Looking Both Ways

Hiding in plain sight

Janus (Giano) Bifronte (detail) by ‘Maestro dei Mesi’ (c. 1225–1230), Cattedrale di Ferrara. © Nicola Quirico. CC by-SA 4.0. Source.

There was something odd about the ant on the window. It had the elements you might expect in an ant — six legs, two antennae, and a head, thorax and abdomen — but it didn’t have the essential ant-ness — the formal formicidacity* — that makes you think ‘yep, that’s an ant’. As I watched the creature walk purposefully across the glass, it dawned on me. This wasn’t an ant; it was an ant-mimicking spider.

Of course, by the time I’d fetched my camera, the ant mimic had disappeared. Such is the way of photo opportunities. Only landscapes and statues wait for the photographer. Ants amble, spiders skedaddle, subjects move on.

So how anty did it look? But what about the issue of six legs and paired antennae? These are characteristics of insects not spiders.

Some ant-mimicking spiders hold up their skinny front legs or second pair of legs to resemble antennae.

This is a spider! Count the legs and eyes. Red Weaver Ant-mimicking Spider (Myrmaplata plataleoides) family Salticidae. Singapore. ©Yunhan. Public Domain.

And the tripartite body? That’s slightly trickier because spiders only have two parts — cephalothorax (head + thorax) and opisthosoma (abdomen). But Myrmarachne, a jumping spider (Salticidae), has a pinched-in cephalothorax giving the impression of a separate…