10 Differences between Monoecious and Dioecious

10 Differences between Monoecious and Dioecious plants

The term is commonly used to refer the reproductive behaviour of plants. Around 90% of the plant species are bisexual or called as `perfect' flowers; these hermaphrodites are both staminate (with stamens or male parts) and pistillate (with one or more carpels; female parts) on the same flower.

Rest 10% of plants have evolved unisexuality as spatial separation of flowers. They can be Monoecious and Dioecious. Monoecious ("Mono" =one - and the term "monoecious" is literally "one house"), plants have male flowers and female flowers in separate structures on the same plant. In dioecious plants (“two house”), male and female flowers are present on separate plant.

Monoecious	Dioecious
It means single house; the same plant “houses” both male and female flowers	It means two house; there is male plant with male flowers and female plant with female flowers
Both male and female flowers are present on the same plant	Male and female flowers are on different plants. That means there is male plant and female plant
Unisexual flowers on the same plant	Unisexual flowers on different plant
Produce male and female gametes by the same plant	Produce male and female gametes by the separate plants
Plants are capable of both self pollination and cross pollination	Plants are capable of only cross pollination
All plants are capable of seed production as there is female flowers	Seeds are produced in female plant only. That is only 50% of the individuals in populations contribute to seed production
Low genetic variation and increased homozygosity due to self pollination or inbreeding	High genetic variation and increased heterozygosity due to cross pollination
Reproductive isolation has no effect as capable of self pollination	Reproductive isolation can prevent pollination
Comparatively less efficient pollinating mechanisms as self pollination is common	Efficient pollinating mechanisms such as more flower production, large fleshy fruits etc and with different pollinating agents including insects, birds etc
Eg: Corn (Zea mays), Cucurbits (Cucumis sativus)	Eg: Papaya (Carica papaya), Date palm (Phoenix dactylifera)
Eg. of Monoecious animals: (Hermaphrodites): earthworms, Slugs, Planarians	Eg. of Dioecious animals: Mammals, insects, birds

Reference:

• Ainsworth, C. (2000). Boys and girls come out to play: the molecular biology of dioecious plants. Annals of Botany, 86(2), 211-221.
• McKown, A. D., Klapste, J., Guy, R. D., Soolanayakanahally, R. Y., Mantia, J., Porth, I.,& Hamelin, R. C. (2017). Sexual homomorphism in dioecious trees: extensive tests fail to detect sexual dimorphism in Populus. Scientific reports, 7(1), 1831.