Cambridge trees stripped white by caterpillar invasion

Damage to trees caused by ermine moths
Image caption The avenue of bird cherry trees has been stripped bare by the hungry creatures
Damage to tree caused by ermine moths
Image caption The 1in (2.5cm) caterpillars will eventually become tiny white ermine moths
Damage to tree caused by ermine moths
Image caption The caterpillars spin webs around the trees to protect themselves while they feed

Trees in a Cambridge park have been stripped of bark and turned "ghostly" white by a caterpillar infestation.

The native ermine moth caterpillars have taken a liking to an avenue of bird cherry trees on Jesus Green, spinning fine white webs around them.

Guy Belcher, nature conservation officer at the city council, said: "They strip the trees and it does look ghostly and very dramatic.

"However, the trees grow back and are fine. It's a wonder of nature."

He said it was likely there were hundreds of thousands of the pale, creamy-yellow caterpillars, each measuring just under 1in (2.5cm) in length.


"They are host-specific, and only like the bird cherry tree. The ones on Jesus Green have obviously proved favourable to them," Mr Belcher said.

"This year is obviously good for them, for whatever reason, and there's a big infestation."

The silk webs surrounding the trunks and branches were the "combined effort of many, many caterpillars", he said.

"They form a protective web over the tree on which they're feeding to try and protect themselves from birds and parasitic wasps.

"The caterpillars are actually a fantastic food source for other creatures in the park."

Mr Belcher said past infestations had been monitored and the trees were not harmed.

"It's not damaging the tree, so we just let nature take its course," he added.

He said the creatures were nearing the end of the caterpillar stage and would soon pupate into a "tiny micro-moth" - white with black spots - hence the name ermine moth.

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