title: The spermatodesm of Cloeon dipterum (L.): fine structure and sperm movement.
abstract: Sperm bundles of the ephemeropteran Cloeon dipterum (L.) were found in the seminal vesicle. They are apically protected by cyst cells and sperm anterior regions are embedded in a secretion produced by these cells. Cyst cells further degenerate making sperm cells free. The sperm bundles are able to perform a forward progression only when sperm are stick together with their tail posterior tips. On the contrary, when sperm have their tail ends free, they beat but are unable to progress. The functional significance of the sperm bundles is discussed.
authors.affiliation: Department of Evolutionary Biology, University of Siena, via A.Moro 2, 53100 Siena, Italy.
authors.forename: Pietro
authors.initials: P
authors.lastname: Lupetti
authors.forename: Caterina
authors.initials: C
authors.lastname: Mencarelli
authors.forename: David
authors.initials: D
authors.lastname: Mercati
authors.forename: Elda
authors.initials: E
authors.lastname: Gaino
authors.forename: Romano
authors.initials: R
authors.lastname: Dallai
mesh_terms: D000818:Animals; D007313:Insecta / Q000502:physiology / Q000648:ultrastructure*; D008297:Male; D008855:Microscopy, Electron, Scanning; D046529:Microscopy, Electron, Transmission; D013081:Sperm Motility; D013094:Spermatozoa / Q000648:ultrastructure*