title: Giant sperm cells with accessory macrotubules in a neuropteran insect.
abstract: The flagellar axoneme of the atypical spermatozoa (paraspermatozoa) of Mantispa perla (Neuroptera, Planipennia) contains accessory microtubules or rather macrotubules that are 55 nm in diameter and that has a wall consisting of about 40 protofilaments. The sperm tail further contains two giant mitochondrial derivatives, which during spermiogenesis store an electron dense material. The mature spermatozoon has a flattened acrosome and a elliptical nucleus. These giant spermatozoa may furnish nutrients to the functional spermatozoa (euspermatozoa) when they reach the female genital tracts or/and they function in sperm competition filling the spermatheca.
authors.affiliation: Department of Evolutionary Biology, University of Siena, Via A. Moro 2, I-53100 Siena, Italy. dallai@unisi.it
authors.forename: Romano
authors.initials: R
authors.lastname: Dallai
authors.forename: Pietro
authors.initials: P
authors.lastname: Lupetti
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Osella
authors.forename: Björn A
authors.initials: BA
authors.lastname: Afzelius
mesh_terms: D000818:Animals; D005407:Flagella / Q000648:ultrastructure; D007313:Insecta / Q000648:ultrastructure*; D008297:Male; D008854:Microscopy, Electron; D008870:Microtubules / Q000648:ultrastructure; D008928:Mitochondria / Q000648:ultrastructure; D013082:Sperm Tail / Q000648:ultrastructure; D013094:Spermatozoa / Q000648:ultrastructure*