Today, Chris Baker from the RSPB on the Ladybird Spider 

The ladybird spider was thought to be extinct in Britain for more than 70 years, its recent success down to luck, a very good guess, and an old fashioned eureka moment.

The heath-dwelling invertebrate has gone from one known colony to 11, and there are now more than 1,000 individual spiders at large – 36 of them at the RSPB’s Arne nature reserve.

The spider was rediscovered near Bere Regis in 1980 in part of a conifer plantation that hadn’t quite taken – it had last been seen, also in Dorset, in 1906.

Ecologist Ian Hughes said: "It was sheer luck it had not gone already".

The trees where the spider was found had not grown that well, the open heath had not quite been shaded out, although a few years longer and it would probably have been lost.

Dr Andrew Nicholson, of Natural England, was carrying out an invertebrate survey at the time, although he had no particular reason to think it was the right spot.

He said: "Back then this was a fairly isolated piece of heath, I chose it as an example of a small site surrounded by forestry. 

"We put in a pitfall trap and, lo and behold, a ladybird spider fell in."

The spider, named because of the mature male’s ladybird-like abdomen, coloured pillar box red with black spots – the young male and the female are all black – depends entirely on lowland heath, a habitat that has declined by about 90 per cent since the 1900s.

By 1980 the spider had become so scarce it was possible to count each individual living on Dorset’s heaths, the extent of its British range.  

Indeed, it is only common in a few places in Europe, notably sandy heaths in Denmark.   

As well as depending on a single, now scarce habitat, the ladybird spider is not particularly good at colonising new sites, and a helping hand was needed to rebuild the population.

The first attempt at translocation, done by Hughes, occurred in 2000, to a site not far away from where the animal was rediscovered.

He said: “I was using a combination of a cold frame and little paper tubes but I was having to break the webs.

“I thought there had to be a better way than this, and I was drinking from a plastic water bottle out on a heath one hot day and I had an epiphany.”

His idea was surprisingly simple: take a 500 millilitre plastic bottle (not far short of a pint in 1906 measurements, or 1980 measurements for that matter), cut off the top and bottom, fill the bottom with sand, the middle with peat, moss and lichen, to replicate where the spiders like to make their burrows, and once you have your spider put it all back together.

Hughes said: “For the actual relocation the top and bottom of the bottle come away, a bit like the stages dropping off an Apollo rocket, and the central part, with the spider in, goes into the heath, where it can stay for five years, if needs be.”

Woodpeckers attempting to peck into the bottles, and sometimes succeeding, have been a nuisance but chicken wire stretched over the top has seen to that – the spiders don’t seem to mind and they weave their webs around the wire.

The bottles and their spiders are stored over winter, in a well ventilated greenhouse to keep them safe from frost, until it’s time for the invertebrates to be placed at their new home.

Here another little serendipity occurred; to begin with the licence authorising the translocation stipulated the spiders had to be at their new site in two weeks, but predation was a problem and the rules were relaxed, allowing Hughes to keep some over winter.

Survivability shot up and now all the collected spiders are gathered in summer and translocated the following spring – Hughes currently has 45 in his greenhouse waiting for next year. 

Hughes’ bottles are now used for all translocations. There are now ten new sites dotted around Dorset’s surviving heaths, plus the original where the insect was rediscovered.

One measure of success is what has occurred at RSPB Arne: the introduction started in 2011 and spanned three years, but until 2015 no more than 12 webs had been seen.

This summer 36 large and medium-sized webs were counted – meaning 36 adult spiders.

Two more translocations are scheduled to take place at the reserve next year.

Hughes said: “The British population was down to five known webs at one point and things have really improved, but they’re still really rare.

“I wondered how many ladybird spiders there were in the world recently and I worked out you could only half-fill a dustbin with them.”

To keep up to date with all of the autumnwatch news, follow RSPB Arne on: Facebook.com/RSPBEastDorset @RSPBArne www.rspb.org.uk/arne

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