A new record of the fairyfly Cosmocomoidea tenuis (Hymenoptera: Mymaridae) from Japan, with notes on its host associations

The fairyfly Cosmocomoidea tenuis Xu, Lin and Hu (Hymenoptera: Mymaridae), which was previously known only from mainland China (Fujian) and Taiwan, is for the first time recorded from Japan where it was reared from organic kiwifruit, Actinidia chinensis and A. deliciosa (Actinidiaceae), leaves in Yamanashi Prefecture on Honshu Island. Both sexes of C. tenuis are redescribed and illustrated based on specimens from Japan. Its apparent host association with black-tipped leafhopper Bothrogonia ferruginea (Fabricius) (Hemiptera: Cicadellidae: Cicadellinae) is discussed. This sharpshooter leafhopper is a common but minor pest in organic vineyards and kiwifruit orchards in Japan and a known vector of the phytopathogenic bacterium Xyllella fastidiosa on cultivated grapes in Taiwan. Egg parasitoids of B. ferruginea, a widespread species in parts of Asia, have been previously unknown. Cosmocomoidea tenuis is also identified as an egg parasitoid of another known vector of X. fastidiosa in Taiwan, a sharpshooter (Cicadellinae) leafhopper Kolla paulula (Walker).