This is the seventeenth in a series by Joh Henschel of EnviroMEND about the Namib Desert. Its wonders have many forms, some of which are tiny, easily overlooked creatures such as dancing white lady spiders.

Tap dancer of the dune night

Photographs by Joh Henschel

The moonless night is still around me, and the evening chorus of barking geckos has subsided to an occasional ‘gek-gek-gek-gecko’.

The dull shadow of the dune slope stretches into the pitch-blackness of the horizon, rolling in waves from dune crest to dune crest. The dome of the unblemished star-spangled sky arcs across and shapes the horizon.

My geophones come alive with ‘tap-ta-tappity-tap’! The night scope shows an open trapdoor, and – about a metre away – the ghost-like form of a dancing white lady spider, Leucorchestris arenicola.

Waves of motion flow from leg to leg, foot taps blending into drum rolls, leaving eight footprints in the sand across a leg span of some ten centimetres. The tap dancer pauses. He is rewarded with a distant reply. He can feel it through the faint vibrations that change the shape of the narrow slit-like sensors on his leg joints.

These are his geophones. His next ‘tap-ta-tappity-tap’ sends waves of vibrations across the dune surface and through the sand to his rival. No answer. When there is still no response to his next drum roll, he reckons that his rival has retreated. He advances, moving boldly away from his burrow. He is in search of distant adventures.

He? Isn’t this spider referred to as the dancing white lady? Indeed! But this ‘lady’ is a gent. The boxing gloves on his pedipalps – the spider’s short arms next to his face – are a giveaway. His legs have longer hairs and more spines than a female, and he is leggy. Leggy, hmm?

Although I’m treading ever so gingerly as I follow him, he is nevertheless startled, realising that he has been discovered. He kicks several long legs up into the air, momentarily flashing black stockings before lowering these legs and kicking up the next lot in another direction, and again vice versa. His galvanised flamboyancy spells ‘don’t touch’, and he looks like a cancan dancer in a chorusline, hence the common name dancing white lady spider.

When I retreat a little and he is no longer uncomfortable, he resumes tap dancing. Now there is no challenger, so he advances. He’s walking across terrain that is prime estate to other white lady spiders, but none of them are up to challenging him.

He is bigger and can be braved only by other large males; ones he can compete with through tap dancing. Suddenly, a formidable female pops out of a nearby burrow.

She makes a quick-step tap dance, ‘tippety-tap-ti-tippety’, to which he now responds with a longer, smoother shuffling albeit vibrant tap dance ‘tap-tshsh-brrr-tshsh-tap’, again and again. Turning in ever smaller circles, the two dancers come closer to each other, until he embraces her gently with his boxing gloves. Silently they mate.

Then he jumps free and retreats to a safe distance. When the female has gone down into her burrow he looks around. Where is he? I could tell him! He’s about a hundred metres north-west of his burrow.

But he knows his way home and makes a beeline for it. The upside-down landscape of the starlit night sky, or rather of the contrasting pitch-black horizon against the sky, gives him orientation.

He needs to walk slowly for his supersensitive eyes to see in the scant light. He also uses a sixth-sense backup: computation of his position, based on step size and direction. Silently he tiptoes across the undulating dune. Home! No more tap dancing tonight.

This article was originally published in the February 2013 Flamingo magazine (Air Namibia's in-fligt magazine).