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Spider Species (spider + species)
Selected AbstractsAlien spider introductions to Europe supported by global tradeDIVERSITY AND DISTRIBUTIONS, Issue 2 2008Manuel Kobelt ABSTRACT Global trade is permanently ongoing and increases its volume every year. In this study, the occurrence of 87 unintentionally introduced spider species alien to Europe is analysed. The analysis includes (1) the introduction potential of six different origin areas of the world according to trade volume, area size, and geographical distance; (2) the body size of native and alien species; and (3) occurrence in or at buildings (synanthropic) or in natural habitats. We found the eastern Palearctic as the most influencing origin area with 44 introduced spider species to Europe. The eastern Palearctic and the Indomalayan provided a significantly higher number of introductions than expected, whereas the Nearctic, Neotropical, and Afrotropical provided a significantly lower number of introduced species than expected. This can be explained with their lower trade volume, smaller area, larger geographical distance to Europe, and stronger climate differences to Europe. Comparing the body size of introduced and native European spider species of the same family, we found for Theridiidae significantly larger alien spiders and for all other tested families a trend to a larger body size of alien species compared to the native spiders. The family affiliation of alien spiders is the most important factor for synanthropic occurrence in Europe. On the base of a very conservative estimation of spider species introductions to Europe combined with possible effects of climate change, we predict for the near future a permanent increase in the number of alien spider species in Europe. [source] Male Performance and Body Size Affect Female Re-Mating Occurrence in the Orb-Web Spider Leucauge mariana (Araneae, Tetragnathidae)ETHOLOGY, Issue 12 2009Anita Aisenberg Females can affect male probabilities of paternity success through behavioural, morphological and/or physiological processes occurring during or after copulation. These processes under female-control include the acceptance or rejection of mating attempts by subsequent males. Leucauge mariana is an orb weaving spider that shows male mate guarding of penultimate females, male,male competition on female webs and copulatory plugs, suggesting a polyandric mating system. The aim of the present study was to ascertain whether male behaviour during courtship and copulation in L. mariana relate with female re-mating decisions. Forty-three virgin females were exposed to up to three males until they mated. In 24 cases, the copulatory plug was absent after mating and females were exposed the next day to up to three other males. Eighteen females accepted a second mating. Relatively larger females were more receptive to second matings and were more likely to copulate if the second male was smaller. Longer duration of female tapping and abdominal bobbing during courtship, and first copulations with less short insertions and more flubs, were associated with increased female acceptance to second matings. The results indicate cryptic female choice on male courtship and copulatory performance and suggest female-control over the determination of male mating success in this spider species. [source] Scent of a Woman , The Effect of Female Presence on Sexual Cannibalism in an Orb-Weaving Spider (Araneae: Araneidae)ETHOLOGY, Issue 7 2009Stefan H. Nessler Post-mating sexual cannibalism occurs as a regular element of mating behaviour in a number of spider species. Frequencies of cannibalism, however, are highly variable between and within species. In Argiope bruennichi, males apparently differ in their motivation to escape a female attack but causes for this variability are unknown. We observed that the probability of sexual cannibalism is positively correlated with male age, i.e. the number of days that passed between male maturation and copulation. The mating season in this species is short with 3,4 wk and males mostly mature days before the females, whose maturation phase is longer. Consequently, as the season progresses, the availability of virgin females increases, quickly reaches a peak and then rapidly declines. In addition, the age of still unmated males increases with the season and both of these factors can potentially affect the degree of sexual cannibalism. To separate these factors, males were collected in their penultimate stage and kept until mating either with or without contact to female pheromones. Thereby, we experimentally manipulated the male's perception of female presence. Within each treatment, we formed three