abstract: Human-induced rapid environmental change (HIREC) influences nearly all of Earth's ecosystems through processes such as urbanization. Previous studies have found that urbanization influences biodiversity patterns, often yielding an increase in the abundance of a few urban-adapted taxa at the expense of native species diversity. The western black widow spider, Latrodectus hesperus, is a medically-important pest species that often forms dense urban subpopulations (i.e., infestations) relative to the low-density subpopulations found throughout undisturbed, desert habitat. Here, I employ field and laboratory studies to examine the population ecology and stoichiometry of this urban pest to increase our understanding of the mechanisms underlying its success. The population ecology of ten black widow subpopulations spread across metropolitan Phoenix, AZ was examined during the peak breeding season (June-August). This study revealed that arthropod prey abundance, female mass and population density of females showed significant spatial variation across the ten subpopulations. Additionally, prey abundance and foraging success, measured as the number of carcasses found in webs, were a strong determinant of female mass and population density within each subpopulation. To test the mechanisms that drive black widow infestations, I used ecological stoichiometry to examine the nutrient (nitrogen and phosphorus) composition of spiders and arthropod prey from urban habitat, desert habitat and a laboratory diet regime. These studies revealed that (1) spiders are more nutrient rich than cricket prey in the field, (2) spider subpopulations exhibit significant spatial variation in their nitrogen composition, (3) nutrient composition of urban spider subpopulations does not differ significantly from Sonoran desert subpopulations, (4) laboratory-reared spiders fed a diet of only laboratory-reared crickets are more nitrogen and phosphorus limited than field-captured spiders, and (5) cannibalism by laboratory-reared spiders alleviated phosphorus limitation, but not nitrogen limitation, when compared to field-captured spiders. This work highlights the need to examine the population ecology of species relationships, such as predator-prey dynamics, to fully understand the fecundity and population growth of urban pest species. Moreover, the integration of population ecology and stoichiometry illustrates the need to address mechanisms like nutrient limitation that may explain why urban pest populations thrive and native species diversity suffers following HIREC. / Dissertation/Thesis / M.S. Biology 2012

abstract: Urbanization provides an excellent opportunity to examine the effects of human-induced rapid environmental change (HIREC) on natural ecosystems. Certain species can dominate in urban habitats at the expense of biodiversity. Phenotypic plasticity may be the mechanism by which these 'urban exploiters' flourish in urban areas. Color displays and condition-dependent phenotypes are known to be highly plastic. However, conspicuous color displays are perplexing in that they can be costly to produce and may increase detection by enemies. The Western black widow spider () is a superabundant pest species that forms dense aggregations throughout metropolitan Phoenix, Arizona, USA. Adult female display a red hourglass on their abdomen, which is speculated to function as a conspicuous warning signal to enemies. Here, I performed field studies to identify how widow morphology and hourglass color differ between urban and desert subpopulations. I also conducted laboratory experiments to examine the dietary sensitivity of hourglass coloration and to identify its functional role in the contexts of agonism, mating, and predator defense. My field data reveal significant spatial variation across urban and desert subpopulations in ecology and color. Furthermore, hourglass coloration was significantly influenced by environmental factors unique to urban habitats. Desert spiders were found to be smaller and less colorful than urban spiders. Throughout, I observed a positive correlation between body condition and hourglass size. Laboratory diet manipulations empirically confirm the condition-dependence of hourglass size. Additionally, widows with extreme body conditions exhibited condition-dependent coloration. However, hourglass obstruction and enlargement did not produce any effects on the outcome of agonistic encounters, male courtship, or predator deterrence. This work offers important insights into the effects of urbanization on the ecology and coloration of a superabundant pest species. While the function of the hourglass remains undetermined, my findings characterize the black widow's hourglass as extremely plastic. Plastic responses to novel environmental conditions can modify the targets of natural selection and subsequently influence evolutionary outcomes. Therefore, assuming a heritable component to this plasticity, the response of hourglass plasticity to the abrupt environmental changes in urban habitats may result in the rapid evolution of this phenotype. / Dissertation/Thesis / M.S. Biology 2014

