Presampling sensory information and prey density assessment by wolf spiders (Araneae, Lycosidae)

Decisions regarding foraging patch residence time and the assessmentof patch quality may be mediated by various sources of information.This study examined the use of sensory cues by hunting spidersto assess prey density in the absence of prey capture. Adultfemale wolf spiders [Schizocosa ocreata (Hentz); Lycosidae]had food withheld for 4 days and then were exposed to artificialforaging patches containing four densities of crickets (0, 3,10, 20) with different sensory stimuli (visual and vibratoryinformation, visual only, and vibratory only). The spiders werenot allowed to feed during trials, and patch residence timewas recorded. The spiders varied patch residence time basedon sensory cues alone and spent more time in patches with higherprey density. With visual information only, spiders could apparentlydistinguish among prey densities almost as well as with visualand vibratory cues combined, but residence time did not differamong prey densities when only vibratory information was presented.Measurements of vibration levels produced by cricket activityunder experimental sensory treatments conform to test results,suggesting that visual detection of crickets is important inpatch assessment used in determining patch residence time.     

Developmental changes in the spinning apparatus over the life cycle of wolf spiders (Araneae: Lycosidae)

Spiders are characterized by their spinning activity. Much of the current knowledge of the spinning apparatus comes from studies on orb web spiders and their relatives, whereas wolf spiders have been more or less neglected in this respect. Therefore, we studied developmental changes in the spinning apparatus of four wolf spiders (Tricca lutetiana, Arctosa alpigena lamperti, Pardosa amentata, and Xerolycosa nemoralis) throughout their life cycles. Each of these lycosids has a stenochronous life cycle, but of varied length (from 1 to 3 years) and number of instars (from seven to ten). Use of the spinning apparatus begins in the first instar, after leaving the egg sac. Secondary ampullate, all piriform, and all but four aciniform glands are tartipore‐accommodated. The tartipores, collared openings through which silk gland ducts pass during proecdysis, appear on the spinning field starting with the second instar. Tartipore‐accommodated glands can function during proecdysis and their evolution corresponds with the way spiders secure themselves when molting. We suggest that the function of aciniform silk in juvenile wolf spiders is to serve as an ancillary “scaffold” supporting the spider's body during ecdysis.     

Interactions among young stages of the wolf spiders Pardosamoesta and P. mackenziana (Araneae: Lycosidae)

Young stages of the wolf spiders Pardosa moesta and P . mackenziana coexist on the forest floor in a deciduous forest in central Alberta, yet nothing is known of the potential interactions between and among these ubiquitous species. An experiment, using a series of 0.25-m² arenas, was designed to test for inter- and intraspecific exploitative competition. Experimental treatments were established in the arenas in late July. Treatments involved stocking recently hatched spiderlings of each species alone, and with both species together at natural (10 spiderlings per arena) and two times the natural densities. In September the arenas were searched for Pardosa spiderlings, and the survival and mass gain of each species were determined. Other predatory arthropods, and Collembola, a common prey of young wolf spiders, were counted in the arenas before the experimental treatments were established and at the end of the experiment. No evidence for competitive interactions was uncovered, but spiderling survival was 29% for P . moesta and 20% for P . mackenziana , suggesting other mortality factors (e.g., cannibalism, intraguild predation) may be important. Top-down effects (predatory arthropods) had no effect on Pardosa survival. Bottom-up effects, however, were significant as treatments containing spiderlings had fewer Collembola compared to control arenas, further supporting the importance of spiders in leaf-litter food webs.     

Fecundity and sexual size dimorphism of wolf spiders (Araneae: Lycosidae) along an elevational gradient in the Arctic

Fecundity and body size are central fitness-related traits, and their intra-specific responses to environmental variation are receiving increasing attention in the context of climate change. Recent results from Greenland indicate that temporal and spatial variation in body size differences between sexes (sexual size dimorphism) may be widespread among wolf spider species and could be related to climate. Here, we tested whether variation in elevation affected body size of three wolf spider (Araneae: Lycosidae) species in low-Arctic Canada, whether the sexes differed in their response to the cline, and whether changes in local density influenced this relationship. We also tested whether fecundity changed with elevation in two of the species, independent of body size variation. We found a significant sex–elevation interaction for Pardosa lapponica: female size decreased more in response to elevation than that of males. Males and females of Pardosa uintana decreased significantly in size with elevation at a similar rate. Alopecosa aculeata males increased in body size along the gradient while females did not. Pardosa lapponica females, but not P. uintana females, showed significant reduction in fecundity in response to elevation. P. uintana showed significant decreases in body size with increases in its population density. Changes in temperature and potential resource availability along the elevational gradient are probably causing these species- and sex-specific responses. Further summer warming of the region may alleviate current constraints on growth and reproduction of these species although sex-specific responses may affect their population dynamics.     

