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Size–number trade‐off and allocation to flower production in animal‐pollinated flowers
Author(s) -
Sakai Satoki
Publication year - 2000
Publication title -
plant species biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.419
H-Index - 36
eISSN - 1442-1984
pISSN - 0913-557X
DOI - 10.1111/j.1442-1984.2000.00045.x
Subject(s) - biology , pollinator , human fertilization , pollination , hermaphrodite , trade off , self pollination , botany , horticulture , pollen , ecology , agronomy
The evolutionarily stable size of attractive structures of a flower was analyzed theoretically to examine the factors that select for the differences in the size of attractive structures of a flower depending on the sexuality and self‐fertilization rate. In the first analysis, it was assumed that the size–number trade‐off for flowers is non‐linear (the size of individual flowers increases less rapidly than in a linear trade‐off with a decrease in the number of flowers, as would occur during a linear trade‐off) and the frequency of pollinator visits per flower depends on the size of attractive structures of individual flowers, but is independent of the number of flowers on the plant. In this case the size of attractive structures is larger in male flowers than in female flowers in dioecious plants, and this size decreases with an increase in the self‐fertilization rate for hermaphroditic plants (where both are consistent with the general trends observed). In the second analysis, it was assumed that the size–number trade‐off for flowers is linear and the frequency of pollinator visits per flower depends not only on the size of attractive structures of individual flowers, but also on the number of flowers on the plant. However, the results were inconsistent with the general trends in this case; namely, that the size of the attractive structures is smaller in male flowers than in female flowers in dioecious plants, and this size increases with an increase in self‐fertilization rate for hermaphroditic plants. I therefore conclude that the non‐linearity in size–number trade‐offs for flowers is a more useful factor to use to explain the general trends in the size of attractive structures of a flower. This also suggests that the attractive function hypothesis, that is, the differences in fitness gains through allocation to attractive structures between males and females and among plants with different self‐fertilization rates, are important factors, but alone cannot explain the general trends.