Thread by @Cataranea

Today's #DailySpider is the brown recluse, Loxosceles reclusa (family Sicariidae).

These secretive, six-eyed #spiders are almost certainly the most feared & misunderstood in North America.

Spiders in the genus #Loxosceles* are considered medically important because their venom can be harmful to humans (unlike that of the vast majority of other spiders).

*There are several species in North America. Pictured here: the Arizona recluse (L) & Big Bend recluse (R).

Recluse spiders are not aggressive. They do not go around looking for people to bite. They feed on insects & other arthropods, not human blood. #DailySpider

Recluse spiders will bite defensively, for instance if trapped between clothes or bedding & skin.

But in general they are shy & secretive, & if we leave them alone, they will leave us alone. Here's one sitting calmly on my hand.

*Don't try this at home. Accidents can happen.

When bites happen, most require no medical intervention. Some do result in severe necrosis, but these are rare.

& despite what the tabloids & internet say, no one has ever had a limb amputated because of a recluse bite.

re photo: don't go around handling recluses

This is not to say that recluse spiders are harmless. Bites can be severe, and serious reactions have resulted in two deaths (ever), both children, in North America.

(So do as I say, not as I do, and don't mess around with them!)

HOWEVER, most "recluse bites" are not. Everyone knows someone who claims to have been bitten by a recluse. I've met 100s of such people Canada (where recluse spiders decidedly do not occur).

Unfortunately, misdiagnoses of other skin lesions as recluse bites are common.

Spider bites can only be reliably diagnosed if the spider is caught in the act (or found crushed at the scene of the crime) and identified.

Unfortunately, recluse bites are often based on symptoms alone, in the absence of the presence of any spider.

This is a problem because the recommended treatment for a recluse bite is RICE (rest, ice, compression, elevation).

Other serious conditions that can be mistaken for bites include infections (bacterial, viral, & fungal), cancers & Lyme disease, which require other treatments.

I have lost track of the number of times I've heard versions of this story:

Person never saw a spider but got a mystery bite. Then diagnosed with a recluse bite (in Canada or somewhere they do not occur), doctor prescribes antibiotics, the person gets better.

What likely happens is that the doctor says something like, "symptoms are consistent with either a recluse bite* or a bacterial infection, so here are some antibiotics"

What the person remembers is the bit about the recluse bite.

*still irresponsible/ridiculous in Canada

I could go on all day about recluses, but I'll stop here for now.

If you'd like to learn more, most of what I know about these spiders is based on the excellent work of Rick Vetter, and I highly recommend his book: goodreads.com/book/show/2530…

If you see a brown spider and you're wondering if it's a recluse, send a photo to @RecluseOrNot!

& here's even more information about recluses, where they occur, & what you can do if you find them in your home: spiderbytes.org/recluse-or-not/

UPDATE: I forgot to mention in yesterday's #DailySpider thread that brown recluses do build webs!

They are ecribellate (in the group of spiders that make their silk sticky with glue), but their silk is dry, like that of the cribellate (wooly silk) spiders.