The role of the male cloacal gland in reproductive success in Japanese quail (Coturnix japonica)

Abstract

The adult male Japanese quail has a well developed cloacal gland that produces meringue-like white foam. The physiological significance of the cloacal gland and its foam is still unclear. Therefore, we conducted two experiments to establish the functional role of the cloacal gland and its foam in natural mating and oviducal sperm transport. In the first experiment, artificial insemination of equal numbers of spermatozoa diluted in foam extract and normal saline once in a week were used to determine the role of foam in sperm transport in the female oviduct. After artificial insemination, eggs were collected to measure fertility, the duration of the fertile period, sperm holes and attached spermatozoa in the perivitelline membrane. Higher (P < 0.05) fertility and greater duration of the fertile period were observed when semen was inseminated along with foam extract compared with normal saline. Further, the sperm holes and trapped spermatozoa in the perivitelline membrane were also higher (P < 0.05) in the presence of foam extract. In the second experiment, two males with bigger and smaller cloacal gland areas were allowed to mate with a female. The mating attempts of males with larger cloacal gland were more successful (P < 0.05) than males with smaller cloacal glands. Our results indicated that cloacal foam improves sperm transport in the female oviduct and that males with larger cloacal gland areas are preferred during mating.