monoecie

Monoecie, or monoecy, is a biological term for organisms that have both male and female reproductive structures or functions on a single individual. In botany, monoecious plants bear distinct male flowers and female flowers on the same plant. The male flowers produce pollen and the female flowers develop ovules and seeds. The arrangement can vary: male and female flowers may appear on separate inflorescences on the same plant, or, in some species, the flowers may be unisexual rather than bisexual. Monoecy is contrasted with dioecy, in which individual plants are strictly male or female.

In animals, the term is used less frequently, but it describes simultaneous hermaphroditism, where an individual possesses both male and female reproductive organs at the same time. This contrasts with sequential hermaphroditism, where an individual changes sex during its lifetime. Simultaneous monoecy is common in many invertebrates, such as earthworms and numerous gastropods, and can influence mating systems and population dynamics.

Examples in plants include maize (corn), cucumbers, melons, squash, and many trees such as oaks and some conifers, which bear both types of flowers on the same plant. In animals, organisms like earthworms and many terrestrial snails exhibit monoecy, enabling reproduction when mates are scarce or dispersed.

Ecologically, monoecy can enhance reproductive assurance and flexibility in fragmented or isolated habitats. However, it may also increase the potential for self-fertilization in some plant species, leading to inbreeding unless counteracting mechanisms limit selfing.