Morphology of the male reproductive system and spermiogenesis in Hypanthidium foveolatum (Alfken, 1930) (Hymenoptera: Apidae: Megachilinae)

Abstract

The morphological aspects of male reproductive tract, spermiogenesis and spermatozoa are typical for each species and reflect its evolution, establishing a unique source of characters, which has been used to help solve phylogenetic problems. In Hypanthidium foveolatum the reproductive tract is composed of the testes comprising 28 testicular tubules, deferent ducts, seminal vesicles, accessory glands and an ejaculatory duct. The differentiation of spermatids occurs within cysts of up to 128 germ line cells each one. During the early spermatid phase, the nucleus resembles that of somatic cells. There follows a gradual chromatin condensation with an increase in nuclear electron density. In the spermatozoon, the nucleus contains heterogeneous chromatin with a loose appearance. The acrosome, shaped with the active participation of the Golgi complex, shows an electron-dense perforatorium involved by four electron-lucent acrosomal vesicle projections. The sperm tail presents an axoneme with a 9 + 9 + 2 microtubule pattern and two mitochondrial derivatives, which appear with different sizes. A dense crystalloid is formed initially in the mitochondrial matrix of the large derivative. The mitochondrial derivatives' differentiation occurs concomitantly with an axoneme outgrowth. The centriolar adjunct is observed near the axoneme, anterior to the smaller mithocondrial derivative and exhibits an approximately triangular shape in cross-sections. Microtubules were observed around the head region and flagellar components during spermiogenesis.

Morphology of spermatozoa of Dissomphalus connubialis (Ashmead, 1893) (Hymenoptera: Bethylidae)

“…In Scelionidae, only one mitochondrial derivative was observed, extending to the anterior extremity of the nucleus (Lino-Neto and Dolder, 2001a). The termination of the mitochondrial derivatives in the final portion of the flagellum in D. connubialis is similar to that observed in most Aculeata Apidae (Zama et al, 2001(Zama et al, , 2004(Zama et al, , 2005aFiorillo et al, 2005Fiorillo et al, , 2009Gracielle et al, 2009), Sphecidae (Zama et al, 2005b) and Vespidae (Mancini et al, 2006(Mancini et al, , 2009, in which one mitochondrial derivative terminates before the other, but differs from P. nasuta, in which the two mitochondrial derivatives terminate together (Oliveira et al, 2010).…”

“…However, alterations in chromatin compaction are evident in some species of Aculeata, including P. nasuta, in which chromatin in the nuclear periphery appears to be loose (Oliveira et al, 2010). In some Apidae the chromatin is decompressed throughout the nuclear area (Zama et al, 2004;Fiorillo et al, 2005;Gracielle et al, 2009). In Formicidae (Lino-Neto and Dolder, 2002;Moya et al, 2007) and other bee species, including Dialictus spp.…”

Delayed sexual maturity in males of Vespa velutina

“…The general structure of the V. velutina male tract is similar to that of other hymenopterans, and it is known that the testicular follicles number per testis varies significantly among species. The basal Apidae, for example, can have 3 (Mellitinae and Apidae s. stricto ; Roig‐Alsina et al ., ) to 28 tubules ( H. foveolatum ; Genissel et al ., ), while Apis mellifera can have 250 tubules (Chapman, ). In 3 parasitoids wasps of the Chalcidoidea family, Fiorillo et al .…”

Morphological aspects of testes and sperm ultrastructure in the “symphyta” Digelasinus diversipes kirby 1882 (hymenoptera: Argidae: Dielocerinae)

“…The number of follicles per testis, for example, may vary considerably. In Aculeata Apidae, some bees subfamilies, such as Colletinae, Halictinae and Andreninae, and some members of the Megachilinae have three follicles per testis (Ferreira et al, 2004), while the majority of Apinae, Mellitinae, and Megachilinae have four follicles per testis (Araú jo et al, 2005b;Ferreira et al, 2004;Roig-Alsina and Michener, 1993), with the exception of Apis mellifera, which has 250 follicles (Chapman, 1998), and Hypanthidium foveolatum, which has 28 follicles (Gracielle et al, 2009). In Formicidae, the number of follicles ranges from 1 to 25 (Wheeler and Krutzsch, 1992).…”