Spiders Used as Prey by the Hunting Wasp Trypoxylon (Trypargilum) agamemnon Richards (Hymenoptera: Crabronidae)

摘要

The purpose of this study was to monitor the spider fauna in Trypoxylon agamemnon nests. The study was carried out from Dec. 2001 to Dec. 2006 in the Parque Municipal das Araucarias, in the municipality of Guarapuava, state of Parana, southern Brazil. Nests of T. agamemnon were obtained using trap-nests made of wooden blocks. To investigate the similarity between spider species in T. agamemnon's diet, spiders species were grouped according to their abundances, using the Bray-Curtis coefficient as a metric method and the unweighted pair group method average (UPGMA) as the clustering method. Spider species dominance was calculated, and Chi-square tests were used to test the null hypothesis that there was no significant difference among the proportions of collected juvenile, male, and female spiders. In contrast to what was recorded for other species of spider-hunting wasps, T. agamemnon exclusively captures spiders (of the Anyphaenidae) that forage on the vegetation. This probably maintains niche partitioning between Trypoxylon species that occur in the Parque Municipal das Araucarias, reducing competition for prey resources.