Invasion of Japan by exotic leafminers Liriomyza spp. (Diptera: Agromyzidae) and its consequences

Identifying patterns and causes of species displacement is important from the viewpoints of ecology and evolutionary biology as this phenomenon affects community structure. Here I review the species displacement between Liriomyza trifolii (Burgess) and Liriomyza sativae Blanchard (Diptera: Agromyzidae) in Japan. These two species and Liriomyza huidobrensis (Blanchard) originated from the New World and are considered to have invaded Japan from around 1990 to the early 2000s. During this period, L. trifolii was apparently displaced by L. sativae, but the direction of displacement in Japan has been contrary to that observed between the same two species in the USA and China. While the displacement of L. sativae by L. trifolii in these two countries can be attributed to the lower insecticide susceptibility of L. trifolii there, species displacement in the opposite direction in Japan is probably due to the relatively high fecundity of L. sativae and differential effects of the introduced parasitoid Dacnusa sibirica Telenga (Hymenoptera: Braconidae) on both Liriomyza species, except in the south of the country.