Hi, We have a spider (photos below) which we think might be a false widow living in our conservatory about six or seven feet up in a crevice. It is eating up flies furiously and seems to be growing bigger rapidly! We have also spotted a number of smaller versions of this same spider, presumably babies in differsnt areas of the conservatory. We are wanting to decorate but are not sure what to do with them. If we relocate them to the garden - are they likely to come back - and are there likely to be more than the ones we have seen?
If anyone can identify this as a female false widow is it likely to have even more babies that may infest our home and is it true that only females bite?
We are very spider friendly but we don't want to risk a bite or move it unnecessarily!
Many thanks for any help!
Yes, this is a female noble false widow (Steatoda nobilis). They do seem to like conservatories, no doubt due to all the nooks & crannies high off the ground - typical places in which they like to live.
If you were to relocate them to the garden, it is likely that new individuals would gradually repopulate the conservatory. Spiders like the one in the photo may be very hard to catch, as they move pretty fast when bolting for cover. They're quite easily spooked, so it might be possible to coax them into hiding, redecorate, then they may rebuild their webs after?
Watch any webs after dusk/in low light to see if their owners come out onto the webs? They're quite territorial, males tend to pass through temporarily, spiderlings often disperse fairly soon after hatching. You might notice nominal increases/decreases in numbers, but it's unlikely that you will be inundated by swarms of them.
I'd also have a close look at the other spiders, it's not impossible that you have some Zygiella x-notata (missing sector orb weavers) mixed in with the Steatodas? They can be mistaken for each other, the Zygiellas seem able to live in much higher concentrations that the Steatodas (e.g. several to the same pane of glass, wheras Steatodas are typically more spread out). The Zygiellas spin the classic orb web, that hangs vertically and the spiders sit in the middle at night time, the Steatoda's webs are more canopy/shelf-like and they often hang in them horizontally, belly up.
I'd certainly move any you find at floor level, or wandering the walls, outside (they're much easier to catch away from a web & on a flat surface).
Many thanks for replying so fully.
We think the others are the same species as they are not close together and they seem to have similar habits, marking and webs.
Can you tell us whether it's common to have them running around floors and walls? We haven't seen any yet but as we are quite often out there without shoes, as well as leaving shoes out there, we're just wondering how watchful we need to be and whether they hide in shoes/clothes etc. Also are they likely to migrate into the house? The conservatory is not heated and gets cold in winter and so we were wondering if they would come in at the change of seasons? At the moment we are tending to keep the door closed so that they don't but it's pretty hot keeping it closed in this weather.
Thanks for any advice you may give.
No, it's not common to see them wandering around floors & walls, but does happen on occasion, more likely regarding males.
I'd be inclined not to leave clothes & shoes in the conservatory, risk of a bite is still very low, but it would seem like tempting fate? Bites are commonly the result of the spider being inadvertantly squashed against the skin.
They tend to hole up over the winter, but can be seen occasionally, it's unlikely that they will migrate into the house, more probably hide out and stay put over the colder months, which they seem to tolerate well enough (females can live 2 years or more). I wouldn't think you need to shut them in the conservatory, they have food & safety there. Keep clutter away from the entrance to the conservatory, less places for them to hide themselves, maybe keep a light on at night in the adjacent room (more active after dark)?