male age groups: (1) 2,6 d, (2) 12,16 d and (3) 22,28 d. Our results demonstrate that the probability of cannibalism was independent of male age but was explained by the treatment of males: males exposed to virgin female pheromones were significantly more likely to be cannibalised than males that were kept without female pheromones. This suggests that males change their reproductive strategy according to perceived mating prospects. [source] Contrasting Patch Residence Strategy in Two Species of Sit-and-Wait Foragers Under the Same Environment: A Constraint by Life History?ETHOLOGY, Issue 2 2005Tadashi Miyashita The present study explored the significance of life history constraints on patch residence strategy by using two congeneric web spider species living in the same habitat. Nephila maculata had a large body size but had a shorter developmental period compared with N. clavata, indicating that N. maculata should have a greater foraging efficiency to reach maturity and reproduce. Residence time at web-sites in N. maculata was shorter than that in N. clavata, irrespective of the season. However, supplementation of food to N. maculata increased residence time, suggesting that it searches web-sites with higher prey intake. Investment of web materials, an important trait influencing web relocation frequency, was not greater in N. maculata. In addition, microhabitat and prey size did not differ significantly after controlling for the effect of body size. Because N. maculata needs to attain a large body size in a shorter period of time, this species appears to take a risk of moving patches to seek high quality web-sites. [source] Diversification of nubbin expression patterns in arthropods: data from an additional spider species, Cupiennius saleiEVOLUTION AND DEVELOPMENT, Issue 4 2005Nikola-Michael Prpic First page of article [source] Identification and characterization of multiple Spidroin 1 genes encoding major ampullate silk proteins in Nephila clavipesINSECT MOLECULAR BIOLOGY, Issue 5 2008W. A. Gaines IV Abstract Spider dragline silk is primarily composed of proteins called major ampullate spidroins (MaSps) that consist of a large repeat array flanked by nonrepetitive N- and C-terminal domains. Until recently, there has been little evidence for more than one gene encoding each of the two major spidroin silk proteins, MaSp1 and MaSp2. Here, we report the deduced N-terminal domain sequences for two distinct MaSp1 genes from Nephila clavipes (MaSp1A and MaSp1B) and for MaSp2. All three MaSp genes are co-expressed in the major ampullate gland. A search of the GenBank database also revealed two distinct MaSp1 C-terminal domain sequences. Sequencing confirmed that both MaSp1 genes are present in all seven Nephila clavipes spiders examined. The presence of nucleotide polymorphisms in these genes confirmed that MaSp1A and MaSp1B are distinct genetic loci and not merely alleles of the same gene. We experimentally determined the transcription start sites for all three MaSp genes and established preliminary pairing between the two MaSp1 N- and C-terminal domains. Phylogenetic analysis of these new sequences and other published MaSp N- and C-terminal domain sequences illustrated that duplications of MaSp genes may be widespread among spider species. [source] The effects of plant structure on the spatial and microspatial distribution of a bromeliad-living jumping spider (Salticidae)JOURNAL OF ANIMAL ECOLOGY, Issue 1 2005GUSTAVO Q. ROMERO Summary 1In several regions of South America, the neotropical jumping spider Psecas chapoda inhabits and reproduces strictly on the bromeliad Bromelia balansae. Previous studies reported that this spider is more frequent on bromeliads in grasslands than on those growing in forests, and on larger plants, but only when the bromeliads are without inflorescence. Upon blooming, B. balansae fold their leaves back, thereby changing the plant architecture from a tri-dimensional to a bi-dimensional flattened shape, and our hypothesis is that this alteration affects the spider's habitat-selection decisions. 2In the present study, we examined experimentally the effects of inflorescence, plant size and blockade of the axil of the leaves (spider shelters) of forest bromeliads on the colonization of a bromeliad by P. chapoda. By using sticky traps, we also compared prey availability in grassland and forest. 