Variation in wing pattern and palatability in a female-limited polymorphic mimicry system

Area of Science:

• Evolutionary Biology
• Ecology
• Animal Behavior

Background:

• Butterflies in the genera Euphydryas and Chlosyne show color pattern variations across California.
• These variations suggest potential mimicry, particularly a female-limited polymorphic mimicry (FPM) system in Chlosyne palla.
• Polymorphic models challenge traditional mimicry theory predictions.

Purpose of the Study:

• To investigate the palatability of different color morphs of checkerspot butterflies to a common predator.
• To determine if observed color patterns in Euphydryas chalcedona and Chlosyne species represent a mimetic relationship.
• To test the hypothesis of a female-limited polymorphic mimicry system in Chlosyne palla.

Main Methods:

• Palatability trials were conducted using European starlings (Sturnus vulgaris) as avian predators.
• Different color morphs of Euphydryas chalcedona, Chlosyne palla, and Chlosyne hoffmanni were presented to predators.
• Predator learning and rejection behaviors were observed and analyzed.

Main Results:

• The black morph of Euphydryas chalcedona was found to be distasteful but not toxic to predators.
• The red morph of E. chalcedona, along with both morphs of Chlosyne palla and Chlosyne hoffmanni, were palatable.
• Predators that learned to avoid the distasteful black E. chalcedona also rejected black C. palla.

Conclusions:

• The results support a mimetic relationship between black Euphydryas chalcedona and black Chlosyne palla, with C. palla acting as a female-limited polymorphic mimic.
• Chlosyne hoffmanni does not appear to be involved in this specific mimicry system.
• The study provides empirical evidence for polymorphic mimicry and challenges existing mimicry theory.