Nanoa, an enigmatic new genus of pimoid spiders from western North America (Pimoidae, Araneae)

The spider genus Nanoa gen. nov. (Araneae, Pimoidae) is described to place Nanoa enana , a new species of pimoids from Western North America. Parsimony analysis of morphological characters provides support for the monophyly of Pimoa plus Nanoa and corroborates the monophyly of Pimoidae and of the clade Linyphiidae plus Pimoidae. © 2005 The Linnean Society of London, Zoological Journal of the Linnean Society , 2005, 145 , 249–262.     

拟环纹豹蛛的生物生态学研究

运用田间观察和室内外饲养相结合的方法,对稻田蜘蛛优势种拟环纹豹蛛Pardosa pseudoannulata的生物生态学特性进行了研究。拟环纹豹蛛在湘西北1年发生2～3代,第3代不完整,以第2代历期最短,第3代（越冬代）历期最长;以成蛛、亚成蛛或幼蛛越冬,其分布图式为聚集分布;4月下旬即由田埂向稻田内迁移,在水稻生育期有3次数量高峰; 属游猎型蜘蛛,可步行在水稻、水面、陆地等处捕食飞虱、叶蝉等多种目标害虫; 受惊时潜入水中或潜伏。雌雄蛛均可多次交配,雌蛛一生最多可产卵5次,实验种群卵囊含卵量76～337粒,平均156粒。孵化的幼蛛,先群集在雌蛛背面,3～5天后开始扩散,6～7天扩散到高峰。幼蛛期47～158天;成蛛期121～236天,雌蛛较雄蛛长21～62天。性比除第2代外的各代均为雄性多于雌性。本文详细记述了拟环纹豹蛛的求偶与交配行为,产卵与护卵习性,孵化与携幼行为,幼蛛生长、蜕皮、各龄期形态特征及耐饥、耐旱能力等。     

Taxonomic revision of the tarantula genus Aphonopelma Pocock, 1901 (Araneae,Mygalomorphae, Theraphosidae) within the United States

This systematic study documents the taxonomy, diversity, and distribution of the tarantula spider genus Aphonopelma Pocock, 1901 within the United States. By employing phylogenomic, morphological, and geospatial data, we evaluated all 55 nominal species in the United States to examine the evolutionary history of Aphonopelma and the group’s taxonomy by implementing an integrative approach to species delimitation. Based on our analyses, we now recognize only 29 distinct species in the United States. We propose 33 new synonymies (Aphonopelma apacheum, Aphonopelma minchi, Aphonopelma rothi, Aphonopelma schmidti, Aphonopelma stahnkei = Aphonopelma chalcodes; Aphonopelma arnoldi = Aphonopelma armada; Aphonopelma behlei, Aphonopelma vogelae = Aphonopelma marxi; Aphonopelma breenei = Aphonopelma anax; Aphonopelma chambersi, Aphonopelma clarum, Aphonopelma cryptethum, Aphonopelma sandersoni, Aphonopelma sullivani = Aphonopelma eutylenum; Aphonopelma clarki, Aphonopelma coloradanum, Aphonopelma echinum, Aphonopelma gurleyi, Aphonopelma harlingenum, Aphonopelma odelli, Aphonopelma waconum, Aphonopelma wichitanum = Aphonopelma hentzi; Aphonopelma heterops = Aphonopelma moderatum; Aphonopelma jungi, Aphonopelma punzoi = Aphonopelma vorhiesi; Aphonopelma brunnius, Aphonopelma chamberlini, Aphonopelma iviei, Aphonopelma lithodomum, Aphonopelma smithi, Aphonopelma zionis = Aphonopelma iodius; Aphonopelma phanum, Aphonopelma reversum = Aphonopelma steindachneri), 14 new species (Aphonopelma atomicum sp. n., Aphonopelma catalina sp. n., Aphonopelma chiricahua sp. n., Aphonopelma icenoglei sp. n., Aphonopelma johnnycashi sp. n., Aphonopelma madera sp. n., Aphonopelma mareki sp. n., Aphonopelma moellendorfi sp. n., Aphonopelma parvum sp. n., Aphonopelma peloncillo sp. n., Aphonopelma prenticei sp. n., Aphonopelma saguaro sp. n., Aphonopelma superstitionense sp. n., and Aphonopelma xwalxwal sp. n.), and seven nomina dubia (Aphonopelma baergi, Aphonopelma cratium, Aphonopelma hollyi, Aphonopelma mordax, Aphonopelma radinum, Aphonopelma rusticum, Aphonopelma texense). Our proposed species tree based on Anchored Enrichment data delimits five major lineages: a monotypic group confined to California, a western group, an eastern group, a group primarily distributed in high-elevation areas, and a group that comprises several miniaturized species. Multiple species are distributed throughout two biodiversity hotspots in the United States (i.e., California Floristic Province and Madrean Pine-Oak Woodlands). Keys are provided for identification of both males and females. By conducting the most comprehensive sampling of a single theraphosid genus to date, this research significantly broadens the scope of prior molecular and morphological investigations, finally bringing a modern understanding of species delimitation in this dynamic and charismatic group of spiders.     

