Country diary: How extraordinary to see with an insect's eye | Kate Blincoe

Source: The Guardian
Author: Kate Blincoe

Caistor St Edmund, Norfolk: Algae is red, nettles are blue - this is all perfectly normal for creatures who, unlike humans, can see biofluorescence

It was a long time coming, but spring is here at the farm. The swallows are back, the annual bluebell open day completed, and the infertile but broody goose is tending her surrogate goslings.

Now, as night falls, I gather with a group of people for a walk with a difference. We're handed ultraviolet torches. I switch mine on and I'm suddenly standing in a pool of scarlet blood. Our guide, David Atthowe, explains that the greenish algae underfoot is now glowing bright red.

We're discovering the natural biofluorescence of many plants, animals and fungi. Unlike most creatures, humans are unable to see this without artificial UV light. We're gaining an insect's-eye view.

I know this land like the back of my hand, but suddenly I'm Alice in Wonderland - everything is strange and different. The redder something appears, the more chlorophyll it contains, so cleavers and branches covered in lichen are fire orange. A purple woodlouse stands out against the tree bark. Nettle and bramble leaves are patched with a gorgeous dragonfly blue, indicating a fungal infection.

As we stroll, the hawthorn flowers are dark in the low light, but under the UV beam the centre of each glows like moonlight, acting as a guide for pollinators. They are eerily beautiful, perfect for a gothic wedding. I find a brimstone moth, the brightest moth species in the UK. It shines neon yellow, like the glow-in-the-dark stars my children once stuck on their bedroom ceilings.

Then we see a crab spider. It would have been impossible to find without our magic torches. Incredibly bright, the purpose of its glow is to outshine the gentler fluorescence of the host plant, garlic mustard. This means insects are drawn to it in preference, bringing an easy meal.

Occasionally, I think I've seen something special, radiating vivid electric blue, only to find it is a scrap of fabric or plastic. Our impact on the planet is starkly visible at the ultraviolet level. Does this pollution affect creatures who can see on this spectrum, constantly distracting them from pollinating or seeking a mate?

Biofluorescence is complex and only partly understood. This mysterious layer of the world is usually hidden, beyond our ability to see. I'm humbled, not just by such incandescent beauty, but also with the recognition of my own limited vision.