Stress decreases pollen foraging performance in honeybees

Area of Science:

• Behavioral Ecology
• Insect Physiology

Background:

• Foraging in honeybees (Apis mellifera) is crucial for colony survival but energetically demanding.
• Stressors can increase metabolic demands, potentially impairing essential activities like foraging.

Purpose of the Study:

• To investigate the impact of a controlled stressor on honeybee foraging performance and preferences.
• To explore the neurochemical and behavioral changes associated with stress in foraging bees.

Main Methods:

• Honeybees were subjected to a controlled, non-pathogenic immune challenge as a stressor.
• Foraging preferences, trip duration, and octopamine levels in the brain were measured in stressed and control bees.
• Pollen and nectar foraging energetic costs and returns were considered based on existing literature.

Main Results:

• Immune-challenged bees exhibited altered foraging preferences, reducing pollen collection.
• Pollen foragers experienced increased trip durations under stress.
• Octopamine levels in the brains of pollen foragers were reduced by the stressor.

Conclusions:

• Stress, even at low levels, detrimentally affects honeybee foraging, particularly for pollen.
• Stressed bees may prioritize nectar foraging due to its higher energetic return relative to effort.
• These behavioral shifts can have significant implications for the colony's nutritional balance.