Abstract: 【Aim】 In order to clarify the sperm morphology of Cicadidae and their significance in insect taxonomy and phylogeny, the sperm ultrastructures of Meimuna mongolica, Cryptotympana atrata, Pycna repanda, and Tettigetta sp. were compared in this study. 【Methods】 The morphological characteristics of sperm of four species of Cicadidae were observed using light and transmission electron microscopies, respectively. 【Results】 The sperm morphologies of M. mongolica, C. atrata, P. repanda and Tettigetta sp. are similar, but the sperm length is significantly different within and between species. Spemotozoa of all these investigated species show polymegaly. Based on the length of spermatozoa, spermatozoa in P. repanda can be divided into three types, i.e., long spermatozoa, medium spermatozoa, and short spermatozoa. The spermatozoa of M. mongolica, C. atrata and Tettigetta sp. are only divided into two types, i.e., long spermatozoa and short spermatozoa. The sperm ultrastructures of these four species are similar, i.e., the head region contains the acrosome and the nucleus, the neck region is composed of a centriole and a centriolar adjunct, the tail region generally consists of an axoneme and a pair of mitochondrial derivatives, and the axoneme has a 9+9+2 arrangement of microtubules (9 accessory microtubules, 9 doublet microtubules, and 2 central microtubules). However, some differences were revealed in sperm ultrastructure among different species. Some spermatozoa in the three species of the subfamily Cicadinae possess multiple mitochondrial derivatives. An electron-dense deltoid region exists in the sperm tail of P. repanda, which has never been found in other cicadas. The structure of the centriolar adjunct of spermatozoa is significantly distinct among different subfamilies within the Cicadidae. The centriolar adjunct exhibits a lamellar structure in Cicadettinae, but has a sheath structure in Cicadinae. 【Conclusion】 Compared with the spermatozoa in Membracoidea and Cercopoidea within Cicadomorpha, only the spermatozoa in Cicadidae show polymegaly, which is a synapomorphy of this family. Whether the occurrence of multiple mitochondrial derivatives in the tail of flagellum is ubiquitous within the subfamily Cicadinae still needs further study. The differences in sperm morphology in different groups of Cicadidae provide significant information for the taxonomy of Cicadidae and the phylogenetic analysis of Cicadomorpha.

Key words: Cicadomorpha, Cicadoidea, Cicadettinae, Cicadinae, sperm, morphology, polymegaly