Ultrastructural organization of the seminal vesicles of Baculum thaii (Phasmida, Phasmatidae) during sexual maturity

Abstract

A morphological and ultrastructural study was carried out on the seminal vesicles of Baculum thaii removed from individuals killed at 4, 10 and 20 days from the imaginai moult, with the intention of showing any modifications that these structures undergo during sexual maturity. From the comparative examination, clear evidence was found of epithelial transformations of these organs during sexual maturity: there was a gradual increase in cellular volume accompanied by a progressive development of the apparatus of synthesis. The most particular characteristics, however, in the individuals killed at 10 and 20 days from the moult were, in addition to a marked secretory activity, the presence of spermiophagic activity, which had never been found in the genital tracts of this order of insects. In the light of these results, it can be affirmed that the seminal vesicles of B. thaii, apart from being the site of the secretory activity necessary for maintaining the sperm in this area, also assume an important role in the processes of "controlling" and "regulating" sexual material that is kept ready for transfer to the female genitalia.

Morphostructural analysis of the male reproductive system and DNA barcoding in Balclutha brevis Lindberg 1954 (Homoptera, Cicadellidae)

“…The presence of voluminous nuclei, always observed in the epithelial cells of the various reproductive tracts of B. brevis, could be related to their polyploidy; in accordance with previous considerations concerning the polyploidy in several species of insects of different orders, also within the Homoptera (Chevaillier, 1962(Chevaillier, , 1963Vitale et al, 2011;Vitale and Viscuso, 2015), it cannot be ruled out that, also in B. brevis, this features could be connected to a marked synthesis activity. The synthesis activity in B. brevis is also shown by other ultrastructural features found in the various examined structure, where the secretion mechanisms, moreover, would seem to be of merocrine/apocrine type, in accordance with previous observations on the genital tracts of different insects, also of other orders (Viscuso et al, 2005;Vitale et al, 2011;Vitale and Viscuso, 2015). Although our investigation did not take into account the nature and the specific role of the secretion in the various structures, the finding of spermatozoa gathered in bundles from the seminal vesicles, as opposed to mainly free spermatozoa from the lateral ejaculatory ducts, leads us to hypothesize that the secretion of these two structures is chemically different and, only in the lateral ejaculatory duct, this material is in some way involved in the disaggregation of the bundles.…”

Morphological and ultrastructural organization of the spermatheca of some Tettigoniidae (Insecta, Orthoptera)

“…It is known that in the genital tracts of various insect species the high secretory activity of some cells is often accompanied by a cytoplasmic vacuolization (Hamon et al 1982;Viscuso et al 1985Viscuso et al , 1996aViscuso et al , 1996bViscuso et al , 2005, which can precede the lysis of these cells (Riemann 1973;Viscuso et al 1985). Nevertheless, when this lysis seems to involve different parts of the genital tract at the same time, it could indicate the end of the reproductive period of an individual.…”

Structure of male accessory glands of Bolivarius siculus (fischer) (Orthoptera, Tettigoniidae) and protein analysis of their secretions

“…A macroapocrine secretory process was also recently described in the male mesodermal accessory glands of two Diptera Tephritidae, Ceratitis capitata, and Bactrocera oleae (Marchini et al, 2003;Marchini and Del Bene, 2006). Although the mode of secretion of the electron-dense granular and globular component has never been clearly identified, it likely takes place between the apical microvilli by a merocrine mode, frequent in the accessory glands or genital tracts of other insects (Viscuso et al, 1997(Viscuso et al, , 2005.…”