Worcestershire Record No. 26 April 2009 pp. 13-14
Good afternoon. Did you know that 33% of women and 25% of men are arachnophobic, according to a survey recently carried out in Germany? I would suggest that the figure is actually higher, judging by the numbers that stay away from any talk involving spiders. So I shall not mind too much if that percentage of you have your eyes closed.
I’m going to look at nine species this afternoon.
The first ought to be in the Guinness Book of records as the most hoovered-up spider in Britain. That ought to have given enough of a clue that I’m introducing one of the most common household spiders - the cobweb spider, alias the Daddy Longlegs Spiders aka Pholcus phalangioides, and probably many other words as well.
Why put this one in? Well I’m sure that its numbers have increased in the 12 years that I have been collecting records. There is little doubt that it is not found in pub toilets to the extent that it used to be, presumably because they are cleaned better, but the incidence in houses, and the northwards spread, both seem to be increasing.
The reasons for this include higher temperatures generally, and increased incidence of central heating in houses. There has been a knock-on effect, at least according to anecdotal evidence, in a reduction in the Big Hairy House Spider, otherwise known as the Tegenarias, and usually represented round here by Tegenaria gigantea. Alan Shepherd has a photograph of Pholcus eating Tegenaria in the former Consultancy building here at Smite.
Moving outdoors, and not really a spider, there has been an even greater growth in both numbers and distribution of Dicranopalpus ramosus – the double headed palp harvestman, shown here in its typical resting pose, with all four legs sticking out almost parallel with each other. The other distinguishing feature is the double palp, with the female having the longer spare part. No English name seems to have been produced for this yet, but no doubt BugLife will produce one soon. This species was first recorded in the Bournemouth area in 1957, appeared in Worcestershire in 1985, and is now found on almost every recording trip that is made. It tends to live up in trees and bushes, but I have seen it on my front door frame. As far as I know, there have been no knock-on effects – the Leiobonums which keep to similar habitats do not seem to have reduced in numbers.
Moving on to some newer arrivals still, this one will not be recognisable to most people without a close up view. Some of you will know that in the family money spiders – the Linyphiids – some of the adult males have strangely deformed heads, and this could be called the hole-in-the-head spider. Trematocephalus cristatus . I first came across it as a juvenile that looked odd when spidering in Ockeridge Wood. I sent it off to Dr. Peter Merrett, who just happened to be the first to find it in Britain, and he gave a reasonably certain identification. Later I found several more specimens around the county; they are redder than most linyphiids, and a dark line down the centre of he head can be seen with the naked eye. After I had mentioned this to a few people, more turned up in the south of England. I am dedicating the distribution map to Harry. As you may know, he likes a little moan occasionally, and we get it at the Records Centre when a distribution map is published with Worcestershire as white space. The map shown has Worcestershire well-dotted, with white space all around
That is genuine – taken off the BAS website. The spider is 2–2.5 mm tip to tail. It is still a rare species, and its origins are obscure. At one time it was thought to have come from New Zealand in potted plants, but there is now a theory that we exported it to them, and I don’t see how anyone is ever going to know.
The second enigmatic species Xysticus acerbus turned up in a small meadow off the green lane that runs from Bentley down to almost opposite Eades Meadow. I have made some attempt to have the site investigated and classified, but had no effect so far. This is a seemingly un-managed field, with a stream running through it, and so with a variety of vegetation.
The list of habitats for this species in the Spider Atlas is rather varied – chalk or limestone grassland in Dorset, Hampshire and Gloucestershire, short meadow grassland in Sussex and Glamorgan, and sand Dunes in Devon – so producing an Action Plan for this may prove rather problematic.
My next species of spider are three that have got themselves into the news recently, with the journalists trying to scare people about alien invaders. The first is one of those which been labelled a False Widow – in this case Steatoda grossa. This is in Worcestershire – so far there are two records from the Malvern area – and it can bite, with an effect likened to a wasp sting. However, it is not aggressive, and is only likely to bite if severely aggravated. It is most often found in and around buildings, and seems to be discovered when people tidy up the bit behind the shed, the garage or the outhouse.
The next Argiope bruennichi has yet to appear in the county as far as I know. You would think that it would be unmissable as a large brightly coloured spider, but I am told that it is quite good at concealing itself in the long grass where it builds its web. The web itself is noticeable as the only large web in this country with this extra piece added – the stabilimentum. No-one seems to know the function of this bit, although there are theories that it help to hide the spider when the spider is in the centre of the web. I would suspect that as we supposedly have a climate similar to that of Essex, that it could spread quite rapidly once it arrive here.
The last of the spider species Segestria florentina is another journalist’s nasty, and some of the ‘phone calls that I got last autumn suggest that some people find them threatening, but I suspect that they find any spider that moves to be threatening. It has been called the tube-web spider, which of course immediately gets associated with the funnel-web spider. We have a Segestria species – Segestria senoculata – which is common in the county, often found in holes in dead wood, which never seems to cause any problems, but this one has been known to bite. There is a suggestion that it is moving around the country in building materials, particularly bricks, so it could turn up almost anywhere. Its temperature requirements appear to be unknown.
Arachnophobes can now open their eyes, and we’ll see who has actually nodded off.
I’m going to finish with a couple of Homoptera, or Auchenorhyncha as we are calling them at present – the leaf and plant hoppers. Although there is a national recording scheme, it has a long way to go before it is publishing distribution maps on the NBN Gateway, and so it is difficult to nail down the spread of this group. However, a book published in 2000 did have a few maps which I have made use of.
This is the first species Athysanus argentarius which is fairly readily identifiable in the field if it stays still long enough to look at and if your eye sight is good – the black line around the front of the head being the key feature.
The map is reconstructed from the book, with the Worcestershire records added.
The second of the hoppers is the Rhododendron leaf hopper Graphocephalus fennahi, found by Gary Farmer in 2007 and again in 2008 at Witley Court. The other dot is Arley Arboretum, in 2007. Perhaps it will be able to spread a little further before all the Rhododendrons are cut down to stop the spread of one of the new plant diseases coming in – Phytophthora ramorun I think.
Well that’s all, apart from acknowledging where I pinched all the material from. Thank you and thank them.
Please note that the majority of the images used were taken from the internet and so copyright reasons preclude me reproducing them here, but using Google images will soon find pictures. Spider distribution maps can be found by visiting www.britishspiders.org.uk, and using the search engine. The Homoptera maps and images were used in Worcestershire Record Issue 23, and can be found at TWO SPREADING PLANT HOPPERS
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