Frequency dependence of pollination - from individual behaviour to community dynamics

• Applicant: Dr. Gita Benadi
• Subject Area: Ecology and Biodiversity of Animals and Ecosystems, Organismic Interactions ; Ecology and Biodiversity of Plants and Ecosystems
• Term: from 2016 to 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 323765545

How species with similar resource requirements are able to coexist is one of the oldest and most central questions in ecology. Theoretical work has shown that a negative relationship between each species' relative abundance and its fitness (negative frequency dependence) is necessary for stable coexistence, while positive frequency dependence destabilizes coexistence and leads to a loss of diversity. In many plant species, fitness depends on pollination by animals, but how the pollination success of plant species varies with their frequency is not fully understood. Previous theoretical studies have suggested that pollination success should be positively frequency dependent under most conditions, but these predictions were based on simple models of pollinator foraging behaviour. Moreover, it is currently unclear how plant and pollinator traits and environmental conditions influence the strength and direction of frequency dependence of pollination.The aim of this proposed research project is to investigate the effect of plant frequency on pollination success using a combination of individual-based modelling, a laboratory experiment and a field study. The individual-based approach will allow me to model pollinator foraging behaviour in more detail than previous studies and account for limited information in individual decision-making. I will then compare the model's predictions to empirical data from a laboratory experiment of bumblebees foraging on artificial flowers, which enables me to control all environmental factors that can influence the foraging decisions of pollinators. In a field study of an entire species-rich plant community in the Fynbos biome of South Africa, I will test the model's predictions under more complex natural conditions with frequency variation at multiple spatial scales, and assess the effects of the structure of the plant-pollinator network on flower visitation and seed set in relation to frequency. Overall, this project will help us understand under which conditions pollination by animals promotes or impedes species coexistence in plant communities, and thereby contribute to preserving species-rich communities of flowering plants in a rapidly changing world.

• DFG Programme: Research Grants