Who's the Daddy?

Late last year I wrote in this blog about a spider (Steotoda nobilis) which was living in our bathroom and which we came to call Lassie. Concerned about Lassie’s apparently self-destructive diet regime we gave her a square meal and observed her return to prime condition. As winter progressed through January her appearances became less frequent and soon her web became redundant. We assume that she crawled away and found a new home outside, perhaps in the nearby shed where Luke and I noticed by torchlight one night that several more of her species were riding out the winter, lurking in the gaps under the roof.

A quite different spider came to our attention more recently, this time in the kitchen. As with our previous visitor, we had to gaze upwards to find it – clinging onto the ceiling. However this spider is rather more familiar by sight to most of us, owing to its distinctive, very slender frame and its common occurrence most times of the year in places that can’t quite be reached by the duster. It goes by several common names, eg. cobweb spider, cellar spider and daddy long-legs, although more punctilious arachnologists would call it Pholcus phalangioides. It is a native spider, widespread in England and Wales but less so in northern Britain. It almost always occurs in houses and other buildings where it finds the shelter and climate to its liking; the year-round stability of cellars is particularly favoured.

Pholcus phalangioides in typical pose, enjoying the tactile experience of our kitchen ceiling.

It makes a messy-looking, 3-dimensional web, often up where the wall meets the ceiling, but also in undisturbed spaces behind cupboards, the telly, the toilet (especially at the volunteers’ chalet at RSPB Arne), under the bath, etc. Here it hangs, more or less upside down and motionless by day, keeping itself to itself. At night it may wander off and settle somewhere new or at least stroll around a bit and take up a slightly different position in the web.

The one we originally spotted in the kitchen didn’t stay put for long, neither did the one which I transferred (for its own safety) from the bathroom to the living room. Hopefully it has settled down somewhere comfortable and out of reach of the weekly incursions by the vacuum cleaner. I might recommend the top of the bookcase, alongside the abandoned fez, the cormorant wood-carving and the old Argos catalogue, which provides a commanding view of both the telly and the Radipole reserve through the window.

For me, the most extraordinary thing about this species was what I learned of its predatory capability. As you would expect they catch small insects and woodlice which stray into the web (they are particularly useful in helping to keep mosquitos down at the aforementioned Arne chalet) and when times are hard they don’t dismiss cannibalism. The surprising thing is the fact that they can tackle other more robust spiders including Tegenaria species – the alarmingly big house spiders which you occasionally find stranded in the bath, or lurking in the dark corner of the tool shed or brazenly scuttling across the floor during the Ten O’clock News.

As the picture shows, Pholcus phalangioides is a pretty fragile looking creature which you would reasonably expect to come second best every time in hand-to-hand combat with an adversary like a house spider. However, it relies more on guile than brawn to get through the trials of life and triumphs in such confrontations thanks to its web. Apparently, even a large spider, once it has carelessly wandered into the web and got stuck, is immobilised enough for the Pholcus to skillfully sling more threads over it using those long legs and thus subdue it further. It then delivers its venomous bite to an accessible part of its prey’s anatomy and waits for it to take effect.

Pholcus phalangioides has unwittingly been implicated in an often repeated modern myth which tells us that the daddy long-legs has one of the most deadly venoms but we are only saved from being killed in our beds because it hasn’t any fangs with which to inflict a fatal bite. It is hard to know where and how the myth originated, as the common name daddy long-legs is used not only for this spider, but also the crane fly and the harvestman. Of the last two, the former is a slender non-venomous insect with non-biting mouthparts, dangly legs and no apparent sense of direction when seen flying dementedly around your kitchen light in the late summer. The latter is a close relative of true spiders which deftly stalks the woodland floor on impossibly thin legs, spins no silk and has no venom or fangs.

The myth can be pooh-poohed as it has no scientific basis – the venom of  Pholcus phalangioides is not known to be especially potent – although if you are a small blundering insect or indeed a hulking great house spider, don’t expect a confrontation with this spindly chap to be a walkover.