Trioecy , also spelled triecy, is a sexual system characterized by the coexistence of Male, females, and . It has been found in both plants and .
Terminology
Trioecy is also called
tridioecy and
subdioecy .
The term trioecy comes from the Neo-Latin word Trioecia, a former order of trioecious plants.
Evolution of trioecy
Trioecy may be an unstable transient state
associated with evolutionary transitioning from
gynodioecy to
dioecy.
In
brachiopod species, trioecy usually breaks into androdioecy or gynodioecy.
Other studies show that trioecious populations originated from
Gonochorism ancestors which were invaded by a mutant selfing hermaphrodite, creating a trioecious population.
It has been suggested that chromosomal duplication plays an important part in the evolution of trioecy.
But one study found that trioecy can be stable under nucleocytoplasmic sex determination.
Occurrence
Trioecy is a relatively common sexual system in plants,
estimated to occur in about 3.6% of
flowering plant species,
although most reports of trioecy could be misinterpretations of
gynodioecy.
It is rare as well as poorly understood in animals.
Species that exhibit trioecy
The following species have been observed to exhibit a trioecious breeding system.
Plants
Animals
-
Aiptasia diaphana
-
Auanema rhodensis
-
Auanema freiburgensis
-
Hydra viridissima
-
Thor manningi
-
Semimytilus algosus Pacific mussel
See also
