Arthropod diversity, abundance and biomass on 50-70-year-old longleaf pine (Pinus palustris) tree boles were examined to determine the origin of the prey available to the endangered red-cockaded woodpecker (Picoides borealis) and the variability of this prey over time. Traps designed to capture arthropods crawling on the bark (crawl traps), alighting on the bark (flight traps), and crawling on the ground (pitfall traps) were operated continuously for 12 months. Flight and crawl traps were placed at different heights. One-half of the trees with crawl traps were fitted with a barrier to prevent arthropods from crawling up from the ground. Arthropods were identified to genus from one weekly sample per month and subsamples were oven-dried and weighed to estimate biomass. The arthropod community on the bark included over 400 genera. Crawl trap captures were the most similar to the prey of P. borealis. Arthropod fauna captured in crawl traps had a 58% similarity to pitfall trap captures and a 60% similarity with flight trap captures. Flight and pitfall trap captures had a 10% similarity. Barriers to arthropod movement up the tree reduced the arthropod biomass on the bole of the trees by 40-70%. Arthropod biomass was relatively evenly distributed over the tree, but varied seasonally with the highest biomass captured in the fall of the year. In general, the study showed that little of the arthropod biomass on the bark is in the form of arthropods that live exclusively in that habitat and that a large portion of the biomass is crawling up from the soil/litter layer.