Pollen Wars: Explosive Pollination Removes Pollen Deposited from Previously Visited Flowers

Area of Science:

• Plant reproductive biology
• Ecology
• Evolutionary biology

Background:

• Flowers produce excess pollen, leading to competition for ovule access.
• Pollen competition can occur on pollinators due to limited space for pollen deposition.

Purpose of the Study:

• To investigate explosive pollen deposition in Hypenia macrantha.
• To determine if this mechanism enhances male reproductive success by reducing pollen loads from prior visits.

Main Methods:

• Simulated floral visits using a hummingbird skull.
• Quantified pollen grain dislodgement from triggered and untriggered flowers.

Main Results:

• Untriggered flowers dislodged nearly twice as many pollen grains compared to already-triggered flowers.
• Pollen removal increased with the amount of pollen deposited by the explosive mechanism.
• Pollen deposition precision and force are critical for effective pollen removal.

Conclusions:

• Explosive pollen placement in H. macrantha may offer a prepollination male advantage.
• This mechanism, found in diverse angiosperms, could be a widespread evolutionary strategy.
• The findings shed light on the intricate dynamics of pollen competition and plant mating systems.