Table 2.
Comparison of open-pollinated flowers |
|||
---|---|---|---|
Comparison of outcrossed flowers | F < H | F = H | F > H |
F < H | FD | – | – |
F = H | FD due to pollen limitation | No FA | FA mainly due to the avoidance of ID |
F > H | FD due to pollen limitation. FA may be pollinator dependent* | FA may be pollinator dependent* | FA not (entirely) due to the avoidance of ID |
When female (F) vs. hermaphrodite (H) comparisons were performed in both open-pollinated and artificially outcrossed flowers, several combinations of results could be found for a given trait. Whereas comparisons of open-pollinated flowers highlight whether females benefit from a female advantage (FA) or disadvantage (FD) in natural conditions, comparisons based on hand-pollinated (outcross) flowers provide information on whether the avoidance of self-pollination and associated inbreeding depression (ID) may be one proximal explanation of this fitness advantage, as soon as they were performed in the same ecological conditions as open pollinations.
A dash indicates situations that have not been reported in this review. In cases marked by an asterisk, a female advantage could occur (probably due to resource reallocation, rather than avoidance of ID) in non-pollen-limited situations.