Ask The Entomologist, Community

Ask the Entomologist: Massive spider

This past week I had an identification request from a bit closer to home. This giant spider was perched right below one of our windows and my wife wanted to know what it was.

Araneus gemma, the Gem-Shaped or Cat-Faced Spider.

While I’d seen and admired her webs before, this was the first time I met the web’s weaver. She must have spent most days hidden behind the window AC unit. Revealed now that we’d removed it, now that fire season and the heat of summer seem to be past.

As an entomologist, I have to say that I’ve met larger spiders, but this is the largest one I’ve seen up here in Trego. She’s an Orb-Weaver, a spider in family Araneidae. These are classic storybook spiders, straight out of Charlotte’s Web. When you see those beautiful wheel-shaped webs, big and round, full of droplets from the morning’s dew, these are the spiders responsible.

I rather like Orb-Weavers – these spiders have pronounced sexual dimorphism. Females are often far larger than males – routinely twice the size, sometimes up to four times as large. Our A. gemma was quite large for her species, a 2/3 inches across the abdomen, and over an inch in length if we measure from the tip of her abdomen to her outstretched legs.

At over an inch in length, she’s one of the largest spiders I’ve met here.

As far as medical importance is concerned, the Gem-Shaped Spider’s bite is harmless to healthy humans. Additionally, I’ve handled many related Argiope orb weavers, and have never been bitten by them, so I don’t think receiving a bite from one of these is likely. However, if you or your loved ones are immunocompromised, elderly, or very young, more caution may be merited.

Which common name do you prefer – the Gem-Shaped Spider or the Cat-Faced Spider?

1 thought on “Ask the Entomologist: Massive spider”

  1. I grew up in Northwest Wyoming and had one of these beautiful spiders make her home annually in our horse trailer. She was so docile and I was completely enamored. My dad instilled a respect and love for most critters that I am still grateful for today. I’ve lived all over the country since I left home and have never seen another specimen like that until today. Most people didn’t believe me when I told them how big she used to get. Now I have confirmation that it wasn’t my imagination. Thank you for sharing the cat-faced spider with others so more people can learn to appreciate these amazing creators as well!


Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s