Coming to a home near you: Britain’s biggest wild spiders which can grow up to 8cm long

October 4, 2012 | by | 0 Comments

Ecologists have released hundreds of Britain’s largest breed of spider into the wild – which can grow to a whopping eight centimetres.

The great raft spider has been saved by a breeding programme involving ten zoos.

With a leg span of up to 8cm, the arachnid is capable of catching and eating a fish as it glides across the surface of water.

Carmen Solan with some of the young great raft spiders

Carmen Solan with some of the young great raft spiders

The spiders can grow up to 8cm long and are Britain's biggest bread

The spiders can grow up to 8cm long and are Britain’s biggest breed

Around 200 baby spiders have already been released at the RSPB’s Strumpshaw Fen reserve near Norwich.

Ecologist Dr Helen Smith said: “Most invertebrate groups don’t receive a lot of conservation effort.

“The ones that tend to receive the attention are the big and spectacular ones … this is very much the case with great raft spiders.

“They’re big, they’re beautiful and they have to fly the flag for other species.”

Funding from Natural England, the BBC Wildlife Fund and the Broads Authority hopes to reintroduce the spider to the Norfolk Broads, where it was once commonplace.

A Raft spider in a test tube

A Raft spider in a test tube

The critter shows off its long legs

The critter shows off its long legs

An adult male great raft spider similar to the ones which are being released as part of the Bristol Zoo conservation programme

An adult male great raft spider similar to the ones which are being released as part of the Bristol Zoo conservation programme

Instead of being raised in their usual nursery webs, suspended from wetland plants, the tiny animals were individually housed in test tubes – where iron-willed volunteers fed them by mouth.

Bristol Zoo Gardens keeper Carmen Solan  raised 170 of the arachnids, using a special tube operated with her mouth to feed the tiny critters dead flies.

She said: “It does take a lot of time.

“You have to be careful to make sure they’ve got enough humidity to be able to moult.”

Carmen even had favourite spiders – which in the wild are capable of catching a stickleback.

Dr Smith said: “Having invested their summer into feeding them individually, people do get quite attached.

“But when you return the next year and see 500 to 700 babies, it’s worth the effort.”

The ecologist, who has 20 years’ experience working with raft spiders, says the conservation programme is designed to give the spiders the best chance in the wild – boosting survival rates by as much as 90 per cent.

She said: “We’re all improving our captive-rearing expertise through this process.

“It’s early days. We’re two years down the line now but the indications are that the spiders are settled in well.”

Previous batches of spiderlings released have been discovered to be breeding well in the fen, and four nursery webs were spotted, each containing around 200 tiny spiders.

Dr Smith said: “With animals that are this rare you can make lots of arguments about food chains and food webs, and how important that is.

“We simply don’t know what pulling out one brick will do further down the heap.”

The spiders can live up to two and a half years, but thankfully they will not be appearing in bathtubs any time soon, as they cannot survive outside their marshland habitat.

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