抄録
The dispersal distance of adults of the Japanese horntail, Urocerus japonicus, was studied in the field by the mark-recapture method. Twenty-two attractant-traps were set up on 3 transect belts which were set spokewise from a fixed release point in a Chamaecyparis obutusa stand. Traps were 10-150 m apart from the release point. Adults emerging in cages were relased at the release point after being marked on the thoraces with paint. Traps were examined weekly. Two hundred and eighty males and 56 females were released, and a total of 22 males and 16 females were recaptured. The recapture ratio was significantly higher for females than for males. All males were recaptured in the traps at 10 m from the release point, although some females were captured over 30 m from the release point. One female was captured in a trap 90 m from the release point and the longest dispersal distance of females was estimated to be 105 m. Thus, the dispersal distance of females is concluded to be farther than that of males.
