In Scotland the Lichen running-spider (Philodromus margaritatus) is generally found in the Caledonian pinewoods of the Highlands, which is the UK stronghold for this species. There is another, distant, UK population in the broadleaf woodlands of Southern England. Due to felling of native trees and pollution, this wonderful spider was listed as Nationally Scarce in the UK Red Data Book and is a UK Biodiversity Action Plan priority species.
|Lichen running-spider (Philodromus margaritatus) © Jane Bowman|
The Lichen running-spider belongs to a group known as ‘running crab spiders’ (Philodromidae), named for their flattened bodies, outstretched legs and ability to walk sideways and backwards. Unlike many spiders, running crab spiders do not spin a web to catch prey. Instead, they usually lie in wait, perfectly camouflaged, and use their powerful legs to overpower their quarry.
The sure-footed Lichen-running spider is able to run over trees with exceptional agility thanks to special brushes of hairs on their feet, called ‘scopulae’. The scopulae provide phenomenal grip, by adhering to the extremely thin film of water that coats most surfaces. The scapulae also help the spider to hold its prey. It is also a master of camouflage, thanks to its markings and ability to change colour to some extent, allowing it to blend seamlessly into the background on a lichen-covered tree. Imagine you are looking at the trunk of a pine tree, when a piece of grey-green lichen gets up and runs away, revealing itself as the Lichen running-spider!
Development and woodland felling continue to threaten this formidable and very special predator of the Caledonian Forest.
In order to conserve spiders, such as the Lichen-running spider, it is essential that we have an understanding of their distribution and ecological requirements. The British Arachnological Society and the Biological Records Centre are working to improve our knowledge through Phase Two of the Spider Recording Scheme (SRS). The information provided by this and detailed research will help inform conservation action. To learn more about the SRS, click here.