Could Blue Spiders Be the Key to Natural Blue Food Dye?


Have you ever heard of a blue tarantula? Well, you have now and it’s not as uncommon as you might think. There are 40 different species of blue tarantulas and they all emit almost the same blue hue.

What makes blue spiders so interesting is how they achieve their color. It is not pigmentation that creates their blue color, but photonic nanostructures located in the bodies and appendages of the spiders. What baffles scientists is, why a nocturnal creature like a tarantula would want to be so blue in the first place.

One answer could be that the color is something other than the green colors found everywhere in the rainforests in which they live. But wait … wouldn’t that make them stand out more? Yes and no. Scientists believe that predators in rain forests have adapted to spot green color and to follow the movement of green-colored prey so much that they might not even notice a blue spider hiding nearby. That’s clever camouflage if you’re a spider.

But, the real reason scientists are so intrigued by blue spiders isn’t because it helps them survive, but because the photonic nanostructures may be a more constant way to create colors in objects without using toxic dyes made from synthetic food pigments. This has posed a significant barrier to food manufacturers in the past.

The blue nanostructures found in the spiders create color that is unique. Unlike the nanostructures found in some birds and bugs, the spider’s blue color doesn’t seem to change when you look at it from different angles. This makes the spider nanostructures less iridescent and more stable.

Why is this so important? Photonic nanostructures could be used to color electronic screens or, perhaps even clothing, but they have to be tamed and not so iridescent. Iridescence has been a big barrier in these applications to date. Tarantula blues promise to be brighter and less likely to fade than pigment-based color.

From a production standpoint, photonic nanostructures could be beneficial to manufacturing, making for a more eco-friendly way to create color in objects in the future. We say the future because the means to develop the kind of nanostructure used by spiders is not yet economically feasible, but now blue spiders have given researchers the will to find the way.

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