Ant-Mimicking Jumping Spider

Great video. I live in Argentina, and have found in my garden one of these mimicking spiders. It was an almost-perfect copy of a Camponotus ant, with silvery grey abdomen and all.
I´ve also seen ant-mimicking bugs, and a wasp-mimicking fly. The last one was an amazing copy of a big paper wasp, you could only tell them apart by the fly-like head and the tiny halteres.

Who even knew arachnids were so enthusiastic about Hallowe'en?

Seriously, that is an amazing video. My question as a lay person is this: how does the spider species benefit from this particular subterfuge? Are the spider's usual prey unintimidated by ants? Are Camponoti known as pushovers?

Thanks for posting. My daughter, a budding entomologist, will love this.

Yours,
CBB

CBB: pleased to give your daughter something fascinating to think about. i am not a "spiderologist" (i study evolution of birds), so i can't ID the species -- which would help me provide a more accurate explanation. however, that said, i do know that jumping spiders are active predators that hunt down their prey instead of "sit and wait" predators as most spiders are (who wait for their lunch to blunder into their webs). in this case, mimicry would allow jumping spiders to mingle with ants without being detected (i assume that these spiders also mimic the ants' pheromones so ants are completely fooled). i suspect that these ant-mimicking spiders live among their lunch (the ants in their nests) and thus are able to eat whenever they are hungry. but until a species ID is provided, my comments are merely speculation based on what i know about evolution and biomimicry.

It's a species of jumping spider, from the genus Myrmarachne, possibly Myrmarachne Assimilis or Myrmarachne Plataleoides. Still pretty cool though.

Maybe it's a jumping spider mimicking an ant? :p Either way, very impressive.

It's a jumping spider of the genus Peckhamia. Unfortunately, it's not possible to identify it to species from a video, but there are 6 species of Peckhamia found in the US.

Definitely a jumping spider from the genus Peckhamia... I believe only four species are found in the US, and we can discount americana because of color (black), likewise scorpionia (mustard-brown), and also seminola because of location (only Florida), so this is possibly P. spicata

photo of Peckhamia spicata

diagnostic drawing of P. spicata

Other species in the genus: americana (US and Mexico), argentinensis (Argentina), prescotti (El Salvador, Panama), seminola (US), scorpionia (US and Canada), variegata (Panama)

You're not reading your sciblings. Didn't Ed Yong cover this a short while ago?

IanW, similar...

Spiders Gather in Groups to Impersonate Ants, Not Exactly Rocket Science, June 2009