Gynodioecy is the co-occurrence of females and hermaphrodites in populations. It is usually due to the combined action of cytoplasmic male sterility (CMS) genes and nuclear genes that restore male fertility. According to previous theoretical studies, it is very difficult to explain the maintenance of gynodioecy with CMS and male-fertile cytotypes, although it has been observed in some species. However, only very specific situations have been investigated so far. We present a model to investigate the conditions that promote the maintenance of this breeding system in the case of an outcrossed species when CMS and male-fertile (non-CMS) cytotypes are present in an infinite panmictic population. We show that the type of cost of restoration strongly affects the conditions for stable maintenance of gynodioecy. Stable nuclear-cytoplasmic gynodioecy requires a female advantage, which is a classical condition for gynodioecy, but also a cost of CMS for female fitness, which had been rarely investigated. A cost of restoration is also needed, which could affect either pollen or seeds. Finally, we found that gynodioecy was attainable for a large set of parameter values, including low differences in fitness among genotypes and phenotypes. Our theoretical predictions are compared with previous theoretical work and with results of empirical studies on various gynodioecious species.

The high diversity of mutualisms has probably limited the development of a general theory about their evolution and their stability. Here we review conflicts of interests occurring in the 13 known nursery pollination systems, where pollinators reproduce within the inflorescence they pollinate. We found three main conflicts of interest between mutualists that correspond to the following evolutionary questions: 1) Why do plants not kill their pollinators’ larvae? 2) Why do pollinators visit deceptive flowers? and 3) Why do pollinators pollinate? We show that the reproductive system of the plant is strongly correlated not only with the set of conflicts of interests that actually occur but also with the proximal resolution of these conflicts. In many cases the evolutionary stability of nursery pollination mutualisms relies on the avoidance of intra‐specific competition among pollinator larvae. This stabilizing factor could perhaps also explain the absence of overexploitation in other mutualisms.

It was found that a female advantage occurred in 40 species, with a magnitude comprised between 1 and 2 in the majority of cases. In many species, reduced selfing may not be a necessary cause of this advantage. Finally, female advantage varied among populations in some species, but both positive and negative correlations were found with female frequency. The role of reduced selfing in females for the evolution of gynodioecy, as well as the various processes that affect sex ratios and female advantage in populations are discussed.

This review highlights the great potential of analysing floral scent variation and including it in integrated studies of floral phenotypes. We also have identified the current gaps in our understanding of this complex signal and we propose several methodological and conceptual future directions in this research area.