DOCSLIB.ORG

Evolução Do Cleptoparasitismo Em Argyrodes Elevatus (Theridiidae

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Evolução Do Cleptoparasitismo Em Argyrodes Elevatus (Theridiidae Universidade de São Paulo Instituto de Psicologia Neurociências e Comportamento EVOLUÇÃO DO CLEPTOPARASITISMO EM ARGYRODES ELEVATUS (THERIDIIDAE, ARANEAE) Dissertação de mestrado Maio / 2009 aluno: Marco Cesar Silveira orientador: Hilton Ferreira Japyassú EVOLUÇÃO DO CLEPTOPARASITISMO EM ARGYRODES ELEVATUS (THERIDIIDAE, ARANEAE) Marco Cesar Silveira Dissertação entregue ao Departamento de Neurociências e Comportamento do Instituto de Psicologia da Universidade de São Paulo para obtenção de título de Mestre em Neurociências e Comportamento. Orientação: Prof. Dr. Hilton Ferreira Japyassú São Paulo, Maio de 2009 AGRADECIMENTOS São muitos os que contribuíram para este trabalho, dentre acadêmicos e não acadêmicos, professores e alunos, amigos e irmãos, biólogos, psicólogos, pedagogos, bioquímicos, músicos, filósofos... Dentre tantos, torno público o meu ‘muito obrigado’: Ao amigo e orientador Hilton Japyassú, pela transmissão lamarckiana de caracteres; Aos etólogos Camila, Danilo, Vanessa e Tatiana, por tudo que aprendemos juntos, no laboratório, no campo e na vida; pela força braçal, moral e afetiva; Ao Dr. Antônio Brescovit, por identificar os animais; aos amigos Claudião e Igor, pelo grande apoio nas coletas; Danilo, Flávio e Rafael, pela disposição de sempre contribuir com belas fotos; e a todos os pesquisadores, estagiários e funcionários do Laboratório de Artrópodes do Instituto Butantan, por diversos motivos, dos quais os principais, sem dúvida, são o companheirismo e o bom humor; Aos docentes Emma Otta, Fernando Ribeiro, Vera Bussab, César Ades, Ricardo Pinto da Rocha, John Wenzel. Não só pelo primor de suas aulas, mas por importantes observações sobre o projeto e a execução deste trabalho; Aos membros dos laboratórios LAL, FiliLal, e LIEE (ecofisiologia evolutiva), com os quais sempre tive conversas muito enriquecedoras; À minha família, que investiu em mim com muito amor; Ao Futebol de toda quinta-feira, ao Chorinho de toda terça-feira, e às demais tradições, simplesmente por serem tradições; Ao Conselho Nacional de Pesquisa – CNPq, pelo financiamento; Ao anônimo que, certo dia, espontaneamente, me desejou um bom dia; À Lucia, a quem dedico esta dissertação. ÍNDICE Resumo..............................................................................................................................3 Abstract..............................................................................................................................4 Apresentação.....................................................................................................................5 SEÇÃO 1: Das diversas formas de cleptoparasitismo e como se manifestam em Argyrodes elevatus Cleptoparasitismo....................................................................................................6 Tipos de cleptoparasitismo......................................................................................7 Cleptoparasitismo em abelhas: uma nomenclatura a parte...................................8 Cleptoparasitismo em aranhas................................................................................9 Nossas observações...............................................................................................10 Metodologia................................................................................................................12 Sujeitos experimentais...........................................................................................12 Manutenção das aranhas em laboratório..............................................................13 Observando o cleptoparasitismo...........................................................................14 Resultados e discussão...............................................................................................15 Atividade geral de Argyrodes elevatus...................................................................15 Furtos de presa capturada.....................................................................................17 Alimentar-se com o hospedeiro.............................................................................19 Argyrodes elevatus, também araneófago..............................................................21 Comportamentos agonistas entre hospedeira e cleptoparasita...........................25 Captura de presas vivas..........................................................................................26 Roubo de ooteca....................................................................................................27 Considerações.............................................................................................................29 SEÇÃO 2 – Argyrodes elevatus em teia de Latrodectus curacaviensis: análise quantitativa do cleptoparasitismo Categorização do comportamento de Argyrodes elevatus...................................31 Metodologia................................................................................................................32 Protocolo de registro em vídeo..............................................................................32 Transcrição e decodificação das sequências..........................................................33 Conexões entre categorias e elaboração do fluxograma......................................33 Resultados e discussão...............................................................................................35 Categorias comportamentais observadas no forrageamento de Argyrodes