Our paper on anther rubbing is now in press in The American Naturalist. It is expected to appear in the January 2019 issue. In this paper we describe a novel mechanism promoting self-fertilization in the Brassicaceae species Erysimum incanum.
This video shows anther rubbing in E. 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.
We also produced two additional videos showing flower oppening in other species:
Anther rubbing and its consequences are described in this paper:
Abdelaziz M, Bakkali M, Gómez JM, Olivieri E, Perfectti F. (2019).
Anther rubbing, a new mechanism that actively promotes selfing in plants.
The American Naturalist (in press) DOI