Resource competition, character displacement, and the evolution of deep corolla tubes

Authored by Miguel A Rodriguez-Girones, Luis Santamaria

Date Published: 2007

DOI: 10.1086/520121

Sponsors: Spanish Ministries

Platforms: No platforms listed

Model Documentation: Other Narrative Mathematical description

Model Code URLs: Model code not found

Abstract

It is normally thought that deep corolla tubes evolve when the plant's successful reproduction is contingent on having a corolla tube longer than the tongue of the flower's pollinators. Combining optimal foraging theory and quantitative genetics in a spatially explicit, individual-based model, we show that flowers with long corolla tubes can alternatively evolve because they promote resource partitioning among nectar feeders and increase the probability of conspecific pollen transfer. When there is competition for resources, long-tongued flower visitors feed preferentially at deep flowers and short-tongued visitors at shallow flowers. Both plant species thus benefit when the depths of their corollas are so different that each flower visitor specializes on one species. Resource competition can promote the evolution of deep corollas despite the presence of significant amounts of noise, such as deviations from optimal foraging behavior due to perceptual errors or temporal fluctuations in the relative abundance of competing pollinator species. Our results can explain the evolution of long corollas in a number of systems that do not conform to the traditional view.

Tags

morphology selection Community Constraints Hypothesis Bumble bees Fly pollination Flower visitors Long tongues Sphingidae