elevatus..................................................................................................................35 Conexões entre categorias: fluxogramas...............................................................47 Fluxogramas de Faiditus ululans e Argyrodes elevatus.........................................49 Considerações.............................................................................................................57 SEÇÃO 3: Implicações evolutivas sobre o cleptoparasitismo em Argyrodes elevatus Hipóteses evolutivas sobre o cleptoparasitismo em Argyrodinae........................58 Plasticidade e evolução comportamental..............................................................60 Metodologia................................................................................................................63 Comparação entre categorias de diferentes espécies...........................................63 Conectando categorias: rotinas comportamentais...............................................64 Resultados e discussão...............................................................................................66 Comparando categorias.........................................................................................66 Distribuição das categorias comportamentais na filogenia...................................68 A importância do contexto no comportamento....................................................71 Rotinas como caracteres........................................................................................72 Rotinas como estados............................................................................................73 Considerações.............................................................................................................76 SEÇÃO 4: Considerações finais As hipóteses evolutivas sobre cleptoparasitismo: nossas contribuições..............78 Como explicar o aumento da plasticidade comportamental de Argyrodes elevatus?................................................................................................................80 Referências bibliográficas................................................................................................87 RESUMO O cleptoparasitismo é uma interação entre animais que consiste no furto ou roubo de itens alimentares já coletados ou processados. Este tipo de interação ocorre em diversos táxons animais. Entre aranhas, a subfamília Argyrodinae (Theridiidae) é um dos grupos com mais espécies cleptoparasitas. Neste estudo, apresentamos um apanhado de ações que o cleptoparasita Argyrodes elevatus foi capaz de realizar nas teias de aranhas hospedeiras. As principais espécies de hospedeiras observadas foram Latrodectus curacaviensis, Latrodectus geometricus e Achaearanea tepidariorum (Theridiidae); destas, apenas A. tepidariorum é uma hospedeira natural de A. elevatus. A maioria das observações se deu em laboratório, mas também relatamos dados de campo. Registramos que A. elevatus pode, na teia de sua hospedeira, furtar presas sem ser percebido ou roubá-las coercivamente. Ele pode ainda furtar ootecas; capturar presas por si próprio e até mesmo predar a aranha hospedeira. Em seguida, apresentamos as sequências de categorias comportamentais que A. elevatus executa durante o furto de presas em teias da hospedeira L. curacaviensis. A partir destas sequencias, o programa EthoSeq nos mostra os conjuntos de categorias com mais probabilidade de conexão entre si (rotinas comportamentais) e nos permite a elaboração de um fluxograma do comportamento de furto de presas. Posteriormente, comparamos as categorias e as rotinas comportamentais que ocorrem no furto de presas com as categorias e rotinas que ocorrem no forrageamento de aranhas não cleptoparasitas. Com isto, demonstramos que A. elevatus tem maior plasticidade comportamental e capacidade cognitiva mais alta que espécies não cleptoparasitas da mesma família. Esta maior plasticidade comportamental está associada à execução, em contexto de aquisição de alimento, de
Load more

Recommended publications
  • Western Black Widow Spider
    Arachnida Western Black Widow Spider Class Order Family Species Arachnida Araneae Theridiidae Latrodectus hesperus Range Reproduction Special Adaptations The genus is worldwide. Growth: gradual, molts several times. Venom: Although never Western Texas, Okla- Egg: produced in bunches of 40 or more, wrapped in silk and sus- aggressive, the females homa and Kansas north pended from the web, can hatch within a week of being laid. occasionally bite hu- to Canada and west to the Immature: pure white after hatching and slowly gaining color with each mans but only in self defense (males do not Pacific Coaststates molt. Adult: may live for several years. The female can store sperm for many bite humans). They months. It is a fallacy that the female always eats the male after can cause a serious but Habitat mating. rarely fatal result. The venom is neurotoxic and Found in tropical, temper- Physical Characteristics is reported to be 15 times ate and arid zones in a as poisonous as that of the rattlesnake. Symptoms multitude of habitats. Mouthparts: chelicerate, fangs are perpendicular to body line. Duct from a include a painful tight- poison gland opens from the base of each fang. The mouth and ening of the abdomenal jaws are on the underside of the head. Niche wall muscles, increased Legs: 8 long, narow legs. blood pressure and body Eyes: 8 eyes. Usually found in temperature, nausea, lo- Egg: their eggs are layed in clusters and covered with silk to undisturbed places like calized edema, asphyxia form an egg sac. wood piles, outhouses, and convulsions. Medical Immature: white at first , gaining color with each molt.
