Functional consequences of temporal reversal of height dimorphism for pollen and seed dispersal in a dioecious plant

Dioecious plants commonly exhibit sexual dimorphism in height although its ecological and evolutionary significance have rarely been examined experimentally. Here, we investigate the functional consequences of the temporal reversal of height dimorphism for pollen and seed dispersal in dioecious Rumex hastatulus, a species in which males are taller than females at flowering and the reverse pattern occurs at fruiting.

Populations of this colonizing weed of open fields are wind-pollinated and seeds wind dispersed.In a glasshouse experiment we manipulated the height of pollen donors and using sex-specific genetic markers compared the paternal success of males of contrasting height and whether seed families showed evidence of sexual dimorphism in early life history traits. In a second glasshouse experiment using fruiting plants we also examined how female height influenced the distance that seeds were dispersed.Taller males had significantly higher siring success than males of equivalent height to flowering females.