365 Urban Species. #098: Woodlouse Spider

[urbpan]

Urban species #098: Woodlouse spider Dysdera crocata

While handling this spider trying (unsuccessfully) to get a better photograph, I became unnerved when I noticed its fangs. Usually on a spider this size (maybe 3/4 or an inch, or a little less than 2 cm) the fangs are inconspicuous, tucked away underneath. The woodlouse spider has long, obvious fangs, presumably strong and sharp for piercing the shell of their crustacean prey. Most spiders' fangs are not strong enough to bite through human skin, but some are, and this individual looked capable. But it showed no inclination to bite, instead clambering in a panic to remove itself from the light.

Research after the fact indicates that it indeed could have bitten me, but it wouldn't have injured me seriously. Or to use some delicious technical language: "D. crocata bites have been implicated in causing a localized, intensely pruritic rash with coalescing dermal papules 4-5 mm in diameter.  The bites apparently do not result in any systemic neurotoxicity or cytotoxicity." (http://www.ento.psu.edu/extension/factsheets/Spider/spiders.htm)

The woodlouse spider, unsurprisingly, is found anywhere woodlice are. Under logs and stones and other debris near buildings is where you will most likely encounter one. They were apparently introduced to North America and Australia, along with their favored prey, from Europe. It's possible that no introduced woodlice are considered invasive because their predator comes along with them when they travel.

Comments

Woodlouse Spider

[(Anonymous)]

I've got those in my bathroom!

I bought a damp old house in 2004 and realise over time that the woodlice were disappearing. I thought that was me - keeping the house warm and clean and making the woodlice unwelcome.

Until.... I went downstairs to use the bathroom one night and switched the light on. Jeeeeeeepers!

I don't know who was the more scared. If you include the legs it spans approx 35 - 40mm, has HUGE fangs and can rocket to the gap under my bath in split seconds.

Occasionally, I've seen little orange baby spiders as well so I know it's not a one off.

Thanks to a weird immune system and a couple of large and lairy wolf spiders, I've got to be wary of being bitten by spiders.

I don't know which is worse - knowing my house is damp and dark enought for these guys to take up permanent residence (albeit doing a good job) or knowing that I'm hostess to one of the few spiders in Britain that could do me serious harm if it bit me.

Still, over four and a half years I've only spotted an adult twice - so I think I'm safe!