Shiny animals outwit predators with optical illusions

Who doesn’t love a bit of sparkle? We’ve seen it with many singers in their bling-filled performances. Yet, this desire for dazzle isn’t just confined to the world of pop music.

In the animal kingdom, you can find shiny creatures like jewel beetles and the fabulous Opaluma rupaul – a fly named after the iconic entertainer RuPaul – that boast flashy appearances.

Now, wouldn’t such obvious displays make these animals easy targets for predators? As surprising as it may sound, science suggests otherwise.

Power of changeability

One might think that standing out like a brilliant beacon would guarantee a predator’s attention. However, these unusually bright features aren’t just for attracting attention.

A particular trait of these shiny appearances – their changeability – can actually aid the animals in evading predators.

Environment as camouflage

Shiny animals, when they reflect the sun, produce bright flashes. The mirror-like aspect of their bodies also reflects the environment around them.

This constant change of reflections as the animals move can be compared to a mirror ball. For a predator, tracking down a prey that exhibits such visual variability becomes a difficult task.

Challenges of chasing shiny animals

Tests involving both bird and insect predators have revealed a common struggle – they find it challenging to be accurate when they attack a visually changing prey.

So, what exactly triggers this effect? Is it the predator’s inability to track the prey visually ? Or perhaps it involves a misjudgment of prey speed? Are optical illusions at play?

Illusion of speed and position

Studies involving humans have shown the potential for optical illusions to disrupt prey speed perception. For instance, black and white stripes can make a target appear to be moving faster or slower than its actual speed.

When a predator encounters highly reflective, shiny targets, a similar effect could lead them to misjudge the prey’s speed.

Moreover, bright flashes from a shiny animal may cause a flash-lag illusion, making the predators perceive the prey’s position to be slightly behind its real position.

Shiny animals confuse predators

Both the disruption of speed perception and the flash-lag illusion can result in directional errors in predator behaviors.

This means predator tracking and attacks might often be ahead of or trailing behind the target, relative to the target’s actual movement direction.

Additionally, the unpredictable appearance of the shiny prey might confuse predators about the precise location of a moving prey. Ultimately, the tracking and final attack by a predator might end up being less accurate.

Experimenting with jumping spiders

A group of scientists from The University of Melbourne used a high-speed camera to film jumping spiders attacking fake, moving targets.

Jumping spiders were selected for this experiment because they prefer moving prey, eat both shiny and matte prey, and possess excellent vision. Plus, they willingly attack fake moving prey in a lab setting.

Interpreting the findings

The high-speed footage enabled the researchers to quantify how well the jumping spiders visually tracked different targets and how accurate their attacks were.

The results revealed that jumping spiders had a harder time tracking and attacking shiny targets compared to matte ones or to those that matched the background. Specifically, their tracking was nearly twice as variable with shiny targets, and their attacks were significantly further away from these same targets.

Notably, these results were not directional relative to the target’s path of movement. This does not support the idea that shininess disrupts speed perception, or that localization is disrupted by the flash-lag illusion.

Dazzle and dodge: Defense of shiny animals

In conclusion, while shiny animals may catch the eye, they prove difficult to localize and capture. The research study sheds light on how shiny colors might disrupt perception and lead to these effects.

However, this research is only the tip of the iceberg. There’s still much to understand about how these effects are visually processed in animals with different eyes, and how other factors such as sunlight, prey size, shape, and movement behavior influence the perception of shiny animals.

So, next time you see a pop star shine on stage, or even a glistening insect out in the wild, remember there’s more to their shimmer than meets the eye.

The study is published in the journal Current Biology.

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