Convergent flight morphology among Müllerian mimic mutualists

Area of Science:

• Evolutionary Biology
• Ecology
• Animal Behavior

Background:

• Müllerian mimicry relies on shared warning signals between prey species to deter predators.
• While color patterns are well-studied, other traits like flight morphology are less understood in mimicry systems.
• Predators use multiple cues, not just color, to identify prey.

Purpose of the Study:

• To investigate convergent evolution in flight-related morphology within butterfly mimicry complexes.
• To test if morphological convergence aligns with color-based mimicry groups.
• To understand how flight mechanics might influence mimicry evolution.

Main Methods:

• Phylogenetic comparative analyses of 51 butterfly species across eight mimicry complexes in Ecuador.
• Examined 14 flight-related morphological variables.
• Clustered species based on morphological traits to identify patterns of convergence and divergence.

Main Results:

• Identified three distinct clusters of morphological space: 'large yellow transparent,' 'tiger,' and 'transparent'.
• Found evidence of convergence within and between mimicry complexes within these clusters.
• Demonstrated divergence between mimicry complexes from different morphospace clusters.
• Morphological clusters differed in size, body, and wing shape, suggesting convergent flight biomechanics.

Conclusions:

• Flight-related morphology converges among mimic species, forming distinct clusters independent of color patterns alone.
• Locomotor mimicry is supported, where flight biomechanics align with visual signals.
• Constraints like predator discrimination and evolutionary rates limit morphological diversity, explaining the observed clustering.
• The interplay between morphology and color pattern evolution suggests that color changes may be constrained by existing flight morphology.