Abstract

Pollen competitive ability will only be selected if competitive situations are frequent under natural conditions. A trait must also exist that, in various instances, increases competitive ability and has a variance large enough to allow differences to persist even when affected by stochastic factors imposed by pollinator behaviour. An indication of these prerequisites is that non-random mating is common in a species. In this study on pollen competition in Viola tricolor, one donor was superior at siring ovules in 23 of 34 crosses, which indicates that nonrandom mating is common in this species. We also found maternal effects on siring ability, although they were not large enough to reverse ranking order of donors. Of two pollen traits potentially important for pollen competitive ability (i.e. tube growth rate and germination ability), only pollen tube growth rate had significant effects on siring ability. Variability in pollen tube growth rate was high enough to allow fast tube growth to be beneficial even when the effect of stochastic factors (i.e. time and place of pollen deposition) was taken into account. Taken together, these results make it plausible that sexual selection can act on pollen tube growth rate in Viola tricolor.

Keywords

mate choice; non-random mating; plants; pollen tube growth rate; sexual selection; Viola tricolor

Published in

Evolutionary Ecology Research
1999, Volume: 1, number: 8, pages: 971-985
Publisher: EVOLUTIONARY ECOLOGY LTD

UKÄ Subject classification

Evolutionary Biology
Ecology


Permanent link to this page (URI)

https://res.slu.se/id/publ/42103