The brightly-coloured strawberry spider (Araneus alsine) is rare and highly localised in Scotland, living in small, damp clearings in deciduous woodland.
Global distribution
The strawberry spider occurs in much of Europe, from Britain and Scandinavia through France, Germany and Poland to Italy, Romania and Bulgaria. It also occurs in Turkey but is apparently absent from Ireland.
Distribution in Scotland
The strawberry spider has a very localised distribution in Scotland, having been found only at Killiecrankie in Perthshire and at Corrimony, near Glen Affric, prior to 2002. Subsequently, it was recorded near Fort Augustus and Spean Bridge, before being found on Dundreggan during a spider survey there in 2009. Since then, it has been found in other parts of Glen Moriston, in Glen Garry and at Loch Arkaig, with the Glen Moriston records comprising the bulk of the currently-known population in Scotland.
Elsewhere in the UK, the strawberry spider has been recorded from a number of sites in the southeast of England, and there are a few records from Lincolnshire and south Wales. This gives it an unusual overall distribution in Britain, the reasons for which are not immediately apparent.
The strawberry spider has not been assessed for its conservation status at an international level, so it does not feature on the IUCN Red List of Threatened Species. However, it is included in the national Red Lists for several countries, including Belgium (where it is listed as Vulnerable), Denmark (where it is classified as Endangered) and Norway (where it is rated as Near Threatened). In Britain, the strawberry spider is also listed as Near Threatened and Nationally Scarce.
The strawberry spider is a relatively large spider in the Araneidae family. This is the family of spiders that make orb webs – the spiral, wheel-shaped webs that are commonly found in gardens, verges and woodlands – and it gives rise to the species’ alternative common name, the orange wheelweaving spider.
The strawberry spider is very distinctively coloured, being bright orange to deep red, with a pattern of pale spots on its abdomen, which provides the resemblance to a strawberry that is indicated by its name. As with most spiders, the female, at 7-13 mm. from the top of the head to the tip of the abdomen, is larger than the male, which reaches a size of 5-6 mm and is slightly darker in colour. The female has a larger, more spherical abdomen, and this becomes particularly enlarged when she is pregnant.
The strawberry spider’s body consists of two main parts – the cephalothorax (which includes the head and the attachment point for the legs) and the abdomen. There are four pairs of legs, which are covered in hairs and spines. Like most spiders, the strawberry spider has eight eyes, and these are arranged in two rows, with four in a central, square formation and a pair set to each side, one above the other. The eyes are ‘simple’, in that they do not have the multiple facets that are found in the compound eyes of insects.
A pair of appendages that are attached to the front of the cephalothorax are called palps. In the male, these are much larger, looking like miniature boxing gloves, and are used during mating to transfer sperm into the female’s genital opening. The spider’s mouth is on the front underside of the cephalothorax, and is flanked by the chelicerae, or fangs, which are used to bite prey and inject venom.
At the rear end of the abdomen the spider has three pairs of spinners, which extrude the silk that is produced by glands in the abdomen itself. The strawberry spider spins a small web, which is situated in a horizontal plane, a few cm. above the ground. The web is circular in overall shape, but is made from a continuous spiral thread of silk, and is almost invisible to the unaided human eye. A stronger section of thread, known as the signal thread, is spun from the hub or centre of the web to the spider’s retreat, where the spider waits, with one leg on the thread, to detect any movement that indicates that prey has become ensnared.
The female strawberry spider makes a retreat for herself, in which she spends much time, waiting either for prey to be captured in her web, or for a male to appear, for courtship. The retreat is made from a leaf, usually from a birch tree (Betula spp.), which she sews together with her silk into a conical shape, with the pointed end facing upwards. This is attached to some low vegetation, which in Scotland is almost always the leaves of purple moor grass (Molinia caerulea), at a height of about 15-20 cm. above the ground.
Occasionally leaves from another tree such as oak (Quercus petraea) may be used instead, and instances have also been found where the leaves of bog myrtle ( Myrica gale ) have been used, attached in amongst the living foliage of the plant itself. The retreat provides both a good vantage point to see her web, which is spun beneath the retreat, and also excellent protection from predators, as the spider is invisible from above.
