Honeybees use absolute rather than relative numerosity in number discrimination

Area of Science:

• Comparative Cognition
• Animal Behavior
• Numerical Cognition

Background:

• Vertebrates often rely on relative numerosity (e.g., larger/smaller) for quantity comparisons.
• Honeybee numerical abilities share similarities with vertebrates, but their numerosity use is unexplored.

Purpose of the Study:

• To investigate whether honeybees use absolute or relative numerosity in quantity assessments.
• To compare honeybee numerical processing with that of vertebrates.

Main Methods:

• Free-flying honeybees were trained to discriminate images with three dots against varying distractors.
• Two groups were trained on 'larger' (3 vs. 2) or 'smaller' (3 vs. 4) numerosity tasks.
• Novel stimuli were used for testing, varying stimulus characteristics and position across trials.

Main Results:

• Both bee groups preferred the three-item stimulus, indicating absolute numerosity use.
• Honeybees demonstrated ratio-dependent numerical discrimination, performing better on 2 vs. 3 than 3 vs. 4.
• This ratio-dependency is a numerical property also observed in vertebrates.

Conclusions:

• Honeybees utilize absolute numerosity, differing from the relative numerosity typically used by vertebrates.
• Despite this difference, honeybees share fundamental numerical processing properties with vertebrates.
• The findings highlight both unique and common aspects of numerical cognition across species.