Tree density, pollen-ovule ratio, and sex ratio in dioecious wind pollinated trees

• Published in: Journal of theoretical biology Vol. 97; no. 2; pp. 289 - 298
• Main Author: Lewis, Allen R.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.01.1982
• ISSN: 0022-5193; 1095-8541
• DOI: 10.1016/0022-5193(82)90105-9

The comparative reproductive success of male and female trees of a wind pollinated species is studied by simulation. Young trees are recruited into an established forest. When the sex ratio of the established forest is even, the reproductive success of both male and female recruits increases with forest density, and in general a recruit of either sex contributes the same number of successful gametes. When the sex ratio of the established forest deviates from unity, the recruit of the minority sex has a reproductive advantage over the recruit of the majority sex. Because a forest with a biased sex ratio can produce the same level of pollination as a forest with an even sex ratio, the quantity of pollen reaching the stigma of a flower does not convey enough information to permit the sex ratio of progeny to be biased adaptively as has been claimed. The male recruit has a slight advantage over the female recruit when the pollen-ovule ratio is low and vice versa. The biological importance of this phenomenon is uncertain.