3Plants with simulated inflorescence were colonized at a lower frequency than those without inflorescence simulation. Grassland bromeliads in which the rosettes were blocked with dry leaves were colonized less frequently than open bromeliads, whereas forest bromeliads from which dry leaves had been removed were not colonized. Spiders generally abandoned bromeliads in which three-quarters of the length of the leaves had been removed, although females with eggsacs remained on these plants. Prey availability (biomass and number) was up to 18 fold higher in the grassland than in the forest. These results suggest that microhabitat structure and prey availability shape the spatial distribution of P. chapoda populations. 4Our findings suggest that Psecas chapoda can evaluate, in fine detail, the physical state of its microhabitat, and this unusual spider,plant association is readily destabilized by changes in the microhabitat (i.e., it is strictly dependent on the size and morphology of the host plant). This study is one of the few to report a strict association between a spider species and its host plant, and also one of the few to examine the effects of habitat and microhabitat structure on the spatial distribution of active hunters on plants. [source] Aged pesticide residues are detrimental to agrobiont spiders (Araneae)JOURNAL OF APPLIED ENTOMOLOGY, Issue 8 2008S. Pekár Abstract Spiders are among the most abundant arthropods in agroecosystems, playing an important role as natural enemies of various pests. In this study we evaluated residual activity of selected pesticides on the mortality and behaviour of four spider species (Dictyna uncinata, Pardosa palustris, Philodromus cespitum and Theridion impressum). We used three pesticides: a herbicide Command (clomazone), and insecticides Decis (deltamethrin) and Nurelle (chlorpyrifos and cypermethrin). Mortality was recorded after exposure of spiders to fresh (2-h), 5, 10, 15 and 20-day-old residues. For each residue mortality was evaluated after 24,72 h. Residual effect differed between preparations and, in some cases, between spiders. All of the Nurelle residues (fresh to 20-day-old) caused 100% mortality in all spider species. Residues of Command were rather harmless (causing <20% mortality) to all spider species as the herbicide activity declined with age. Residues of Decis had species-specific effects as the mortality varied between 0 and 90%. In Dictyna the mortality gradually declined with the age of residues, while in Pardosa the mortality increased. In Philodromus and Theridion the mortality declined up to 10-day-old residues and then increased so that 20-day-old residues caused almost as high mortality as the new ones. Exposure to pesticide residues immediately affected the movement of Pardosa spiders. Residues of Decis and Nurelle decreased spider locomotion, while those of Command increased locomotion in comparison with the control. In another experiment, we studied repellence of fresh pesticide residues to Pardosa spiders. In comparison with the control, spiders stayed a similar time on the surface treated with Command, but four times less on Decis and nine times less on Nurelle-treated surfaces, respectively. In conclusion, aged insecticide residues possess a high activity and can cause long-term decline in the abundance and prolonged behavioural disturbance of spiders in agroecosystems. [source] Contrasting responses of arable spiders to the landscape matrix at different spatial scalesJOURNAL OF BIOGEOGRAPHY, Issue 1 2008Martin H. Schmidt Abstract Aim, Animal communities can be influenced by the composition of the surrounding landscape through immigration. Depending on habitat preferences, however, the effect of the landscape matrix can be positive or negative and can vary with scale. We tested this idea with arable spiders and tried to infer dispersal distances from relationships between local density and landscape composition at different spatial scales. Location, Thirty-eight landscapes around the cities of Göttingen and Giessen, Germany. Methods, Spiders were captured with pitfall traps in one field of winter wheat in each landscape. Landscape composition around the fields was characterized at 11 scales from 95 m to 3 km radius by land-use mapping and subsequent GIS analysis. Correlation tests were performed between landscape composition and local densities or species richness. Results, In both study regions, local species richness was enhanced by non-crop habitats on a landscape scale. The overall densities of wolf spiders (Lycosidae), long-jawed spiders (Tetragnathidae), crab spiders (Thomisidae), and dwarf sheet spiders (Hahniidae) increased significantly in landscapes with high percentages of non-crop habitats. Out of the 40 species tested, 19 responded positively to the percentage of non-crop habitats in the surrounding landscape, and five responded negatively. Depending on the species, the spatial scales with the highest explanatory power ranged from 95 m to 3 km radius around the study fields, potentially reflecting dispersal distances. Main