Downed woody material (fallen logs) offers spiders (Araneae) and ants (Hymenoptera: Formicidae) ideal nesting and foraging sites. In a maple forest of Forillon National Park, I compared spider and ant assemblages on, adjacent to, and away from fallen logs, and on these I tested the effects of log type and decay stage. In a second study, spider and ant assemblages were compared on, adjacent to, and away from fallen logs in different forest types. / In the first experiment spiders were highly affected by trap placement, and diversity was highest on the wood surface compared to the forest floor. In contrast, wood type and decomposition stage of logs had few significant effects on spiders. Log type did not affect the estimated number of spider species nor the spider catch rates. Decomposition stage did not affect spider collections, but less decayed logs were more diverse in spider than heavily decayed logs. / The second experiment showed that use of dead wood by spiders depends on forest type. Ant diversity and abundance was generally low, making it difficult to offer concrete conclusions related to log use by ant assemblages. This work brings additional support for the important role of dead wood to forest arthropod biodiversity.

Made available in DSpace on 2015-07-22T20:49:22Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-07-28 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Aranhas do gênero Loxosceles, são responsáveis por acidentes em todo o mundo, com grande importância clínica no Sul do Brasil. Os venenos destas aranhas são compostos por diversas toxinas, entre elas proteínas, responsáveis pelo quadro conhecido como loxoscelismo. No intuito de descrever o perfil transcricional da glândula produtora de veneno da aranha Loxosceles intermedia geramos uma biblioteca de cDNA bastante ampla e seus transcritos foram funcionalmente caracterizados. Após o processamento inicial das sequências, 1.843 ESTs (Expressed Sequence Tags) apresentavam qualidade suficiente para as análises posteriores. Estas sequências foram montadas em 538 clusters, sendo que 281 eram singletons. Após análises de similaridade, mais de 50% das ESTs demonstraram algum grau de semelhança com proteínas conhecidas. As análises de similaridade também demonstraram que os transcritos que codificavam para toxinas, perfaziam 43% de todas as sequências e abrangem uma parte significativa das ESTs. As toxinas mais frequentes foram anotadas como pertencentes à família LiTx de toxinas inseticidas. As fosfolipases-D e as metaloproteases semelhantes à astacinas perfazem, cada uma, cerca de 9% do total de transcritos. Componentes tóxicos tais como inibidores de serino-proteases, hialuronidase e proteínas alergênicas foram também identificadas, porém com menor representação. Quase 10% das ESTs codificam para proteínas envolvidas em processos celulares. O presente trabalho descreve também as etapas para clonagem, expressão heteróloga e purificação de um transcrito semelhante a um inibidor de serino-protease, identificado na biblioteca de cDNA. É sabido que proteínas desta família apresentam um grande potencial de aplicação como drogas antitrombóticas, atuando como agentes terapêuticos que influenciam a atividade de fatores de coagulação. Esses dados fornecem uma visão global do perfil de expressão da glândula de veneno de L. intermedia, revelam diferenças significantes entre venenos de aranhas do gênero Loxosceles e descrevem a produção de uma nova toxina recombinante. / Loxosceles genus spiders are responsible for accidents all over the world and have clinical importance in the South of Brazil. The venom of these spiders is made up of several toxins, including proteins, which are responsible for the clinical pattern called loxoscelism. To describe the transcriptional profile of the L. intermedia venom gland, we generated a wide cDNA library, and its transcripts were functionally and structurally analyzed. After initial analyses, 1,843 ESTs produced readable sequences that were grouped into 538 clusters, 281 of which were singletons. Nine hundred eighty-five reads (53% of total ESTs) matched to known proteins. Similarity searches showed that toxinencoding transcripts totalize 43% of the total library and comprise a great number of ESTs. The most frequent toxins were from the LiTx family, which are known for their insecticidal activity. Both phospholipase-D and astacin-like metalloproteases toxins account for approximately 9% of total transcripts. Toxins components such as serine proteases, hyaluronidases and venom allergens were also found but with minor representation. Almost 10% of the ESTs encode for proteins involved in cellular processes. This work also describes the stages for cloning, heterologous expression and purification of a cDNA similar to a protease inhibitor identified in the cDNA library. It is known that proteins belonging to this family have an application potential as antithrombotic drugs, acting as therapeutic agents that influences the activity of coagulation factors. These data provide an important overview of the L. intermedia venom gland expression scenario, revealed significant differences from profiles of other spiders from the Loxosceles genus and describe the production of a novel recombinant toxin. / TEDE / BV UNIFESP: Teses e dissertações

