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What happens when a spider bites you?

Wait, am I crazy or what? We all know damn well what happens when a spider bites us. We become Spidermen “ta-da”. It might be true in case of radio-active spiders from a fictional universe, but let’s get back to reality. This article will discuss the effects of various spider-bites on our body.

The most stereotypical characters of spiders are

  • Eight legs
  • Two venomous fangs in the front
  • And their marvelous spinneret butts
Apart from these you may have noticed that they only have two body segments connected by a small peduncle. The first segment (where the eyes are) is called the Prosoma and the second segment is called the Opisthosoma(Abdomen). The legs, the fangs, and the eyes are attached to the prosoma while the spiders heart, respiratory organ, and the spinneret is inside the Opisthosoma.

Now, there are two common arrangements of fangs in spiders. The fangs may either bite up to down like a snake, or in sideways.

A spider with sharp fangs that poin downwards
Fangs that bite from up to down
Wolf spider fang close up
Spider fang that closes sideways

Most spiders are harmless to human beings because both their fangs and their venom are not meant for us. As spiders can’t eat humans it is pointless for them to invest in costly evolutionary mechanisms meant to kill human beings. Their fangs are either too weak or too small to penetrate the hard human skin, and their venom does not cause serious damage because as I said it was not designed for us.

But it does not mean that there are no spiders capable of harming us or even killing us, because there are.

The Black Widow :

Black widows are a group of spiders belonging to the genus Latrodectus. The reason why these spiders are widows is not because a cruel bird specifically targeted the male spiders of this genus but because of the prevalence of sexual cannibalism. The female spiders of these species eat their male mates after the mating ends (Now that is TOXIC FEMINISM).

The venom of black widow spiders is a neurotoxin, it targets the nervous system. The venom contains a specific protein called α-latrotoxin which opens pre-synaptic calcium ion channels and increases the release of neurotransmitters leading to muscular spasms1. Scientists believe the reason why the black widow has this α-latrotoxin, which is a vertebrate specific neurotoxin(which has no effect on insects ) is because black widow spiders are large enough to trap and kill small lizards2. Also black widows only bite human beings when trapped and biting is the only option to escape. So black widow’s venom is meant to kill small vertebrates like lizards, but unfortunately has harmful effects to human beings.

The Brown Recluse Spider :

Recluse spiders belong to the genus Loxosceles. The venom of the brown recluse is a Haematoxin. It leads to a condition called Dermonecrosis. That is it leads to necrosis(death) of skin cells. In rare cases it causes hemolysis, the destruction of Red Blood Cells.

The brown recluse spider

Summary :

  • Most spider bites are harmless,
  • Those spiders that do harm us do it only when they are threatened,
  • They got the ability to hurt us not because they wanted to hurt us but as a side effect when they evolved to attack small invertebrates.

Disclaimer : This article is not intended as medical advice, if you got bit by a spider seek appropriate medical attention

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  1. Diaz JH, Leblanc KE. Common spider bites. Am Fam Physician. 2007;75(6):869‐873.
  2. Pennisi E. Untangling spider biology. Science. 2017;358(6361):288‐291. doi:10.1126/science.358.6361.288
  3. Wikipedia
  4. Pixabay
  5. Pexels

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