Sunday, August 14, 2016

Myrmarachne formicaria

On Thursday, I saw an ant walking around on a houseplant in our kitchen. Ants are not generally welcome in my house, so I carried the plant outside to deposit the ant there, and somewhere during the walk from the kitchen to the door I realized... that's not an ant:

The mimicry was really excellent, but it was definitely mimicry. Not an ant, a spider! This is an ant-mimic jumping spider, Myrmarachne formicaria:

This is actually a non-native species, first introduced and observed in Ohio a decade or so ago, and its range is gradually expanding (it's obviously made it as far as central New York by now). And I don't know for sure what benefits this spider gets from looking so much like an ant; perhaps this disguise helps protect it from predators, or perhaps it lets the spider get closer to the creatures it hunts. Either way, I'm super impressed. Only the large quasi-iridescent mouthparts gave it away as not-ant:

And oh yeah, spider eyes!

Here's a brief video of this spider, because it was so amazingly ant-like in its movements, even waving its front legs around like a pair of antennae, completing the illusion:

So that was a cool surprise! How many more mimics can I find around my house?