The effect of species role and trait-matching on plant fitness in a plant-hummingbird interaction network*

In animal-pollinated plants, fitness is affected by pollinator attraction and plant-pollinator trait matching. Plantpollinator interactions are often characterized using metrics derived from mutualistic networks, such as centrality and interaction selectivity. This approach often focuses on the species level, thus neglecting significant among-individual variation in attracting foraging pollinators and associated fitness consequences for plants. Here, we tested if centrality and interaction selectivity were related to fitness at the species and the individual level for 14 hummingbird-pollinated plant species in the Atlantic Forest. In addition, we tested if plant-pollinator trait-matching influenced plant fitness. At the species-level, we did not find a relationship between plant fitness and centrality nor interaction selectivity; we found instead that plant fitness increased with higher trait-matching between bill and corolla lengths. At the individual-level we found that individuals with higher centrality values produced less seeds, likely due to lower quality in pollen deposition. Moreover, individuals with a lower interaction selectivity also produced more seeds, probably because of higher conspecific pollen flow. Our results show that individual position and interaction selectivity within pollination networks may have important implications for pollination effectiveness and hence plant fitness.

Automated summary

This study examined the relationship between fitness and interaction selectivity at both the species and individual level in 14 hummingbird-pollinated plant species in the Atlantic Forest. At the species level, there was no relationship between plant fitness and centrality or interaction selectivity, but there was a positive relationship between plant fitness and trait-matching between bill and corolla lengths. At the individual level, individuals with higher centrality values produced fewer seeds likely due to lower pollen deposition quality, while individuals with lower interaction selectivity produced more seeds probably due to higher conspecific pollen flow.