Twenty-One Mayfly Gynandromorphic Cases from China

Gynandromorphism of mayfly has unique biological and scientific value. However, most cases of previous studies on this phenomenon were from Europe and America, with only two cases reported from China. In this study, we examined the mayfly collections in our laboratory and obtained 21 intersex specimens belonging to three families (Baetidae, Leptophlebiidae, and Siphlonuridae) and seven species (Baetis rutilocylindratus, three unnamed Baetis species, Neoleptophlebia sp., Choroterpes facialis, and Siphlonurus lacustris), which greatly enrich the diversity of mayfly gynanders of China. Biogeographically, this phenomenon appears cosmopolitan. Regarding the potential causes of mayfly gynandromorphism, we hypothesize that inorganic factors may play a significant role.