Overview on spermatogenesis and sperm structure of Hexapoda

Testis Morphology and Dichotomic Spermatogenesis in the Sugarcane Borer Diatraea saccharalis (F.) (Lepidoptera: Crambidae)

“…At the end of spermiogenesis, the eupyrene spermatid presents one more electron-dense, large mitochondrial derivative and a less electron-dense, small derivative as reported by others (Garvey et al 2000). The presence of reticular and lacinate appendages in the eupyrene sperm in D. saccharalis was reported by Dallai (2014) and demonstrates that these structures are exclusive of the eupyrene sperm of lepidopterans.…”

“…Eupyrene spermatozoa (nucleated) have an acrosome, two mitochondrial derivatives, a "9+9+2" axoneme, and extracellular appendages, which are specific of lepidopterans. Apyrene (anucleated) spermatozoa have a dense cap, two mitochondrial derivatives, and an axoneme with a "9+9+2" microtubular pattern (França & Báo 2000, Mancini & Dolder 2004a, Friedlander et al 2005, Mancini et al 2005, Dallai 2014). The spermatogenesis process occurs inside of the testes; the larvae contain paired organs, but the organ may fuse together into a single structure or remain separated in adults (LaChance & Olstad 1988, Friedlander et al 2005.…”

“…The sperm polymorphism has been described in insects of different orders (Dallai 2014), and the study of the sperm morphology has long been considered to provide important information on the phylogeny and reproductive biology of insect species (Baccetti & Afzelius 1976, Jamieson 1987, Jamieson et al 1999.…”

The sperm of Matsucoccus feytaudi (Insecta, Coccoidea): Can the microtubular bundle be considered as a true flagellum?

“…Moreover, the centriole of L. tuzetae consists of a single ring of nine microtubules with a single axial tubule (Molon-Noblot, 1976). Among hexapods, Protura have 12, 13, 14 or 16 doublets (Dallai et al, 1985(Dallai et al, , 1992(Dallai et al, , 2006Riparbelli et al, 2009); the trichopteran Wormaldia 13 (Dallai et al, 1995;Dallai, 2014); the Sciaridae 70 or 350 (Phillips, 1966;Dallai et al, 2006); and the cecidomyiid dipterans from 10 as in Xylopriona, Polyardis and Micromya, to 20 as in Anaretella and up to 2500 in Asphondylia (Dallai et al, 2006;Dallai, 2014). It has been suggested that the ninefold symmetry of ciliary and flagellar axonemes depends on the result of an evolutionary optimization of the motility of these structures (Pickett-Heaps, 1974;CavalierSmith, 1978;Mitchell, 2004;Satir et al, 2008).…”

A microtubule organizing centre (MTOC) is responsible for the production of the sperm flagellum in Matsucoccus feytaudi (Hemiptera: Coccoidea)

“…This material is also known as "centriole adjunct", a misleading term proposed by Gatenby and Tahmisian (1959) and now accepted in the specialized literature. It is a structure generally present in almost all insects (Dallai, 2014), although its origin, chemical composition and function have yet to be established. Using radioactive uridine 5-3 H, Baccetti et al (1970) suggested the presence of RNA in the centriole adjunct, while Cantacuz ene (1970) used enzymatic extraction to identify basic proteins extruded from the maturing nucleus.…”