Spider changing colour

Hedera · #1 (**permalink**) 16-10-2009, 10:28 PM

I have been observing a large A. diadematus just outside my patio door for some time. She is changing from a brown/white colour to a bright orangey tan and losing the white markings. She has also built herself a sort of tent on the window frame, and only goes out in her very large, strong web in the sunshine hours. It's been very interesting to see what she caught: wasps. hoverflies and a cricket among other things. There is a little pile of parcels in the flowerpot under the web now.

No.9 Spider · #2 (**permalink**) 17-10-2009, 07:59 AM

A. diadematus has quite a large colour variation as spiders go. They range from yellow/green thru' orange to brown and red. Your spider may have undergone a recent moult and has just attained it's mature colours.
One old book I have from 1796 has colour plates depicting various, though un-named species and features about 5 or 6 representations of what is obviously Araneus diadematus in various colours. At the time they were assumed to all be separate species, hence the repetition.

No.9 Spider

Hedera · #3 (**permalink**) 17-10-2009, 09:59 AM

That's interesting, thank you. I have looked at three others I have around the garden, and one is also changed to orange this last few days, but is not so big as my "tiger lady".

Meta menardi · #4 (**permalink**) 17-10-2009, 04:47 PM

One other time spiders change colour is when they lose a great deal of body mass, such as when they lay a heap of eggs, they can change colour dramatically. I have pics of a gravid Araneus quadratus, sort of khaki colour, then next day a very much reduced spider that is a deep red colour.
The reason this happens is that the colour is caused by chromatophores (search the net for it, the answers are interesting if you have not come across this before). Skin shrinks, colour changes.

Hedera · #5 (**permalink**) 17-10-2009, 10:14 PM

She is still the same size as before, and spent a short time in her web, now still tucked up in her tent. Here's a pic taken today. I can't see signs of any eggs; where would she be likely to lay them? Under the door sill or in her "nest"?

Hedera · #6 (**permalink**) 20-10-2009, 11:41 AM

My "fat lady" has disappeared: I looked this morning and she'd gone. The little tent is still there with some small fly bodies, but her very big strong web has also gone. I am loath to look under the doorsill for her (as there are other spiders there), but there are plenty of places for her to hide. We did have some rain last night and it's got colder so I expect she thought it time to decamp! I shall miss her though.