A revision of the genus Trabaea Simon (Araneae: Lycosidae)

The genus Trabaea Simon is revised. Nine species are included in the genus of which two are described as new. Trabaeosa straeleni Roewer is newly synonymised with Trabaea purcelli Roewer. A key to the species of Trabaea is provided and the relationships of the genus are discussed.     

DNA sequences corroborate Soesiladeepakius as a non‐salticoid genus of jumping spiders: placement with lapsiines,phylogeny, and description of six new species (Araneae,Salticidae)

Species of the Amazonian jumping spider genus Soesiladeepakius Makhan are confirmed as non‐salticoids. Sequences of nuclear (28S, Actin) and mitochondrial (16S through NADH dehydrogenase subunit I, ‘16S‐ND1’) gene regions, analysed under parsimony and maximum likelihood, placed the genus within the lapsiines, closely related to Galianora Maddison. Additionally, six new species of this genus are herein described, namely Soesiladeepakius lyra sp. nov. , Soesiladeepakius retroversus sp. nov. , Soesiladeepakius arthrostylus sp. nov. , Soesiladeepakius gasnieri sp. nov. , Soesiladeepakius biarmatus sp. nov. , and Soesiladeepakius uncinatus sp. nov. , all from the Amazon region in Brazil. To test the monophyly of Soesiladeepakius within lapsiines, a cladistic analysis was carried out using a data matrix comprising 24 morphological characters scored for 12 taxa. The analysis resulted in two equally parsimonious trees of 29 steps. One of these trees is used to discuss the relationships among the species of Soesiladeepakius and character evolution. © 2012 The Linnean Society of London, Zoological Journal of the Linnean Society, 2012, 165 , 274–295.     

Phylogenetic relationships of Central European wolf spiders (Araneae: lycosidae) inferred from 12S ribosomal DNA sequences

We have analyzed a sequence dataset of a portion of mitochondrial 12S rRNA gene of the ribosomal small subunit for 27 species of the family Lycosidae (wolf spiders) from Central Europe, belonging to six genera (Alopecosa, Arctosa, Pardosa, Pirata, Trochosa, and Xerolycosa) and four subfamilies (Evippinae, Lycosinae, Pardosinae and Venoniinae). Phylogenetic analyses were performed in two steps and corroborate the monophyly of all the genera analyzed with strong bootstrap support. In the first step focusing on the most ancestral splits the genus Pirata consistently emerged as the most ancestral branch, followed by the two genera Arctosa and Xerolycosa, with conflicting branching order, however. The second step of analysis placed Xerolycosa more ancestral than Arctosa. Arctosa appeared as sister group to the genera Alopecosa, Trochosa, and Pardosa. The palearctic genus Xerolycosa was not yet included in previous studies derived from morphological characters, but its placement based on mtDNA sequences is in good agreement to that according to current diagnostic morphological features. Further, the single representative of the genus Arctosa examined in our study was placed at a more ancestral position than in a previous investigation based on phenotypic characters. The superimposition of the currently used diagnostic phenotypic characters on the DNA-based phylogeny shows that both character sets are widely congruent; only 3 out of 16 phenotypic characters were resolved as homoplasious, suggesting their parallel evolution and/or reversal. Among the three different styles of predation found in the Lycosids, tube builders appear to be the most ancestral from which burrow dwellers descended and from which two groups of vagrant hunters evolved in parallel.     

