Do Black Widow Spiders have red markings on top?

Yesterday I removed from underneath my mailbox a shiny black spider with a big bulbous back end. On the back end were the traditional red hourglass markings of a black widow spider, as well as another red spot. I couldn’t see underneath it, because I didn’t want to make her mad. I moved her and her big egg sac across the road to long grass in an open field. I didn’t kill her, but do I need to keep an eye out for venomous spiders?

StG

Yup.

Some people are real sensitive to the venom. I have a friend who got bit almost 20 years ago and it just flares up every few years. It looks sorta like a new bite. It gets all red , puffy and looks infected.

Thanks. Good to know. I live in a 160-year old farmhouse with lots of hidey places. I’ll keep my eyes open.

StG

It depends on where you’re located (which determines what species of black widow, if any, is local) and also on how old the black widow is. Note, in general any spider question is A LOT easier to answer when we’re told up front whether you’re in Alaska, Alabama or Australia. “Toon town” doesn’t convey anything to me, location-wise.

The western black widow (anywhere west of Kansas) has no red on the upper surface, as an adult. The southern black widow (east of Kansas and south of NY) has 1-3 red spots above the spinnerets. The Australian Redback has a solid red band on the back half of the abdomen. There are numerous others in the group each with their own little quirks. And to complicate it all, immature specimens have all kinds of different dorsal patterns, depending on the exact life stage and which species they are. Here are some examples from the Western Black Widow:

Now, to look on the bright side: just because you have black widows around doesn’t mean anyone will get bitten. True spider bites are really rare events, regardless of whether the spider is toxic to humans or not. The “common spider bites” you hear about are actually medical misdiagnoses of conditions that have nothing to do with any kind of a real bite. And no human of any age has died from a black widow bite in the USA since the 1960s - so they’re not exactly public enemy no. 1.

arachnologus - I’m in Middle Tennessee, outside of Nashville (Music City, AKA Toontown). The Southern spider looks about right. I’m not afraid of spiders, but would prefer that my letter carrier not stick her hand into a web with a protective mother. I moved her across the road into grass by a big tree.

StG