Gall midges of wild yam (Dioscorea: Dioscoreaceae) in Japan, with integrative descriptions of two new species

Abstract

Dioscorea, or yam, is the largest genus of Dioscoreaceae and includes several species that are cultivated and recognized as the fourth most important tuber crop. Despite the economic importance, only three described gall midge species (Diptera: Cecidomyiidae: Cecidomyiinae) are known to be associated with Dioscorea worldwide. Among these, only Dasineura dioscoreae (Shinji) that forms leaf galls on D. nipponica was previously known in Japan. However, the type specimens of this species have been lost, its galls are rarely encountered, and little is known about its morphology. In the present study, we describe two new species of gall midges associated with wild Dioscorea species in Japan based on an integrative taxonomic approach. Schizomyia blastianthus Elsayed, n. sp. typically develops in the male flower buds of D. tokoro, D. gracillima, D. nipponica, D. septemloba and D. quinquelobata. Ametrodiplosis aderces Elsayed, n. sp. develops in the male flower buds of D. nipponica and D. septemloba. Additionally, we report the rediscovery of the rare species Dasineura dioscoreae, provide a redescription, and designate a neotype. A description of larva, pupa and adults, illustrations, molecular phylogeny and notes on life history are given for each species.