The flexibility in the sexual expression of a species and the evolution of sequential hermaphroditism in previously gonochoristic populations can be simulated by setting the initial frequencies of each sex and the predominance of lifetime males and females, with which can occurs four flexibility strategies (Warner, 1975): (1) change from a male to female (protandry); (2) change from female to male (protogyny); (3) change from female to hermaphrodite (protogynous hermaphroditism); (4) change from male to hermaphrodite (
protandrous hermaphroditism).
Involvement of estradiol 17 on the processes of natural and control sex reversal in
protandrous black porgy (Acanthopagrus schlegeli).
Reproduction, development and population biology of the Caribbean ophiuroid Ophionereis olivacea, a
protandrous hermaphrodite that broods its young.
Such changes in the sex ratio with age provide indirect evidence that Saxidumus purpuratus is likely a
protandrous hermaphrodite that undergoes a sex change.
Three strategies are observed: protogynous (female-to-male, common amongst coral reef fishes such as groupers, parrotfishes and wrasses);
protandrous (male-to-female, as in anemone fishes); and sequentially bidirectional sex change (sex change in either direction, common in gobies).
Activation of brain steroidogenesis and neurogenesis during the gonadal differentiation in
protandrous black porgy, Acanthopagrus schlegelii.
danaeifolium (90 days), they may be either
protandrous or protogynous.
Similar results of
protandrous have been observed in previous studies (Young et al., 2002; Wani et al., 2006).
The first is called "Type I" or "
protandrous", because the staminate structure matures first.
In carrot each flower has 2 ovules; however, a
protandrous condition is prevalent in the flowers [44].
Typical of the tribe Cichorieae, all florets possessed ligulate corollas, were perfect, and
protandrous. On the first day of anthesis, the flowers were functionally male; the fused anthers extended upward and were dehisced with the style retracted within the staminal tube and the stigmadc lobes appressed.
In contrast, species with a hermaphroditic life history (either protogynous or
protandrous) might not have an adequate abundance of sexually mature individuals across sizes and ages (Provost and Jensen (1)).