Ultrastructural organization of the genital tracts in amphigonic females of Euceraphis betulae Koch (Aphididae: Calaphidinae)

Abstract

The ultrastructure of the genital tracts in amphigonic females of Aphidoidea is described for the first time, using Euceraphis betulae Koch (Aphididae: Calaphidinae) as a representative. The female reproductive apparatus consists of two ovaries, each one with three/four meroistic telotrophic ovarioles; two sac‐like accessory glands lie laterally to a sac‐like seminal receptacle, opening into the dorso‐medial part of the common oviduct by means of a spermathecal duct. A marked secretory activity takes place in the epithelial cells of all the investigated tracts as shown by ultrastructural observation of many organelles involved in this process. No evident golgian area was observed in the cytoplasm of these cells. Extensive smooth endoplasmic reticulum, whose probable role is here discussed, was observed in epithelial cells of the wall of the accessory gland. Spermathecal duct and seminal receptacle had peculiar features that could be related to different secretory activities carried out by these two parts of the spermatheca.

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.…”

“…It should be stressed, in this regard, that the follicular number, as much as other aspects of the male reproductive system, is a character used to show some correlations within phyletic lineages of various groups of insects; in the Hemiptera Homoptera, in particular, both Auchenorrhyncha and Sternorrhyncha, the species with a lower follicular number are deemed to be most evolutionarily recent (Kuznetsova and Kirillova, 1993;Kuznetsova et al, 1997;Vitale et al, 2011). The reduction in the follicular number would be also part of a more general evolutionary trend, within the order Hemiptera, concerning the simplification of the body structures (von Dohlen and Moran, 1995;Vitale et al, 2011;Vitale and Viscuso, 2015).…”

“…Since diversified functional activities by different tracts of a same reproductive structure have been found in many species of insects (Riemann e Thorson, 1979;Marchini et al, 2009;Vitale and Viscuso, 2015), it cannot be ruled out that the features found in the accessory glands of B.…”

Spermatodesm reorganization in the spermatophore and in the spermatheca of the bushcricket Tylopsis liliifolia (Fabricius) (Orthoptera, Tettigoniidae)

“…The spermatheca is of ectodermal origin and shows differences in relation to the number, shape and to its structural organization, in the different species considered (Chapman, 1998;Fritz and Turner, 2002;Dallai et al, 2012;Vitale and Viscuso, 2015). In general, a spermatheca consists of a dilated portion (seminal receptacle), where the gametes are stored, isolated or gathered in bundles called spermatodesms (Cholodkovsky, 1913), and by a spermathecal duct which opens into the vagina or into the bursa copulatrix (Snodgrass, 1937;Smith, 1968;Grass e, 1977;Chapman, 1998).…”

The chorion of eggs in a NamibianAriadnaspecies (Araneae: Segestriidae): morphological and SEM analyses

“…In fact, a mucous secretion covers the chorion during the egg transit in the oviduct and gradually decreases until it disappears. Because the chorion genesis of insects mainly occurs within the ovary, this mucous secretion would ensure the adherence of the eggs to each other and could also be useful in limiting their dehydration (Vitale & Viscuso 2015). The milky-white mucous secretion of the eggs of Ariadna sp., therefore, could play similar functions, thus ensuring favorable conditions for the survival of freshly laid eggs whose chorion is not yet adequately sclerified.…”