People are being urged not to touch a strange froth found on plants this May because they are a key part of the food chain.

As the warm weather brings our gardens to life, many of us are hoping to find our green spaces teeming with nature, including everything from ants to wasps and beetles. And it's at this time of year that you might notice this odd 'spittle', sometimes called cuckoo’s spit, on your garden plants. The froth has already been spotted in gardens in the north of England including Leeds and Sheffield.

But gardeners are being urged NOT to mess with or remove the bubbles or spittle on plants because they are not a pest, according to the Royal Horticultural Society.

You may have seen it clumped on plant stems or in a patch of grass and wondered what it is. It looks like a ball of froth, or foam, a bit like someone has spat on your plants. So what is that ball of spit on your plants and is it harmful?

The spittle, as it's known, is made by an insect called a spittlebug, so named because it produces the weird frothy substance which then gets left behind on plants and in long grass. The spittlebug coats itself in a ball of foam for protection as it sucks on the sap from a plant for nutrition.

The red and black creature's offspring, also known as froghoppers, then hatch on a plant which has the leftover ball of foam.

The insect is usually active from the end of May to the end of June, so it's peak season for sightings right now. Though the insects feed on the plants, they don't remove enough nutrition to harm it and they don't hurt humans, so you don't need to do anything or get rid of the spittle.

Given that insect numbers have reduced by as much as 60 percent in the past 20 years alone according to studies in the UK, it's actually an extremely good sign to see insects breeding in gardens.

As per the food chain, if insects die out, there'll be nothing to pollinate flowers (it's not just bees), and nothing to feed animals higher up the chain that keep the entire ecosystem's cycle running smoothly. The end result is, without insects, we won't be able to grow any food at all.

So for that reason, it's really important to allow the insects to breed, and not to wash off or interrupt their delicate life cycle.

The RHS says: "Cuckoo spit is a white frothy liquid secreted by the nymphs of sap-sucking true bugs known as a froghoppers. They are also known as spittlebugs. It appears in spring at a time when the familiar call of cuckoos can be heard, but has no connection with the bird.

"Spittlebugs are not a pest, so please don't remove them; they are an innocent carrier of Xylella outside of the UK and are part of the biodiversity of a healthy garden ecosystem."