    [Show full text]
  • Spider Bites
    Infectious Disease Epidemiology Section Office of Public Health, Louisiana Dept of Health & Hospitals 800-256-2748 (24 hr number) www.infectiousdisease.dhh.louisiana.gov SPIDER BITES Revised 6/13/2007 Epidemiology There are over 3,000 species of spiders native to the United States. Due to fragility or inadequate length of fangs, only a limited number of species are capable of inflicting noticeable wounds on human beings, although several small species of spiders are able to bite humans, but with little or no demonstrable effect. The final determination of etiology of 80% of suspected spider bites in the U.S. is, in fact, an alternate diagnosis. Therefore the perceived risk of spider bites far exceeds actual risk. Tick bites, chemical burns, lesions from poison ivy or oak, cutaneous anthrax, diabetic ulcer, erythema migrans from Lyme disease, erythema from Rocky Mountain Spotted Fever, sporotrichosis, Staphylococcus infections, Stephens Johnson syndrome, syphilitic chancre, thromboembolic effects of Leishmaniasis, toxic epidermal necrolyis, shingles, early chicken pox lesions, bites from other arthropods and idiopathic dermal necrosis have all been misdiagnosed as spider bites. Almost all bites from spiders are inflicted by the spider in self defense, when a human inadvertently upsets or invades the spider’s space. Of spiders in the United States capable of biting, only a few are considered dangerous to human beings. Bites from the following species of spiders can result in serious sequelae: Louisiana Office of Public Health – Infectious Disease Epidemiology Section Page 1 of 14 The Brown Recluse: Loxosceles reclusa Photo Courtesy of the Texas Department of State Health Services The most common species associated with medically important spider bites: • Physical characteristics o Length: Approximately 1 inch o Appearance: A violin shaped mark can be visualized on the dorsum (top).
    [Show full text]
  • Arthropod Envenomations: Immunologic and Toxicologic Considerations Cyrus Rangan, MD, FAAP, ACMT
    Emergency Department Evaluation and Treatment for Children With Arthropod Envenomations: Immunologic and Toxicologic Considerations Cyrus Rangan, MD, FAAP, ACMT Arthropod envenomations are a significant cause of environmental injury in children. Bees, wasps, and spiders inflict injury via specialized venoms with a broad range of components, mechanisms, and potential treatments. Immunologic and toxicologic considerations in the evaluation and management of arthropod envenomations are important for the under- standing of the progression of envenomations, prompt diagnosis of severe conditions including anaphylaxis, and the use of antivenom in selected cases. Clin Ped Emerg Med 8:104-109 ª 2007 Published by Elsevier Inc. KEYWORDS envenomation, arthropod, arachnida, hymenoptera rthropod bites and stings accounted for more than ever, clinical symptoms of envenomation and treatment A75000 reports to poison control centers in the are similar. Bees are attracted to carbon dioxide (hence, United States in 2005 [1]. The phylum Arthropoda the predilection for bees to fly around the facial area), includes 2 clinically important classes: Insecta (order: bright colors (ie, clothing), and sweet odors (ie, Hymenoptera—bees, wasps, yellow jackets, and ants), perfumes, fragrances). Children commonly believe that and Arachnida (ticks, scorpions, and spiders). Virtually bees are aggressive insects, but they are mostly docile all arthropods possess some form of venom for immobi- creatures; indeed, the sometimes fearful behavior of lization and digestion of prey, yet only a select few species children around a nearby bee may increase the risk of a have developed venom delivery mechanisms capable of sting. Mass envenomations may occur when a hive is poisoning humans [2]. Pathophysiologic mechanisms of physically disturbed by children throwing rocks or other venom vary considerably among arthropods, and clinical objects at the hive [3].