O Brasil é o maior produtor mundial de citros, com aproximadamente 455 milhões de caixas por ano. No país os principais problemas da cultura estão relacionados a fitopatologias e ataques de fitófagos, que diminuem a produtividade e afetam os preços do produto no mercado. Nesse contexto, o controle desses insetos se faz necessário para que sejam evitadas perdas econômicas e produtivas. Assim, as aranhas surgem como potenciais agentes de controle, devido à estratégia trófica que adotam, sendo completamente dependentes da predação, auxiliando na regulação de espécies-praga em cultivos comerciais. O presente trabalho teve como finalidade lançar mão da análise dos isótopos estáveis 13C e 15N, para determinar as principais fontes de carbono e nível trófico das principais famílias e grupos de aranhas presentes em cultivos de citros no município de Gavião Peixoto - SP. Foram coletados 4.832 indivíduos, distribuídos em 17 famílias, das quais 12 eram comuns às duas áreas estudadas; as famílias foram classificas em sete guildas funcionais. Através análise dos isótopos 13C e 15N foi possível determinar o percentual de carbono dos citros presente na alimentação das principais famílias e grupos amostrados, além do nível trófico médio. Os resultados indicaram que as famílias diferem na dependência de teias alimentares baseadas nos citros. Além disso, os dados coletados sugerem que a estrutura do ambiente, a arquitetura vegetal, o estado fenológico dos citros, as práticas de manejo e variações sazonais do clima, podem ter sido os principais fatores de variação na abundância das famílias e dependência do carbono dos citros por parte das aranhas. Salticidae e Theridiidae foram as principais famílias amostradas, por apresentarem maior abundância relativa e estarem presentes ao longo de todo o período de coletas. / Brazil is the world largest citrus producer, with about 455 million boxes per year. In the country the main problems faced by the planters are related to phytopathologies and phytophagous attacks that reduce productivity and can affect the prices of the product in the market. In this scenario, the control of phytophagous is necessary to avoid economic and productivity losses. Thus, spiders populations emerge as a potential control agent, due to the trophic strategy, completely dependent upon predation, therefore assisting in the regulation of pest species in the field. This study aimed to determine, through the analysis of 13C and 15N isotopes, the main sources of carbon and the trophic level of the most abundant families of spiders collected in two citrus orchards in the municipality of Gavião Peixoto - SP. 4832 spiders distributed among 17 families were collected, of which 12 were common to the two studied areas. The families were assembled into 7 functional guilds. By analyzing the isotopes 13C and 15N it was possible to measure the percentage of carbon coming from the citrus, present in tissues of the main spider families and groups sampled, plus the average trophic level. The results indicated that families differ in dependence on food webs based on citrus. Furthermore, the data allow to hypothesize that the structure of the environment, architecture of the vegetation, phenological state of the plants, management practices and seasonal variations of the weather, may have been the main factors of variation in the abundance of families and dependence on citrus food webs by the spiders. Salticidae and Theridiidae were the main sampled families, due to their larger relative abundance and presence throughout the sampling period.

