DOCSLIB.ORG

Seasonality of Spiders (Araneae) in Mediterranean Ecosystems and Its Implications in the Optimum Sampling Period

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Seasonality of Spiders (Araneae) in Mediterranean Ecosystems and Its Implications in the Optimum Sampling Period Ecological Entomology (2007), 32, 516–526 DOI: 10.1111/j.1365-2311.2007.00894.x Seasonality of spiders (Araneae) in Mediterranean ecosystems and its implications in the optimum sampling period PEDRO CARDOSO 1,2 , ISRAEL SILVA 2 , NUNO G. DE OLIVEIRA 2 a n d ARTUR R. M. SERRANO 2 1 Zoological Museum and Centre of Macroecology, University of Copenhagen, Denmark , 2Centre of Environmental Biology, Faculty of Sciences, University of Lisbon, Portugal Abstract. 1. Fields such as ecology, macroecology, and conservation biology rely on accurate and comparable data. This is especially important for mostly unknown and megadiverse taxa such as spiders and regions such as the Mediterranean. Short-term sampling programmes are increasingly seen as the best option for sampling spiders. Comparability of results, however, demands standard procedures both in methodology and in sampling period. Cost-efficiency dictates that this period should be the most species rich. 2. Pitfall trapping was conducted in 23 sites from north to south Portugal, comprising three large-scale environmental zones and many different habitat types, during 10 months in each site. The annual richness pattern, differences in this pattern between areas and habitats, the complementarity between sampling periods and possible environmental correlates of richness were studied. 3. May and June present the optimal time for collecting spiders in Mediterranean areas. Northern areas have a later peak in richness and dense tree-cover sites offer more flexibility for sampling, with a higher proportion of species present at each period throughout the year. 4. Day length is the environmental factor most correlated with species richness. Maximum daily temperature may reduce richness, especially in southernmost areas, where summer temperatures can be extremely harsh. 5. It is recommended that short-term sampling programmes, intended to give a reasonable picture of spider communities in Portugal and in the Iberian Peninsula (and possibly extending to all the Mediterranean), should be conducted during May or June, with variable flexibility according to area and habitat. The proposed suggestions should appeal to everyone working in the field, given the cost-efficiency and comparability of results by adopting a common standardised approach. Key words. Arachnids , biodiversity , complementarity , cost-effi ciency , inventory , phenology , pitfall , Portugal , Spain , standardised protocols . Introduction even misleading; however, incomplete data sets, if not exceed- ingly data deficient, can also provide good basis for different Biological surveys inevitably produce samples of the total applications ( Gaston & Rodrigues, 2003 ). Therefore, standardi- fauna, not complete inventories. If the databases used for sation and calibration of sampling methods and protocols are (macro)ecological studies, or conservation priority analyses, are fundamental for the comparison of sites or the definition of pri- incomplete or inadequate, the result will often be inaccurate or ority areas for conservation ( Stork, 1994; Cannon, 1997; Jones & Eggleton, 2000; Kitching et al. , 2001 ). Correspondence: Pedro Cardoso, Agricultural Sciences Department, Once one has chosen where to sample, there is the decision of CITA-A, University of Azores, Terra-Chã, 9701 – 851 Angra do how it is done. The sampling protocol and respective methodol- Heroísmo, Portugal. E-mail: [email protected] ogy are obviously taxon-specific. For spiders, complete protocols, © 2007 The Authors 516 Journal compilation © 2007 The Royal Entomological Society Mediterranean spiders optimum sampling period 517 or sampling packages, that gather information from a series of Materials and methods semiquantitative methods are considered the best approach for comprehensive and standardised sampling ( Coddington et al. , Study sites 1991 ). They allow optimum results with a minimum effort, al- though this is always considerable. Such methods are suitable for Four protected areas in Portugal were studied during three capturing a large number of species and simultaneously a large consecutive years, one year each area ( Fig. 1 ): (i) Douro number of specimens with replicate samples ( Coddington et al. , Internacional Nature Park (PNDI), located in north-eastern 1996; Dobyns, 1997; Toti et al. , 2000; Sørensen et al. , 2002; Portugal, sampled during 2001; (ii) Serras de Aire e Candeeiros Scharff et al. , 2003 ). Nature Park (PNSAC), located in central western Portugal, sam- Besides deciding where and how to sample the question of pled during 2002; (iii) Paúl do Boquilobo Nature Reserve when to sample must also be addressed. The answer relies (RNPB), located very close to PNSAC, sampled during 2002; fundamentally on the study of fluctuations in species rich- and (iv) Vale do Guadiana Nature Park (PNVG), located in ness of the target taxon according to the time