Utilization patterns of trap-nests by some aculeate species were studied at the secondary growth forest on the hilly area of Sanda City, Hyogo Prefecture, using bamboo stems as trap-nests. A total of 30 trap-sites at five block locations were selected. They were layed at intervals (2, 5, 10, 20 and 40 m) along the summit of the hill. Each block was arranged 40 m apart its neighboring blocks. Traps were exposed in a field situation from late May to early December. Five species were obtained from these trap-nests: Anterhynchium flavomarginatum, Auplopus sp. , Chalicodoma sculpturali sD,ipogon sp. and Orancistroceru sdrewseni. Among these, Auplopus sp. was the most frequent occupant of trap-nests in terms of the number of trap-sites, stems used, and brood cells produced. The mean number of stems utilized per trap-site increased with between-trap-distance in C. sculpturalis, in contrast to Auplopus sp. which did not show such trait sin stem utilizati opnatterns. A simila rtendency was also found in the number of brood cells produced per trap-site. These differences may arise due to factors such as, effective area of trap-nest, foraging range, abundance of resources, etc. All species preferred the middle and large sized tubes (more than 6 mm in diameter) , except Dipogon sp. Several problems are discussed here concerning the application of trap-nest techniques to environmental evaluation.