    [Show full text]
  • Koexistence a Rozdělení Niky U Pavouků Rodu Philodromus
    Masarykova univerzita Přírodovědecká fakulta Ústav botaniky a zoologie Koexistence a rozdělení niky u pavouků rodu Philodromus Diplomová práce Autor: Radek Michalko Brno 2012 Vedoucí DP: doc. Mgr. Stano Pekár Ph.D. 1 Souhlasím s uloţením této diplomové práce v knihovně Ústavu botaniky a zoologie PřF MU v Brně, případně v jiné knihovně MU, s jejím veřejným půjčováním a vyuţitím pro vědecké, vzdělávací nebo jiné veřejně prospěšné účely, a to za předpokladu, ţe převzaté informace budou řádně citovány a nebudou vyuţívány komerčně. V Brně 8.1.2012 ………………………………… Podpis 2 PODĚKOVÁNÍ Zejména bych chtěl poděkovat vedoucímu mé diplomové práce panu docentu Stanu Pekárovi, ţe mi umoţnil pracovat na tomto tématu, za trpělivé vedení a uţitečné rady. Dále bych chtěl velice poděkovat mým rodičům, bez jejichţ osobní a finanční podpory by tato práce nevznikla. Rovněţ bych chtěl poděkovat Lence Sentenské, Evě Líznarové, Pavlovi Šebkovi a Stanovi Korenkovi za podporu a cenné rady všeho druhu. 3 ABSTRAKT Koexistence a rozdělení niky pavouků rodu Philodromus V této diplomové práci byl zkoumán mechanismus umoţňující koexistenci mezi Philodromus albidus, P. aureolus a P. cespitum. Studie probíhala na území významného krajinného prvku U Kříţe v Brně Starém Lískovci. Studované území se skládá ze třech typů biotopů: listnatý les, křoviny a monokultura švestek. Pavouci byli získáváni pomocí sklepávání. U zkoumaných druhů byly porovnávány různé dimenze niky. Prostorová nika byla zkoumána na základě mikro- aţ makrobiotopových preferencí. Trofická nika byla zkoumána na základě velikosti a typu přirozené kořisti a pomocí laboratorních experimentů potravních preferencí. Časová nika byla zkoumána na základě fenologie jednotlivých druhů. Studované druhy se lišily v prostorové a trofické nice.
    [Show full text]
  • Approach and Management of Spider Bites for the Primary Care Physician
    Osteopathic Family Physician (2011) 3, 149-153 Approach and management of spider bites for the primary care physician John Ashurst, DO,a Joe Sexton, MD,a Matt Cook, DOb From the Departments of aEmergency Medicine and bToxicology, Lehigh Valley Health Network, Allentown, PA. KEYWORDS: Summary The class Arachnida of the phylum Arthropoda comprises an estimated 100,000 species Spider bite; worldwide. However, only a handful of these species can cause clinical effects in humans because many Black widow; are unable to penetrate the skin, whereas others only inject prey-specific venom. The bite from a widow Brown recluse spider will produce local symptoms that include muscle spasm and systemic symptoms that resemble acute abdomen. The bite from a brown recluse locally will resemble a target lesion but will develop into an ulcerative, necrotic lesion over time. Spider bites can be prevented by several simple measures including home cleanliness and wearing the proper attire while working outdoors. Although most spider bites cause only local tissue swelling, early species identification coupled with species-specific man- agement may decrease the rate of morbidity associated with bites. © 2011 Elsevier Inc. All rights reserved. More than 100,000 species of spiders are found world- homes and yards in the southwestern United States, and wide. Persons seeking medical attention as a result of spider related species occur in the temperate climate zones across bites is estimated at 50,000 patients per year.1,2 Although the globe.2,5 The second, Lactrodectus, or the common almost all species of spiders possess some level of venom, widow spider, are found in both temperate and tropical 2 the majority are considered harmless to humans.