of year, its phe- south-eastern Portugal, sampled during 2003. These areas are nology. Probably more important, it also relies on the degree located in the three environmental zones defined by Metzger to which such fluctuations are predictable year after year, its et al. (2005) as being present in Portugal – Lusitanian (PNSAC, seasonality (as defined by Wolda, 1988 ). Highly seasonal RNPB), Mediterranean North (PNDI) and Mediterranean South phenomena can allow the reliable planning of fieldwork (PNVG). Only one of the zones present in the Mediterranean activities. Many studies are devoted to seasonal changes in biome was not sampled, the aptly named Mediterranean abundance, the number of captured individuals (e.g. Chatzaki Mountains. et al. , 1998, 2005a , b ) or biomass (e.g. Pearson & Derr, 1986 ); In each protected area, most of its habitat types were sam- however, the focus of this study is on species richness, not pled, summing 23 sites. A complete data set was therefore cre- abundance or biomass, which mainly concerns individuals. ated, which allowed the comparison between many different Fluctuations in the richness of arthropods are usually much habitat types in the different geographical areas and respective higher in temperate than in tropical regions, with the latter environmental zones ( Table 1 ). having a high proportion of species that are present through- out the year ( Novotny & Basset, 1998 ). None the less, large seasonal differences in spider community composition, rich- Sampling periods ness or abundance are invariably found, even surpassing habitat differences in many cases ( Weeks & Holtzer, 2000; Although the ideal situation would have been to sample all sites Whitmore et al. , 2002 ). Given these facts, one has to con- simultaneously, this was logistically unfeasible, given that the sider the implementation of long-lasting sampling pro- objective demanded to study areas as distant from each other as grammes, of at least 1 year if not longer. Owing to the lack of possible. Logistical reasons have also made it impossible to sam- human, material, and time resources, however, this is largely ple continuously during a whole year at each area. Given that unfeasible. It is therefore imperative to optimise the duration December and January were thought a priori to be very poor in of protocols and the time of the year when they are imple- spider species, the remaining 10 sampled months were considered mented. This is best achieved by carrying out standard mini- as representative of the entire year. All sites were sampled continu- mum sampling programmes, which minimise the number and ously, from the end of January (29 – 31, depending on the year) extension of collecting periods and simultaneously giving until the beginning of December (3 – 5). Sampling periods lasted the most complete picture of diversity of any site ( Oliver & for 2 weeks, providing 22 samples each year. Short-term sampling Beattie, 1996; Duelli, 1997; Duelli et al. , 1999; Zonneveld protocols usually take between 1 and 2 weeks of fieldwork and this et al. , 2003 ). All the protocols proposed to date have tried to 2-week period was adequate for the proposed objectives. answer the most obvious question: When should one collect to guarantee maximum diversity with minimum time spent on the task? Sampling method The first objective of this work was to choose the season that consistently presented highest richness in different geographi- The main objective is to recommend the best time of year for cal regions (corresponding to broad environmental zones as de- collecting as many species as possible independently of the fined by Metzger et al. , 2005 ) and habitat types in Portugal. methods to be employed. To test all or even most of the available Second, to understand if and how do season, area, and habitat capture methods for several years and in so many sites, however, type potentially influence the sampled species richness. Third, would be a formidable challenge. Therefore, a single method was to verify the effect on accumulated richness of increasing the chosen to meet the objectives, the one that could provide the most number and duration of samples. Fourth, to assess if richness is comprehensive information with the least effort. One of the most correlated to any seasonal and easily predicted environmental frequently employed and cost-effective methods for capturing factor. Finally, to give recommendations on the best sampling spiders and other arthropods is pitfall trapping (e.g. Churchill, procedure for maximising spider species richness spending the 1993; Samu & Lövei, 1995; Brennan et al. , 1999; Churchill & least
Load more

Recommended publications
  • Final Project Completion Report
