Giant sperm cells with accessory macrotubules in a neuropteran insect.
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.
Dallai
Romano
R
Department of Evolutionary Biology, University of Siena, Via A. Moro 2, I-53100 Siena, Italy. dallai@unisi.it
Lupetti
Pietro
P
Osella
Giuseppe
G
Afzelius
Björn A
BA
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*