Most adult spiders live as loners, but members of the species Anelosimus eximius form colonies by the thousands. These tiny red spiders are smaller than the eraser on a pencil, but they work together to build nonstick webs that can span meters. When a moth, grasshopper, or other insect falls into the web, a mob of spiders must descend on it quickly before it can escape.
This creepy crawly cohort moves toward its prey in stop motion: The spiders pause, then rush forward in unison, then pause again. The staccato approach allows the spiders to sense their prey’s vibrations and synchronize the hunting party’s arrival.
To understand how these spiders match their movements, scientists observed the hunting behavior of two wild colonies in French Guiana. The researchers placed a miniature motor in the nests and adjusted its vibration pattern and intensity to simulate the movements of a prey insect. They collected videos of the spiders to see how they coordinated their approach to the vibrating lure.
No spider leader dictates these synchronized pauses, the team reports today in the Proceedings of the National Academy of Sciences. Instead, each individual spider senses the vibrations from its colony mates and stops moving as soon as they threaten to drown out the prey’s movement. Once their own reverberations have died down, the spiders start to move again. This tingling spider sense helps A. eximius colonies reach and subdue their prey as quickly as possible.