    CEPF SMALL GRANT FINAL PROJECT COMPLETION REPORT Organization Legal Name: - Tarantula (Araneae: Theraphosidae) spider diversity, distribution and habitat-use: A study on Protected Area adequacy and Project Title: conservation planning at a landscape level in the Western Ghats of Uttara Kannada district, Karnataka Date of Report: 18 August 2011 Dr. Manju Siliwal Wildlife Information Liaison Development Society Report Author and Contact 9-A, Lal Bahadur Colony, Near Bharathi Colony Information Peelamedu Coimbatore 641004 Tamil Nadu, India CEPF Region: The Western Ghats Region (Sahyadri-Konkan and Malnad-Kodugu Corridors). 2. Strategic Direction: To improve the conservation of globally threatened species of the Western Ghats through systematic conservation planning and action. The present project aimed to improve the conservation status of two globally threatened (Molur et al. 2008b, Siliwal et al., 2008b) ground dwelling theraphosid species, Thrigmopoeus insignis and T. truculentus endemic to the Western Ghats through systematic conservation planning and action. Investment Priority 2.1 Monitor and assess the conservation status of globally threatened species with an emphasis on lesser-known organisms such as reptiles and fish. The present project was focused on an ignored or lesser-known group of spiders called Tarantulas/ Theraphosid spiders and provided valuable information on population status and potential conservation sites in Uttara Kannada district, which will help in future monitoring and assessment of conservation status of the two globally threatened theraphosid species T. insignis and Near Threatened T. truculentus. Investment Priority 2.3. Evaluate the existing protected area network for adequate globally threatened species representation and assess effectiveness of protected area types in biodiversity conservation.
    [Show full text]
  • Arthropods of Elm Fork Preserve
    Arthropods of Elm Fork Preserve Arthropods are characterized by having jointed limbs and exoskeletons. They include a diverse assortment of creatures: Insects, spiders, crustaceans (crayfish, crabs, pill bugs), centipedes and millipedes among others. Column Headings Scientific Name: The phenomenal diversity of arthropods, creates numerous difficulties in the determination of species. Positive identification is often achieved only by specialists using obscure monographs to ‘key out’ a species by examining microscopic differences in anatomy. For our purposes in this survey of the fauna, classification at a lower level of resolution still yields valuable information. For instance, knowing that ant lions belong to the Family, Myrmeleontidae, allows us to quickly look them up on the Internet and be confident we are not being fooled by a common name that may also apply to some other, unrelated something. With the Family name firmly in hand, we may explore the natural history of ant lions without needing to know exactly which species we are viewing. In some instances identification is only readily available at an even higher ranking such as Class. Millipedes are in the Class Diplopoda. There are many Orders (O) of millipedes and they are not easily differentiated so this entry is best left at the rank of Class. A great deal of taxonomic reorganization has been occurring lately with advances in DNA analysis pointing out underlying connections and differences that were previously unrealized. For this reason, all other rankings aside from Family, Genus and Species have been omitted from the interior of the tables since many of these ranks are in a state of flux.
    [Show full text]
  • Species Delimitation and Phylogeography of Aphonopelma Hentzi (Araneae, Mygalomorphae, Theraphosidae): Cryptic Diversity in North American Tarantulas
    Species Delimitation and Phylogeography of Aphonopelma hentzi (Araneae, Mygalomorphae, Theraphosidae): Cryptic Diversity in North American Tarantulas Chris A. Hamilton1*, Daniel R. Formanowicz2, Jason E. Bond1 1 Auburn University Museum of Natural History and Department of Biological Sciences, Auburn University, Auburn, Alabama, United States of America, 2 Department of Biology, The University of Texas at Arlington, Arlington, Texas, United States of America Abstract Background: The primary objective of this study is to reconstruct the phylogeny of the hentzi species group and sister species in the North American tarantula genus, Aphonopelma, using a set of mitochondrial DNA markers that include the animal ‘‘barcoding gene’’. An mtDNA genealogy is used to consider questions regarding species boundary delimitation and to evaluate timing of divergence to infer historical biogeographic events that played a role in shaping the present-day diversity and distribution. We aimed to identify potential refugial locations, directionality of range expansion, and test whether A. hentzi post-glacial expansion fit a predicted time frame. Methods and Findings: A Bayesian phylogenetic approach was used to analyze a 2051 base pair (bp) mtDNA data matrix comprising aligned fragments of the gene regions CO1 (1165 bp) and ND1-16S (886 bp). Multiple species delimitation techniques (DNA tree-based methods, a ‘‘barcode gap’’ using percent of pairwise sequence divergence (uncorrected p- distances), and the GMYC method) consistently recognized a number of divergent and genealogically exclusive groups. Conclusions: The use of numerous species delimitation methods, in concert, provide an effective approach to dissecting species boundaries in this spider group; as well they seem to provide strong evidence for a number of nominal, previously undiscovered, and cryptic species.
