Abstract
Our previous work showed that Cryptomeria japonica D. DON feeders and Torreya nucifera SIEB. et ZUCC. feeders of Aspidiotus cryptomeriae KUWANA are separate host races due to distinct morphological characters and virtually monophagous feeding habits. However, in the present work some A. cryptomeriae crawlers of the T. nucifera feeding race, which had been experimentally transferred to the non-host plant, C. japonica, grew to adults. The morphological characters of the C. japonica (non host) feeding T. nucifera race of A. cryptomeriae females were compared to those of the T. nucifera feeding T. nucifera race to examine whether the host plant had any effect on morphological characters. The two populations of A. cryptomeriae were reared under the same conditions except for the host plant. There were no significant differences between them for five morphological characters (p>0.05, t-test) except for pygidium length. Linear discriminant analysis using two characters (anal location and dorsal macroduct length) showed that the T. nucifera feeding race reared on C. japonica kept their normal morphological characters. Furthermore, eggs layed on the non-host plant by the adult A. cryptomeriae females reared on the non-host plant did not hatch. These results strongly suggest that the T. nucifera feeding race has very stable morphology that is not affected by the host plant. Even when A. cryptomeriae crawlers develop to the adult stage on non-host plants, they may not reproduce the next generation.
