抄録
The individual variation of R. pedestris males and females in their attractiveness to the same species and the amounts of five pheromone components were examined in field experiments and GC-MS analysis, respectively. The number of adults attracted by a single male varied greatly among the individuals tested. The number of adults attracted was 0.92±0.12 (mean±SE/day). Of 64 males examined individually, four attracted three or more adults per day, while 12 males attracted only 0.5 adults or fewer per day and 14 individuals attracted no adults. The five pheromone components also differed greatly among those males. As for tetradecyl isobutyrate (14:iBu), which is thought to be an essential component of the pheromone, it was apparently detected from 46 males while eight had only a low amount of 14:iBu and ten had no 14:iBu. Some of the males had 14:iBu without having (E)-2-hexenyl (E)-2-hexenoate (E2-6:E2Hx) and (E)-2-hexenyl (Z)-3-hexenoate (E2-6:Z3Hx), which are synergistic components of the pheromone, and the rest had E2-6:E2Hx and/or E2-6:Z3Hx without having 14:iBu. The amount of 14:iBu or octadecyl isobutyrate (the fourth pheromone component) showed a positive and significant co-relationship with the number of attracted adults. Males with a well-developed fat-body tended to have more 14:iBu and to attract more adults than those with an undeveloped fat-body. Most of the females tested individually did not attract conspecific adults, and had only (E)-2-hexenyl hexanoate, the fifth component of the pheromone.
