The Ladybird Spider in Dorset by Andrew Whitehouse, Buglife
Perhaps the UK’s most spectacular spider, the ladybird spider (eresus sandaliatus) is also one of our most endangered. This amazing looking creature is only found on a handful of heathland sites in Dorset, and the RSPB Arne nature reserve is one of those places.
The ladybird spider was thought to be extinct in Britain for over 70 years, until it was rediscovered in 1980. Since then no other populations have been found. Across the rest of its range in northern Europe, the ladybird spider is only locally common in a very few places.
This spider is so endangered in the UK that it is possible to count each individual spider living in Dorset, where it has managed to keep a small but determined eight-legged foothold.
The ladybird spider depends on lowland heathland – and this poses a problem. Heathland has suffered drastic declines over the last 100 years or so, being ploughed up for agriculture and forestry, or built on.
The Ladybird Spider Project is working to prevent the extinction of this species and ensure it has a brighter future.
A Spectacular SpiderIt is only the male ladybird spider which displays the spectacular red and black markings on his abdomen, and only when he reaches maturity after three or four years. The female spider is much larger than the male – up to16mm in length – and although lacking the bright red abdomen, she is just as gorgeous, with a velvety black or dark grey body, and silver stripes on her legs.
Photo 1: Ladybird spider (c) Ian Hughes
Ladybird spiders in the UK are at the northern edge of their range and so they require warm sheltered spots to survive. They favour south-facing, sheltered slopes on patchy heathland with well drained sandy soil. In amongst the stones and heather, they build vertical silk-lined burrows crowned with a canopy of silk.
Ladybird spiders are ambush predators, they lie in wait in their burrow until an ant, beetle or other small insect passes close enough to their web. Silken trip wires extend from the entrance to the burrow, which when triggered enable the spiders to catch their prey.
Life cycle of Ladybird spiderMale ladybird spiders reach maturity after approximately three years. As mature males, they emerge from their underground burrows around late April - early May on warm, sunny, calm days. They search for the web of a female, and enter the burrow to mate. After mating with one or more females, the males then die.
After mating, the female ladybird spider lays up to 80 eggs. She cares for the eggs and then the spiderlings, tending to and feeding them, until she eventually dies. The spiderlings will remain in their web nursery until the following spring when they emerge and will begin constructing their own burrow, often only a short distance from their mother’s burrow.
Photo 2: Ladybird spider burrow 8 (c) Andrew Whitehouse
How We Are HelpingAlong with the destruction and fragmentation of its heathland habitat, the ladybird spider’s long life-cycle, very specific habitat requirements, and restricted mobility, have all added to its vulnerability.
When it was first rediscovered in 1980, the last remaining site supported only a few spiders, but successful habitat management has resulted in the population expanding to its current size of nearly 1000 individuals.
Since 2000, other colonies have been established on Dorset heathland. Ladybird spiders do not naturally travel far and so the Ladybird Spider Project has been giving them a helping hand. Spiders have been carefully released onto new sites – increasing the number of ladybird spider populations in Dorset from one to twelve. But there is still a lot of work to do. To safeguard this spider, we need to establish at least twenty populations in the wild.
The Ladybird Spider Project continues the programme of releasing spiders onto new sites, we monitor the existing populations to ensure that they are healthy and doing well, and we carry out habitat management work to ensure that the sites remain in the right condition for the spider to thrive.
The Ladybird Spider Project is a partnership between Buglife, the RSPB, Natural England, the Forestry Commission, Dorset Wildlife Trust, the Amphibian and Reptile Conservation Trust, Dudley Zoo, the British Arachnological Society, the National Trust, the Ministry of Defence, Life-Forms and Perenco.
The project is currently supported by The Ernest Kleinwort Charitable Trust, the Veolia Environmental Trust, the project partners, and by individual donations.Web: www.buglife.org.uk/campaigns-and-our-work/ladybird-spiderFacebook: facebook.com/buglife/?fref=tsTwitter: @Buzz_dont_tweet