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Item Sperm structure and ultrastructure of the Melittobia hawaiiensis, Perkins and M. australica, Girault (Chalcidoidea: Eulophidae)(Tissue and Cell, 2009-04) Lino-Neto, José; Brito, Pedro; Dolder, HeidiSpermatozoa morphology has, for some years, been used to help answer some phylogenetic questions for Hymenoptera. This is the second study describing spermatozoa morphology of an Eulophidae species in which important characteristics were observed. Melittobia spermatozoa are spiralled and measure approximately 270 μm in length. The head contains a small acrosome, apparently formed only by an acrosomal vesicle, which, together with the initial nuclear region, is surrounded by an extracellular sheath, from which innumerable filaments irradiate. The nucleus is helicoidal and completely filled with compact chromatin. A centriolar adjunct is observed at the nucleus–flagellum transition; it associates laterally with the nucleus and exhibits two small expansions, which reach around the centriole. In the flagellum there are two mitochondrial derivatives, which in cross-sections are asymmetric. In the derivative with the larger diameter, two distinct regions are observed, a small one, near the axoneme, with a clear “fissure” inside, and a larger region where the cristae occur. Both derivatives initiate at the nuclear base, but the larger diameter derivative finishes first, before the flagellum extremity. At the end of the axoneme, the accessory microtubules are the first to finish.Item Sperm ultrastructure of the honey bee (Apis mellifera) (L) (Hymenoptera, Apidae) with emphasis on the nucleus-flagellum transition region(Tissue and Cell, 2000-05-26) Lino-Neto, J.; Báo, S.N.; Dolder, H.The flagellum of Apis mellifera (Hymenoptera, Apidae) consists of two mitochondrial derivatives, an axoneme and two accessory bodies. The mitochondrial derivatives are of unequal size and lie parallel to the axoneme. In the larger derivative four regions can be distinguished while in the smaller, only three. The region occurring only in the larger derivative consists of paracystalline material. The smaller mitochondrial derivative terminates anterior to the larger one. An extremely long centriolar adjunct is observed between the nucleus and the smaller mitochondrial derivative. This adjunct is compact, very electron dense and gradually tapers from base toward apex, finishing at the anterior extremity of the axonemal microtubules. In this flagellar region, there is only one accessory body present between the larger mitochondrial derivative and the axoneme. Anteriorly, the tips of the axonemal microtubules are inserted in a well developed mass of granular appearance. This material surrounds the nuclear base, separating it from the anterior end of the larger mitochondrial derivative. We believe that the structure identified here as a centriolar adjunct is homologous to that observed in Formicidae, Ichneumonoidea and Symphyta. Therefore, very probably, it is common to most Hymenoptera.Item Sperm structure and ultrastructure of the fire ant Solenopsis invicta (Buren) (Hymenoptera, Formicidae)(Tissue and Cell, 2002-03-22) Lino-Neto, José; Dolder, HThe spermatozoa of Solenopsis invicta are long and slender, measuring about 70 μm in length, of which the head region measures approximately 13 μm. The head consists of an acrosome formed by an acrosomal vesicle covering a perforatorium and a nucleus. This latter measures about 12 μm, has compact chromatin, and many translucent areas. The flagellum consists of an axoneme of 9+9+2 microtubules that begins just below the nuclear base. The two mitochondrial derivatives are of almost equal diameter, and there are two accessory bodies. The nucleus is attached to the flagellum by a centriolar adjunct located between the baso-lateral region of the nucleus and the anterior mitochondrial derivative extremities. Therefore, the nucleus–flagellum transition region of the spermatozoa of S. invicta is very similar to that of other ants and differs from the first description of this species [Ann. Entomol. Soc. Am. 67 (1967) 632]. In relation to other aculeates, it is possible that three characteristics (type of centriolar adjunct, presence of paracrystalline areas in each mitochondrial derivative, and the position of these areas within each derivative) may be autopomorphies for the Formicidae.