No livro The Insect Societies, Wilson propôs categorias de socialidade que foram consideradas uma unificação histórica da terminologia no estudo do comportamento social. Desde então, muitos novos padrões comportamentais foram descritos, mas não podiam ser encaixados em nenhuma das categorias disponíveis, prejudicando o consenso em torno dessa classificação bem estabelecida. Novas classificações gerais tentaram contornar as limitações mostradas pela categorização de Wilson, mas com pouco sucesso. Entre as proposições, algumas mantêm a forma de categorização discreta usando características consideradas importantes pelos autores que as propuseram; outros avançam em um modelo quantitativo de caracterização da socialidade. A análise de Carnap sobre os tipos de conceitos em ciência pode nos ajudar a avançar nesta discussão. Sua distinção entre conceitos qualitativos (classificatórios e comparativos) e conceitos quantitativos é usada aqui como base epistemológica para analisar o desenvolvimento das mudanças conceituais e classificações de socialidade propostas. A abordagem de Carnap reforça a proposta de superar a dicotomia entre espécies sociais e sociais a favor de um modelo de gradientes de socialidade. Concluímos que uma nova métrica de socialidade deve ser construída, usando características que não são arbitrárias, mas sim evolutivamente significativas e que permita a comparação entre o comportamento social de todas as espécies. Nesse sentido, a análise de redes sociais tem sido usada para descrever a estrutura de diferentes sociedades, características da estrutura das redes são comparáveis entre grupos e espécies. Aranhas sociais se constituem como um ótimo objeto de estudo, pois apresentam diferentes níveis de socialidade em diferentes níveis taxonômicos. Nós, portanto, desenvolvemos uma abordagem de redes sociais para quantificar a socialidade em colônias de Anelosimus eximius e descrever sua estrutura. Somado a isso, e considerando que a divisão do trabalho é uma característica importante das espécies eussociais, nós testamos se os indivíduos nas colônias se especializam em tarefas e se organizam em grupos em diferentes contextos sociais. Além disso, avaliamos quais os efeitos do tamanho de grupo nesta organização social. Indivíduos de A. eximius apresentam uma organização em grupos nos diferentes contextos sociais, e as colônias apresentam uma baixa, porém significativa, taxa de especialização em tarefas. Os grupos variam entre contextos, mas são frequentemente similares em contextos ativos. Em colônias menores, os indivíduos não apresentam grupos consistentes, todos os individuos parecem necessários para as tarefas. Complexidade social definida como especialização e formação de grupos dentro da colônia parece ser uma métrica útil de socialidade, permitindo a comparação de uma gama de espécies. O tamanho dos grupos tem que ser levado em conta, porque indivíduos aparentam ser sensíveis às necessidades da colônia / In the book The Insect Societies, Wilson proposed categories of sociality that were considered a landmark unification of terminology in the study of social behavior. Since then, many new behavioral patterns were described, but they could not be fitted in any of the available categories, undermining the consensus around that wellestablished classification. New general classifications tried to circumvent the limitations shown by Wilsons categorization, but with little success. Among the propositions, some maintain the form of discrete categorization using features considered important by the authors who proposed them; others advance a quantitative model of characterization of sociality. Carnap\'s analysis of types of concepts can help moving forward in this discussion. His distinction between qualitative concepts (classificatory and comparative) and quantitative concepts is used here as an epistemological basis for analyzing the development of the proposed conceptual changes and classifications of sociality. Carnaps approach reinforces the proposal of overcoming the dichotomy between eusocial and social species in favor of a model of sociality gradients. We conclude that a new metric of sociality should be built, using characteristics that are non-arbitrary, evolutionarily meaningful, and amenable to comparing social behavior between all species. In this context, social network analysis is currently used as a means to describe social structures in animal systems, and the network structure characteristics can be compared across groups of different composition and species. Social spiders are good models to study social behavior because they present different levels of sociality in different taxonomic levels. We develop a social network approach to quantifying sociality in Anelosimus eximius colonies and describe its structure. In addition, since division of labor is an important feature of eusociality, we evaluated individual specialization in colony tasks and tested for the existence of groups of individuals through different social contexts. We also evaluated the effects of colony size on such organization. A. eximius present a organization in groups in different social contexts, and colonies exhibit a low, but significant, specialization rate in particular tasks. Group composition among spiders was flexible but frequently similar in active tasks. Individuals in smaller colonies did not form consistent groups; all individuals seem necessary to perform the tasks. The evaluation of social complexity in terms of specialization and group organization seems to be a useful metric, allowing the comparison of a wide range of species. Colony size should be an important qualifier of this metric, since individual behavior appears sensitive to colony needs