    [Show full text]
  • Mai Po Nature Reserve Management Plan: 2019-2024
    Mai Po Nature Reserve Management Plan: 2019-2024 ©Anthony Sun June 2021 (Mid-term version) Prepared by WWF-Hong Kong Mai Po Nature Reserve Management Plan: 2019-2024 Page | 1 Table of Contents EXECUTIVE SUMMARY ................................................................................................................................................... 2 1. INTRODUCTION ..................................................................................................................................................... 7 1.1 Regional and Global Context ........................................................................................................................ 8 1.2 Local Biodiversity and Wise Use ................................................................................................................... 9 1.3 Geology and Geological History ................................................................................................................. 10 1.4 Hydrology ................................................................................................................................................... 10 1.5 Climate ....................................................................................................................................................... 10 1.6 Climate Change Impacts ............................................................................................................................. 11 1.7 Biodiversity ................................................................................................................................................
    [Show full text]
  • 110 Mapas De Distribución De Arañas De Importancia
    MAPAS DE DISTRIBUCIÓN DE ARAÑAS DE IMPORTANCIA MÉDICA DEL GÉNERO Latrodectus (ARANEAE: THERIDIIDAE) PARA NORTEAMÉRICA. Rodrigo Monjaraz-Ruedas. Colección Nacional de Arácnidos (CNAN), Departamento de Zoología, Instituto de Biología, Universidad Nacional Autónoma de México. Apartado Postal 70-153, C.P. 04510, Ciudad Universitaria, Distrito Federal, México. E-mail: [email protected]. RESUMEN. Las especies de arañas pertenecientes al género Latrodectus Walckenaer, 1805 son consideradas de importancia médica, debido a la toxicidad de su veneno, el cual representa un riesgo de salud para el ser humano. Se realizó una búsqueda exhaustiva de las localidades en literatura especializada y de material depositado en la Colección Nacional de Arácnidos (CNAN) del Instituto de Biología, UNAM, en la cual han sido registradas las especies con mayor número de registros para Norteamérica: Latrodectus mactans (Fabricius, 1775), Latrodectus variolus Walckenaer, 1837 y Latrodectus geometricus C. L. Koch, 1841. Las localidades fueron georeferenciadas con la ayuda de GEOlocate y Google Earth, mientras que los mapas de registros para las tres especies se elaboraron con el programa gvSIG. Con la elaboración de estos mapas, se pretende incrementar el conocimiento sobre la distribución de las especies con mayores registros en Norteamérica del género Latrodectus, dicha información podrá ser utilizada por el sector médico de los países norteamericanos. Palabras clave: Latrodectus, distribución, importancia médica, Norteamérica. ABSTRACT. The spiders of the genus Latrodectus Walcknaer, 1805 are considered of medical importance, because the toxicity of their venom represents an important health risk to humans. We performed an exhaustive search of the literature and locations of material deposited in Colección Nacional de Arácnidos (CNAN) of the Instituto de Biología, UNAM, for the species that have the highest number of records for North America: Latrodectus mactans (Fabricius, 1775), Latrodectus variolus Walckenaer, 1837 and Latrodectus geometricus C.
