Aranhas de solo (Arachnida; Araneae) em um agroecossistema (Parnaíba, PI, Brasil).

Visando analisar as alterações na composição e diversidade da comunidade de aranhas na fase de implantação de um sistema agroecológico e o papel de corredores ecológicos, foram realizados dois inventários no ambiente, localizado no município de Parnaíba (PI), nos meses de maio e junho de 2008. Foram coletadas 241 aranhas de solo distribuídas em 11 famílias e oito nichos tróficos. A área controle e o corredor ecológico apresentaram a maior diversidade de aranhas de solo (H?=1,89 e 2,09, respectivamente), sendo registrada perda da diversidade de aranhas na área aberta do sistema (H?=1,75), relacionada à retirada da vegetação e conseqüente alteração da estrutura ambiental. Os dados sugerem que os corredores têm papel importante no sistema por fornecer hábitats propícios para as espécies sensíveis às mudanças inerentes ao estabelecimento e manejo dos agroecossistemas.Edição dos anais do 6º Congresso Brasileiro de Agroecologia; 2º Congresso Latinoamericano de Agroecologia, Curitiba, nov. 2009

Flutuação populacional de aranhas na cultura da canola, em Passo Fundo, Rio Grande do Sul, Brasil.

Resumo: A cultura da canola apresenta grande diversidade de insetos-praga, mas também diversos grupos de inimigos naturais que contribuem para o controle biológico desses insetos. Dentre estes destacam-se joaninhas (Coccinellidae), percevejos (Pentatomidae), além das aranhas (Araneae), embora estas, até o presente estudo, ainda não tenham sido inventaridas. Estudos que abordem a dinâmica de aranhas na cultura da canola são escassos no Brasil. O objetivo deste trabalho foi estudar a flutuação populacional de aranhas nessa cultura em uma área no estado do Rio Grande do Sul. O estudo foi conduzido na área experimental da Embrapa Trigo, Passo Fundo/RS, que foi cultivada com canola, Brassica napus, híbrido Hyola 433, numa área de 800 m2, em cada um dos três anos de realização da pesquisa (2015 a 2017). As coletas das aranhas foram realizadas com armadilhas-de-solo, do tipo ?pitfall trap? e rede entomológica. Variáveis climatológicas foram obtidas a partir de Estação Meteorológica localizada na Embrapa Trigo. Entre os anos de 2015 a 2017, foram coletadas 754 aranhas, 336 adultos e 418 imaturos, pertencentes a 16 famílias. As famílias mais abundantes, considerando jovens e adultos, foram Araneidae (25,33%), Thomisidae (21,75%) e Linyphiidae (14,59%). No presente estudo, 21 espécies foram identificadas, sendo Misumenops pallidus a mais abundante, e as espécies Eustala fuscovittata, Lobizon humilis e Anelosimus rupunini registradas pela primeira vez para o estado do Rio Grande do Sul. Houve uma tendência de aumento populacional das aranhas à medida que também houve uma tendência no aumento da temperatura, entre os meses de junho e dezembro. Abstract: Canola crop has a great diversity of insect pests, but also several groups of natural enemies that contribute to the biological control of these insects. Ladybugs (Coccinelidae) and stink bugs (Pentatomidae) stand out among these groups, as well as spiders (Araneae) which have not been listed until this study. Studies concerning the dynamics of spiders in canola crop are scarce in Brazil. This work aimed to carry out the population dynamics of these arachnids in canola crop in an area in the state of Rio Grande do Sul (RS). The study was conducted in the experimental area of Embrapa Trigo, in the city of Passo Fundo/RS, which was cultivated with canola, Brassica napus, Hyola 433 hybrid, in an area of 800 m2, during three years of research (2015 to 2017). The spiders were collected using pitfall traps and entomological nets. Climate variables were obtained from the Weather Station located at Embrapa Trigo. A total of 754 spiders were collected from 2015 to 2017, of which 336 adults and 418 immatures, belonging to 16 families. The most abundant families, considering juveniles and adults, were Araneidae (25.33%), Thomisidae (21.75%) and Linyphiidae (14.59%). A total of 21 species were identified in the present study, with Misumenops pallidus being the most abundant, and the species Eustala fuscovittata, Lobizon humilis and Anelosimus rupunini recorded for the first time for the state of Rio Grande do Sul. There was a tendency for spider populations to increase, as there was also a trend in temperature increase between the months of June and December

Aranhas (Arachnida; Araneae) em horta agroecológica no município de Parnaíba, Piauí, Brasil, e considerações sobre o seu papel como inimigos naturais e indicadores da qualidade ambiental.