Orientador: João Vasconcellos Neto / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-04T21:51:53Z (GMT). No. of bitstreams: 1 Romero_GustavoQuevedo_D.pdf: 5256133 bytes, checksum: 5c71ea8abd971f76045303bc89c57a3b (MD5) Previous issue date: 2005 / Resumo: O entendimento das interações entre artrópodes e plantas tem crescido consideravelmente nos últimos poucos anos. Embora as aranhas estejam entre os grupos de artrópodes mais abundantes e constituam as principais guildas de predadores sobre a vegetação, poucos estudos envolvendo aranhas e plantas foram desenvolvidos. Aqui, reportamos um conjunto de informações mostrando que algumas espécies de salticídeos são estritamente associadas com Bromeliaceae em várias fitofisionomias sul-americanas, incluindo cerrados, florestas semidecíduas e sazonais, vegetação de dunas costeiras, restingas, afloramentos rochosos, florestas de altitude, chacos e florestas ombrófilas densas, em várias localidades do Brasil, Paraguai, Bolívia e Argentina. Enquanto algumas espécies de aranhas foram especialistas, ocorrendo quase exclusivamente em uma única espécie de planta hospedeira (e.g., Psecas chapoda sobre Bromelia balansae), outras foram generalistas e habitaram até 7-8 espécies de bromélias. Geralmente, as aranhas habitaram e selecionaram as bromélias maiores e/ou aquelas com arquitetura natural (e.g., simulação de inflorescência ou inclusão de folhas secas no centro da roseta). Portanto, as aranhas podem avaliar, em detalhes finos, o estado físico dos seus microhabitats. Bromélias podem muitas vezes fornecer microhabitats apropriados específicos para salticídeos. Suas folhas formam uma arquitetura tridimensional complexa (roseta), que pode ser usada por adultos e imaturos como abrigo contra predadores ou condições climáticas severas, como sítios de forrageamento, acasalamento e de oviposição, e como berçários para as recém emergidas das ootecas. Em troca, as aranhas contribuíram para a nutrição das bromélias. Usando métodos isotópicos (15N), nós verificamos que P. chapoda contribuiu com até 40% do N total de B. balansae no campo. Entretanto, os efeitos benéficos das aranhas foram enfraquecidos onde estas ocorreram em baixa abundância, e a condicionalidade foi gerada pela variação especial na densidade de aranhas / Abstract: The understanding of the interactions between arthropods and plants has grown considerably in the last few years. Although the spiders are among the most abundant arthropod group and compose the main predator guild on vegetation, there exist very few studies involving spiders and plants. Here, we report information showing that some salticid species are strictly associated with the Bromeliaceae in several South American phytophysiognomies, including cerrados (savanna-like vegetation), semideciduous and seasonal forests, coastal sand dune vegetation, restingas, inselbergs, highland forests, chacos and rain forests in several localities of Brazil, Paraguay, Bolivia and Argentina. While some species are specialists, occurring almost exclusively on a single host plant species (e.g., Psecas chapoda on Bromelia balansae), others are generalists and inhabit up to 7-8 bromeliad species. Generally, the spiders inhabited the larger bromeliads and/or those with natural architecture (e.g., simulation of inflorescence or inclusion of dry leaves in the center of the rosette). Therefore, the spiders seem to evaluate, in fine detail, the physical state of their microhabitats. Bromeliads may often provide specifically suitable microhabitats for jumping spiders. Their leaves form a complex tri-dimensional architecture (rosette), which can be used by adults and immature as shelter against predators or harsh climatic conditions, as foraging, mating and laying egg sites, and as nursery for spiderlings. In exchange, the spiders contributed to bromeliad nutrition. By using stable isotope methods (15N), we found that P. chapoda contributed with up to 40% of the total nitrogen of B. balansae in the field. However, the beneficial effects of the spiders were weakened where they occurred in low abundance, and conditionality was generated by spatial variation in spider density / Doutorado / Ecologia / Doutor em Ecologia

