Sperm storage in Hemidactylus mabouia : morphological and ultrastructural aspects of a reproductive strategy.

Abstract

Sperm storage is a common phenomenon in most female reptiles. Evidence of sperm storageis based on the observation that female fertilization occurs even when females are sepa-rated from males, as well as the presence of agglomerates of spermatozoa in specific regionsof the oviducts. Lizards are capable of storing sperm in the uterine tube, vagina, or in bothregions. However, representatives of the Gekkonidae family commonly store spermato-zoa in the uterine tube, which is considered an ancestral character state for Squamates.Using comparative techniques of light, transmission and scanning electron microscopy, weobserved stored sperm organized in compact bundles with their heads facing the bottom ofthe crypts of the uterine tube, indicating chemotactic attraction. The alignment and pack-ing of spermatozoa in Hemidactylus mabouia indicates that the process of evacuation ofthe crypts for fertilization may be related to the passage of the egg that exerts mechani-cal pressure against the walls of the uterine tube, causing its distension and the release ofspermatozoa. We conclude that the sperm storage region and the morphological organi-zation of the crypts in the uterine tube of H. mabouia is similar to other previously studiedspecies of lizards, supporting the notion that sperm storage is a common reproductivestrategy among female reptiles.