RESUMO
The aim of this study was to analyze: i) the spider community in vegetative and reproductive branches of Psychotria carthagenensis concerning relative abundance, guild composition and body size distribution; ii) ant abundance in different types of branches and iii) the spider behavior when experimentally put in contact with inflorescences covered with ants. There was no difference between vegetative and reproductive branches in relation to spider abundance, composition of guilds and body size distribution of spiders. However, there was a significant difference in ant abundance. In the behavioral experiment, 90% of the spiders were expelled from inflorescences by ants; in control treatment, 100% remained in the inflorescences. The ant density in different parts of the plant may explain the spider distribution.
Assuntos
Formigas/fisiologia , Psychotria/fisiologia , Aranhas/fisiologia , Animais , Interações Hospedeiro-Parasita , Densidade DemográficaRESUMO
The aim of this study was to analyze: i) the spider community in vegetative and reproductive branches of Psychotria carthagenensis concerning relative abundance, guild composition and body size distribution; ii) ant abundance in diferent types of branches and iii) the spider behavior when experimentally put in contact with inflorescences covered with ants. There was no difference between vegetative and reproductive branches in relation to spider abundance, composition of guilds and body size distribution of spiders. However, there was a significant difference in ant abundance. In the behavioral experiment, 90 percent of the spiders were expelled from inflorescences by ants; in control treatment, 100 percent remained in the inflorescences. The ant density in different parts of the plant may explain the spider distribution.
Aranhas associadas à Psychotria carthagenensis Jacq. (Rubiaceae). O objetivo deste estudo foi analisar: i) a comunidade de aranhas em ramos vegetativos e reprodutivos de P. carthagenensis quanto à abundancia relativa, composição das guildas e distribuição de tamanhos; ii) a abundância de formigas nos diferentes tipos de ramos; e iii) o comportamento das aranhas quando colocadas em inflorescências cobertas por formigas. Não houve diferença significativa entre ramos vegetativos e reprodutivos em relação à composição de guildas, abundância relativa e distribuição de tamanhos de aranhas. Mas quando comparado à abundância de formigas, houve diferença. No experimento comportamental, 90 por cento das aranhas foram expulsas das inflorescências pelas formigas; no tratamento controle; 100 por cento das aranhas permaneceram nas inflorescências. Para P. carthagenensis, talvez a densidade de formigas em diferentes partes da planta explique melhor a distribuição das aranhas.
Assuntos
Animais , Formigas/fisiologia , Psychotria/fisiologia , Aranhas/fisiologia , Interações Hospedeiro-Parasita , Densidade DemográficaRESUMO
The chemopreventive potential of an Agaricus blazei (Ab) Murrill mushroom meal was investigated in a medium-term rat liver carcinogenesis assay. Male Wistar rats initiated for hepatocarcinogenesis with diethylnitrosamine (DEN, 200 mg/kg i.p.) were fed during a 6-week period with the dry powdered mushroom strains Ab 29 or 26, each one with opened (OB) or closed basidiocarp (CB), mixed at 10% level in a basal diet. All experimental animals and controls were subjected to partial hepatectomy at week 3 and killed at week 8. Chemopreventive activity of the mushroom meal was observed for the Ab 29 (OB and CB) and Ab 26 (CB) strains in terms of the number of putative preneoplastic altered foci of hepatocytes which express either the enzyme glutathione S-transferase, placental form (GST-P+) or the transforming growth factor-alpha, and for the Ab 29 (OB) and Ab 26 (CB) strains on the size of GST-P+ foci. This was associated with inhibition of foci cell proliferation in the animals fed the Ab 29 (OB) and Ab 26 (CB) strains. The results suggest that the protective influence of the Ab meal against the DEN potential for rat liver carcinogenicity depends on both the strain and period of mushroom harvest.