Bees assess pollen returns while sonicating Solanum flowers

Area of Science:

• Ecology
• Animal Behavior
• Pollination Biology

Background:

• Recent studies suggest bees cannot accurately assess pollen collection rates during foraging.
• This challenges our understanding of bee foraging efficiency and sensory feedback mechanisms.

Purpose of the Study:

• To investigate whether bees (Ptiloglossa and Bombus) can accurately gauge accumulating pollen loads while foraging.
• To determine if bees adjust their foraging behavior based on real-time pollen availability within flowers.

Main Methods:

• Studied bees foraging on Solanum elaeagnifolium, a pollen-only resource.
• Experimentally manipulated flowers by gluing anthers or emptying them of pollen to eliminate "pollen feedback."
• Compared bee handling times, buzzing, and grooming behaviors on manipulated versus natural flowers.

Main Results:

• Bees (Bombus and Ptiloglossa) significantly altered their floral handling times, buzzing, and grooming based on available pollen.
• Bees spent longer on natural, pollen-rich flowers and exhibited more grooming and buzzing.
• Visits to pollen-depleted flowers were shorter with reduced buzzing and grooming.

Conclusions:

• Bees possess the ability to assess pollen harvest on a flower-by-flower basis.
• Foraging bees actively adjust their harvesting tempo in response to pollen availability (standing crop).
• This sensory feedback mechanism is crucial for efficient pollen collection in bees.