CHARACTERISTICS OF SPERM ULTRASTRUCTURE IN THE GALL MIDGES PORRICONDYLINAE (INSECTA, DIPTERA, CECIDOMYIIDAE), WITH PHYLOGENETIC CONSIDERATIONS ON THE SUBFAMILY

Sperm ultrastructure was studied in ten genera of the Porricondylinae (Cecidomyiidae). Sperm structure is remarkably simplified by the absen ce of the acrosome and the accessory tubules, as happens in all the ce cidomyiid flies. All genera of the Porricondylinae show a peculiar 9+3 axonemal model except Diallactes. which retains the plesiomorphic con dition of a 9+2 axoneme, and Winnertzia, which appears to have seconda rily acquired a 9+0 model. A cladistic analysis of relevant sperm char acters (based on the axonemal model, the number of mitochondrial deriv atives and the size and structure of the centriolar adjunct) was perfo rmed to infer phylogenetic relationships among six tribes of the Porri condylinae. In this cladogram, the Porricondylini are the sister group to the Asynaptini, Heteropezini and Winnertzini and these four taxa f orm the sister group to the Dicerurini. The tribe Diallactini are rega rded as the group with the most plesiomorphic characters within the fa mily.