Genetic and ecological differences between Asphondylia yushimai and the ivy gall midge, Asphondylia sp. (Diptera: Cecidomyiidae), with a new distribution record of the former from Hokkaido and South Korea

The soybean pod gall midge, Asphondylia yushimai, is known to utilize Laurocerasus zippeliana (Rosaceae) and Osmanthus heterophyllus (Oleaceae) as autumn–spring hosts. In addition, ivy, Hedera rhombea (Araliaceae), was thought to be a candidate for an additional autumn–spring host. However, our genetic analysis indicated that no haplotypes of the ivy fruit gall midge, Asphondylia sp., were identical to any of the haplotypes of A. yushimai. Furthermore, the life-history traits of the ivy fruit gall midge, such as voltinism, host-plant range, lower development threshold temperature (LDT), and developmental speed, were clearly different from those of A. yushimai. Thus, the results from genetic analysis and life-history traits revealed that the ivy fruit gall midge was not identical to A. yushimai and that H. rhombea is not an additional autumn–spring host plant for A. yushimai. We also discovered through morphological observation and genetic analysis that A. yushimai is distributed in Hokkaido and South Korea, and that the ivy fruit gall midge exhibits host plant alternation, utilizing both the fruit of Phytolacca americana (Phytolaccaceae) and the flower buds of Paederia foetida (Rubiaceae) as spring–autumn hosts.