A monofilia da subfamília Cteninae é testada com uma análise cladística usando o método da parcimônia. O resultado da análise demonstra que a subfamília é polifilética como atualmente delimitada. A monofilia de Cteninae requer a exclusão do gênero Celaetycheus e de cinco espécies de Ctenus, C. anahitiformis, C. bulimus, C. inazensis, C. miserabilis e C. tarsalis. A subfamília é composta por Ctenus, gênero que contém a espécie-tipo da família, e pelos gêneros Africactenus, Amauropelma, Anahita, Centroctenus, Isoctenus, Ohvida, Parabatinga, Petaloctenus, Phoneutria, Thoriosa, Trogloctenus e pelo menos mais sete linhagens independentes. A subfamília Cteninae pode ser reconhecida por uma sinapomorfia não-ambígua: campo mediano do epígino protuberante. O clado Cteninae também é sustentado por cinco sinapomorfias ambíguas: êmbolo fixo por membrana, apófise média em forma de copo, condutor hialino, mais largo que longo, quatro dentes na retromargem da quelícera e quelícera com dentículos intermarginais. Apenas duas sinapomorfias descritas acima estão presentes em todas as espécies de Cteninae usadas na análise: o setor mediano do epígino protuberante e a apófise média em forma de copo. O gênero Ctenus, com maior número de espécies da família (cerca de 240), aparece como um grupo polifilético como atualmente delimitado. A monofilia de Ctenus requer a exclusão de 22 espécies usadas nesta análise. As 12 espécies que permanecem em Ctenus sensu estrito formam um clado sustentado por duas sinapomorfias nãoambíguas: campo mediano do epígino com região da abertura de copula projetada e abertura de copulação como um lobo. Alguns padrões evolutivos observados na análise são discutidos. O gênero Celaetycheus Simon é revisado e transferido para a subfamília Calocteninae com base nos resultados da análise cladística de Cteninae. A espécie-tipo, Celaetycheus flavostriatus Simon, é redescrita e oito espécies novas são descritas, todas coletadas no Estado da Bahia, Brasil: Celaetycheus sp. 1 de Uruçuca e Barro Preto; Celaetycheus sp. 2 de Mascote, Pau Brasil, Jussari e Camacan; Celaetycheus sp. 3 de Coaraci, Itagibá e Jequié; Celaetycheus sp. 4 de Prado e Itamarajú; Celaetycheus sp. 5 de Salvador, Mata de São João, Cachoeira e Cruz das Almas; Celaetycheus sp. 6 de Porto Seguro; Celaetycheus sp. 7 de Ilhéus e Uruçuca; Celaetycheus sp. 8 de Camacan. A espécie Celaetycheus modestus Bryant é transferida para o gênero Ohvida Polotow & Brescovit. Um mapa de distribuição das espécies é fornecido. / A cladistic analysis using the parcimony method is used to test the monophyly of the subfamily Cteninae. The results of the analysis indicate that the subfamily is poliphiletic as currently delimited. The monophyly of Cteninae requires the exclusion of the genus Celaetycheus and five Ctenus species, C. anahitiformis, C. bulimus, C. inazensis, C. miserabilis and C. tarsalis. The subfamily is composed by Ctenus, the genus which contain the type species of the family, and by the genera Africactenus, Amauropelma, Anahita, Centroctenus, Isoctenus, Ohvida, Parabatinga, Petaloctenus, Phoneutria, Thoriosa, Trogloctenus and at least more seven independent lineages. The subfamily Cteninae can be recognized by one non-ambiguous synapomorphy: swollen median field of the epigynum. The Cteninae clade is also supported by five ambiguous synapomophies: embolus fixed by membranous area, cup-shaped median apophysis, hyaline conductor wider than long, four teeth in the chelicerae retromargin and chelicerae with intermarginal denticles. Only two of the synapomorphies described above are present in all Cteninae species used in the analysis: swollen median field of the epigynum and cup-shaped median apophysis. The genus Ctenus, with the high number of species of the family (about 240), appears as a poliphylec group as currently delimited. The monophyly of Ctenus requires the exclusion of 22 species used in this analysis. The 12 species which remain in Ctenus sensu strict form a clade supported by two non-ambiguous synapomorphies: median field of the epigynum with area of the copulatory opening projected and copulatory opening as a lobe. Some evolutive patterns observed in the analysis are discussed. The genus Celaetycheus Simon is revised and trasferred to the subfamily Calocteninae with basis on the new results of the cladistic analysis of Cteninae. The type species, Celaetycheus flavostriatus Simon is redescribed and eight new species are described, all collected in the State of Bahia, Brazil: Celaetycheus sp. 1 from Uruçuca and Barro Preto; Celaetycheus sp. 2 from Mascote, Pau Brasil, Jussari and Camacan; Celaetycheus sp. 3 from Coaraci, Itagibá and Jequié; Celaetycheus sp. 4 from Prado and Itamarajú; Celaetycheus sp. 5 from Salvador, Mata de São João, Cachoeira and Cruz das Almas; Celaetycheus sp. 6 from Porto Seguro; Celaetycheus sp. 7 from Ilhéus and Uruçuca; Celaetycheus sp. 8 from Camacan. The species Celaetycheus modestus Bryant is transferred to Ohvida Polotow & Brescovit. A distribution map is provided.

