Balanced polymorphisms and their divergence in a Heliconius butterfly

Area of Science:

• Evolutionary Biology
• Ecology
• Behavioral Ecology

Background:

• Müllerian mimicry theory predicts convergence of warning signals in similarly defended species for predator deterrence.
• However, significant diversity in warning patterns exists among Müllerian mimics, such as Heliconius butterflies.
• Polymorphic mimicry, where multiple warning patterns coexist within a population, presents an evolutionary paradox due to potential predator punishment of novel signals.

Purpose of the Study:

• To investigate the selective pressures maintaining polymorphic mimicry in the Heliconius doris butterfly species.
• To understand the role of positive frequency-dependent selection in shaping mimetic warning coloration diversity.

Main Methods:

• Utilized artificial butterfly models across Central and South America to assess predator interactions.
• Analyzed selective pressures acting on different warning patterns within Heliconius doris populations.

Main Results:

• Demonstrated the complex nature of positive frequency-dependent selection, a key driver of Müllerian mimicry.
• Showcased how this selection regime influences interspecific variation in mimetic warning coloration.
• Highlighted that frequency-dependent selection can both impede and promote the diversification of mimetic traits.

Conclusions:

• The study elucidates the intricate mechanisms sustaining polymorphic mimicry in Heliconius butterflies.
• Findings underscore the multifaceted impact of frequency-dependent selection on the evolution of warning signals.
• Suggests that positive frequency-dependent selection plays a crucial role in balancing signal convergence and diversification.