Rubber bathtub mats, rope-soled deck shoes, and astronauts’ Velcro-soled booties attest to humans’ preference for nonskid footing. For pollinating creatures such as bees, the same seems to be true. A new study has revealed that in simulated windy conditions, bees choose flowers that have conical-shaped cells on their petals. The microscopic cell structures provide welcome anchor points for the bees as they perch on wind-tossed petals to slurp up nectar.
“The bees’ claws hook in between the cells, kind of like Velcro, and it helps them hold onto the flower better,” says Katrina Alcorn of the University of Cambridge, first author of the paper. Coauthors Beverley Glover, also at Cambridge, and Heather Whitney of the University of Bristol had previously shown that when it comes to hard-to-handle flowers, such as snapdragons, pollinators prefer petals outfitted with grippy conical cells to those with smoother textures. The researchers wondered if the tactile benefit of the cells extended to other flowering plants with simpler architectures.
To find out, the team presented bumblebees with two kinds of petunias: one with normal conical cells and a mutant with flat cells. Both types of flowers were placed on a platform in the lab that shook the petunias about as if blown by natural breezes.
With the flowers in motion, the bumblebees favored the conical-celled petunias over the slipperier alternative. The results show why the tiny petal structures have proven such a popular feature throughout evolutionary history. “You find the conical cells pretty much across all plant families, so we think that’s fairly good evidence that they evolved early on,” says Alcorn. (Functional Ecology)