Sexual specialization and inbreeding avoidance in the evolution of dioecy
is a trait that is of considerable interest in mapping, and molecular markers have been linked to dioecy
in a number of angiosperms (Ainsworth, 2000; Charlesworth, 2002; Vyskot and Hobza, 2004).
However, given that functional protandric dioecy
has been shown to occur in P.
As a group, molluscs exhibit highly diverse modes of sexual reproduction, ranging from functional hermaphroditism, alternative sexuality, to strict dioecy
and genetic determination (Coe 1943; Guo and Allen 1994a).
In Angiosperms the return to unisporangiate flowers together with monoeicy and dioecy
, is most obviously associated with wind pollination.
in Bromeliaceae has been reported for all three: Tillandsioideae (some populations of taxa in the genus Catopsis Griseb.
The relationship between crop size and fruit removal and its implication for the evolution of dioecy
One reproductive pathway that seems to have occurred repeatedly within the angiosperms is the evolutionary breakdown of hermaphroditism (cosexuality) towards gender dimorphisms such as dioecy
and gynodioecy (de Arroyo and Raven 1975, Webb 1979, Sakai et al.
Evolution of dioecy
in flowering plants* Annual Review of Ecology and Systematics 11: 15-39.
Ecology of plant dioecy
in the intcnnountain region of western North America.
The consequences of limited mate availability for the evolution of SI systems were discussed by Charlesworth (1988) and Lloyd and Webb (1992), and limited mate availability has been invoked in comparisons of reproductive efficiency in dioecy
versus gametophytic SI (Anderson and Stebbins 1984, 1994; Karoly 1994).
The incidence of dioecy
varies considerably in different regional floras (summarized in Steiner 1988), including values as low as 2.