Spiders were sampled at Mpala Research Centre, Laikipia, Kenya by pitfall-trapping and sweep-netting from May 2001 to July 2002, at a Kenyan Long-term Exclosure Experiment. The aim was to establish species composition, checklist and examine spider responses to disturbances caused by cattle, megaherbivores (giraffe and elephants) and mesoherbivores (other ungulates) by looking at three levels of resolution, namely the overall community, guilds and individual species. This is the first controlled replicated experimental study on the effects on invertebrates (spiders) by different land uses (access by large herbivores). A total of 10,487 individuals from 132 species belonging to 30 families were recorded. The family Salticidae had the highest number of species (24), followed by Gnaphosidae (20), Araneidae and Lycosidae (15 each), Theridiidae and Thomisidae (8 each) and Zodariidae (4). Most of the other families had fewer than 4 species. Throughout the study period, species not previously sampled emerged after rainfall peaks. Exclosure treatments affected plant cover, spider diversity and total species mainly through the effects of cattle, whose presence significantly reduced relative vegetation cover. An increase in vegetation cover significantly increased the diversity, total species and species evenness of the overall spider community (total samples data set). Megaherbivores and mesoherbivores had no effects on overall spider diversity. Relative vegetation cover explained approximately 20-30% of variation in community diversity, species richness and species evenness. At the guild level of resolution, the exclosure treatments had no significant effects on diversity, species richness and species evenness of web builders, plant wanderers and ground wanderers. Plant wanderers were significantly and positively correlated with relative vegetation cover, which explained 17% of variation in their diversity. Six individual species responded strongly and in contrasting ways to the same environmental variables, indicating that this level was more sensitive to environmental changes than guilds or the overall spider community. Spider diversity, relative vegetation cover and rainfall varied at a temporal scale of months and not at a spatial scale of hundreds of metres. Only species diversity and species richness from sweep-netting samples and total species from pitfall-trapping varied significantly at a spatial scale of hundreds of metres. Ordination analysis revealed that sweep-netting samples were a better indicator of grazing impacts than pitfalltrapping or combined samples and grouped to reflect cattle grazing, non-cattle grazing and to a small extent the control treatments. Other ordination analyses showed that only samples from sweep-netting and not from pitfall-trapping, were spatially partitioned at a scale of hundreds of metres. This study concludes that the spider fauna of black cotton soil habitats is rich and useful for environmental monitoring and that monitoring of several individual species as indicator of grazing impacts in savanna could be useful and relatively easy.

O envenenamento por aranhas Loxosceles pode resultar dois tipos de manifestações clínicas: o loxoscelismo cutâneo e o sistêmico. Hemólise, agregação plaquetária, inflamação persistente, falência renal e morte podem ser observados em pacientes com manifestações sistêmicas. Apesar da pouca incidência de vítimas com falência renal, esta é a principal causa de óbito, ocorrendo principalmente em crianças. O principal fator do veneno da aranha Loxosceles, responsável pelas manifestações locais e sistêmicas, é a esfingomielinase D. O presente estudo teve como objetivo investigar a ação tóxica do veneno de L. intermedia e das SMases D sobre células renais humanas, o possível envolvimento de metaloproteases endógenas e do sistema complemento neste processo. Os resultados obtidos mostram que tanto o veneno, como a SMase D, foram capazes de provocar morte celular, a qual foi relacionada a ativação de metaloproteases de matriz extracelular, MMP-2 e MMP-9 e, ainda, por ação lítica do complemento, após clivagem do MCP, por ação de metaloproteases da família das adamlisinas. A remoção de MCP permitiu ativação do Complemento, como determinado pelo aumento da deposição de C3 e C4 e da morte celular. Também foi observado um aumento na deposição do fator H e da properdina, mas não de C4bp após a tratamento das células com veneno/ SMase D. Diminuição na expressão das moléculas de superfície MHC-I, <font face=\"Symbol\">b2 microglobulina, EPCR e EGFR foi observada e está relacionada com a ativação de metaloproteases da família das adamlisinas. A expressão de outros reguladores do complemento, como DAF e CD59, não foi afetada pelo tratamento. Em conjunto, tais resultados mostram que o veneno e a SMase D induzem aumento na expressão/ativação de metaloproteases endógenas, operantes nos eventos de morte celular por apoptose e necrose, os quais podem ter um papel relevante para os danos renais presentes no loxoscelismo sistêmico humano. / Envenomation by Loxosceles spider can result two forms of clinical manifestations: cutaneous and systemic loxoscelism. Haemolysis, platelet aggregation, inflammation persistent, renal failure and death can be observed in patients with systemic manifestations. Despite the low incidence of renal failure victims, this is the main cause of death, occurring mainly in children. The sphingomyelinase D is the main factor in Loxosceles spider venom responsible for local and systemic manifestations This study aimed to investigate the toxicity of the L. intermedia venom and SMase D on human kidney cells and the possible involvement of endogenous metalloproteinases and complement this process. Results showed that venom and SMase D were able to cause cell death, which was related to activation of extracellular matrix metalloproteases, MMP-2 and MMP-9 and also by lytic action of complement, after MCP cleavage by the action of the family of metalloproteases adamlisins. The removal of MCP, by action of the venom/ SMase D, allowes activation of complement, as determined by increases deposition of C3 and C4 and cell death. There was also an increases in deposition of properdin and factor H, but not C4bp, after treatment of cells with venom/ SMase D. decreased expression of surface molecules MHC-I, <font face=\"Symbol\">b2 microglobulin, EPCR and EGFR was observed after incubation of the renal cells with venom or SMase D and is related to activation of metalloproteinases family adamlisins. The expression of others complement regulators such as DAF and CD59 was not affected by treatment. Together, theses results show that the venom and SMase D induce increased expression/ activation of endogenous metalloproteases, operating in the event of cell death by apoptosis and necrosis, which may have an important role for the kidney injury loxoscelism in the human system.

