Two Regional Strains of a Phoretic Egg Parasitoid, Telenomus euproctidis (Hymenoptera: Scelionidae), That Use Different Sex Pheromones of Two Allopatric Tussock Moth Species as Kairomones

The egg parasitoid, Telenomus euproctidis Wilcox (Hymenoptera: Scelionidae), is phoretic on females of two allopatrically distributed tussock moths, Euproctis pseudoconspersa (Strand) and Euproctis taiwana (Shiraki) (Lepidoptera: Lymantriidae). Crossing experiments between the two regional parasitoid strains indicated no evidence for their reproductive isolation. More wasps were found on the locally occurring host, E. pseudoconspersa, than on E. taiwana, when virgin females of the two moth species were exposed concurrently in the field for 24 hr in Ibaraki Japan. In Ibaraki, many wasps were caught in traps baited with the synthetic sex pheromone of E. pseudoconspersa, 10,14-dimethylpentadecyl isobutyrate (10Me14Me-15:iBu), but none with that of E. taiwana, (Z)-16-methyl-9-heptadecenyl isobutyrate (16Me-Z9-17:iBu) or blank traps. In Okinawa, Japan, more wasps were found on E. taiwana than on E. pseudoconspersa, and many wasps were caught in traps baited with 16Me-Z9-17:iBu, but only a few with 10Me14Me-15:iBu, and none with blank traps. These results suggest that local wasp strains discriminate between the two sex pheromones, and they strongly prefer the sex pheromone of the moth occurring at their location.