Northern Ireland

A web of intrigue in Ballymoney

Image caption The webs gave the tree a silvery appearance

Something strange is going on in Ballymoney - in the hours of darkness there has been an invasion of uninvited visitors.

Well, in one family's garden at least, on one rather large shrub.

Liam Kearney says his family first noticed something odd was happening a few weeks ago.

"About three weeks ago my wife commented one Saturday morning, she said did we have a silver tree out front, she had never noticed one," he said.

"I said no and when I went out to look, surely we had this tree just massively covered in cobwebs."

But these aren't ordinary spiders' webs. They are thick and strong and sticky and they cover the entire plant.

'Stripped bush'

Liam says their new Halloween-themed garden feature has been drawing quite a bit of attention.

"It has created quite a bit of attention locally. People came, stopped by and took photographs and as time went on, we noticed that caterpillars appeared in bunches of maybe 10 or 20 among the cobwebs and they gradually stripped the bush of every green leaf."

The Kearneys are uncertain what type of tree or shrub it is, but they have lived at the house for over a decade and have never seen anything like this before.

The mystery, however, has been solved by Ulster Wildlife's moth expert Andy Crory.

He says it is most likely an Ermine moth which is specific to this particular tree which is called Spindle.

Sticky webs

"I've only ever seen this in books. It is something which occurs naturally and it's caused by something called an Ermine moth. It's actually a micro-moth and it's only about 1 cm long."

But why so many and why the strong sticky webs?

"These things work on cycles, so some years you might not see it at all and then there will just be like a pulse, hundreds of thousands of these moths emerging at the same time.

"The silk is a defence strategy, some caterpillars are green, they are camouflaged and can hide from birds. Some are spiky or unpleasant to eat, but this spins silk and the birds can't get at it."

Andy says had this happened a few hundred years ago the Kearneys might have been in trouble.

"They'll cover park benches, they'll cover other trees, they'll cover footpaths, walls, and you know, it does look quite spooky and it's the sort of thing that hundreds of years ago somebody would have got burnt as a witch for."

But instead there is good news for the Kearneys. The tree should recover and with a bit of wind and rain, the silk should eventually disappear.