The missing male in plant reproduction and floral evolution

More than 90% of the flowering plant species are hermaphroditic, and gain their fitness through both sexes.

However, current understanding of plant reproductive ecology and floral evolution is nearly exclusively based on female function.

This strikingly contrasts with a theoretically expected higher importance of male function, due to higher variance in male reproductive success (RS) compared to female RS. This project addresses key knowledge gaps in our understanding of floral evolution by focusing on the male part.

Specifically, we will empirically test the following theoretical predictions:1) The flower is a male structure, i.e., traits are closer to the optimum for seed siring than for seed production.2) Sexually antagonistic selection maintains trait variation, in particular in traits involved in pollen-pistil interactions. 3) Selection via male RS occurs both in the pollination and post-pollination phase, and the relative importance of the latter increases with pollination intensity. 4) Sexual conflict is context-dependent: Selection via female fitness and sexual conflict is strongest at low pollination intensity, and selection via male fitness dominates at high pollination intensity. 5) High pollination intensity leads to the evolution of more ´male-biased´ traits.We will couple paternity analyses of pollen and seeds with selection and experimental evolution experiments to test the role of male function and sexual conflict in the evolution of plant reproductive traits.