I was in the restroom at South Park – an indoor building with an outdoor feel. There were harvestmen (daddy-long legs) loafing among the stalls and random bugs flying around. I noticed a weird spider on the wall, not a big spider, approximately 5 millimeters from head to end of the abdomen. It kind of looked like a common house spider, but something was odd. There was no visible web and the shape of the abdomen had more of a heart shape than the teardrop abdomen shape of a house spider. It had 2 bright, white spots on the top of its abdomen and it’s front 2 legs were very spiny, long, and curved. It had beautiful markings: overall light greenish with dark brown spots and banding (stripes on legs). It was just chillin in the middle of nowhere. I had never seen anything like it, so I caught it to take home for further observation.
I was able to easily identify the spider using Richard Bradley’s, Common Spiders of North America just by looking at the visual standouts mentioned above. I had found a female PIRATE spider, Mimetus puritanus! Everything checked out – it was a spider found in Southwestern, PA, the seasonality was right (July), and the size was right.
Why are they called pirate spiders, you ask? This family of spiders (at least 20 species in North America) eats other spiders. They do not make their own webs, but approach other webs and “steal” the resident spider right out of it. I HAD to check it out! I went straight to the old garage which is filled with house spiders. “House spider” is a general name for the kinds of spiders everyone finds everywhere around every part of every house. You’ve seen them. They have a swirly brown and white colored abdomen which is way bigger than the head making the spider seem like it has a really big butt. They make messy, seemingly random webs, and often have at least one brown, papery egg sac that the female closely guards. These spiders are completely harmless; a nuisance at most. So there I was in the garage, now a pirate spider restaurant, selecting the perfect dinner specimen. I do admit that I felt a tinge of guilt, being the spider lover I am, so I scooped up a medium-sized victim, bid a quick thanks to the spider gods, mumbled something out loud about, “It’s for science!”, and quickly headed back to the LaBoratory.
Pirate spiders don’t usually get “take-out” so introducing prey to the pirate spider was a total experiment. In the wild, pirate spiders wander and cautiously approach established webs by gently plucking the silk strands which tricks the resident spider into thinking a meal has been snared, but NOPE! The tables have turned!
I added the house spider into the container and watched. The pirate spider didn’t move at first while the house spider immediately started attaching silk back and forth, to and fro, without noticing the pirate spider off to the side. Then, the pirate spider slowly raised her front legs and began “feeling” and tapping on the silk. House spider didn’t stop. The pirate spider began orienting itself very slowly towards its prey and looked like it was gently coaxing the silk with those long, spiny front legs. The house spider (still seemed like it had no idea of its fate) got about 1 centimeter away when the pirate spider lunged biting the house spider like, BAM! It was super fast! The cobweb spider was instantly still. I’ve never seen venom take effect that quickly. There was no struggle at all! Here is some video.
The pirate spider lived for about a month. One day, I noticed that her posture looked off and she didn’t do her “feeler leg” thing when I nudged the container. The next day, she had dropped from her hanging spot to the bottom of the container. At that point, I preserved her in alcohol. I never gave her a name (Clemente or Honus would’ve been perfect) but, she was definitely one of my favorites to watch…even though I had to sacrifice other spiders. I haven’t seen one since then (2015) until I found one on a recent camping trip this June in Sligo, PA. It was a smaller male, same species. Not long after that, a friend from Dormont, PA sent a “what spider is this?” text and it was another pirate spider! 
Notice those long, spiny legs and the white dots? Notice how there is no web? Keep your eyes peeled! Pirate spiders are not super common, but they’re around if you know what to look for. Another great example of spider diversity!
SpiderMentor 