Submitted by Renata Lopes (renatasil82@gmail.com) on 2016-09-20T17:41:13Z No. of bitstreams: 1 renancastrosantana.pdf: 1526105 bytes, checksum: 6952badff2c85299fef2af6f59b8502e (MD5) / Approved for entry into archive by Diamantino Mayra (mayra.diamantino@ufjf.edu.br) on 2016-09-26T20:24:46Z (GMT) No. of bitstreams: 1 renancastrosantana.pdf: 1526105 bytes, checksum: 6952badff2c85299fef2af6f59b8502e (MD5) / Made available in DSpace on 2016-09-26T20:24:46Z (GMT). No. of bitstreams: 1 renancastrosantana.pdf: 1526105 bytes, checksum: 6952badff2c85299fef2af6f59b8502e (MD5) Previous issue date: 2010-01-26 / As aranhas constituem um grupo megadiverso, sendo o sétimo em riqueza, ultrapassado somente por cinco ordens de insetos e a ordem Acari. Sensíveis a variações abióticas e bióticas do ambiente são consideradas potenciais bioindicadoras. Predadoras generalistas exercem um papel importante na regulação de populações de artrópodes. Mesmo apresentando tamanha importância, a ordem Araneae está longe de ser totalmente conhecida, sendo estimadas mais de cem mil espécies no mundo. As regiões tropicais e subtropicais estão subamostradas, carecendo de pesquisadores na área. Influenciadas pela estratificação temporal e espacial, o grupo apresenta uma grande variedade de estratégias de captura de presas. A separação da comunidade de aranhas em guildas pode auxiliar no entendimento da dinâmica do ecossistema, sendo uma importante ferramenta para o estudo ecológico. Reconhecendo a importância da comunidade de aranhas de solo, esta dissertação objetivou caracterizar a araneofauna de solo, analisar as guildas presentes e as dominâncias das espécies encontradas, verificando a influência de fatores climáticos sobre esta fauna em uma floresta estacional semidecidual no interior do Bioma Cerrado. A área de estudo foi o Parque Ecológico Jatobá Centenário, um fragmento de 90 hectares, localizado no município de Morrinhos no estado de Goiás. O clima da região é Aw de acordo com a classificação de Koppen, caracterizado por duas estações, uma quente e úmida e outra fria e seca. As aranhas de solo foram amostradas quatro vezes durante um ano através da utilização de armadilhas de queda do tipo pitfall, cada uma delas permaneceu em campo por sete dias completos. Foram coletadas 4139 aranhas distribuídas em 35 famílias e 118 morfoespécies. Na estação chuvosa observou-se maior abundância, riqueza e diversidade em relação ao período seco. A umidade, temperatura e precipitação também apresentaram diferenças entre as duas estações amostradas. O cálculo da dominância revelou a presença de uma espécie eudominante e três dominantes, estas representando aproximadamente 40% do total de aranhas coletadas. A presença de poucas espécies dominantes e muitas raras é típica de comunidades tropicais. As famílias foram agrupadas em oito guildas, as mais representativas pertenceram às “caçadoras ativas de solo e vegetação” e as “tecelãs de solo e vegetação”. A abundância de indivíduos dentro das guildas foi diferente entre as duas estações, o período chuvoso apresentando maior quantidade de indivíduos. Os dados são expressivos observando que poucos estudos restritos a araneofauna de solo ultrapassam xi a quantidade de espécies e espécimes coletados. A ausência de relação das variáveis bióticas com as abióticas pode estar relacionada à comunidade ser sensível a fatores microclimáticos e/ou diferenças estruturais do ambiente, como quantidade de serapilheira, sombreamento e diversidade de presas. As guildas amostradas refletem a metodologia utilizada, observando que esta é seletiva para aranhas de solo, enquanto as guildas restritas ao ambiente arbóreo-arbustivo que foram amostradas podem ter sido coletadas de forma acidental e/ou em período de dispersão as quais podem utilizar o solo como substrato de acesso a outras plantas. / Spiders are a megadiverse group, the seventh most richness, surpassed only by five insect orders and Acari. They are considered good bioindicators due to their great sensibility to biotic and abiotic variations. As generalist predators they have an important whole in regulation of arthropod populations. Despite these facts the Araneae order is few known being expected more than ten thousand species in the world. The tropical and subtropical regions are bad sampled, main due to the lack of taxonomists. Due to temporal and spatial stratification, this group presents a great variety in prey capture strategies. The separation of the spider community in guilds can help to understand the ecosystem dynamic, being an important tool to ecological studies. Thus, due to the importance of soil spider community, this dissertation intended to establish a characterization of ground araneofauna, to analyse the present guilds and species dominance, studying the influence of climatic factors acting on this fauna in a semidecidual forest in the tropical savanna Cerrado. The study site was Parque Ecológico Jatobá Centenário, a fragment of 90 hectares, placed in the municipality of Morrinhos, Goiás state. The climate in the area is AW according to Koppen, presenting two typical seasons, one hot and moist and another dry and cold. Spiders were sampled four times through the year using pitfall traps, each one remained in the field for seven days. Were collected 4139 spiders, of 35 families and 118 species. In the rainy season was observed the higher abundance, richness and diversity. Temperature, humidity and rainfall presented differences between seasons. Dominance analysis showed the presence of one self-dominant and three dominant species, that represented 40% of the total sample. The presence of few dominant species and several rare is typical of tropical communities. The families were grouped in eight guilds, the more representative belonging to “ground and vegetation active hunters” and “ground and vegetation weavers”. The intra guild abundance of individuals was different between seasons, the rainy season presented higher abundance. The present data have significant importance considering that few others presented more species or individuals. The absence of relation between biotic and abiotic variables may be influenced by microclimate and structural differences in the environment, as for example the amount of litter, shadows and prey diversity. The sampled guilds were influenced by the xiii methods, directed to ground dwelling spiders, the species of shrub communities were accidentally sampled, probably captured when moving between plants or dispersing.

