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

In Digelasinus diversipes, spermatozoa are maintained in bundles, with 74 spermatozoa on average, in the seminal vesicle. These spermatozoa are very short (20 μm) and consist of a head and flagellum. The head includes an acrosome (perforatorium covered by the acrosomal vesicle) and a nucleus. A regular electron‐lucent region separates the acrosomal vesicle from the perforatorium, which is inserted parallel to the anterior ending of the nucleus. The small flagellum is composed of two symmetrical mitochondrial derivatives, a centriolar adjunct, an axoneme (9 + 9 + 2), and two accessory bodies. The centriolar adjunct begins above the posterior end of the nucleus and ends covering the anterior tip of two mitochondrial derivatives. In the terminal region of the axoneme, the central microtubules terminate first. The presence of a subacrosomal space, a short mitochondrial derivative diameter, and a short spermatodesm is the ultrastructure characteristics of spermatozoa shared by all “symphyta” species. Differences in the insertion of the perforatorium into the nucleus and the position of the centriolar adjunct distinguish Dielocerinae and the Arginae studied previously. The number of spermatozoa per cyst is variable. Furthermore, additional characteristics that had not been described for “symphyta” were also found, such as the number of follicles per testis. Microsc. Res. Tech., 2012. © 2011 Wiley Periodicals, Inc.