Abstract: To assess the differentiation among the geographical populations of exotic leaf beetle Ophraella communa in China, a laboratory experiment was conducted to observe the assortative mating among the O. communa populations from Nanjing (32°N, 118.7°E), Changsha (28° N, 112.9°E), and Fuzhou (26°N, 119.3°E) and the offspring developmental parameters. The mating choice trial showed that in the six hours of observation, the probability of mating for the individuals of O. communa population from Nanjing with those from Fuzhou was significantly lower than that for the individuals within the population from Nanjing, but no significant differences were observed for the individuals between the populations from Nanjing and Changsha and within the population from Nanjing. When given choice between the females from different populations, the males of the populations from Nanjing and Fuzhou made more mating choice for the females from their own populations, but the males of the populations from Nanjing and Changsha exercised the same mating choice for the females from their own and other populations. The offspring from the mating among populations did not show any significant differences in egg hatching, pupation, and adult emergence rates. This study suggested that definite degree pre-mating isolation occurred between the O. communa populations from Nanjing and Fuzhou.

Key words: Soybean, O₃, CO₂, Interaction