The effect of prey movement on attack behavior and patch residence decision rules of wolf spiders (Araneae: Lycosidae)

We used a video imaging technique to test the effects of prey movement on attack behavior and foraging patch residence time decision rules of wolf spiders. TwelveSchizocosa ocreata (Hentz) (Lycosidae) were tested in an artificial foraging patch stimulus chamber consisting of a microscreen television displaying a computer digitized, animated image of a cricket. Four prey movement treatments were used: (1) a blank screen, (2) a stationary cricket control, (3) a cricket moving for 1 min, and (4) a cricket moving for 10 min. Spiders stayed significantly longer in treatments with higher cricket activity. Spiders also stayed longer when they attacked the stimulus than when they did not. The distribution of patch residence times of spiders indicates a decision rule based on a fixed probability of leaving.     

Phylogeny of the orb-web building spiders (Araneae, Orbiculariae: Deinopoidea, Araneoidea)

This phylogenetic analysis of 31 exemplar taxa treats the 12 families of Araneoidea (Anapidae, Araneidae, Cyatholipidae, Linyphiidae, Mysmenidae, Nesticidae, Pimoidae, Symphytognathidae, Synotaxidae, Tetragnathidae, Theridiidae, and Theridiosomatidae). The data set comprises 93 characters: 23 from male genitalia, 3 from female genitalia, 18 from cephalothorax morphology, 6 from abdomen morphology, 14 from limb morphology, 15 from the spinnerets, and 14 from web architecture and other behaviour. Criteria for tree choice were minimum length parsimony and parsimony under implied weights. The outgroup for Araneoidea is Deinopoidea (Deinopidae and Uloboridae). The preferred shortest tree specifies the relationships ((Uloboridae, Deinopidae) (Araneidae (Tetragnathidae ((Theridiosomatidae (Mysmenidae (Symphytognathidae, Anapidae))) ((Linyphiidae, Pimoidae) ((Theridiidae, Nesticidae) (Cyatholipidae, Synotaxidae))))))). The monophyly of Tetragnathidae (including metines and nephilines), the symphytognathoids, theridiid-nesticid lineage, and Synotaxidae are confirmed. Cyatholipidae are sister to Synotaxidae, not closely related to either the Araneidae or Linyphiidae, as previously suggested. Four new clades are proposed: the cyatholipoids (Cyatholipidae plus Synotaxidae), the 'spineless femur clade' (theridioid lineage plus cyatholipoids), the 'araneoid sheet web builders' (linyphioids plus the spineless femur clade), and the 'reduced piriform clade' (symphytognathoids plus araneoid sheet web builders). The results imply a coherent scenario for web evolution in which the monophyletic orb gives rise to the monophyletic araneoid sheet, which in turn gives rise to the gumfoot web of the theridiid-nesticid lineage. While the spinning complement of single pairs of glands does not change much over the evolution of the group, multiple sets of glands are dramatically reduced in number, implying that derived araneoids are incapable of spinning many silk fibers at the same time.     

Respiratory organs in wolf spiders: morphometric analysis of lungs and tracheae in Pardosa lugubris (L.) (Arachnida, Araneae, Lycosidae)

