142 research outputs found
A structured inventory of spiders (Arachnida, Araneae) in natural and artificial forest gaps at Porto Urucu, Western Brazilian Amazonia
Flutuação populacional de aranhas na cultura da soja, em Passo Fundo, Rio Grande do Sul, Brasil.
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.
bitstream/CPAMN-2009-09/21620/1/CircularTec43.pd
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
Predatoroonops.
68 p. : ill., maps ; 26 cm.The new endemic goblin spider genus Predatoroonops is erected for 17 new soft-bodied oonopid species from Brazil: Predatoroonops schwarzeneggeri, sp. nov., is the type species of the genus, P. poncho, sp. nov., P. billy, sp. nov., P. valverde, sp. nov., P. blain, sp. nov., P. maceliot, sp. nov., P. anna, sp. nov., P. rickhawkins, sp. nov., P. dutch, sp. nov., P. dillon, sp. nov., P. vallarta, sp. nov., P. phillips, sp. nov., P. yautja, sp. nov., P. peterharlli, sp. nov., P. mctiernani, sp. nov., P. chicano, sp. nov., and P. olddemon, sp. nov. Males of this new genus are easily diagnosed and separated from other Oonopinae genera by the extremely modified male chelicerae that frontally have median furrows and accentuated projections. The females can be recognized by the genitalia, which have a conspicuous posterior receptaculum, usually exposed between the epigastric folds. An auxiliary character for both sexes could be the presence of very long pairs of ventral spines with pronounced bases on the legs I and II tibiae and metatarsi. The genus is considered endemic and the species are recorded mainly from the Brazilian Atlantic Forest. An identification key is provided for all Predatoroonops species known to date
Guaraguaoonops.
13 p. : ill., map ; 26 cm.A new endemic goblin spider genus Guaraguaoonops is erected to include two new soft-bodied oonopid species from Brazil: the type species, G. hemhem, distributed in the states of Maranhão, Piauí, and Ceará, and G. humbom, known only from Piauí. These spiders are unique among oonopids and easily diagnosed by the flattened carapace with a porrect clypeus, modified lateral setae on the carapace in both sexes, and male with a sinuous, flattened distal cheliceral projection and palp with ventral conical tegular projection. These species probably occupy a soil cryptic habit and are found in dry sand of "cerrado" areas in northeastern Brazil
Goblin spider genus Neoxyphinus.
75 p. : ill., maps ; 26 cm.The Neotropical spider genus Neoxyphinus Birabén, 1953, is revised, comprising 10 species found from the West Indies to northern Argentina. The genus is characterized by a unique combination of characters, which include the presence of a set of low tubercles or large spikes on the posterior surface of carapace; male endites with an apical, retrolateral excavation bearing a subapical toothlike apophysis; palpal bulb strongly inflated; embolus compact, S-shaped, with large, round ejaculatory opening; epigynal atrium large, with angular lateral corners. The large, round ejaculatory duct may be a synapomorphy of the genus. The genus Hawkeswoodoonops Makhan and Ezzatpanah, 2011, is synonymized with Neoxyphinus and the two species included in that genus are considered as nomina dubia. The monotypic genus Decuana Dumitrescu and Georgescu, 1987, is also synonymized with Neoxyphinus and its type species, D. hispida Dumitrescu and Georgescu, 1987, is transferred to the genus and redescribed. Confirming a hypothesis raised in the literature, Dysderina termitophila Bristowe, 1938, is transferred to Neoxyphinus and recognized as the senior synonym of the type species N. ogloblini Birabén, 1953. Two other species are transferred from Dysderina to Neoxyphinus: D. keyserlingi Simon, 1907, here recognized as the senior synonym of D. rugosa Bristowe, 1938, and D. furtiva Chickering, 1968, of which the male is described for the first time. In addition to the redescription of N. termitophilus, n. comb., N. hispidus, n. comb., N. xyphinoides (Chamberlin and Ivie, 1942), N. keyserlingi, n. comb., and N. furtivus, n. comb., five new species are described: N. petrogoblin Abrahim and Ott, from the Amazon basin in Brazil, Colombia, Ecuador, and Peru; N. gregoblin Abrahim and Santos, from Venezuela; N. axe Abrahim and Brescovit, from Bahia, Brazil; N. boibumba Abrahim and Rheims, from Pará, Brazil; and N. barreirosi Abrahim and Bonaldo, from Brazil, Colombia, Guyana, and Venezuela. With the exception of N. boibumba, known only from males, all new species are described from both sexes
First records of millipedes (Myriapoda, Diplopoda) associated to cultivation of Canola Brassica spp. (Brassicaceae) in Brazil.
Abstract: Millipedes are known by their importance in ecological systems, although some species are regarded as agricultural pests in some poly- or monocultures. Canola (Brassicaceae: Brassica spp.) is an important feedstock for biodiesel production and a potential ingredient in the food industry, but with several arthropod pests causing damage to its cultivation. In this perspective, this study reports the still unknown relation of millipedes with cultivation of canola. Pitfall traps were plotted in cultivation of Brassica napus L. var. oleifera in Passo Fundo, Rio Grande do Sul state, Brazil, and checked weekly during the years of 2015 and 2016. A total of 66 individuals were captured in 2015 and 41 individuals in 2016, all belonging to the families Chelodesmidae and Paradoxosomatidae (Polydesmida). The most abundant species sampled in both years was Brasilodesmus austrocrucis Hoffman, 1981, with 100 specimens in total. Catharosomatini sp. was recorded with 4 specimens, Brasilodesmus triseriatus (Attems, 1931) with 2 specimens, and Oncoleptodesmus uniconus (Attems, 1931) with only one specimen. In the present study, the sampled species were not reported causing any damage to crops, suggesting that millipedes may not be considered pests in canola
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