A close-up shot of a parson spider.

I’m pretty certain you all know about the common medically important spiders (even if they’re not indigenous to where you live) like the widows and brown spiders and maybe even the sac spiders too.  But did you know there is another really common group of spiders that have medical significance? 

I’m talking about the group collectively known as the ‘Ground’ spiders (Family: Gnaphosidae ) These spiders spend the day hiding in silken retreats under objects like stones, logs, or beneath stored items outside around the home.

They are active nighttime hunters and commonly enter homes wandering about in search of prey. Often, they themselves become prey victims of other spiders by stumbling into their snares.

This wandering activity really seems to spike as temperatures start to cool off in the early fall and they’re looking for winter shelter. I probably had a dozen or more of them coming in my basement a few months ago.  Some of these were indeed the Parson spider, (Herpyllus ecclesiasticus) which is named for its’ distinctive abdominal markings which are said to resemble a garment worn by 18^th century clergy and another species, Gnaphosa, or Haplodrassus but I’m not sure which.

I never really used to care too much about them a few years ago that is until one bit my wife.  It was an accidental bite to be sure because the spider had crawled up on her at night while she was sleeping.  It managed to get itself crushed between her left arm leaving a quarter-sized bruise. She woke up with a headache and mild fever. This seems to confirm what others have said about this species.

According to a University of Nebraska extension bulletin, some people have experienced varying symptoms (not life-threatening) to bites from this spider. Contact Colonial Pest Control for expert spider control.

Further Reading

For more information and images, visit the following links.

• http://www.spiders.us/species/herpyllus-ecclesiasticus/
• http://lancaster.unl.edu/pest/resources/medspider006.shtml
• http://bugguide.net/node/view/189497/bgimage

Photo credit: E_Journeys / Foter / CC BY-NC-SA