    [Show full text]
  • SA Spider Checklist
    REVIEW ZOOS' PRINT JOURNAL 22(2): 2551-2597 CHECKLIST OF SPIDERS (ARACHNIDA: ARANEAE) OF SOUTH ASIA INCLUDING THE 2006 UPDATE OF INDIAN SPIDER CHECKLIST Manju Siliwal 1 and Sanjay Molur 2,3 1,2 Wildlife Information & Liaison Development (WILD) Society, 3 Zoo Outreach Organisation (ZOO) 29-1, Bharathi Colony, Peelamedu, Coimbatore, Tamil Nadu 641004, India Email: 1 [email protected]; 3 [email protected] ABSTRACT Thesaurus, (Vol. 1) in 1734 (Smith, 2001). Most of the spiders After one year since publication of the Indian Checklist, this is described during the British period from South Asia were by an attempt to provide a comprehensive checklist of spiders of foreigners based on the specimens deposited in different South Asia with eight countries - Afghanistan, Bangladesh, Bhutan, India, Maldives, Nepal, Pakistan and Sri Lanka. The European Museums. Indian checklist is also updated for 2006. The South Asian While the Indian checklist (Siliwal et al., 2005) is more spider list is also compiled following The World Spider Catalog accurate, the South Asian spider checklist is not critically by Platnick and other peer-reviewed publications since the last scrutinized due to lack of complete literature, but it gives an update. In total, 2299 species of spiders in 67 families have overview of species found in various South Asian countries, been reported from South Asia. There are 39 species included in this regions checklist that are not listed in the World Catalog gives the endemism of species and forms a basis for careful of Spiders. Taxonomic verification is recommended for 51 species. and participatory work by arachnologists in the region.
    [Show full text]
  • Integrating Climate Change Vulnerability Assessments Into Adaptation Planning
    Integrating climate change vulnerability assessments into adaptation planning A case study using the NatureServe Climate Change Vulnerability Index to inform conservation planning for species in Florida A Report Prepared for the Florida Fish and Wildlife Conservation Commission Natalie Dubois, Astrid Caldas, Judy Boshoven & Aimee Delach Defenders of Wildlife is a national, nonprofit, membership organization dedicated to the protection of all native wild animals and plants in their natural communities. Jamie Rappaport Clark, President Donald Barry, Executive Vice President This report was made possible with the generous support of the Doris Duke Charitable Foundation, the Kresge Foundation and the Educational Foundation of America AUTHORS Natalie Dubois Astrid Caldas Judy Boshoven Aimee Delach With additional input from Amielle DeWan and Kathleen Theoharides PRODUCTION Claire Colegrove © 2011 Defenders of Wildlife, 1130 17th St NW, Washington D.C. 20036 http:/www.defenders.org Disclaimer: This document represents the work and views of the authors and does not necessarily imply endorsement by the Florida Fish and Wildlife Conservation Commission. Suggested citation: Dubois, N., A. Caldas, J. Boshoven, and A. Delach. 2011. Integrating Climate Change Vulnerability Assessments into Adaptation Planning: A Case Study Using the NatureServe Climate Change Vulnerability Index to Inform Conservation Planning for Species in Florida [Final Report]. Defenders of Wildlife, Washington D.C. CONTENTS Executive Summary ...................................................................................
    [Show full text]
  • Widow Spider Parasitoids Philolema Latrodecti
    EENY515 Widow Spider Parasitoids Philolema latrodecti (Fullaway) (Insecta: Hymenoptera: Eurytomidae) and Baeus latrodecti Dozier (Insecta: Hymenoptera: Platygastridae) 1 Christopher S. Bibbs and Lyle J. Buss2 Introduction Another parasitoid of note is a scelionid wasp, Baeus latrodecti Dozier, which was recorded as emerging from the The genus of widow spiders, Latrodectus, has limited egg sacs of the southern black widow, Latrodectus mactans records of the pathogens, parasites, and parasitoids known Fabricius (Dozier 1931). to affect them. In the United States, a known associated parasitoid is Synonymy Philolema latrodecti (Fullaway). Little is documented Philolema latrodecti was originally described as Eurytoma regarding this species, but it is confirmed to target multiple latrodecti (Fullaway 1953). It was later moved into the new widow spider species as hosts for reproduction (Boucek genus Desantisca with other egg sac parasitoids that were 1988, Fullaway 1953). originally described in the genus Eurytoma (Burks 1971). Research to phylogenetically reclassify the large family Eurytomidae using morphological differences placed it into the genus Philolema (Lotfalizadeh et al. 2007). Baeus latrodecti was described twice, once as B. latrodecti (Dozier 1931) and again as B. californicus (Pierce 1939, Krombein et al. 1979). Neither P. latrodecti nor B. latrodecti have an official com- mon name sanctioned by the Entomological Society of America. Figure 1. Adult Philolema latrodecti (Fullaway), a parasitoid of the widow spiders in Latrodectus Walckenaer. Credits: Christopher S. Bibbs, University of Florida 1. This document is EENY515, one of a series of the Entomology and Nematology Department, UF/IFAS Extension. Original publication date January 2012. Reviewed January 2019. Visit the EDIS website at http://edis.ifas.ufl.edu.