M.Sc. (Zoology) / Spiders of the genus Cyrtophora Simon, 1864 are commonly called tropical tent‒web spiders due to the unique shape of their webs. Forty three Cyrtophora species are known throughout the world and five of them have been recorded from Africa, but none formally from South Africa (SA). The only species of Cyrtophora so far suspected to occur in SA is the cosmopolitan species C. citricola (Forsskål, 1775). The South African Cyrtophora species show extensive morphologic variation, especially in colouration and abdominal characteristics. In SA they frequently make their webs in aloes and cycads and live solitary or in small to large aggregations. This social behaviour offers many advantages but also subjects the community to threats such as birds. A behavioural trait that is fairly uncommon in spiders, but is exhibited by Cyrtophora, is that the webs are only repaired when small holes, due to prey capture, are made; new webs are only built above the old webs in cases where extensive damage occurs. Morphologically, sexual dimorphism is prevalent, and juveniles vary greatly from adults. This causes several problems for traditional taxonomy. Both males and females have the ability to alter the degree of colour in the abdomen in response to the environment. This is usually a defence mechanism and is used for camouflage. DNA barcoding of the mitochondrial cytochrome c oxidase 1 (CO1) gene was done on fresh and museum specimens sampled from 2006‒2011. Barcoding of the nuclear histone H3 gene was done on some of the male and female specimens for use as a comparison. Analysis was done using the SPIDER programme. Morphological analysis of the genitalia was used to compare the species determined by the genetic results. Abdomen traits were observed to determine morphologic variation between and within species. General behaviour was recorded through observation of a study site and photographs previously taken around SA, noting specifically reproduction, prey capture, colour change and other general behavioural characteristics. Ecological patterns such as seasonality (phenology) and distribution patterns were recorded using collection data from museum and freshly collected specimens. Genetic results of the H3 gene indicate three species whereas the CO1 gene indicates 10 species. Both genes were concordant regarding two species, one of which was a specimen from Madagascar (and as this is a study on South African species was therefore not included in morphological analysis). A combined analysis of both gene datasets indicated three species. However, the CO1 gene had strong support but the H3 gene had poor resolution. For this reason the H3 gene was not recommended for analysis of Cyrtophora. Morphologically, the specimens showed diverse abdominal variation but genitalia assessment determined the presence of only two species. The two species indicated by genetics and morphology combined were C. citricola and an unidentified species from Malelane, Mpumalanga. In conclusion, it is evident that C. citricola is not the only species under this genus in SA. Even though morphology indicates only two species, the CO1 gene indicates a minimum of eight species, possibly 10. Comprehensive morphological and ecological study could show characteristics that correspond with the genetic results. This information will help to aid future biodiversity assessments and conservation programmes. The behavioural information obtained may also help initiatives such as the South African National Survey of Arachnida (SANSA) and red list authorities. The effectiveness of the CO1 gene for identification of this species will also help initiatives

To determine whether the spider communities in spruce Picea abies plantations in southern Sweden differ between trees of various ages, the spiders from minor, young and older trees has been collected during May and June 2016. The minor trees were 1.5–2.0 m, the young trees were 19–20 m and the older trees were over 22 m high. The spiders were collected from five plantations of each age category and from ten trees in each plantation. The spiders from ten of the dead branches inside of each older plantation were collected as well. 59 different species were found and all together 970 spider specimens were collected. The results showed many different things, for example that the species on the dead branches were mainly web spiders and that many of the species on the minor trees prefer the field layer as habitat. My study was compared to three other spider studies, one from Sweden, one from the Czech Republic and one from Norway. The comparison showed differences in the collected spider species which could be explained by the various methods used in the different studies and whether the spiders in the study had been collected during early summer or throughout the whole season. The spiders collected in this study could in the future be used to detect changes in the spider fauna caused by climate change.

