SPERMATOZOA FROM THE SUPERTRIBES LASIOPTERIDI AND STOMATOSEMATIDI (INSECTA, DIPTERA, CECIDOMYIIDAE) - ULTRASTRUCTURE DATA AND PHYLOGENY OF THE SUBFAMILY CECIDOMYIINAE

Spermatozoa from seven gall-midge species, representing the supertribe s Lasiopteridi and Stomatosematidi, have been examined by electron mic roscopy and compared to the spermatozoa of 30 previously examined gall -midge species of the subfamily Cecidomyiinae. Derived characteristics of all examined representatives of this subfamily are the lack of acr osome and the absence of accessory tubules in their axoneme. The sperm axoneme of Didactylomyia has a unique '9+5 pattern', i.e. with 9 oute r doublets and 5 inner singlet microtubules. Unlike other members of C ecidomyiinae, Didactylomyia has retained some plesiomorphic traits, na mely crystal-containing mitochondria and a homogeneously condensed nuc leus. Stomatosema has a 10+0 axoneme and an irregular nuclear condensa tion. Thus, Didactylomyia may serve as an useful outgroup for phylogen etic analysis within the subfamily Cecidomyiinae. The supertribe Stoma tosematidi is a paraphyletic assemblage. Nearly all members of Lasiopt eridi, Ozirhincus, Arnoldiola, Brachineura and Ledomyia, have a synapo morphic character in the great number of microtubules in parallel to t he axoneme. A notable exception is Rhizomyia, which shares certain apo morphic traits with several genera that have previously been classifie d within the Cecidomyiidi, i.e. Contarinia, Allocontarinia, Lestodiplo sis and Myricomyia. Moreover, these genera have a hat sperm tail and m icrotubular doublers located close to the cell membrane, both characte ristics that differ markedly from the very peculiar sperm tail found i n other members of Cecidomyiidi. Cladistic analysis of sperm character s suggests that the supertribe Cecidomyiidi is a polyphyletic taxon an d supports the existence of a sister-group relationship between the su pertribe Lasiopteridi and the genera Rhizomyia, Contarinia, Allocontar inia, Lestodiplosis and Myricomyia. (C) 1996 The Norwegian Academy of Science and Letters.