    [Show full text]
  • Bees and Wasps of the East Sussex South Downs
    A SURVEY OF THE BEES AND WASPS OF FIFTEEN CHALK GRASSLAND AND CHALK HEATH SITES WITHIN THE EAST SUSSEX SOUTH DOWNS Steven Falk, 2011 A SURVEY OF THE BEES AND WASPS OF FIFTEEN CHALK GRASSLAND AND CHALK HEATH SITES WITHIN THE EAST SUSSEX SOUTH DOWNS Steven Falk, 2011 Abstract For six years between 2003 and 2008, over 100 site visits were made to fifteen chalk grassland and chalk heath sites within the South Downs of Vice-county 14 (East Sussex). This produced a list of 227 bee and wasp species and revealed the comparative frequency of different species, the comparative richness of different sites and provided a basic insight into how many of the species interact with the South Downs at a site and landscape level. The study revealed that, in addition to the character of the semi-natural grasslands present, the bee and wasp fauna is also influenced by the more intensively-managed agricultural landscapes of the Downs, with many species taking advantage of blossoming hedge shrubs, flowery fallow fields, flowery arable field margins, flowering crops such as Rape, plus plants such as buttercups, thistles and dandelions within relatively improved pasture. Some very rare species were encountered, notably the bee Halictus eurygnathus Blüthgen which had not been seen in Britain since 1946. This was eventually recorded at seven sites and was associated with an abundance of Greater Knapweed. The very rare bees Anthophora retusa (Linnaeus) and Andrena niveata Friese were also observed foraging on several dates during their flight periods, providing a better insight into their ecology and conservation requirements.
    [Show full text]
  • Arthropods in Linear Elements
    Arthropods in linear elements Occurrence, behaviour and conservation management Thesis committee Thesis supervisor: Prof. dr. Karlè V. Sýkora Professor of Ecological Construction and Management of Infrastructure Nature Conservation and Plant Ecology Group Wageningen University Thesis co‐supervisor: Dr. ir. André P. Schaffers Scientific researcher Nature Conservation and Plant Ecology Group Wageningen University Other members: Prof. dr. Dries Bonte Ghent University, Belgium Prof. dr. Hans Van Dyck Université catholique de Louvain, Belgium Prof. dr. Paul F.M. Opdam Wageningen University Prof. dr. Menno Schilthuizen University of Groningen This research was conducted under the auspices of SENSE (School for the Socio‐Economic and Natural Sciences of the Environment) Arthropods in linear elements Occurrence, behaviour and conservation management Jinze Noordijk Thesis submitted in partial fulfilment of the requirements for the degree of doctor at Wageningen University by the authority of the Rector Magnificus Prof. dr. M.J. Kropff, in the presence of the Thesis Committee appointed by the Doctorate Board to be defended in public on Tuesday 3 November 2009 at 1.30 PM in the Aula Noordijk J (2009) Arthropods in linear elements – occurrence, behaviour and conservation management Thesis, Wageningen University, Wageningen NL with references, with summaries in English and Dutch ISBN 978‐90‐8585‐492‐0 C’est une prairie au petit jour, quelque part sur la Terre. Caché sous cette prairie s’étend un monde démesuré, grand comme une planète. Les herbes folles s’y transforment en jungles impénétrables, les cailloux deviennent montagnes et le plus modeste trou d’eau prend les dimensions d’un océan. Nuridsany C & Pérennou M 1996.
    [Show full text]
  • Observations on the Natural History O F Sphodros Abbott and Sphodros Rufipes (Araneae, Atypidae), with Evidence for a Contact Sex Pheromon E
    Coyle, F . A. and W. A . Shear. 1981 . Observations on the natural history of Sphodros abboti and Sphodros rufipes (Araneae, Atypidae), with evidence for a contact sex pheromone . J. Arachnol ., 9 :317-326 . OBSERVATIONS ON THE NATURAL HISTORY O F SPHODROS ABBOTT AND SPHODROS RUFIPES (ARANEAE, ATYPIDAE), WITH EVIDENCE FOR A CONTACT SEX PHEROMON E Frederick A. Coyle Department of Biology Western Carolina University Cullowhee, North Carolina 2872 3 Wllliam A. Shear Department of Biology Hampden-Sydney College Hampden-Sydney, Virginia 23943 ABSTRAC T The three populations of S. abboti studied exhibit much higher densities than the two of S. rufipes. In S. abboti mating occurs in July, egg laying in August, hatching in September, and the fully equipped and self-sufficient third instar spiderlings develop by November . The tubes of S. abboti are proportionately longer and have a greater aerial length to underground length ratio than do those of S. rufipes. Other differences in tube architecture exist . Both species capture and feed upon a wide variet y of ground arthropods and discard prey remains through the upper end of the tube . S. abboti males search for mates in daylight and appear to be generalized wasp-ant mimics . Our observations of S. abboti male behavior suggests that adult female tubes are marked by a contact sex pheromone . INTRODUCTION Despite their covert behavior and patchy abundance, purse-web spiders (Atypidae ) have attracted considerable attention from araneologists for at least two reasons . First , atypids possess an interesting mixture of primitive and specialized characteristics, thei r outstanding specializations being part of a unique strategy of capturing prey through th e walls of a silk tube, the purse-web.
    [Show full text]
  • Hogg's Phantom Spider from Central
    1998. P. A. Selden (ed.). Proceedings of the 17th European Colloquium of Arachnology, Edinburgh 1997. Hogg’s phantom spider from Central Australia: a century-old mystery solved Barbara York Main Zoology Department, University of Western Australia, Nedlands, Western Australia 6907 Summary A trapdoor spider collected by the Horn Scientific Expedition to Central Australia in 1894 was identified by H. R. Hogg as belonging to the New Zealand species Migas paradoxus L. Koch of the family Migidae. A few years later, Hogg suggested that the species should be in a new genus. The Migidae is a Gondwanan family. Several genera are known from Australia, where all species occur in wet habitats. No spiders of the family have ever subsequently been collected from Central Australia. Hogg’s fragmented specimen has not been traced, and later authors have doubted his identification. The taxonomic and biological rationale for now regarding Hogg’s specimen as a species of Conothele Thorell is presented. It is suggested that Conothele should be synonymized with Ummidia Thorell. Introduction plants and animals, and on the social customs of the Aborigines, of the area. The collections were In his introduction to the report of The Horn first returned to Adelaide and Melbourne, then Scientific Expedition to Central Australia of they were dispersed amongst specialists for 1894, Horn (1896) cited the opinion of identification and description. Professor Australian scientists of the day “that when the Baldwin Spencer of Melbourne, who had been rest of the continent was submerged the elevated in the expedition team, subsequently edited the portions of the McDonnell Range existed as an resultant scientific reports (Spencer, 1896a).
