Brown Widow Spider Bites

Black widow is pretty notorious for its venomous bite. However, little people seem to know that its brown sister is also rather dangerous. Brown widow spider bites are considered less intensive as they do not produce so severe symptoms. However, they are still very serious. Besides, it is essential to know how they manifest themselves and especially if a person lives in the area of this species habitat.

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Brown widow (or Latrodectus geometricus) is a relative to a black widow spider. One always hears about the danger of the bite of the latter. However, brown widow spider bites are actually the same; it is just this kind of a spider does not generally injects that much amount of venom.

What about the venom?

Venom toxicity can be measured in various ways, by either taking all the venom or its components into consideration. The LD50 stands for the Lethal Dose 50% and it is the exact dose that kills 50% of test animals in trials.

If a dose is higher, it means that the venom is less toxic, and vice versa. Here is the chart from the study of spider venom effect on mice (here is to read more about the study), and it clearly shows that brown widows have less toxic venom than their black siblings.

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The thing is that it doesn’t make brown widow spiders less harmful. They are more shy, so to say, but nevertheless, their venom is quite potent, they just don’t produce it in large quantities.

Here is the catch: brown widow spider venom is thrice as toxic as the venom of its black widow sister. However, the latter are being much more feared. And why is so? | Published online July 14, 2011 | DOI:10.1016/S0140-6736(10)62230-1

If you check this chart that was published in the Lancet in 2011, it explains everything pretty clearly. The bites of brown widows appeared to be less painful and they also didn’t produce any of the effects noticed in the cases of other widows’ bites. Not many of potential hospitalization causes was detected – not even hypertension.

It might look quite reassuring at first, but it is not. There is a high chance to be bitten by such a spider if you live in the US (especially in Florida, Georgia, North and South Carolina, Alabama, Mississippi, Louisiana, Texas, also California and Hawaii), so, it is better to be well-aware of the risks.

Why so scary?

As it has been aforementioned, black widow is being afraid of due to the effect of its bite when a large amount of venom is injected into a person’s organism. Brown widow spider bites can be no less potent and it should be taken into consideration especially if kids or seniors are bitten. And its effect should not in any case been underestimated in case of people with weak immune system.


In terms of the symptoms of brown widow spider bites and a black one, they are a bit different. With black widow they tend to spread of over the body, while they stay localized after a bite of a brown widow. Among the most frequent ones are swelling, nausea sensation and the abdomen muscles rigidity, legs also, vomiting happens frequently and in many cases blood pressure rises dramatically.

How to differ

It is useful to differentiate the two species in order to know how to handle the bite.

Photograph by Joel Sartore, National Geographic Photo Ark

To start with a black widow – it is rather hard to confuse. It is jet black and shiny with an hourglass bright red. It is bigger in size than a brown widow and its egg sack resembles a pear and is smooth.

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When it comes to a brown widow, it is smaller and varied in color from sandy to dark brown and even black. It has got two-toned legs and its egg sack has got spikes. As it was mentioned above, brown widow spider bites less intensively as the black one.

Brown’s not the only color that bites…

Moreover, there are other kinds of widows besides brown and notorious black ones. Actually, America has got four of such species: southern and northern black widows, red widow and brown widow. Red widow spider is most frequently found in Australia as well. Here are other nice-looking relatives:

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Take good care

Brown widow spider bites can be pretty dangerous and its effect rather unpleasant. That is why it is very important to take precautions. They are simple but are able to keep a person from being bitten.

It is essential to know that brown widows love to be left alone, so they prefer the secluded places where they are less likely to be disturbed.

  • Thus, stay away from wood piles and other places with lots of thick bushes, places where trash is accumulated, under pots and stairs and porches, everywhere like this.
  • It is also recommended to check the shelves and basements before entering. These recommendations will help to avoid unpleasant intercourses and prevent form brown widow spider bites.


Spider bite – US National Library of Medicine

Brown Widow Spider – University of California, Riverside, Center for Invasive Species Research

Latrodectus geometricus C.L. Koch 1841 (Arachnida: Araneae: Theridiidae) – Featured Creatures

Are Brown Widows as Dangerous as Black Widows? –

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