Bug News

Bug News

Observations, factoids, funny clips, and lots of bugs and other nature related images.

4-Minute Read

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… 😄

Castleback Orbweaver, Micrathena gracilis, in profile

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…

Castleback Orbweaver, Micrathena gracilis

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?

Castleback Orbweaver, Micrathena gracilis, upside down
Castleback Orbweaver, Micrathena gracilis

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:

Questions? Comments?

We’re still trying to figure out how to add comment boxes to the blog, so in the meantime, send me an email!
We’re also on Facebook now so you can leave a comment or start a discussion there too if you want.

Join the email list

Want Bug News stories & announcements sent to your inbox? Join the Bug News email list

Support the blog!

Like my blog? Want to help keep the new content coming and the pages ad free? Consider becoming one of my Patreon Patrons! Any amount, big or small, helps me spend more time creating and less time trying to keep the lights on. Patreon Patrons can also get exclusive access to monthly newsletters, story sneak peeks, story requests, and more! Please consider supporting the blog and check out my Patreon Patron support page.

Ok, you say, but what is this Patreon thing you are talking about? Patreon is a service that helps connect content creators with folks who want to help support creative endeavors. Patreon is setup to be able to safely handle the financial side of transactions so both the patron and the creator can be confident their information is secure. You can read more about what Patreon is HERE.

Thank you!!

Not interested in a Patreon monthly subscription? Prefer to make a one-time contribution? We have that option too! Help support the blog with a one-time donation through PayPal instead! Thank you!!

Recent Posts

Blog Topics

Quick Links

Support Bug News!
There are many ways you can help support the blog:

One time donation
Patreon Subscription
Bug Jewelry
Bug Swag

Email List
Want stay up to date? Sign up for our free email list for new story announcements and the occasional blog update:

Email Signup

Written by an entomologist for the enjoyment of all... The goal is to post 1 new story every week or so. Stay tuned!