Phosphatases in the central nervous system of spiders (Arachnida, Araneae).

The central nervous systems of web-building spiders (Araneidae, Agelenidae) and hunting spiders (Lycosidae, Salticidae) were tested for non-specific and specific phosphatases. Acid phosphatase exhibited weakly to moderately positive reactions in the neuronal cell bodies and in the neuropile fibre mass of all species investigated. Alkaline phosphatase could only be demonstrated in the external and internal neural lamellae of the brain and ventral cord of several specimens of the araneid species investigated. Tests for thiamine pyrophosphatase were negative with both the lead and calcium-cobalt methods. Distinctive positive reactions for adenosine triphosphatase were visible in the nervous system of all the species used, being especially strong in the optic ganglia of the hunting spiders. The demonstration of adenosine triphosphatase was only possible when applying the calcium-cobalt method after Padykula and Herman, while the lead method after Wachstein and Meisel did not produce any staining reaction at all. Controls of the histochemical reaction showed that the enzyme was activated by Ca2+ and inhibited by sulphydryl destroying reagents (e.g. PCMB), but was insensitive to ouabain. It could be probably classified as a mitochondrial proton-translocating adenosine triphosphatase.     

Comparative quantitative aspects of putative neurotransmitters in the central nervous system of spiders (Arachnida: Araneida)

The amounts of eight putative neurotransmitters or modulators (acetylcholine, dopamine, noradrenaline, adrenaline, GABA, taurine, glutamic acid, glycine) were determined from the CNS of 12 species of five different spider families (Theraphosidae, Agelenidae, Araneidae, Lycosidae, Salticidae). Comparatively high contents of acetylcholine and noradrenaline could be found in the CNS of hunting spiders, higher contents of GABA and taurine were visible in the web-building spider families, while extraordinarily high amounts of glutamic acid were confined to the Theraphosidae. The results obtained are compared with findings from other arthropod groups and the role of putative transmitters or modulators in the spider CNS is discussed in relation to behavioural differences within the families investigated.     

New data on spiders (Arachnida: Araneae) of Iraq

Until recently only 33 species of spiders had been known from Iraq. New material collected in northern Iraq reveals 20 species, 13 genera and six families new to the country. One species, Pterotricha arzhantsevi sp. n. is described as new to science. Comparative figures are provided for seven species; the 54 species currently known from Iraq are listed and their occurrence in neighbouring Iran and Turkey is shown.

http://www.zoobank.org/urn:lsid:zoobank.org:pub:4812F8A8-7A95-4D66-8E2D-CE42F73E7E91     

Complex female genitalia indicate sperm dumping in armored goblin spiders (Arachnida,Araneae, Oonopidae)

In promiscuous females, sperm ejection from the sperm storage site can be a strong mechanism to influence sperm priority patterns. Sperm dumping is reported from different animals including birds, insects, and humans. In spiders, it has been documented for four species including the oonopid Silhouettella loricatula. Oonopidae are a diverse spider family comprising many species with peculiar female genitalia. Especially in species where studies of mating behavior are difficult, morphological investigations of the genitalia help to understand their function and evolution. In the present study, the genitalia of the oonopids Myrmopopaea sp., Grymeus sp., and Lionneta sp. are investigated by means of histological serial sections and scanning electron microscopy (SEM). The results are compared with previous findings on S. loricatula. In Myrmopopaea sp. and Grymeus sp., the same morphological components are present that are involved in sperm dumping in S. loricatula. Inside the receptaculum, sperm are enclosed in a secretory sac which can be moved to the genital opening and dumped during copulation by muscle contractions. The female genitalia of Lionneta sp. are asymmetric. They show the same characteristics as S. loricatula but all the investigated females were unmated. The results strongly suggest that sperm dumping occurs in Myrmopopaea sp., Grymeus sp., and Lionneta sp. and happens by the same mechanism as in S. loricatula. Sperm dumping might even be common within a clade of oonopids. As in S. loricatula, the sperm transfer forms in the investigated species consist of several spermatozoa. Papillae with unknown function occur on the receptacula of all females.     

The fauna of spiders (Arachnida,Araneae) in agricultural landscapes of the Moscow area and the Kuban Plain

Six years of collecting in agricultural landscapes of the Moscow area and the Kuban Plain (Krasnodar Territory) revealed 286 species of spiders from 146 genera of 20 families. Two species, Clubiona pseudoneglecta Wund. and Palliduphantes insignis O.P.-C. are recorded for the Russian fauna for the first time, and 20 species are new to Moscow Province. Linyphiidae is the most species-rich family comprising about half of the species found in Moscow Province and about a quarter of those found in Krasnodar Territory. The species are classified into 13 arealogical groups. The bulk of the fauna is formed by the widespread, mostly Eurasian and Holarctic species. The spider fauna of Krasnodar Territory has smaller fractions of the Holarctic and Euro-Siberian species and larger fractions of the Palaearctic and Euro-Mediterranean species, as compared to the Moscow fauna. In general, the faunas of both the regions studied may be classified as European. The spider fauna of agrocenoses of Moscow Province is more similar to the faunas of European regions situated at the same latitude than to the fauna of Krasnodar Territory (the Kuban Plain).     

