The female seminal receptacle and accessory glands in Pyrrhosoma nymphula (Sulzer) (Zygoptera: Coenagrionidae)
Odonatologica , Volume 33 - Issue 3 p. 237- 244
Sperm, transmitted to the 2 as individual filamentous cells suspended in a liquid medium, are discharged into a thick-walled pouch, the receptaculum seminis, on the dorsum of the vaginal canal. Spermatozoa soon appear concentrated in a single, smaller, pear-shaped accessory sac, the spermatheca, attached to the receptaculum-vagina junction. Particular cells in the wall of the accessory sac secrete a material that is thought to be added to the sperm concentrate. The purpose of the accessory sac is to serve as a store of spermatozoa for use in fertilization. A pair of posterior accessory glands has each an efferent duct that opens into the distal region of the vaginal canal; these ducts are provided with an elaborate muscular apparatus probably serving as a pump; in fresh material, efferently directed peristaltic waves have been observed. The glands are presumed to contribute to the investment of the eggs. The apical domains of the glandular epithelial cells contain intraplasmic assemblages of multiplicating bacteroids. They are likely to be transferred to the ooplasm and thereby transmitted to a new generation.
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