Micrathena Sagitatta: Arrow-shaped Micrathena Spider

Canon EOS 6D Mark II & Tamron 90 mm Macro Lens, ISO 400, f/2.8 @ 1/400s Manual exposure

In my last post, I talked about how I really wanted to get a chance to photograph some spiders.  I could not believe it but today I got my chance.  I went out in my backyard today, to start cleaning out a garden that we had just let get away from us over the last few years.  But as I started to trim back some of the branches off the bush in front of me, I saw two different Arrow-shaped Micrathena Spiders.  After some research I found out they were both females.  I managed a few good photographs, and I hope over the next few days I get a few more.  One of the spiders was rebuilding its web so I focused a lot of my time on that spider.  I just could not believe that these spiders have probably been in my backyard all summer.  To me they are some of the craziest looking spiders around here.  Ever since I photographed and wrote a post about them back in 2012, I had not really seen any.  (Link to 2012 Post)  Maybe I just was not looking hard enough.  Since then I have done some research a few times but I never posted anything about these spiders.  So I figured I would put a little information about them here.

Canon EOS 6D Mark II & Tamron 90 mm Macro Lens, ISO 400, f/2.8 @ 1/400s Manual exposure

What do they look like?

Arrow-shaped Micrathena Spiders are one of the smaller species of orb-weaving spider.  They are sexually dimorphic.  The males are smaller averaging around 0.5cm and females about 1.0 cm. (without including the legs)  The females have the more striking features and beautiful colors.  Both have the distinctive arrow shape, but the females are more pronounced.  The females also have additional small spikes on the abdomen near the thorax.

Web Structure:

The most interesting thing I did not know about them is that the web consists of two portions the frame and the orb.  The frame is a relatively permanent structure and some spiders will leave them up for days and weeks.  The orb however is built each day at dawn before being taken down in the evening.  When they take it down they consume it.  They also typically stay in the hole at the center of the orb where it hangs upside down waiting for its prey to wander into the web.  In my case because they were upside down the good side was facing into the bush.  So I had to climb in behind the bush and the brush to be able to get the shots.

Where are they located?

Micrathena Sagitatta is one of only three Micrathena spiders found in North America.  It is most common to the eastern half of the country.  Nationally it is found in nearly every state east of Kansas, and as far north as Maine.

Are they dangerous?

Most people who look these spiders up are rightly concerned as to whether these spiders are dangerous?  For the most part, they aren't dangerous to people.  They have venom that they use to paralyze and kill bugs, but their venom isn't strong enough to do the same to larger creatures.  The venom may be a concern for those who are allergic to it, but this is rare.  That said, the bite can be painful, so you should try and avoid accidentally sticking your hand into their web.

Even though these spiders are not really dangerous they do look quite scary.  Once you get past the fear of them they can be very interesting just to watch.  I hope over the next week I get some more opportunities to photograph them, and as I clean out the garden maybe I will find more interesting bugs.  Until next time.