O veneno produzido pela aranha Phoneutria nigriventer causa priapismo. O pré-tratamento de camundongos com inibidores da Óxido nítrico-sintase, antes de se injetar a toxina, inibe este priapismo. A toxina causa ativação do gene c-fos no núcleo paraventricular do hipotálamo (NPV). Este estudo tem como objetivo ampliar os conhecimentos relacionados ao mecanismo da ereção peniana causada pela toxina Tx2-6. A toxina foi injetada no NPV e os resultados não mostraram o envolvimento direto do mesmo com o priapismo. Procuramos então avaliar se há aumento na produção de óxido nítrico (NO) quando o tecido é submetido à TX2-6 e o resultado foi negativo. Foram feitos também experimentos com animais que sofreram ablação cirúrgica bilateral dos nervos cavernosos. Estes, quando injetados com a toxina, tiveram ereção peniana, porém não apresentaram exposição total do pênis, possivelmente devido à fibrose causada pela denervação. Estes resultados nos levam a crer que a ereção causada pela toxina Tx2-6 pode não ser mediada pela produção de NO e não depende da inervação peniana. / The venom produced by Phoneutria nigriventer spider causes priapism. Mice pretreatment with Nitric oxide-synthase inhibitors, before injecting the toxin, inhibits the priapism. The toxin causes c-fos gene activation in paraventricular nucleus of hypothalamus (PVN). This study aims to widen some knowledge concerning penile erection mechanism caused by Tx2-6 toxin. The toxin was injected in the PVN and the results didnt show its direct relation with the priapism. We analyzed if there is any increase of nitric oxide (NO) production when the tissue is submitted to TX2-6 and the result was negative. Experiments were carried out on mice which suffered bilateral surgical ablation of the cavernosum nerves. When these animals were injected with the Tx2-6 toxin, there was penile erection. However, the erection of the denervation group didnt present total penis exposition possibly due to the fibrosis caused by the denervation. These results reveal that erection caused by Tx2-6 toxin might not be mediated by NO production and it does not depend on penile nerves.

O gênero Plesiopelma Pocock, 1901 é revisado taxonomicamente e realizada análise cladística de suas espécies. A matriz com 30 táxons terminais e 49 caracteres foi analisada com dois programas para reconstrução filogenética, considerando tanto caracteres aditivos como não-aditivos. As quatro análises apresentaram diferenças na topologia, porém três delas demonstram que Plesiopelma é um gênero monofilético. A diagnose e a distribuição geográfica das espécies são apresentadas. São consideradas válidas as espécies P. flavohirtum (Simon, 1889), P. semiaurantiacum (Simon, 1897),P. myodes Pocock, 1901, P. insulare (Mello-Leitão, 1923), P. physopus (Mello-Leitão, 1926), P. minense (Mello-Leitão, 1943) e P. simoni (Soares e Camargo, 1948). É proposta a sinonímia de P. rectimanum (Mello-Leitão, 1923) e P. longisternale (Schiapelli e Gerschman, 1942) com P. myodes. São reconhecidas seis espécies novas para o Brasil. É proposta a transferência de P. imperatrix Piza, 1976 para o gênero Megaphobema Pocock, 1901 e P. gertschi (Caporiacco, 1955) é considerada Incertae sedis. / The genus Plesiopelma Pocock, 1901 is taxonomically revised and a cladistic analysis of its species is done. The matrix with 30 terminal taxa and 49 characters was analysed with two programs for phylogenetic reconstruction. The four analyses showed different topologies on the internal group, however, three of them show Plesiopelma being a monophyletic genus. The diagnoses and geographic distribution of all species are presented. It is herein considered valid the species P. flavohirtum (Simon, 1889), P. semiaurantiacum (Simon, 1897), P. myodes Pocock, 1901, P. insulare (Mello-Leitão, 1923), P. physopus (Mello-Leitão, 1926), P. minense (Mello-Leitão, 1943) and P. simoni (Soares e Camargo, 1948). The species P. rectimanum (Mello-Leitão, 1923) and P. longisternale (Schiapelli & Gerschman, 1942) are considered junior-synonyms of P. myodes. It is recognized six new species from Brazil. It is proposed the transfer of P. imperatrix Piza, 1976 to Megaphobema Pocock, 1901 and P. gertschi (Caporiacco, 1955) is considered Incertae sedis.