Is it an ant eating something? An egg sac of some sort? A weird fungal growth maybe? Nah. None of those things actually. It’s all just part of one weird looking Orb Weaver Spider – the Spined Micrathena, Micrathena gracilis.
I’ve been seeing these critters pop up on a bunch discussion boards with folks wondering what in the world they are. Well, what better reason than public inquiry to write a blog post? That, and I found one I could take a photo of… Can’t have a blog post without photos… 😄
Like other orb weaver spiders (Araneidae family), the Spined Micrathena, also known as the Castleback Orbweaver (for obvious reasons lol), is harmless. Unless you’re a small bug. If you are a small bug, they are very dangerous and you should steer clear… If you can see their web that is. It’s usually very difficult to see their webs until it’s too late and you’ve already gotten a face full of web and sometimes spider… Did I mention it’s good they’re harmless? The Castleback Orbweaver does have the unfortunate habit of making webs right in the middle of walkways, pathways, trails, etc. If you’ve ever gone for a hike through a wooded park, there’s a good chance that the face full of web you got was from one of these gals. Bleh! NOT a fan of spider face. There is a reason they put their webs where they do though. The same pathways that people create and use to travel are frequently also used by insects - as “flyways”. I mean, if the path is already clear, why not right? So I guess it’s actually pretty smart of the Castleback Orbweaver to make their webs in the middle of pathways…
Around now, July through October depending on your exact location, is when the female Castleback Orbweavers are most commonly seen, or, hehm, “run into”. Lol. Sorry, I love spinning puns…. 😆 This is one of those species where the females get all the cool features – the males pretty much just look like a regular spider (I don’t have a photo of the males, but you can see some on BugGuide if you’re interested). The reason the females look so weird and have all the spikey-spines on their backs is presumably for defensive purposes. Most critters would rather eat a plump juicy looking spider instead of a pincushion… Wouldn’t you?
Want to learn more about the Castleback Orbweaver? Check out these resources:
Unfortunately, we had a few casualties at my parent’s house… Instead of leaving the dead spiders for ant food, I thought it would be nice to do something with them. Here are the results if you want to give a Castleback Spider a forever home:
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