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The three Pegoscapus species present the same internal reproductive tract features comprising testes with a single testicular tubule, seminal vesicles, vasa deferentia, accessory glands and an ejaculatory duct. The seminal vesicle shows two morphologically distinct portions although they do not resemble the separate chambers found in other Chalcidoidea. The anterior portion of the seminal vesicle shows a prominent epithelium and stores the mature spermatozoa, while the posterior region is formed by a thicker muscular sheath that participates on ejaculation. The sexual maturation in Pegoscapus is achieved at emergence, when the testicular degeneration occurs. The spermatozoa of Pegoscapus reveal a basic structure similar to that of other Chalcidoidea. In Pegoscapus sp1. and Pegoscapus sp2. they present the same features, whereas Pegoscapus tonduzi comprises some different characteristics. It measures approximately 160 microm in Pegoscapus sp1. and Pegoscapus sp2., while in P. tonduzi the spermatozoa measure about 360 microm. The extracellular sheath thickness is another difference among the species. While Pegoscapus sp1. and Pegoscapus sp2. show a thick extracellular sheath, in P. tonduzi this sheath is very thin resulting in a large space intervening between the extracellular sheath and the nucleus. Despite these differences, the three species analyzed share some characteristics that allow the establishment of an identity to the spermatozoon of the genus Pegoscapus: the seminal vesicle not divided in chambers; the absence of acrosomal structures in the spermatozoa; the length of the extracellular sheath; the central microtubules being the firsts to terminate in the sequence of microtubular cutoff at the final axonemal portion.

The spermatozoa in Halictidae are sometimes observed in spermatodesmata in the seminal vesicle. They are linear, long, slender and their lengths vary from 213 microm to about 330 pm. The head region consists in the anterior acrosomal complex, formed by a conical acrosomal vesicle that shows an inner paracrystalline perforatorium extending into the nucleus. The nucleus, measuring about 16 microm to 46 microm, is linear and strongly electron-dense, however some electron-lucent lacunae with electron-dense granules homogeneously organized were observed. The nucleus is attached to the flagellum by the centriolar adjunct, which is compact and electron-dense. It begins at the nuclear base and finishes just above the smaller mitochondrial derivative. The flagellum consists of two mitochondrial derivatives, an axoneme and two accessory bodies. Halictidae have an axoneme with 9+9+2 microtubule pattern which gradually disorganizes towards the final region. The mitochondrial derivatives are asymmetric in both length and diameter and only the larger presents the paracrystalline region. The typical pattern for Halictidae spermatozoa here described may provide useful additional information for future phylogenetic analysis of the superfamily Apoidea.

Fiorillo, B. S., Zama, U., Lino-Neto, J. and Báo, S. N. 2010. Structural and ultrastructural studies of male reproductive tract and spermatozoa in Xylocopa frontalis (Hymenoptera, Apidae). — Acta Zoologica (Stockholm) 91: 176–183. In Xylocopa frontalis the reproductive tract is composed of testes, deferent ducts, seminal vesicles, accessory glands and an ejaculatory duct. Each testis comprises four testicular tubules in which multiple cysts are present containing approximately 64 spermatozoa per cyst. The seminal vesicle consists of an epithelium, a thick basement lamina and a muscular external sheet. In the luminal region some vesicles can be observed; however, the epithelial cells of the seminal vesicle do not display morphological features associated with secretory functions. The spermatozoa, measuring approximately 260 µm long, are similar to the hymenopteran pattern. The head region consists of an acrosome with an inner perforatorium that penetrates an asymmetrical nuclear tip. The nucleus is linear, electron-dense and its posterior tip projects into the beginning of the axoneme. The centriolar adjunct is asymmetric with many electron-lucent lacunae interspersed throughout. The axoneme has the 9 + 9 + 2 pattern of microtubules and in the posterior region the central microtubules finish first, followed by the doublets and finally the accessory microtubules. The mitochondrial derivatives are asymmetric in both length and diameter with paracrystalline material present only in the larger one. These features may be useful characters for taxonomy and phylogenetic studies. [ABSTRACT FROM AUTHOR]