Saturday, August 21, 2010

ID the Spider!

I have a task for all you invertebrate fans out there: identify this spider. It's been a very good summer for mites, harvestmen, and whatever spider this is, because all three arachnids are everything this year. Something about overcast, rainy skies I guess. Let's go down the list of this spider's features.

It comes in a surprising range of sizes, but the abdomens of the biggest ones I saw were a tiny bit smaller than my thumbnail. It is an orb-weaver, and builds a wheel-shaped web with lots of support strands. The color of the abdomen varies between light green and brown, but all of the individuals I saw had white speckles across the abdomen. The thorax is mostly pale yellow to orange, but has three brown bands moving down the thorax and head. The third pair of legs are the smallest. The legs are mostly the same pale yellow, but the joints are browish. The legs have large hairs.

There is one individual living on my grill, and it has built a surprisingly large web. The orb itself isn't all that impressive, but there number of support strands seems like overkill. The spider does not live on the web, but has constructed a little web-house beneath the grill. Surprisingly, there's a been a much smaller male living in the same web the whole season. His abdomen is a fraction the size of her's, although his leg span is probably similar. His has swollen palps. I watched him try to coax the female into mating one time, but she wasn't having it. Two of her legs were up, and he wasn't budging.

Anyway, it'd be cool if somebody knew what species this spider is. It's everywhere this year. We generally call them "pillow spiders" because of their fat abdomens.


Christopher said...

looks like Araneus diadematus.

Neil said...

Yup, I'd second that ID. It's an interesting question as to whether this wide-spread old world species was introduced to North America or colonized naturally via ballooning?

If you care to dig into genitalia you can probably confirm or reject that ID with this:

Kristen Asmus, aka Kea Giles said...

Orb Weaver - one of the nicest, most beautiful, and artistic spiders out there.

lantaro said...

ew ew it's gross and has spiny little legs!

there. it's been ID'd.