Efeito do forrageamento de formigas de correição (Hym; Formicidae-Ecitonini) sobre artrópodos, especialmente sobre a comunidade de aranhas (Araneae) em uma floresta tropical de terra firme na Amazônia Central

Abstract

This study, investigated the effect of the predation ot two generalist army-ant species ( E c i t o n b u r c h e l l i e Labidus praedator on spider community and others arthopods, a terra firme rainforest, central Amazon. Spiders were sampled using pitfall traps, line transects and extraction of litter samples with a Kempson apparatus. They were identified as belonging to 26 families, especially Ochyroceratidae, Salticidae, Ctenidae and Araneidae. E c i t o n b u r c h e l l i showed a density of 0.021 colonies/ha, feeding on 20 arthropod orders. However, relative abundance of prey fraqments showed that only four arthropod groups made up 89% of the prey (Blattodea 26,5%; Hymenoptera-Formicidae 23,7%; Orthoptera 12, 9%; Araneae 12, 8%) . Ten spider families were eaten, but E. b u r c h e l l i hunted principally on spiders of the Ctenidae family (84% genus Ctenus) . The prey spiders showed an average prosoma length of 4,80 mm. It was estimated that colonies of E. b u r c h e l l i caught 40% of the Ctenus spiders inhabiting the area in which they foraged. Labidus praedator ate 20 arthropod orders, especially Blattodea 31%, Araneae 17%, Chilopoda 5,5%, Lepidoptera 4,3%r Uropygi 3,5%, Hymenoptera-Formicidae 3,0%, Orthoptera and Scorpiones 2,7% and Dermaptera 2,3%. Labidus preyed on 18 spider families. Ctenidae again suffered most predation. The average prosoma length of the prey was 2,51 mm. The results suggest that repeated hunting by these two army ant species in the same area can have a substantial impact on ground-living spider assemblages.