Predator-prey interactions between web-invading jumping spiders and a web-building spider, Holocnemus pluchei (Araneae, Pholcidae)

Three species of web-invading salticid spiders, with different predatory strategies, were tested with Holocnemus pluchei in the laboratory: Portia fimbriata and Portia labiata , which practise aggressive mimicry, and Euyattus sp., which leaps from outside on to spiders in webs but does not practise aggressive mimicry. Portia was shown to be more efficient than Euryattus at catching H. pluchei. Portia fimbriata from Queensland was more consistent at using aggressive mimicry than was Portia labiata and was also more efficient at catching H. pluchei . The web-invaders that were more efficient at catching H. pluchei were also better able to avoid setting off bouncing, a special defence behaviour used by H. pluchei . An experiment, in which H. pluchei was artificially induced to bounce whenever the predator was near, provided additional evidence that bouncing is effective in defending H. pluchei against web-invaders.     

Diversity of grass-dwelling spiders (Arachnida: Araneae) in calcareous fens of the Coastal Lowland,Latvia

Calcareous fens have a high conservation priority in the European Union. They are very unique, very sensitive and very rare habitats in Latvia as well as in many other European countries. Because of their rarity, many organisms living in calcareous fens are nowadays considered threatened. The same is applied to spiders. Spiders have been suggested as good biodiversity indicators because they have numerous direct and indirect relationships with other organisms. Only few investigations have been carried out on fen inhabiting spiders. The knowledge of grass-dwelling spiders is especially lacking. Thus the aim of this study was to evaluate grass-dwelling spider diversity in several calcareous fens of Latvia, compare these fens and to find out the habitat features that might affect grass-layer inhabiting spiders. The research was carried out in eight calcareous fens located in the Coastal Lowland of Latvia. A total of 760 spiders from nine families and 20 species were collected with a sweep net. Two of the most abundant spider species were Dolomedes fimbriatus (Clerck, 1757) and Tibellus maritimus (Menge, 1875). Diversity indices suggested that the grass-dwelling spider community consists of few abundant species and numerous rare species. Correlation analysis as well as DCA showed that plant species diversity did not significantly affect spider species richness and diversity, although at the same time there were a lot of significant associations between spiders and individual plant species. It was shown that various spider species responded very differently to the presence of particular plant species, and thus habitat structural heterogeneity emerges to be an important factor influencing the grass-dwelling spider diversity and community structure. Correlation analysis also revealed that spider abundance was negatively affected by the vegetation height and wind speed.     

Phosphatases in the central nervous system of spiders

Summary The central nervous systems of web-building spiders (Araneidae, Agelenidae) and hunting spiders (Lycosidase, Salticidae) were tested for non-specific and specific phosphatases. Acid phosphatase exhibited weakly to moderately positive reactions in the neuronal cell bodies and in the neuropile fibre mass of all species investigated. Alkaline phosphatase could only be demonstrated in the external and internal neural lamellae of the brain and ventral cord of several specimens of the araneid species investigated. Tests for thiamine pyrophosphatase were negative with both the lead and calciumcobalt methods. Distinctive positive reactions for adenosine triphosphatase were visible in the nervous system of all the species used, being especially strong in the optic ganglia of the hunting spiders. The demonstration of adenosine triphosphatase was only possible when applying the calcium-cobalt method after Padykula and Herman, while the lead method after Wachstein and Meisel did not produce any staining reaction at all. Controls of the histochemical reaction showed that the enzyme was activated by Ca²⁺ and inhibited by sulphydryl destroying reagents (e.g. PCMB), but was insensitive to ouabain. It could be probably classified as a mitochondrial proton-translocating adenosine triphosphatase.     

Anti-predator defences of Psilochorus sphaeroides and Smeringopus pallidus (Araneae, Pholcidae), tropical web-building spiders

Anti-predator defence behaviours of Psilochorus sphaeroides from Queensland and Smeringopus pallidus from Sri Lanka were studied in the laboratory. Whirling, in which these web-building pholcid spiders move their bodies rapidly around in circles, with legs remaining on the silk, is the most frequent response of adults to disturbance. Experiments were carried out to determine what types of stimuli elicited whirling. Forceful tactile and air movement stimuli elicited whirling, but there was no evidence that chemical stimuli from potential predators were important. Tactile stimulation was more effective than air movement. The behaviour of these pholcids was compared to that of a cosmopolitan pholcid, Pholcus phalangioides .     

