Cleaner blues: Condition-dependent colour and cleaner fish service quality

Area of Science:

• Animal Behavior
• Ecology
• Sensory Biology

Background:

• Vivid colors in sexual signals often indicate individual quality.
• Interspecific signals are typically associated with species identity and signal detection.
• Assessing individual quality can be advantageous in interspecific interactions, such as client-cleaner relationships.

Purpose of the Study:

• To investigate if color differences in interspecific signals convey information on individual quality.
• To determine if diet-induced oxidative stress affects the blue skin color and cleaning service quality of cleaner wrasses (Labroides dimidiatus).

Main Methods:

• Cleaner wrasses were fed an oxidized diet to induce oxidative stress.
• Blue skin color saturation was measured spectrophotometrically.
• Cleaning service quality was assessed by observing tactile stimulation and mouth contact with clients.
• Visual modeling was used to assess client species' perception of color changes.

Main Results:

• Cleaner wrasses on an oxidized diet showed decreased blue color saturation.
• These cleaners also exhibited reduced cleaning service quality, with less tactile stimulation and mouth contact.
• Visual modeling indicated that some client species could perceive the changes in blue color saturation, while others could not.

Conclusions:

• Vivid colors in interspecific signals, like the blue of cleaner wrasses, can convey information on individual quality.
• This finding parallels the role of color in sexual signals.
• Color changes may serve as an honest indicator of quality in interactions between different species.