The respiratory system of the wolf spider Pardosa lugubris consists of a pair of well-developed lungs and four unbranched tube tracheae. We used stereological morphometric methods to investigate the morphological diffusing capacity of the lungs and of the walls of the tracheae ('lateral diffusing capacity'). We examined three groups of female P. lugubris with different mean body masses. The barrier thickness of the gas-exchange epithelium of the lungs was 0.17 microm for the total diffusion barrier and the calculated oxygen diffusing capacity (D(O2)) for the lungs was between 12.9 and 13.4 microl min(-1)g(-1)kPa(-1). Measured metabolic rates compared with the D(O2) of the lungs result in necessary oxygen partial pressure differences of 0.2 kPa during rest and 2.1 kPa during maximum measured activity. The diffusion barrier of the entire tracheal walls was 0.31-0.50 microm and the calculated lateral D(O2) was 0.05-0.2 microl min(-1)g(-1)kPa(-1). Therefore, tracheae are of no importance for the overall oxygen exchange. However, they might be of some importance in local oxygen supply or in overall carbon dioxide release. The comparison with the respiratory system of the jumping spider Salticus scenicus reveals that the lungs have very similar mass-specific D(O2) in both species, and that, in addition, jumping spiders possess a much better developed tracheal system.     

Theraphosidae phylogeny: relationships of the ‘Ischnocolinae’ genera (Araneae,Mygalomorphae)

The mygalomorph spider subfamily ‘Ischnocolinae’ was originally established as a group based on the presence of divided tarsal scopula. Later, the divided condition of the scopula was considered the plesiomorphic state, which could not support the monophyly of ‘Ischnocolinae’. In Raven 1985, the subfamily was considered paraphyletic, pending a phylogenetic analysis to reinvestigate monophyletic groups. This study comprises such a phylogenetic analysis, based on morphological data, that includes representatives of all genera currently included in ‘Ischnocolinae’ as well as representatives of all other nine Theraphosidae subfamilies (Thrigmopoeinae, Ornithoctoninae, Eumenophorinae, Stromatopelminae, Harpactirinae, Selenogyrinae, Theraphosinae, Aviculariinae and Selenocosmiinae). The family Theraphosidae is considered monophyletic and expanded to include three additional genera previously considered as possible Barychelidae, namely Brachionopus (as Harpactirinae), Trichopelma and Reichlingia (as Ischnocolinae sensu stricto) while ‘Ischnocolinae’ as previously defined does not appear as monophyletic. However, two monophyletic groups were defined as subfamilies to include some former ‘Ischnocolinae’ representatives. The first group includes Acanthopelma rufescens, Trichopelma nitidum, Reichlingia annae, Ischnocolus spp., Holothele rondoni, Holothele culebrae and Holothele aff culebrae and is hereby named as Ischnocolinae (sensu stricto). The other subgroup comprises Sickius longibulbi, Holothele incei, Holothele aff incei, Guyruita spp., Schismatothele lineata, Hemiercus modestus, Holothele colonica and Holothele sp., together established as Schismatothelinae subfam. nov. Several genera included in former ‘Ischnocolinae’ appear as monophyletic (Catumiri, Oligoxystre, Heterothele, Nesiergus, Chaetopelma, Ischnocolus, Guyruita and Plesiophrictus). However, the genera Holothele, Schismatothele and Hemiercus deserve more attention in order to evaluate their intrarelationships and inclusion of species.     

A revision of the assassin spiders of the Eriauchenius gracilicollis group, a clade of spiders endemic to Madagascar (Araneae: Archaeidae)

An endemic group of Malagasy spiders (Araneae: Archaeidae: Eriauchenius ) called the gracilicollis group is revised. The monophyly and phylogenetic relationships of the gracilicollis group are tested based on morphological characters. Archaeid spiders of Madagascar have evolved varying degrees of elongation in the cephalic area. Historically, it was believed that the extremely elongated cephalic area had evolved only once. These morphological data support the monophyly of the gracilicollis group and suggest that the elongated cephalic area has evolved more than once. All 14 species from the gracilicollis group are described and keyed, of which nine are new species: Eriauchenius ambre sp. nov. , Eriauchenius anabohazo sp. nov. , Eriauchenius borimontsina sp. nov. , Eriauchenius griswoldi sp. nov. , Eriauchenius halambohitra sp. nov. , Eriauchenius lavatenda sp. nov. , Eriauchenius namoroka sp. nov. , Eriauchenius spiceri sp. nov. and Eriauchenius voronakely sp. nov . The morphology of the gracilicollis group is examined in detail and figures of the male and female genitalia are presented. The distributions of the gracilicollis group species are presented and discussed and higher species group relationships within the Archaeidae are discussed.  © 2008 The Linnean Society of London, Zoological Journal of the Linnean Society , 2008, 152 , 255–296.     

