DIVERSITY is one of my favorite things about spiders. With over 42,000 species worldwide, spiders have come up with many amazing adaptations. One of the most interesting is ant mimicry. Hundreds of species do this trick and experiments have shown that the reason is protection. Spiders will look like ants, walk like ants, wave their 2 front legs around like antennae, and bob their abdomens like some ants do. Spiders are definitely not the top of the food chain. Wasps, birds, insects, and other arachnids are a few of their known predators. Many animals avoid eating ants – perhaps it’s the power in numbers, they taste bad, or they can put up a good fight, so to blend in with these insect power houses seems like a pretty creative idea. Ant mimic spiders don’t eat the ants they hang with. That would defeat the purpose.
Since humans are so visual, a trained eye can spot the spiders. They look like ants, but there’s something weird. Upon closer inspection, you’ll notice 8 legs, an abdomen that has been modified into a “waist” to look like a thorax, and there are no compound eyes. Oh, and the dead giveaway…the “ant” uses a silk drag line to break its fall. That’s a SPIDER!
Ant mimics are so good at what they do, they don’t just mimic any ole ant, but actually mimic specific types of ants. And sometimes different ants at different instars. THAT is truly amazing! Around here (Pittsburgh and Slippery Rock, PA), I have found small ant mimics (~3mm) and larger ant mimics of the species Myrmarachne formicaria, both from the jumping spider family Salticidae.
Here is a link to fantastic close ups of Myrmarachne formicaria by spider photographer Stefan Sollfers at Eurospiders.com
And some YouTube action of how these guys move like ants.