Myrmarachne | Learning #1

Today I encountered an insect who at first sight looked like a Carpenter ant. But upon further close inspection I observed it hanging with its web. It was really confusing for me, was it an ant who can make webs? Or a spider that resembled ants. I suspected it to be later and killed it as spiders can be very venomous and with this one being out of ordinary, I could not take any chances. Here's a photo of it that I clicked 

the top part is it's head

I then looked about this insect over the internet and found out it's a Myrmarachne, a genus of spider who adopted appearance of ants for various survival reasons that I'll talk about.

Here's a picture of it from the internet

There are several species under the genus Myrmarachne that resemble different species of ants. They walk like ants (in a zig-zag pattern), and they even wave their front legs to resemble an ants antennae. Their large jaws resemble a cargo that ants usually transport.

Ants are not on the top menu for a lot of predators because they don't taste well and are very agressive (defensive). On the other hand spiders are not gifted with defensive skills and taste comparatively better and hence are preferred over ants as food by the predators. This drove the evolution of these spiders to look like ants. It not only reduces their chance of being eaten, it also helps them prey on ants. A normal ant predator would have to chase ants to eat it, while these spiders simply approach them like a fellow ant and then suddenly attack it.

But this phenomenon of resembling ants for survival advantage isn't limited to these spiders. This is so common that it has its own term "Myrmecomorphy" - mimicry of ants by other organisms. There are lots of species under this genus Myrmarachne that resemble different species of ants. There are even plants who show myrmecomorphy.