Tuesday, September 13, 2011

Argiopes, at last!

When we moved to Barrie six years ago, I recall seeing my first black and yellow argiope on the side of my house and was amazed at its size and spectacular colour and markings.  I didn't know what it was at first, but with a bit of googling, I was able to figure it out quite quickly.   That was the summer of 2005.  Since then, whenever out on a nature walk, working in my garden or frog hunting with my kids, I always hoped to come across another one of these beauties.  No such luck.  Not until 2009, when I finally found my next argiope, which was a banded argiope.  This spider is also very impressive, with wonderful markings and colours... even on its legs!  

Banded Argiope with prey.  Note the legs are held in four neat pairs and it sits with its head down in the web. 

Two years go by until my next finds.  Luckily, I found these spiders within days of each other... something I am not quite used to!  The first argiope was a black and yellow argiope and was spotted by my friend John while we were walking the trails at Tiny March, outside of Elmsdale, Ontario.

Black and Yellow Argiope.  Such spectacular markings and fantastic colour.  This spider was about 2 inches including leg span.  The thick, white, zigzag stabilimenta can be seen here running through the centre of the photo. 

It was found hanging out in its web, head down, holding its eight legs in four neat pairs. This is typically how these spiders sit in their webs.  Thankfully, it didn't budge while we took turns photographing it.  Not only is it difficult to get a good shot of a moving spider, but it's also a but unnerving!  The second argiope I found next to a soccer field near my house.  This one was a banded argiope and was found with its web quite low in the goldenrod.  It too, sat motionless on its web, head down, with its legs held in four neat pairs. 

Banded Argiope with dinner. 

Juicy Tidbits

  • The black and yellow argiope can also be called a black and yellow garden spider, a writing spider or a corn spider. 

  • They are a good sized spider, with a body length ranging between 15 and 25 mm.

  • Argiopes have a thick zigzag weaved into their webs.  This is called a stabilimenta.  The function of the stabilimentum in webs is not exactly known.  Initially, it was believed that its function was to help stabilize the web.  This is not widely accepted anymore.  More popular theories are that stabilimentum serve to help camouflage the spider or that the thick, visible zigzag pattern helps to warn bigger unwanted guests that there is a web in their way.   The fewer times a spider has to rebuild its web the better!  For more info on some of the different theories, check out this link:  http://www.bugsinthenews.com/stabilimentum_and_some_notions_on%20function.htm

  • The latin name for the black and yellow argiope is Argiope aurantia

  • The latin name for the banded argiope is Argiope trifasciata

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