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Orb‐web spiders (Araneae: Araneomorphae; Orbiculariae) captured by hunting‐wasps (Hymenoptera: Sphecidae) in an area of Atlantic Forest in south‐eastern Brazil

2005; Taylor & Francis; Volume: 39; Issue: 31 Linguagem: Inglês

10.1080/00222930500183520

1464-5262

Marcelo O. Gonzaga, João Vasconcellos‐Neto,

Fossil Insects in Amber

Abstract Members of two hunting‐wasp families, Pompilidae and Sphecidae, are among the major predators of orb‐web spiders. In this study, we collected paralysed spiders from natural nests and trap‐nests provisioned by sphecids in an area of Brazilian Atlantic Forest, and compared these data with the composition of species collected by visual searching during one year. Prey preferences were analysed based on the relative abundance of spider species, their size and web characteristics. We also compiled a list of orb‐weavers captured by four sphecid genera reported in 40 other studies. A large number of prey was obtained from natural nests of Trypoxylon (Trypargilum) albonigrum in Parque Estadual Intervales, especially species of Eustala, Parawixia, and Araneus (Araneidae). Other prey, stored in trap‐nests by T. lactitarse and unidentified hunting‐wasp species, included Nephila (Tetragnathidae), Parawixia, Ocrepeira, Mecynogea, Acacesia (Araneidae), and other spider species that were less abundant. All the species that were heavily preyed upon had a relatively lower abundance in our samples of prey availability. The range of body sizes of spiders captured by Trypoxylon in our study area include the size of some abundant orb‐weavers always absent in their nests. These results indicate that factors other than abundance in the field and the spider's size influence prey selection or susceptibility to attack. Keywords: Orb‐web spiderspredationSphecidaetrap‐nestsTrypoxylon Acknowledgements We are especially grateful to Adalberto J. Santos for his assistance during the identification of the spiders, and Sérvio Túlio P. Amarante for identifying Trypoxylon (Trypargilum) albonigrum and Trypoxylon (Trypargilum) lactitarse. We also thank Glauco Machado, Paulo S. Oliveira, Hilton F. Japyassú, and Andrea L. T. Souza for comments on the manuscript, and Fundação Florestal do Estado de São Paulo and IBAMA for allowing our studies in Parque Estadual Intervales. This study was financially supported by FAPESP (Proc. 99/06089‐4 to M.O.G.) and CNPq (Proc. 300539/94‐0 to J.V.N.), and is part of BIOTA/FAPESP—The Biodiversity Virtual Institute Programme (www.biotasp.org.br, Proc. 99/05446‐8).