    [Show full text]
  • Metabolic Rates in Spiders
    METABOLIC RATES IN SPIDERS By JOHN FRANCIS ANDERSON A DISSERTATION PRESENTED TO THE GRADUATE COX.TNCIL OF THE UNrVTO^SITY OF FLORIDA IX PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPIIY UNIVERSITY OF FLORIDA 1968 ACKNOWLEDGEMENTS I am deeply indebted to Dr, James L. Nation, under whose direction the present research was conducted. Dr. Robert M. DeWitt must be thanked for his liberal support in providing the necessary supplies and equipment. Grateful acknowledgement is given to Dr. Frank G. Nordlie, Dr. Brian K. McNab, Dr. John D. McCrone, Dr. James L. Nation, and Mr. Thomas Krakauer who gave most generously of their time in evaluating some of my ideas. My thanks go to Dr. Martin H. Muma, Dr. John D. McCrone, and Mr. Cole Benton for supplying certain animals which otherwise would not have been available. For aid in solving various statistical problems, 1 am indebted to Miss Mary E. Glenn, Dr, Rodger Mitchell must be thanked for his assistance in conducting the histological studies. Financial support through appointment to research and teaching positions was provided by Dr. Frank G. Nordlie and Dr. Lewis Berner to whom 1 am grateful. Dr. Nation, Dr. Nordlie, and Dr. McCrone must again be thanked along with other members of my graduate supervisory committee, Dr. Thomas J, Walker and Dr. Howard K. Wallace, who not only critically reviewed the dissertation, but also provided support in solving the many small but important problems that occurred during my tenure as a graduate student. Finally thanks are also due to Mrs. Lillian ingenlath for typing the manuscr i pt.
    [Show full text]
  • Provisional Atlas of the Aculeate Hymenoptera, of Britain and Ireland Part 1
    Ok, Institute of CLt Terrestrial 'Yj fit ifiltrriEq IPIIF Ecology Provisional atlas of the aculeate Hymenoptera, of Britain and Ireland Part 1 • S. Robin Edwards (Eciitor) : Bees, Wasps and Ants ReeOrdInq Society- . • 00 I 0 • ••• • 0 „ . 5 .5 . • .. 5 5 . •• • • • 0.0 • Oa f an 41 • • 4 ••• • a t a •• r , . O. • Centre for Ecology and Hydrology Natural Environment Research Council NERC Copyright 1997 Printed in 1997 by Henry Ling Ltd.. The Dorset Press. Dorchester. Dorset. ISBN 1 870393 39 2 The Institute of Terrestrial Ecology (1TE)is a component research organisation within the Natural Environment Research Council. The Institute is part of the Centre for Ecology and Hydrology, and was established in 1973 by the merger of the research stations of the Nature Conservancy with the Institute of Tree Biology_ It has been at the forefront of ecological research ever since. The six research stations of the Institute provide a ready access to sites and to environmental and ecological problems in any pan of Britain. In addition co the broad environmental knowledge and experience expected of the modern ecologist, each station has a range of special expertise and facilities. Thus. the Institute is able to provide unparallelled opportunities for long-term, multidisciplinary studies of complex environmental and ecological problems. 1TE undertakes specialist ecological research on subjects ranging from micro-organisms to trees and mammals, from coastal habitats to uplands, trom derelict land to air pollution. Understanding the ecology of different species lit- natural and man-made communities plays an increasingly important role in areas such as monitoring ecological aspects of agriculture, improving productivity in forestry, controlling pests, managing and conserving wildlife, assessing the causes and effects of pollution, and rehabilitating disturbed sites.
    [Show full text]
  • Spider Burrows in Ichnological Context: a Review of Literature Data and Burrows of the Wolf Spider Trochosa Hispanica Simon, 1870 from Albania
    Rendiconti Lincei. Scienze Fisiche e Naturali (2018) 29:67–79 https://doi.org/10.1007/s12210-017-0662-7 Spider burrows in ichnological context: a review of literature data and burrows of the wolf spider Trochosa hispanica Simon, 1870 from Albania Alfred Uchman1 · Blerina Vrenozi2 · Bardhyl Muceku3 Received: 28 September 2017 / Accepted: 29 November 2017 / Published online: 22 December 2017 © The Author(s) 2017. This article is an open access publication Abstract A general review of spider burrows and history of their research in eighteenth to nineteenth centuries are provided on the basis of the literature, which is dispersed and almost forgotten by majority of ichnologists. Moreover, burrows of the wolf spider Trochosa hispanica Simon, 1870 from a mountain meadow in Albania are presented. They are composed of an almost straight through gently curved to slightly winding vertical shafts (8.2–17.2 mm in diameter) with a basal, oval chamber, which is 14.5–30.6 mm wide. Above the ground level, some of them show a low, agglutinated chimney a cone composed of soil granules. The burrows are 83–235 mm long. They are comparable with the trace fossil Macanopsis Macsotay, 1967. Other spider burrows can form a simple shaft, which may be ascribed to the ichnogenus Skolithos Haldeman, 1840, or a shaft with the side oblique branches, which is is similar to the ichnogenus Psilonichnus Fürsich, 1981. Many spider burrows show one or more chambers. Their outlet may be closed with a trapdoor or show a chimney sticking above the ground. They may show scratch traces running parallel to the burrow.
