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Updated: Jul 27, 2026

Cytological Analysis of Spermatogenesis: Live and Fixed Preparations of Drosophila Testes
Published on: January 20, 2014
Giant sperm cells with accessory macrotubules in a neuropteran insect
Romano Dallai1, Pietro Lupetti, Giuseppe Osella
1Department of Evolutionary Biology, University of Siena, Via A. Moro 2, I-53100 Siena, Italy. dallai@unisi.it
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.
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