Structure of the male reproductive accessory glands ofPterostichus nigrita(Coleoptera: Carabidae), their role in spermatophore formation

Abstract

Accessory gland secretions of male insects have many important functions including the formation of spermatophores. We used light and electron microscopy to investigate the structure of the accessory glands and posterior vasa deferentia of the carabid beetle Pterostichus nigrita to try to determine where spermatophore material is produced. Each accessory gland and posterior vas deferens had an outer layer of longitudinal muscle, beneath which was a layer of connective tissue and a thin band of circular muscle, all of which surrounded a layer of epithelial cells lining the lumen of the ducts. Based on the ultrastructure of the epithelial cells, and their secretory products, we identified two epithelial cell types in each region (distal and proximal) of the accessory glands and four types in the posterior vas deferens. Most secretory products, which stained positively for proteins and some mucins, were released into the lumen of the ducts by apocrine secretion. The accessory glands produced one type of secretory product whereas in posterior vasa deferentia, four types of secretory products were found layered in the lumen. Our results suggest that most of the structural material used to construct a spermatophore is produced by the cells of the posterior vasa deferentia.

Male reproductive system and spermatogenesis of Limodromus assimilis (Paykull 1790)

“…decemlineata and P . nigrita , which exclusively include proteins and neutral mucines [ 48 , 50 ], the gland secretion of L . assimilis additionally contains acid (carboxylated) mucosubstances.…”

“…The spermatophore formation could proceed in the posterior (glandular) parts of the vas deferens, similar as has been found by Krüger et al . [ 50 ] in P . nigrita .…”

“…assimilis , present also in P . nigrita [ 50 ] and S . sardous [ 16 ], allow via directed contraction the transport of secretion and spermiozeugmata into the posterior regions of the genital organs.…”

Morphology of the male reproductive tract in the water scavenger beetle Tropisternus collaris Fabricius, 1775 (Coleoptera: Hydrophilidae)

“…The anatomy of the reproductive tract of T. collaris is similar to that of most Coleoptera families, which, in general, is composed of testes, vasa deferentia, a pair of seminal vesicles, and a single ejaculatory duct, varying mainly in the number of testicular follicles and type of accessory glands (Cerezke, 1964;Nasserzadeh et al, 2005;Dias et al, 2013;Kruger et al, 2013;Paoli et al, 2014;Schubert et al, 2017;Wu et al, 2017;Nasserzadeh, 2020). For beetles, the morphological characters from reproductive tract are potential sources for phylogenetical hypotheses in higher taxa (Dettner et al, 1986;Opitz, 2014;Nasserzadeh, 2020).…”

“…The morphology of the reproductive tract and aspects of spermatogenesis have been described in several species of Coleoptera (Sharp, 1912;Happ, 1992), including representatives of Bruchidae (Sigh, 1978;Kasap and Crowson, 1979), Carabidae (Sasakawa, 2007;Hodgson et al, 2013;Kruger et al, 2013;Schubert et al, 2017), Chrysomelidae (Kasap and Crowson, 1979;Wang et al, 2007), Curculionidae (Alzahrani et al, 2013;Wu et al, 2017), Dryophthoridae (Paoli et al, 2014), Scarabaeidae (Carrilo-Ruiz et al, 2008;Martínez and Trotta-Moreu, 2010), Scolytidae (Cerezke, 1964), and Tenebrionidae (Dias et al, 2013(Dias et al, , 2015. In Hydrophilidae, a highly diverse family with about 3,100 aquatic species (Madaric et al, 2013;Short and Fikáček, 2013;, some studies on different taxa focus on the morphology of internal organs (eg Gundevia Morphology of the male reproductive tract in the water scavenger beetle Tropisternus collaris Fabricius, 1775 (Coleoptera: Hydrophilidae)…”