Natural Selection for Miillerian Mimicry in Heliconius erato in Costa Rica

Area of Science:

• Ecology
• Evolutionary Biology
• Behavioral Ecology

Background:

• Heliconius erato butterflies are unpalatable and exhibit Müllerian mimicry.
• Müllerian mimicry involves multiple unpalatable species sharing similar warning signals.
• This mimicry is hypothesized to provide a survival advantage against predators.

Purpose of the Study:

• To investigate the protective role of Müllerian mimicry in Heliconius erato.
• To determine if altered warning patterns affect butterfly survival and predation rates.

Main Methods:

• The natural color patterns of Heliconius erato were experimentally modified to a nonmimetic pattern.
• Modified and control (unaltered) butterflies were released into natural populations.
• Observation periods recorded butterfly residency time and quantified wing damage as an indicator of predator attacks.

Main Results:

• Nonmimetic Heliconius erato individuals were preyed upon more frequently than control individuals.
• Modified butterflies had shorter residency times in natural populations.
• Increased wing damage was observed on nonmimetic butterflies, suggesting higher predation pressure.

Conclusions:

• The study provides strong evidence that Müllerian mimicry confers significant protection against predation for Heliconius erato.
• Deviations from the common warning pattern increase vulnerability to predators.
• The findings support the evolutionary significance of mimicry complexes in predator-prey dynamics.