The different ways that animals extract and analyze visual information from their environment is of interest to sensory ecologists. Jumping spiders, well-known for visually guided mating and hunting behavior, are an interesting model for the study of visual attention because they quickly and efficiently integrate information from eight eyes with a small brain. Stimuli in front of the spider are examined by two functionally and morphologically distinct pairs of forward-facing eyes. The principal eyes discern fine details and have small retinas and thus a small visual field. However, their position at the back of moveable tubes within the cephalothorax expands this visual field. The anterolateral eyes, one of the three pairs of secondary eyes, have lower spatial acuity and a larger visual field that overlaps with that of the principal eyes. They act as motion detectors, directing the principal eyes to objects appearing in their visual field. In Chapter 1, using a salticid-specific eyetracker, I explore how characteristics of a stimulus influence whether the secondary eyes redirect the gaze of the principal eyes from a principal stimulus to a new stimulus appearing in the visual field. I found that spiders suppressed redirection of the principal eyes when engaged by a salient stimulus, and redirected to moving peripheral stimuli more frequently than to stationary peripheral stimuli. The principal eyes are also known to engage in a complex behavior called “scanning,” involving both dorsoventral and rotational movement. One hypothesis regarding scanning’s function is that it helps spiders identify important lines and angles in stimuli. However, scanning routines are not well understood. In Chapter 2, I measured scanning behaviors when spiders were watching quickly moving versus still or slowly moving images. I found that spiders spent more time overall looking at still or slowly moving images, and that stimulus speed does not appear to affect rotational movement of the retinas. Overall, I conclude that motion in an appearing stimulus elicits the attention of the principal eyes, but it remains unclear how and whether scanning functions in the extraction of detail from moving stimuli.

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Current knowledge of the spinning apparatus comes namely from studies on orb web spiders and their relatives, whereas that of wolf spiders were more or less neglected. Therefore, developmental changes of the spinning apparatus of four wolf spiders were studied throughout their life cycles. Each of these lycosids possesses stenochronous life cycle with similar number of instars (7-10) but of different length (1-3 years). There is only one period of reproduction in spring/summer in all four species. Sperms are being formed just after the final moult; diplotene in some species is peculiar. The courtship behaviour reflects the microhabitat occupied by the concrete spider species; the copulations are species specific. Ontogeny of the spinning apparatus of developing spiderlings was observed: The spinning apparatus initiate its function in the first instar. Secondary ampullate, all piriform and all but four aciniform glands are tartipore-accommodated; they do not moult in situ. The tartipores, vestigial structures corresponding to spigots of the previous instar, appear on the spinning field starting with the second instar. Tartipore-accommodated glands play roles also during proecdysis and their evolution corresponds with the way how do the spiders secure themselves when moulting. Hence, the not yet...

Orb-weavers (Araneidae) are a diversified spider family comprising more than 3,100 species in more than 170 genera. Together with 13 other families, they con- stitute to superfamily Araneoidea. The presented thesis focuses on karyotype evo- lution of Araneidae, including its comparison with a related family Tetragnathidae. The results obtained from 19 araneid and four tetragnathid species confirm previ- ously postulated hypothesis that the ancestral karyotype of Araneoidea (including Araneidae) consists of 24 acrocentric chromosomes in males, including two acro- centric X chromosomes of system X1X20. However, there is a tendency of 2n decrease in some araneids due to centric fusions. In these cases, centric fusions affected most autosomes (and sometimes gonosomes as well); number of chromosome pairs de- creased from 11 to six. Three independent reduction events were detected in this thesis. Furthermore, pattern of nucleolar organizer regions (NORs) was studied in this thesis using fluorescent in situ hybridization, since data on evolution of this marker are scarce in spiders. Striking variability in NORs number was discovered, ranging from one to 13 loci. Remarkably, multiple centric fusions were always ac- companied by considerable increase of NORs number. In araneids and tetragnathids possessing...