Spiiiiiiiiiiiiiiders.

I know, I know. Gross, ugh, get them off, why do they always have to have their little spider rollerderbies on your face when you’re trying to sleep, etc.

What you may not know is that spiders can be huge bros. See, with the exception of social species (Yes, that is a thing. Yes, you can have a second to scream about it.), spiders have like two things they want to communicate with other spiders: “let’s have sex” and “don’t eat me.” This is because pretty much everything wants a shot at mating, and spiders are kind of bad about eating each other.

Like, we all know about black widows, but they get kind of a bad rap, because spiders in general are not super-picky and really aren’t above just snarfing another spider. Because your odds of getting snarfed decline slightly if you’re of the same species, spiders with good eyesight have developed a fair number of displays that basically tell another spider “Don’t eat me, bro, I’m kind of your bro.” We occasionally test this hypothesis by seeing what happens when blind spiders get hungry. (No, really.)

Jumping spiders tend to have exceptionally good eyesight, even among the ranks of spiders, and also more than their fair share of obligate trophic specialists. “Obligate trophic specialist” is, by the way, a really excellent phrase to dickwave with, in case you find yourself getting into the human version of this:

It basically means they’ve evolved to the point where they can’t or won’t eat anything but this one thing. They’re no longer opportunistic predators who are really good at taking something in particular down when they find it; they won’t recognize anything else as food.

So you get these spiders who already have some fairly complex displays, and then on top of that they already know they’re not going to eat each other. There’s nothing to fear but fear itshey come the fuck back here that was my lunch.

Okay, so what they actually have to fear is intraspecific food theft and the sad shoving-match that tends to result. I mean, it is like literally a bro-fight. Most spiders fight, there’s some tension. The loser might get fucking eaten. The winner might get fucking eaten. Everybody could literally die. Spiders who won’t eat each other just like slap each other around a little bit and then finish with the devastating “glare and sulk” move.

Above: Fight moves available to spiders who lack the will to devour their opponents. Note that one of them actually is to hug it out.

I mean, seriously, here. Even in laboratory settings, where stuff tends to get all lord of the flies really quickly because researchers are dicks who tend to set things up so that everybody has to play Humungus, and nobody has the option of just walking away, all that happens is wrestling, brooding, and some weird spider face-slapping. The spiders are just like “Ugh, I don’t like you but I can’t eat you, I don’t know how to handle these feelings.”

Above: Anatomy of a bro-fight.

There’s an ant-eating spider that frequently tries to steal ants from fellow spiders that have already caught their ant. The preferred method is “aggressive kleptobiosis,” which is a fancy way of saying “bully the successful hunter out of their food and then run away with it.” The fallback method is “sneaking kleptobiosis,” which is so not-sneaky that it’s just…well.

It involves sauntering up to the portion of the ant corpse farthest away from the portion being fed on by the rightful owner, latching on, and not moving. Like, “playing possum” not moving. Like, “la la la pay no attention to what is clearly another spider just hanging off the other end of your ant, nothing to see here” not moving. It just flops down and starts eating and won’t move even if the spider still capable of feeling shame pokes it in the face. It won’t even move if more ants come along. It’s just like, have some pride, spider. Come on. Everybody can see you. Everybody knows what you’re doing. Somebody’s uploading it to youtube. Your mom’s gonna see this.

Above: A spider with no shame (right), a spider who cannot fucking believe this shit (left), and an ant who’s just glad it didn’t have to live to see this (center).

(Black and white drawings from “Poor Display Repertoire, Tolerance and Kleptobiosis: Results of Specialization in an Ant-Eating Spider (Araneae, Zodariidae)”, Journal of Insect Behavior (v.17:4, Jul. 2004), by Stano Pekar)

Spiiiiiiiiiiiiiiders.

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