Subject: can Pholcus phalangioides change its coloration to match its environment?
Location: Jefferson County, Illinois
November 28, 2014 6:35 pm
I am extremely nature friendly and generally let spiders have the run of my house within reason. This year I had a bumper crop of cellar spiders and although I find them interesting, their webs can get to be an issue and I am constantly tidying up after them. Not long ago I noticed a silk-wrapped stilt bug hanging down by the kitchen table and as I bent down to brush it away I noticed something luminous and bright green on it. Upon closer inspection I was fascinated to find that I had discovered both dinner and diner and , most importantly, the diner appeared to be one of “my” cellar spiders that had somehow turned a strange shade of green I’ve never seen before! All of the cellar spiders I have seen here are various shades of tan, brown, or even a light translucent grey, but never this bright green. Even stranger, the spider has been residing among a collection of volleyball trophies on my tabletop and the background color in these trophies is the exact shade of green. Initially I thought well yes, if you are looking at the spider at the right time of day with the right light, the abdomen is likely reflecting the green from the trophies. But the cephalothorax is the expected color, as are the legs, and even in dim light or shadow you can still see the bright green. So I am puzzled and intrigued.
I am aware that many creatures can manipulate their background color but is there anything known about cellar spiders having this ability? If she ( I say she, I can’t see any pedipalps without disturbing the spider) weren’t so fragile I would put her in a different location and watch for changes but I don’t want to harm her.
Anyway I hope I can load the pictures correctly so you can have a look-see.
thank you !
Signature: Wendy T.
This sure looks like a Cellar Spider, but the green coloration is certainly unusual. We are going to post your images and attempt to research this more thoroughly before we weigh in with an opinion, and hopefully one of our readers can either provide a definitive identification or comment on the coloration.