Meeting Abstract
The production of functional sperm is the primary task of the testis, yet we know relatively little about the relationship between testis architecture and sperm morphology. Lizards in the genus Anolis (i.e., anoles) provide an excellent group in which to study spermatogenesis because they exhibit remarkable variation in sperm size both within and among species. Still, whether variation in testis composition is associated with variation in sperm morphology within species is unclear. For example, do individuals with larger testes produce longer sperm, and what components of the testis influence sperm size? In this study, we examined 15-20 males of six species of anoles from the Dominican Republic and Puerto Rico. For each lizard we measured the cross-sectional areas of testes, seminiferous tubules, and of the lumina within the seminiferous tubules of cryosectioned testis tissue. We also measured sperm head, midpiece, and tail lengths for each individual. We found that intraspecific correlations between testis size and tubule and lumen size were generally positive, although the strength of these correlations varied among species. Likewise, correlations between testis components and sperm measures were variable among the six species. These preliminary results suggest that even closely-related species and individuals within a species may vary in the mechanisms of spermatogenesis.
