Data from: Anther rubbing, a new mechanism that actively promotes selfing in plants

Self-fertilization has recurrently evolved in plants, involving different
strategies and traits, often involving loss of attractive functions,
collectively known as the selfing syndrome. However, few traits have been
described that actively promote self-fertilization. Here we describe a
novel mechanism promoting self-fertilization in the Brassicaceae species
Erysimum incanum. This mechanism, which we called anther rubbing, consists
of autonomous, repeated, and coordinated movements of the stamens over the
stigma during flower opening. We have documented anther rubbing by
time-lapse videos and experimentally show that it causes self-pollen
deposition on stigmas and is sufficient to achieve maximal reproductive
output in E. incanum. We predict that these movements should occur in
species with limited inbreeding depression, and indeed we find that
inbreeding depression in seed production is negligible in this species.
While many studies have documented complex floral traits that promote
outcrossing, the occurrence of anther rubbing demonstrates that plants can
evolve elaborate and under-appreciated adaptations to promote
self-fertilization.