Local Spiders Confused for Deadly Relatives
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I’ve been getting a few emails and calls about large, menacing-looking black spiders that are often confused for exotic, and sometimes deadly, Australian Sydney funnel-web spiders (Atrax robustus). Rest assured, we are not being invaded by aggressively dangerous spiders here in North Carolina.
Although tarantulas and trapdoor spiders (Mygalomorphae) seem to be denizens of the tropics and deserts (not North Carolina), we actually have several species of these heavy-bodied spiders. We do not have true tarantulas, but a few groups of “trapdoor” type spiders thrive in the state. Some are classic trapdoor spiders like members of the genus Myrmekiaphila. Others (a personal favorite) are called purse-web spiders, since the spiders live in silken tubes and use their giant fangs to pierce through the tube when insects crawl on it. There’s even a tiny, endangered species found in the Western part of the state — the spruce fir moss spider.
The most common of these spiders in North Carolina are in the genus Ummidia and are called “cork-lid trapdoor spiders”. They are robust and about the size of a Gatorade cap (I would say silver dollar coin, but I’m not sure how many people recognize those these days!). Females of these and many trapdoors spiders never leave their tunnel, instead waiting for males to wander around to find them and mate. When people find females, it’s often due to digging in their yard and uncovering a burrow.
Most Ummidia that people see are males out looking for the burrows of females. Males will die after mating (unlike females) so they are on a mission and not happy when folks get in their way. Thus, they sometimes rear up and bear their fangs in a menacing way (see pic below). If they are further provoked or molested they can deliver a bite, but it’s not dangerous and not much more painful than a wasp sting. Bites, however, are uncommon and do not occur unless the spider is harassed.
North Carolina is home to four species of Ummidia and we should enjoy them as part of our state’s phenomenal biodiversity. We can also breathe easy knowing that they are not dangerous, especially compared to their superficially-similar cousins from Australia.