A grey wall jumper on a white pipe
On a white pipe streaked with green moss in Lombok, a small grey spider sat with its big front eyes fixed on me. It was light brown and compact, with long legs and those unmistakable large eyes that jumping spiders carry like headlights. It did not run when I approached. It just turned to face me, which is the most characteristic thing a jumping spider can do.
This is Menemerus bivittatus, the grey wall jumping spider, a member of the family Salticidae in the order Araneae. The species name bivittatus means two-banded, and it refers to the pale stripes that run down the body, a useful field mark. These spiders live on walls, fences and tree trunks across the tropics and subtropics, and they are among the most commonly seen spiders in urban areas, though most people never notice them.
Like all jumping spiders, Menemerus does not build a web to catch food. It hunts by sight, stalking small insects and pouncing with a leap that is powered by hydraulic pressure in its legs. Its vision is among the best of any spider, with a large pair of forward-facing eyes that give it depth perception sharp enough to judge a jump to the millimetre.
Finding one on a pipe was entirely typical. These spiders treat human structures as prime hunting grounds, and this one was clearly doing its rounds, checking the pipe for breakfast. It is easy to overlook a small grey spider, but look into those front eyes for a second and you will see a fierce little hunter looking back.