conclusions, Arable spider species showed contrasting responses to the landscape context with respect both to the direction and to the spatial scale of the relationship. The variation in landscape requirements among species ensures high spider densities in a wide range of situations, which contributes to ecosystem resilience. However, species richness of arable spiders depends on heterogeneous landscapes with high percentages of non-crop habitats. [source] Diversity of canopy and understorey spiders in north-temperate hardwood forestsAGRICULTURAL AND FOREST ENTOMOLOGY, Issue 2 2009Maxim Larrivée Abstract 1,We characterized and compared diversity patterns of canopy and understorey spiders (Arachnida: Araneae) on sugar maple (Acer saccharum Marsh.) and American beech (Fagus grandifolia Ehrh.) in hardwood forests of southern Québec, Canada. 2,We sampled canopies of 45 sugar maple and 45 American beech trees and associated understorey saplings in mature protected forests near Montréal. Samples were obtained by beating the crown foliage at various heights and by beating saplings around each tree. 3,Eighty-two species were identified from 13 669 individuals. Forty-eight species and 3860 individuals and 72 species and 9809 individuals were collected from the canopy and the understorey, respectively. 4,Multivariate analyses (NMDS ordination and NPMANOVA) showed the composition of canopy and understorey assemblages differed significantly, and canopy assemblages differed between tree species. Rank-abundance distribution models fitted to the canopy and understorey data indicated that different mechanisms structure the assemblages in both habitats. Three abundant spider species were significantly more common in the canopy; ten species were collected significantly more often in the understorey. 5,The forest canopy was shown to be an important reservoir for spider diversity in north-temperate forests. [source] Spider sex pheromones: emission, reception, structures, and functionsBIOLOGICAL REVIEWS, Issue 1 2007A. C. Gaskett Abstract Spiders and their mating systems are useful study subjects with which to investigate questions of widespread interest about sexual selection, pre- and post-copulatory mate choice, sperm competition, mating strategies, and sexual conflict. Conclusions drawn from such studies are broadly applicable to a range of taxa, but rely on accurate understanding of spider sexual interactions. Extensive behavioural experimentation demonstrates the presence of sex pheromones in many spider species, and recent major advances in the identification of spider sex pheromones merit review. Synthesised here are the emission, transmission, structures, and functions of spider sex pheromones, with emphasis on the crucial and dynamic role of sex pheromones in female and male mating strategies generally. Techniques for behavioural, chemical and electrophysiological study are summarised, and I aim to provide guidelines for incorporating sex pheromones into future studies of spider mating. In the spiders, pheromones are generally emitted by females and received by males, but this pattern is not universal. Female spiders emit cuticular and/or silk-based sex pheromones, which can be airborne or received via contact with chemoreceptors on male pedipalps. Airborne pheromones primarily attract males or elicit male searching behaviour. Contact pheromones stimulate male courtship behaviour and provide specific information about the emitter's identity. Male spiders are generally choosy and are often most attracted to adult virgin females and juvenile females prior to their final moult. This suggests the first male to mate with a female has significant advantages, perhaps due to sperm priority patterns, or mated female disinterest. Both sexes may attempt to control female pheromone emission, and thus dictate the frequency and timing of female mating, reflecting the potentially different costs of female signalling and/or polyandry to both sexes. Spider sex pheromones are likely to be lipids or lipid soluble, may be closely related to primary metabolites, and are not necessarily species specific, although they can still assist with species recognition. Newer electrophysiological techniques coupled with chemical analyses assist with the identification of sex pheromone compounds. This provides opportunities for more targeted behavioural experimentation, perhaps with synthetic pheromones, and for theorising about the biosynthesis and evolution of chemical signals generally. Given the intriguing biology of spiders, and the critical role of chemical signals for spiders and many other animal taxa, a deeper understanding of spider sex pheromones should prove productive. [source] | ||||||||||