The Ultimate Death Gaze: How Mothwing Patterns Enable Them to Escape Death

The Ultimate Death Gaze: How Mothwing Patterns Enable Them to Escape Death

A peacock butterfly with eyespots on its wings. Photo credit: Dr. Hannah Rowland

dr Hannah Rowland and Dr. John Skelhorn explain how these defensive patterns on moth wings convince birds that attacking the insects is not worth the risk.

Art reflects real life when it comes to moth wings

Have you ever had the impression that someone in a portrait is keeping an eye on you or following you around a room? The Mona Lisa Effect is the name of this optical illusion in honor of Leonardo da Vinci’s famously enigmatic masterpiece. No matter where the viewer stands, left, right or in front of the picture, eye contact is guaranteed when painters paint their subject’s eyes with perfectly centered pupils. Nature seems to have had the same thought. In the animal kingdom, however, it could be a matter of life and death.

eyespots

Many fish, butterflies, moths, mantises, and beetles have paired circular markings on their bodies that look like eyes. Eye patches can draw a predator’s attention away from vital body parts of a target (prey is much more likely to survive a tail bite than a head bite). In addition, eyespots have the power to intimidate and deter predators.

One theory is that predators mistake eye spots for the eyes of their own predators. In this case, eyespots that appear to be staring directly at them would be the most dangerous. Eye spots, like portraits whose eyes appear to follow you around space, appear to maintain eye contact with predators regardless of their viewing angle. If eyespots were shifted left or right, they would only defend victims against predators approaching from that direction.

Another explanation is that eyespots have nothing to do with eyes. Predators might be deterred not because eye spots look like eyes, but simply because they are patterns that attract attention. In the animal kingdom there are many striking colors and patterns that repel predators but don’t look like eyes – for example the red and black patterns of ladybugs. Humans can perceive ocelli as eyes, but that doesn’t necessarily mean predators do either. You can just see “scary” conspicuous markings.

Create the ultimate death gaze

We tested the idea that forward-facing eyespots appear to stare at predators by placing artificial moths against newly hatched domestic chicks. We created the moths by tacking paper triangles over mealworms – a favorite food of chicks. The paper triangles were printed with eye-spots in one of three configurations: either perfectly concentric circles or with the center circle shifted to the right or left. All prey items have been designed to be equally conspicuous to the predators. To us, these appeared to be facing straight ahead or to the side. Would gaze direction affect chick attack motivation?

face death

Next we built three miniature catwalks (well actually chick catwalks) to lead the chicks to the moth. One led directly to the prey, and the other two instructed the chicks to approach the moth from either the left or the right. We measured how long it took a chick to approach and attack each species of moth from each of the three directions.

Chicks approached slowly from the left when the moth’s eyespot was shifted to the left, and slowly to approach from the right when the moth’s eyespot was shifted to the right. However, when chicks approached these moths from the opposite direction, they quickly approached the moth and ate the mealworm. The chicks approached the moths slowly, with concentric circular eyespots coming from all three directions.

Our results are consistent with the idea that the chicks perceived our artificial eyespots as eyes and that eyespots are most effective when they appear to be staring at predators. Eye spots, which are concentric circles, appear to stare at predators from a wider range of directions, just like the portraits, which maintain eye contact from anywhere. This probably also explains why eyespots are so common in nature.

Reference: “Eyespot configuration and predator approach direction affect eyespot effectiveness against predators” by John Skelhorn and Hannah M. Rowland, October 12, 2022 Frontiers in ecology and evolution.
DOI: 10.3389/fevo.2022.951967

dr John Skelhorn is Lecturer in Animal Cognition at the Biosciences Institute, Newcastle University. The overarching theme of his research is how the sensory and cognitive processes of carnivores influence the evolution of their prey.

dr Hannah Rowland is a research group leader at the Max Planck Institute for Chemical Ecology in Jena, Germany, where she studies evolutionary and ecological interactions between plants, insects and carnivores.


#Ultimate #Death #Gaze #Mothwing #Patterns #Enable #Escape #Death

Leave a Comment

Your email address will not be published. Required fields are marked *