Spermatogenesis and sperm structure before and after insemination in two acarid mites, Acarus siro L. and Tyrophagus putrescentiae (Schrank) (Acari, Astigmata)
1986 - Volume: 27 Issue: 1 pages: 41-51
Structure of spermatogonia, spermatocytes, spermatids as weil as of spermatozoa from male and female genital tracts in two species of acarid mites, Acarus siro L. and Tyrophagus putrescentiae (Schrank), is described. During the course of spermatogenesis the following main events take place: 1) the mitochondria increase in number and decrease in size, Jose their cristae and assume the form of poorly distinguishable, small vesicles; 2) the nuclear envelope disappears and the chromatin condenses into long threads scattered free!y in the cytop!asm; 3) a superficial spongy layer of fenestrated cytoplasmic sheets is formed at primary spermatocyte stage, but it disintegrates !ater on. The spermatozoa from the male genital tract of both investigated species are small, pleomorphic cells with cytoplasm containing loose chromatin threads, numerous small vesicles of mitochondrial origin and occasionally electron-dense Iamellae. In the female genital tract the spermatozoa attain a fusiform shape. The parailei threads of an electron-dense material appear beneath the plasmalemma of spermatozoa. The electron-dense !amellae are peripherally located.
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