Spiders of a young plantation of eucalypt: diversity and potential predator of the most frequent arboreal species

Aranhas de um plantio comercial jovem de eucaliptos: diversidade e potencial predador das espécies arbóreas mais freqüentes. Este estudo foi conduzido em áreas de plantio comercial jovem de Eucalyptus grandis, em Botucatu (São Paulo), Brasil, com o objetivo de estimar a composição e diversidade da fauna de aranhas associadas às árvores e serapilheira. Ao longo de 3 km de transecção foram aplicadas as técnicas da bandeja entomológica, captura manual e armadilha-de-solo tipo alçapão no interior e borda do cultivo. Foram obtidos 944 indivíduos de Araneomorphae pertencentes a 17 famílias e 51 espécies dos quais 87,3 % habitantes da copa das árvores. A assembléia destes predadores potencialmente tem impacto sobre as pragas arbóreas mais proeminentes. Abstract This study was carried out in area of young commercial Eucalyptus grandis plantation (Botucatu, São Paulo, Brazil) for the evaluation of the spider fauna composition inhabiting their trees and litter. Entomological trays, hand captures and pitfall traps were applied within and on the edges of the plantation along a 3-kilometer transeccion. A total of 944 Araneomorphae individuals belonging to 17 families and 51 species were collected, whereas 87.3% inhabiting the trees. This predator assemblage is has potential to impact against the most prominent arboreal pests. Résumé Araignées d’une jeûne plantation commerciale d’eucaliptus: diversité et prédation en potentiel des espèces arboricoles les plus frèquentes. Cette étude a été réalisée dans des aires d’une jeûne plantation commerciale d’Eucalyptus grandis, à Botucatu, État de São Paulo-Brésil, ayant comme objectif d’estimer la composition et la diversité des araignées associées aux arbres et à la litière. Sur une étendue de 3 km, les techniques de plateaux entomologiques, de captures manuelles et de trappes enterrées, ont èté employées pour les èchantillonnáges, à l’intérieur et sur le bord de la plantation. Un total de 944 individus de Araneomorphae appartenant à 17 familles et à 51 espèces a été recueilli, dont 87,3% étaient des résidants de cime d’arbres. Les peuplements de ces prédateurs en potentiel causent impacto sur leurs proies arboricoles les plus proéminantes

Predatory Behavior of Canthon virens

We present a detailed description of the predatory behavior of the beetle Canthon virens Mannerheim, 1829, on the leafcutter ant Atta sp. We observed 51 acts of predation, which were also recorded on film and subjected to behavioral analysis. Canthon virens exhibited 28 behaviors while predating upon Atta sp. queens. Adult beetles search for queens while flying in a zigzag pattern, 15 to 20 cm above the ground. After catching a queen, the predator stands on its back and starts cutting the queen cervix. Once the prey is decapitated, the predator rolls it until an insurmountable obstacle is reached. The distance from the site of predation to the obstacle can vary widely and is unpredictable. The beetle rolling the queen also buries it in a very peculiar way: first, it digs a small hole and pulls the queen inside, while another beetle is attached to the prey. The burial process takes many hours (up to 12) and may depend on the hardness of the soil and the presence of obstacles. In general, one or two beetles are found in a chamber with the queen after it is buried. They make the brood balls, which serve as food for the offspring. This study contributes to the knowledge of the predatory behavior of Canthon virens, a predator poorly studied in Brazil and widespread in the country

Comunidades de aranhas (Araneae) em cultivos de seringueira (Hevea brasiliensis Muell. Arg.) no Estado de S\ue3o Paulo

The spider fauna composition of three rubber tree commercial plantations in the Northwest part of São Paulo State, Brazil, was characterized for both canopy and litter strata. on seven occasions from April 2000 to October 2001, samples were taken by beating sheet and hand capture, resulting in a total of 946 individuals, belonging to 24 families and 119 species. The most common species were Italaman santamaria Brescovit, 1997 and Teudis sp. (Anyphaenidae), Castianeira sp. and Falconina aff. gracilis (Corinnidae), Paracleocnemis sp. (Philodromidae), Ibotyporanga naideae Mello-Leitão, 1944 (Pholcidae), Chira spinipes (Taczanowiski, 1871) and Rudra sp. (Salticidae), Achaearanea hirta (Taczanowiski, 1873) and Coleosoma floridanum (Banks, 1900) (Theridiidae) and Goeldia sp. (Titanoecidae). Anyphaenidae, Theridiidae and Salticidae were the most abundant families in the canopy, while Pholcidae and Corinnidae in the litter. Spider abundance was found to be, in general, positively correlated to the litter volume and density of branches in the trees. The use of acaricides and insecticides for one plantation resulted in a decrease in spider abundance for both strata. Abundance values among the samples suggest that the canopy spider abundance decreases with the loss of leaves in the dry season. Simultaneously, litter spider abundance increased in this season, because of the increase in litter volume. The most active canopy spiders, like runners and stalkers, should be investigated for their potential as pest control agents.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP

Distribution and importance of spiders inhabiting a Brazilian sugar cane plantation

The spider fauna (Araneae) of a sugar eane plantation was surveyed monthly by hand colteetion and beating vegetation in sugar cane fields across Botucatu, State of São Paulo, Brazil. Composition and rchness (family and species where identifieation to species was possible) microhabitat preferenees were reeorded, and diversity and evenness indices were calculated. A total of 1291 spiders belonging to 73 species and 20 families were collected. The most diverse families were Theridiidae, Salticidae, and Araneidae, and the most abundant ones were Theridiidae, Saltieidae, Anyphaenidae, and Araneidae, Seven species represented 58.6% of the total fauna, with Crysso pulcherrima (Mello-Leitão,1917) (Theridiidae) composing 28.2%. About 65% of the spiders occupied the upper part of the plants (above 20 cm). Five spider species were present in the sugar cane throughout crop development. Evidence of spiders feeding on sugar cane pest species was observed

Núcleos de Ensino da Unesp: artigos 2007

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq