Butterfly wing patterns in flight create powerful illusory motion cues

Key Points:

• Researchers developed a biologically informed elementary motion detector (EMD) model to quantify how butterfly wing patterns influence motion detection, simulating avian predator vision with spatial and temporal filtering based on passerine visual acuity and flicker fusion frequency.
• High-speed recordings of butterfly take-offs from seven morphotypes across five species were analyzed using the EMD model to measure motion confusion metrics (forwards and sideways confusion), comparing natural wing patterns to averaged, black, and white treatments.
• A comprehensive dataset of 757 European butterfly morphotypes was scanned and used to create three-dimensional animated flight simulations with species-specific wingbeat frequencies, enabling analysis of wing pattern and shape features influencing motion confusion using random forest models incorporating phylogenetic information.
• In silico evolution experiments employing genetic algorithms simulated natural selection for motion confusion traits across different butterfly wing shapes, demonstrating that butterflies evolved patterns enhancing motion confusion metrics compared to random selection and unevolved populations.
• A behavioral validation study involving 100 human participants playing a high-frame-rate touch-screen butterfly capture game showed that motion confusion metrics predicted variations in capture success and click patterns, supporting the ecological relevance of the model’s predictions on predator-prey interactions.