Intraspecific neighbourhood effects on male and female fitness in Moricandia moricandioides

The spatial arrangement of individuals within plant populations is largely shaped by seed dispersal mechanisms, resulting in characteristic patterns of individual and genetic aggregation. These configurations can directly influence individual fitness, especially in insect-pollinated and self-incompatible species, where neighbourhood density and genetic relatedness may influence pollinator visitation and the likelihood of compatible mating events. In this study, we analysed a natural population of Moricandia moricandioides, a hermaphroditic, self-incompatible, and insect-pollinated species. All individuals in a 15 m×15 m plot were mapped and sampled for genetic analyses. We quantified floral traits (flower number and corolla diameter), fruit, and seed production in 50 of the 179 plants in the plot. Male reproductive success was estimated through the paternity analyses of seedlings. We detected a pattern of isolation by distance. The presence of neighbouring plants was associated with a reduced fruit production, while floral traits significantly influenced all components of female reproductive success, independently of neighbourhood context. In contrast, siring success depended on the interaction between floral traits and the presence of conspecific neighbours. Furthermore, the number of neighbours and their genetic relatedness had a significant negative effect on siring success. However, they were associated with an increase in the mean genetic distance to pollen donors, suggesting that local genetic structure can influence mating patterns. These findings illustrate the complex interplay among neighbourhood composition, floral display, and reproductive success in M. moricandioides, contributing to our understanding of how ecological and genetic neighbourhoods shape plant reproductive strategies.