Conical epidermal cells allow bees to grip flowers and increase foraging efficiency

Area of Science:

• Plant biology
• Evolutionary biology
• Animal behavior

Background:

• Plant epidermal cells typically form a flat surface, with deviations often conferring evolutionary advantages.
• Conical epidermal cells are a key feature of insect-pollinated flowers, particularly on petals.
• Previous studies suggest these conical cells may attract pollinators, as bumblebees avoid snapdragon mutants lacking them.

Purpose of the Study:

• To investigate how petal surface structure influences pollinator behavior through touch-based discrimination.
• To determine the role of conical epidermal cells in facilitating pollinator interactions.

Main Methods:

• Utilized biomimetic replicas of petal surfaces to isolate tactile responses.
• Employed isogenic Antirrhinum (snapdragon) lines differing solely in petal epidermal cell shape.
• Observed and analyzed foraging bumblebee behavior in response to different petal surface structures.

Main Results:

• Bumblebees can discriminate between petal surfaces using tactile cues alone.
• Color cues are used by bumblebees to avoid flowers lacking conical cells, but only at steep angles where physical manipulation is challenging.
• Conical petal cells facilitate the physical handling of flowers by bumblebees.

Conclusions:

• Petal surface structure, specifically conical epidermal cells, plays a crucial role in pollinator interactions.
• The tactile properties conferred by conical cells aid bumblebees in handling flowers, likely contributing to their prevalence in insect-pollinated species.
• This study highlights the importance of physical interaction in plant-pollinator relationships, beyond visual or olfactory cues.