The photophobic spider



Cave Spider

When the sun emerges after days of damp autumn greyness, as it did this morning, it seems that much more precious and to be treasured. I therefore abandoned the laptop screen, Google and business planning in favour of the outdoors, and emerged this morning to that special bright blue of the coast. The warm updrafts from the Berry Head cliffs propelled gulls effortlessly overhead, whilst occasional out-of-season Red Admirals sailed with the breeze. I was hoping for a close up view of dolphins or porpoises and so made my way out to a rock promontory near where we had seen one feeding over a month ago. Although this proved fruitless I was drawn to some nearby caves. I had no torch but used my camera focusing red light beam to do a bit of searching. And that was when I discovered a rather large spider (see picture above), and quickly discovered that this one was by no means alone. In almost every crevice were other specimens and several large white cocoon sacs hung like silk globes from the ceiling.



Cocoon sacs holding spiderlings

Back home and reacquainted with Google, I searched on “Cave Spiders”, to discover that is indeed what had observed. Most likely the species is Meta menardi, one of Britain’s largest spiders, a type of orb weaving spider. Their distribution is wide and patchy across Europe (British Arachnological Society, 2011), perhaps due to their particular preference for permanently dark damp sites, such as caves, which may also mean that they are often overlooked. They are termed as troglophiles (literally “liking caves”) with photophobic tendencies, avoiding light and feeding off other invertebrates sharing their darkness. Interestingly the young spiders are, in contrast, strongly attracted to light (Smithers, 2005), possibly an evolutionary adaptation to ensure the species disperses more widely.

In the meantime my empathy is with the young spiders and was certainly glad to emerge out of the cave back into the sunlight to enjoy the last of the afternoon’s precious rays.

British Arachnological Society (2011) [online] The Checklist of British Spiders. http://srs.britishspiders.org.uk/portal.php/p/Summary/s/Meta+menardi  [Accessed 17/11/11]

Smithers, P. (2005) The early life history and dispersal of the cave spider Meta menardi (Latreille, 1804) (Araneae: Tetragnathidae) Bull. Br. arachnol. Soc. 13 (6): 213-216 [Cited at http://www.enotes.com/topic/Meta_menardi#cite_note-1]

See also this video of Cave Spiders being rescued: http://news.bbc.co.uk/earth/hi/earth_news/newsid_8393000/8393757.stm

Wild Madder goes red

Towards the end of the summer I was out botanising with a friend and we came across a Wild Madder (Rubia peregrina) plant growing on the edge of some woodland. This is a butch, version of the ubiquitous Cleavers (otherwise called Goosegrass or Sticky Willy), being larger, tougher, pricklier, and an evergreen. They are both members of the ‘Bedstraw’ family (Rubiaceae) that are generally sprawling climbers and include the Tropical Coffee plant. In the autumn Wild Madder plants produce characteristic dark black berries, like over-sized elderberries (see image).

I was surprised when Greg said that it was the first time he had seen this plant. Although it was new to me this year I had seen it several times on my walks about Devon this year. However checking the distribution map for this species on the ‘NBN Gateway’ (http://data.nbn.org.uk/) clearly shows a strong south-west preference, with no records from his home county in Essex. I have most commonly seen it recently on coastal walks which also seem to be its preference – perhaps due to its apparent resilience towards sea spray.

The madders were used traditionally for many centuries in the making of various dyes - remains of madder were excavated with Viking material at York (Woodlands.co.uk, 2011). The closely related Common Madder (Rubia tinctorum), was introduced to the UK and formerly grown for its dye (Stace, 2010),  ‘Turkey Red’, a brilliant red permanent dye - this was very well known in 19th century for “maddering” wool and cotton (Koreankye, 2010). Wild Madder provides a subtler, rose-pink dye. The long roots of the madders are particularly rich in these dyes and were used with materials such as leather and wool until towards the end of the Nineteenth century, when they were replaced by the more efficient industrial manufacture of the chemical, Alizarin Red (Woodlands.co.uk, 2011). However some traditionalists are reacquainting themselves with old methods of natural dyeing with plants such as Madder (see http://www.woodlands.co.uk/tv/2010/12/dyeing-with-madder-plant-root-from-woodland/). This seems to be another example of people turning their backs on disconnecting industrialisation and trying to relearn from nature’s amazing secrets.

Korankye, O. (2010) Extraction and application of plant dyes to serve as colourants for food and textiles. [http://dspace.knust.edu.gh:8080/jspui/bitstream/123456789/235/1/Oenewaa%20Korankye.pdf]

Stace, C.A. (2010) New Flora of the British Isles (3^rd edition). Cambridge: Cambridge University Press.

Woodlands.co.uk (2011) [online] Madder - http://www.woodlands.co.uk/blog/flora-and-fauna/wild-madder/ [Accessed 4/11/11]