    [Show full text]
  • Population Dynamics of the Red Widow Spider (Araneae: Theridiidae)
    Carrel: Red Widow Spider Populations 385 POPULATION DYNAMICS OF THE RED WIDOW SPIDER (ARANEAE: THERIDIIDAE) JAMES E. CARREL Division of Biological Sciences, 105 Tucker Hall, University of Missouri-Columbia, Columbia, MO 65211-7400 ABSTRACT Populations of the red widow spider, Latrodectus bishopi, in native Florida scrub at the Arch- bold Biological Station were monitored annually on ten ~0.5 ha transects in late winter from 1987 to 2000. Of 398 L. bishopi detected in the study, all but three had their silken retreats built in palmetto leaves. L. bishopi at rest in retreats in saw palmetto (Serenoa repens) were higher above the ground (~0.5 m) than spiders in scrub palmetto (Sabal etonia) (~0.3 m). From a peak of 31 spiders/ha in 1989, the average L. bishopi density declined exponentially to only 0.3 spiders/ha in 1997, after which L. bishopi densities began to recover. Burning of scrubby transects in spring or summer appeared to have no affect on subsequent L. bishopi populations. There were no significant correlations between L. bishopi population density and local temperature or precipitation data. These results suggest that undescribed biotic factors may regulate populations of the red widow spider in a density-dependent fashion. Key Words: Latrodectus, Florida scrub, ecology, populations, dynamics, fire RESUMEN En diez transectos de ~0.5 ha, determinamos cada invierno de 1987-2000 las poblaciones de la araña Latrodectus bishopi en matorral nativo de Florida en la Estación Biológica Arch- bold. De las 398 L. bishopi que encontramos, todos menos tres habían construido sus retiros sedosus entre las ojas de palmitos.
    [Show full text]
  • Araneae (Spider) Photos
    Araneae (Spider) Photos Araneae (Spiders) About Information on: Spider Photos of Links to WWW Spiders Spiders of North America Relationships Spider Groups Spider Resources -- An Identification Manual About Spiders As in the other arachnid orders, appendage specialization is very important in the evolution of spiders. In spiders the five pairs of appendages of the prosoma (one of the two main body sections) that follow the chelicerae are the pedipalps followed by four pairs of walking legs. The pedipalps are modified to serve as mating organs by mature male spiders. These modifications are often very complicated and differences in their structure are important characteristics used by araneologists in the classification of spiders. Pedipalps in female spiders are structurally much simpler and are used for sensing, manipulating food and sometimes in locomotion. It is relatively easy to tell mature or nearly mature males from female spiders (at least in most groups) by looking at the pedipalps -- in females they look like functional but small legs while in males the ends tend to be enlarged, often greatly so. In young spiders these differences are not evident. There are also appendages on the opisthosoma (the rear body section, the one with no walking legs) the best known being the spinnerets. In the first spiders there were four pairs of spinnerets. Living spiders may have four e.g., (liphistiomorph spiders) or three pairs (e.g., mygalomorph and ecribellate araneomorphs) or three paris of spinnerets and a silk spinning plate called a cribellum (the earliest and many extant araneomorph spiders). Spinnerets' history as appendages is suggested in part by their being projections away from the opisthosoma and the fact that they may retain muscles for movement Much of the success of spiders traces directly to their extensive use of silk and poison.
    [Show full text]