Most spiders hunt by spinning elaborate webs and patiently waiting for their prey to get caught in the sticky architecture. Bolas spiders do things a little differently.
These orbweavers use a sticky blob of silk on the end of a line known as a ‘bolas’ to capture prey. It swings the sticky lasso at moths and flies nearby, capturing them on the end of the line. The technique, which resembles a fisherman using a fishing line, have also earned them the nickname fishing or angling spiders.
The word ‘bolas’ comes from a similar-looking Spanish weapon made of several balls attached to a cord that was commonly used by South American cowboys to capture animals by entangling their limbs.
The blob of liquid on the end of their silk thread is packed with pheromones that mimic female moths. When a male moth approaches, the spider quickly swings its lasso and captures it.
Typically, each spider species produces pheromones for only one type of moth species. But some Bolas spiders have displayed the amazing ability to vary their methods for different types of moth, producing one type of pheromone during part of the day to attract one species, then switching to another at night to attract an entirely different species that would have been repelled by the first scent.
Watch a Bolas spider in action: