Sperm Transfer and Storage in the Lizard , An o lis c a ro I in ens is

The relationship of the hemipenis to the cloaca in copula and sperm storage and transport in the female oviduct were studied in Anolis carolinensis using light and scanning electron microscopy. During copulation, the hemipenis does not penetrate beyond the cloaca, but the two apical openings of the bifurcate sulcus spermaticus appose the openings of the oviducts from the cloaca. Sperm enter the sperm storage tubules between 2 and 6 hr after insemination and small amounts of sperm reach the infundibulum 6 to 24 hr following mating. Sperm storage tubules are embedded in the wall of the utero-vaginal transition, and are formed by the folding and fusion of the oviducal epithelium. The importance of the hemipenile-cloaca1 relationship and the role of sperm storage in the life history of A . carolinensis are discussed. Male squamate reptiles have functionally separate, bilaterally symmetrical reproductive tracts complete with paired intromittent structures called hemipenes. Female squamates also have functionally separate, bilaterally symmetrical reproductive tracts; however, the female tract terminates in a single posterior cloaca. This system raises many important questions concerning the laterality of sperm transfer and fertilization. Investigation of the positional relationship of the male hemipenis to the female cloaca and oviducts in copula is a powerful approach to the resolution of these questions. In snakes, "copulatory adjustment'' (hemipenile-cloaca1 relationship) has been studied by Pope ('411, Ludwig and Rahn ('43), Edgren ('53), and Inger and Marx ('62). These were observational studies, however, and no systematic study of this problem has been undertaken. Furthermore, no study of any kind has been conducted on the hemipenile-cloaca1 relationship in lizards. In the lizard Anolis carolinensis, females exhibit a unique pattern of reproduction in which the two ovaries alternate in the production of single ova throughout the reproductive season (Hamlett, '52; Crews, '73a; Licht, '73). MaleA. carolinensis intromit a single hemipenis during copulation, and tend to alternate in the use of the paired organs (Crews, '78; Figs. 1,2). Males also tend to intromit with the hemipenis ipsilateral to the ovary with the largest (preovulatory) follicle in the female (Crews, 1980). Crews (1980) has speculated that the hemipenis could be intromitted into the ipsilateral oviduct, thus fertilizing the preovulatory follicle. This study of the lizard, Anolis carolinensis, was undertaken with three goals in mind: 1) to elucidate the positional relationship of the male and female reproductive organs in copula to gain insight into the mechanism of sperm transfer; 2) to monitor sperm movement in the oviduct during the 48 hour period following insemination; and 3 ) to study the structure and function of the sperm storage tubules in the female reproductive tract. MATERIALS AND METHODS