Remote perception of floral nectar by bumblebees.

Area of Science:

• Ecology
• Animal Behavior
• Plant-Pollinator Interactions

Background:

• Bumblebees (Bombus spp.) frequently visit flowers but do not always collect nectar.
• Understanding the cues bumblebees use to assess flower rewards is crucial for plant-pollinator dynamics.

Purpose of the Study:

• To investigate how bumblebees assess nectar availability in flowers.
• To determine if bumblebees use external cues to predict nectar rewards and optimize foraging.

Main Methods:

• Laboratory experiments with artificial flowers presenting visual and olfactory cues.
• Field observations of bumblebees foraging on natural plant species (dogbane, red clover, fireweed, monkshood).
• Analysis of nectar content in relation to bee visitation and rejection rates.
• Testing predictions of an optimal foraging model.

Main Results:

• Bumblebees approached and rejected non-rewarding flowers when cues were present.
• Flowers probed by bees had higher nectar content than rejected or randomly chosen flowers.
• An optimal foraging model accurately predicted bumblebee rejection rates and acceptance thresholds based on handling time and resource availability.

Conclusions:

• Bumblebees utilize remotely perceived cues to assess flower profitability.
• Bees adjust their foraging behavior to maximize nectar intake rates, demonstrating sophisticated decision-making.
• These findings highlight the importance of floral cues in mediating plant-pollinator interactions and foraging efficiency.