    [Show full text]
  • Georgia's Purseweb & Trapdoor Spiders
    Georgia’s Purseweb and Trapdoor Spiders By Dirk J. Stevenson In Georgia, trapdoor and purseweb spiders are found statewide. Called mygalomorphs (the species are of the infraorder Mygalomorphae), these arachnids are ground-dwellers related to tarantulas. Male blue purseweb spider (Daniel D. Dye II) Here’s a quick look at both. Purseweb Spiders Three species of purseweb spiders (family Atypidae, genus Sphodros) are known to occur in the state. Each builds tough silken tubes carefully disguised with bits of lichen and moss. The tubes extend up the sides of tree trunks, with the bottoms ending a few inches underground, in damp soil. The tubes serve as shelter and hunting stations. The spiders spend most of their lives in them. Arachnologists enjoy describing the gruesome hunting strategy used by purseweb spiders. When an insect or other potential prey walks over the exposed portion of the tube, the spider, sensing vibrations, attacks from within the tube, impaling the prey with enormous fangs thrust through the tube wall. Once the prey is subdued, the spider cuts a slit in the tube and pulls the insect inside to consume at its leisure. The fastidious spider then stitches up the hole. The bottoms of many purseweb tubes I have excavated were littered with arthropod remains, including the chitonous parts of millipedes and beetles. Adult red-legged purseweb spider on Recent Georgia surveys for purseweb spiders conducted by well-known its tube (Daniel D. Dye II) Florida-based herpetologist Paul Moler and I focused on the status and distribution of the red-legged purseweb spider (Sphodros rufipes) and blue purseweb spider (Sphodros abboti) species.
    [Show full text]
  • First British Mesozoic Spider, from Cretaceous Amber of the Isle of Wight, Southern England
    FIRST BRITISH MESOZOIC SPIDER, FROM CRETACEOUS AMBER OF THE ISLE OF WIGHT, SOUTHERN ENGLAND by PAUL A. SELDEN ABSTRACT. Cretamygale chasei, a new genus and species of spider, is described from a single specimen preserved in amber of early Barremian age from the Isle of Wight. This is the oldest (and second Cretaceous) amber spider to be described, and the first record of a Mesozoic spider from Britain. It belongs to the group Bipectina of the infraorder Mygalomorphae, and is tentatively referred to the family Nemesiidae. It is the oldest bipectinate, extending the record by around 90 myr, the only known fossil nemesiid, and the second oldest fossil mygalomorph. KEY WORDS: Arachnida, Araneae, Arthropoda, Barremian, Chelicerata, Mygalomorphae, Nemesiidae. MESOZOIC mygalomorph spiders were first described by Eskov and Zonshtein (1990) from localities in Lower Cretaceous strata of Transbaikalia and Mongolia. The oldest mygalomorph, Rosamygale grauvo- geli Selden and Gall, 1992 was described from Triassic rocks of north-east France. The supposed Palaeozoicmygalomorph Megarachne servinei Hiinicken (1980) is doubtfully a spider (Eskov and Zonshtein 1990; Jose Corronca, pers. comm. 2001); Cenozoic mygalomorphs are known (reviewed in Eskov and Zonshtein 1990). There are a few records of Cretaceous spiders: indeterminate Araneae from the ?Barremian-Aptian of Koonwarra, South Australia (Jell and Duncan 1986); orbicularian araneo- morphs from the Berriasian-Valanginian of the Sierra de Montsech, Spain (Selden 1989, 1990, 1991); an unnamed lycosoid from Orapa, Botswana ('early Upper Cretaceous'; Rayner and Dippenaar-Schoeman 1995), a poorly preserved specimen from the Albian of Mexico (Feldmann et al. 1998), and many new spider specimens (including mygalomorphs) reported from the Aptian Crato Formation of Brazil, but only one (an araneomorph) has so far been described (Mesquita 1996).
    [Show full text]