Australian gall-inducing scale insects on Eucalyptus: revision of Opisthoscelis Schrader (Coccoidea, Eriococcidae) and descriptions of a new genus and nine new species

We revise the genus Opisthoscelis Schrader, and erect the genus Tanyscelisgen. n. with Opisthoscelis pisiformis Froggatt as its type species. Species of both genera induce sexually dimorphic galls on Eucalyptus (Myrtaceae) in Australia, with Opisthoscelis subrotunda Schrader also in Papua New Guinea. We synonymise the following taxa (junior synonym with senior synonym): Opisthoscelis fibularis Froggatt, syn. n. with Opisthoscelis spinosa Froggatt; Opisthoscelis recurva Froggatt, syn. n. with Opisthoscelis maculata Froggatt; Opisthoscelis globosa Froggatt, syn. n. (= Opisthoscelis ruebsaameni Lindinger) with Opisthoscelis convexa Froggatt; and Opisthoscelis mammularis Froggatt, syn. n. with Opisthoscelis verrucula Froggatt. We transfer seven Opisthoscelis species to Tanyscelis as Tanyscelis conica (Fuller), comb. n., Tanyscelis convexa (Froggatt), comb. n., Tanyscelis maculata (Froggatt), comb. n., Tanyscelis maskelli (Froggatt), comb. n., Tanyscelis pisiformis (Froggatt), comb. n., Tanyscelis spinosa (Froggatt), comb. n., and Tanyscelis verrucula (Froggatt), comb. n. We redescribe and illustrate the adult female of each named species of Opisthoscelis for which the type material is known, as well as the first-instar nymph of the type species of Opisthoscelis (Opisthoscelis subrotunda) and Tanyscelis (Opisthoscelis pisiformis). We describe four new species of Opisthoscelis: Opisthoscelis beardsleyi Hardy & Gullan, sp. n., Opisthoscelis thurgoona Hardy & Gullan, sp. n., Opisthoscelis tuberculataHardy & Gullan, sp. n., and Opisthoscelis ungulifinis Hardy & Gullan, sp. n., and five new species of Tanyscelis: Tanyscelis grallator Hardy & Gullan, sp. n., Tanuscelis megagibba Hardy & Gullan, sp. n., Tanyscelis mollicornuta Hardy & Gullan, sp. n., Tanyscelis tripocula Hardy & Gullan, sp. n., and Tanyscelis villosigibba Hardy & Gullan, sp. n. We designate lectotypes for Opisthoscelis convexa, Opisthoscelis fibularis, Opisthoscelis globosa Froggatt, Opisthoscelis maculata, Opisthoscelis mammularis, Opisthoscelis maskelli, Opisthoscelis pisiformis, Opisthoscelis recurva, Opisthoscelis serrata, Opisthoscelis spinosa, and Opisthoscelis verrucula. As a result of our taxonomic revision, Opisthoscelis has six species and Tanyscelis has 12 species. We describe the galls of females for all 18 species and galls of males for 10 species of Opisthoscelis and Tanyscelis, and provide photographs of the galls for most species. A key to the adult females of the species of both genera is included.     

Absence of social facilitation of courtship in the wolf spider, Schizocosa ocreata (Hentz) (Araneae: Lycosidae)

Males of many animal species are reproductively limited by the difficulty and time costs of finding mates. Males of such species should be selected to take advantage of any cues that might reveal the location of prospective mates. Cues to female location are not restricted to those produced by females, but might also include the highly apparent courtship displays of males that have already found a female. By “eavesdropping” on these courting rivals, initiating sexual displays when courting rivals are detected (i.e., social facilitation of displays); males might effectively exploit the mate-searching efforts of their rivals. We tested the possibility that male Schizocosa ocreata wolf spiders exhibit social facilitation of courtship behaviors using a combination of live behavioral trials and video playback with single stimulus presentations. When exposed to visual cues from another male, male S. ocreata can discern the presence of another individual whether that individual is courting or not. However, we found no evidence of social facilitation of courtship or chemoexploratory behaviors in response to seismic or visual cues presented in isolation or combined. While complex, multimodal, male courtship signals are important in mate choice by female S. ocreata, males do not appear to use these cues to socially facilitate their own courtship.