Gonadal steroid hormone patterns in saddleback wrasses are paralleled by differences in gonadal ultrastructure and steroid hormone synthetic capacity. Females exhibited greater gonadal E2 synthetic capacity than advanced sex changers in vitro when stimulated by salmon gonadotropin, while terminal phase males showed greater 11KT synthesis than females in vitro with advanced sex changers being intermediate . A follow up study compared terminal phase males with female-mimic initial phase males . Initial phase males are externally indistinguishable from females except for the genital papilla. This external similarity is likely important for success in ‘sneaker’ mating tactics (a topic I return to in section 3). Initial phase male saddleback wrasses show both lower plasma levels and lower production of 11KT by the testes in vitro than terminal phase males.
In keeping with other sex modifying kinds, highest amounts of Age
Stoplight parrotfish (Sparisoma viride) exhibit a similar pattern of sexual phenotype differentiation characterized by diandric protogyny with colorful and territorial terminal phase males and initial phase males that are very similar to females in external morphology. As with saddleback wrasses, terminal phase male stoplight parrotfish exhibit higher 11KT levels than females or initial phase males while females exhibit the highest E2 levels [16,17]. Continue reading « Gonadal steroid hormonal designs explained with other gender changing species are fundamentally in line with those to own saddleback wrasses »