New cave-dwelling spiders of the family Dictynidae (Arachnida: Araneae) from Guangxi and Guizhou,China

Twenty-four new spider species of the family Dictynidae from caves of Guangxi and Guizhou in southern China are described,accompanied by line drawings and photomicroscopy images.Fifteen of them belong to Brommella Tullgren,1948:B.baiseensis Li,sp.nov.,B.casseabri Li,sp.nov.,B.chongzuoensis Li,sp.nov.,B.dolabrata Li,sp.nov.,B.funaria Li,sp.nov.,B.josephkohi Li,sp.nov.,B.linyuchengi Li,sp.nov.,B.renguodongi Li,sp.nov.,B.resima Li,sp.nov.,B.sejuncta Li,sp.nov.,B.spirula Li,sp.nov.,B.tongyanfengi Li,sp.nov.,B.wangfengcheni Li,sp.nov.,B.xinganensis Li,sp.nov.and B.yizhouensis Li,sp.nov.;eight to Cicurina Menge,1871:C.avicularia Li,sp.nov.,C.damaoensis Li,sp.nov.,C.dong Li,sp.nov.,C.kailiensis Li,sp.nov.,C.majiangensis Li,sp.nov.,C.parallela Li,sp.nov.,C.wusanani Li,sp.nov.,and C.zhazuweii Li,sp.nov.;one to Lathys Simon,1884:L.inaffecta Li,sp.nov.Types of all new species are deposited in the Institute of Zoology,Chinese Academy of Sciences in Beijing (IZCAS).     

Ground-dwelling spiders (Arachnida, Araneae) in fragmented old forests and surrounding managed forests in southern Finland

We studied the structure of spider assemblages in fragments of old coniferous forest in the southern Finnish taiga We sampled spiders with pitfall traps in the interiors and in the edges of the old-forest patches and in the surrounding managed forests We surveyed assemblages of ground-dwelling spiders and the relation of species to formerly mentioned three forest-habitat categories We analysed spider assemblages in relation to vegetation structure as well As in forest spiders there are no habitat specialists, no strict old-forest species were found However, the spider assemblages of old forests were different from those in the surrounding managed forests The difference was attributable to habitat differences, mainly to reduced tree-canopy cover in managed forests Large hunting-spider species (Gnaphosidae, Lycosidae) benefitted from clearcutting and other management measures, whereas the catches of small forest-living species (Linyphiidae) decreased in plantations and open forests The hunters colonized the edges of old-forest fragments, and were seldom found in the interior of old forest Size of old-forest fragment did not affect significantly the spider assemblage The results indicate that a buffer zone of mature forest with closed canopy should be left to surround the old-growth reserves in order to minimize the edge effect in the fragments     

Diversity of insects captured by weaver spiders (Arachnida: Araneae) in the cocoa agroecosystem in Tabasco, Mexico

The aim of this work was to know the diversity of insects captured by weaver spiders in a plantation of cocoa (Theobroma cacao L.) of 6 ha in the State of Tabasco, Mexico. The study was carried out from July 2004 to June 2005 by means biweekly samples of the insects captured on the spiders webs. The total of 3,041 webs of 54 species of spiders belonging to seven families (Araneidae, Theridiidae, Tetragnathidae, Uloboridae, Pholcidae, Dyctinidae and Linyphiidae) were revised. We found 1,749 specimens belonging to 10 orders of insects, represented by 93 families, the majority of Coleoptera, Diptera and Hemiptera that constituted 74% of the identified families. The biggest number of specimens of all orders was captured by Araneidae, except of Isoptera, whose specimens were captured mainly by the family Theridiidae. The index of diversity (H'), evenness (J') and similarity (Is), applied to know the diversity of families of insects captured among families of spiders, varied from 0.00 to 3.24, 0.00 to 0.81, and 0.04 to 0.522, respectively. We conclude that there is a wide diversity of insects predated by the weaver spiders in the cocoa agroecosystem, and that there are species that can be promising for the biological control of pests.     

Some comments on the hydrostatic system of spiders (Chelicerata,Araneae)

An anatomical study of five spider types has shown that the musculi laterales of the prosoma, together with the subcuticular muscle sheet of the opisthosoma, may be jointly responsible for generating the internal hydrostatic pressures which control the leg extension mechanism.     

Genital morphology of female goblin spiders (Arachnida: Araneae: Oonopidae) with functional implications

Spider genital morphology usually provides the best characters for taxonomy. Furthermore, functional genital morphology helps to understand the evolution of complex genitalia and their role in the context of sexual selection. The genital systems of most haplogyne spider families are poorly investigated with respect to their morphology. The present study investigates the female genitalia of the oonopids Oonops pulcher, Oonopinus kilikus, and Pseudotriaeris sp. by means of light microscopy and SEM. The male palps are briefly described. Females of O. pulcher store spermatozoa in an anterior and a posterior receptaculum (PRe). The genitalia resemble the primitive dysderoid genitalia supporting the hypothesis that the subfamily Oonopinae contains more basal oonopids. In O. kilikus, the anterior receptaculum is reduced to a sclerite. Spermatozoa are stored in a PRe. The receptacula of Pseudotriaeris sp. are reduced to sclerites. Spermatozoa in the uterus internus indicate that fertilization happens there or in the ovary. The anterior sclerite might serve females to lock the uterus during copulation as suggested for other gamasomorphines. The male palp of O. kilikus is simple, whereas the palps of O. pulcher and Pseudotriaeris sp. appear more complex. Complicated structures on the palp of Pseudotriaeris sp. indicate that males exert copulatory courtship.