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Spider assemblage (Arachnida: Araneae) associated with canopies of Vochysia divergens (Vochysiaceae) in the northern region of the Brazilian Pantanal

ABSTRACT This study describes the composition and temporal variation of the spider assemblage (Arachnida: Araneae) associated with canopies of Vochysia divergens Pohl. (Vochysiaceae) in the northern region of the Brazilian Pantanal. Three V. divergens plants were sampled in 2004, at each seasonal period of the northern Pantanal (high water, receding water, dry season and rising water), using thermonebulization of the canopies with insecticide, totaling 396 m2 of sampled canopies. Analysis of abundance and richness of spider families were based on Non-Metric Multidimensional Scaling (NMDS) and Variance Analysis (ANOVA and MANOVA). A total of 7,193 spiders were collected (6,330 immatures; 88.0%; 863 adults, 12.0%) distributed in 30 families. Araneidae (1,676 individuals), Anyphaenidae (1,631 individuals), Salticidae (1,542 individuals) and Pisauridae (906 individuals), were predominant, representing 80.0% of the sample. Ten different guilds were registered: aerial hunters, orb-weavers, nocturnal aerial runners and diurnal space web weavers dominated, sharing most ecological niches. The spider assemblage is affected by changes in the habitat structure, especially by the seasonal hydrological regime and variations in the phenology of V. divergens . The assemblage is composed of different groups of spiders. The dominant taxa and behavioral guilds differ in the different seasonal periods. Spiders were more abundant during the dry and rising water seasons, most likely reflecting a greater supply of potential prey, associated with new foliage and flowering at the canopy. The displacement of soil dwelling spiders to the trunks and canopies before and during the seasonal floods can change the structure and composition of the canopy assemblages. Oonopidae, Gnaphosidae and Caponiidae, were more frequent during the rising and high water seasons, which indicates that these taxa use the canopies of V. divergens as a refuge during the seasonal flooding in the Pantanal

Speciation without changes in genital shape: a case study on Brazilian pholcid spiders (Araneae: Pholcidae

Abstract Speciation in arthropods is usually coupled with marked changes in genital morphology, which explains the usefulness of genitalia in distinguishing closely related species. The present paper describes specimens that are assigned to separate species based on extreme size differences and colour pattern differences, but the shape of the genitalia is essentially identical. We argue that such cryptic species may be more common than currently assumed, but if marked morphological (non-genital) differences are missing, traditional taxonomic methodology is biased against discovering them. The two new species from the Brazilian Atlantic Forest are tentatively assigned to the genus Psilochorus: Psilochorus itaguyrussu n. sp. and Psilochorus ybytyriguara n. sp

The smallest spider of Uloboridae, a new species of Conifaber opell, 1982 (Arachnida: Araneae) from Brazil

A new species, Conifaber manicoba n. sp., is described based on a female from the state of Pará, Brazil. It is characterized as being the smallest uloborid female and by having the thoracic region posteriorly depressed. © TÜBİTAK

Seasonal and vertical distribution of Araneae in an area with predominance of Attalea phalerata MART. (Arecaceae), in the Pantanal of Poconé, Mato Grosso, Brazil

This study was carried out in an "acuri" formation, an area with predominance of Attalea phalerata MART. (Arecaceae), located at the Retiro Novo farm, Pantanal of Mato Grosso. This was done in order to analyze the temporal and spatial distribution of spiders and the species composition, structure and distribution of the litter/soil-dwelling spider community, and to evaluate the influence the flood pulse renders on it. The results are compared with data on canopy spider communities, obtained by canopy fogging. The sampling was done using "WINKLER" extractors during the four extreme abiotic periods in the northern Pantanal: low-water (terrestrial phase), high-water (aquatic phase), dry season (with no rain) and rainy season. During each of the four periods 10 quadratic plots of 1 m2 each were selected for sampling, first litter and then the uppermost 5 cm soil layer, totaling 40 m2 sampled area. Altogether, 343 individuals of spiders (8.6 ± 1.1 ind./m2) from 16 families were obtained. Zodariidae (182 ind.; 53.1 % of the total catch) and Oonopidae (62 ind.; 18.1 %) were most abundant. Ten guilds were differentiated, separated in hunters and weavers, with predominance of nocturnal soil runners. Many different groups of spiders appeared to share the same habitat. Seasonality was strongly marked with highest abundance during low-water (138 ind.; 40.2 % of the total catch) and low abundance during high-water (26 ind.; 7.6 %). Comparing these results with canopy fogging data revealed distinct stratification of the spider fauna. From a total of 24 families obtained from both canopy and litter/soil, only 11 were shared between both habitats. Best sampling success in both investigated habitats was during periods of low humidity