛛做了在30 ℃恒温条件下的抗逆能力测定.结果表明,蜘蛛是一类抗逆能力较强的动物,只要供给水分,其雌蛛的平均寿命在25 d以上;水在蜘蛛生命活动中具有非常重要的作用,在相同的条件下,如果断食断水,蜘蛛的平均寿命显著缩短,只有6 d左右;由于蜘蛛种类和生活环境的不同,其耐饥饿的能力也表现出很大的差异,一般地面活动的蜘蛛或靠水边活动的蜘蛛耐饥、耐水能力较差,而游猎性蜘蛛,尤其是结网的蜘蛛抗逆能力较强;雌蛛的抗逆能力大于雄蛛;三突花蛛的耐饥能力随着龄期的增加而加强.     

中国云南铜蛛属2新种（蜘蛛目：跳蛛科）

本文对采自云南的铜蛛属Chalcoscirtus Bertkau,1880蜘蛛2新种Chalcoscirtus lii sp.nov.和Chalcoscirtus yinae sp.nov..做了详细的文字描述,并附有鉴别特征图和地理分布数据.模式标本保存在湖南师范大学生命科学学院.