Summary
Experiments have been conducted in a black-water region (rio Tarumã-mirim) an in a white-water region (rio Solimões) since January 1976. Each experimental area contained 28 pitfall-traps, 4 ground photo-eclectors and 13 arboreal photo-eclectors (Minimal program for an ecosystem-analysis: Grimm, Funke & Schauermann, 1974). In the Solimões area, the arboreal photo-eclectors have collected 18.197 arthropods and Anura up to May 1976. Formicoidea (14.068 = 77,31%) and Diptera (1.634 = 8,98%) have been dominant. In the rio Tarumã-mirim area 27.594 arthropods and Gastropoda have been collected during the same period. Pseudoscorpiones (7.942 = 28,28%), small Araneae (5.878 = 31,30%) and Formicoidea (5.422 = 19,65%) have been dominant. A lack of soil-fauna is found in the Solimões area, for there is no ground-litter, and only the big Araneae migrate before the rising water. The rio Tarumã-mirim area contained 8 groups of arthropods, particularly the soil-fauna, which migrate. Some arthropods migrate 6-8 weeks before the area is flooded, others wait until the last week prior to inundation.