Researchers have finally figured out how slingshot spiders (Theridiosoma gemmosum) are so accurate when they fire their webs at prey. Everything from the timing to the angle at which they fire their web is tied to the air vibrations—sound, essentially—that their prey emits.
This mystery was solved by researchers at the University of Akron in Ohio who had a hunch that the spiders might be relying on sound more than we previously assumed. They found that sound is, in fact, a vital part of how this family of spiders hunt, and actually more important to how spiders hunt in general.
Slingshot spiders are exceptionally small creatures—smaller than one centimeter. They earned their name from the way they hunt their prey. They build webs that, at a quick glance, might appear to be just a normal orb web. However, when these little hunters are on the prowl, they actually go to the center of the web and pull forward on a line that connects to a nearby rock or structure.
This causes the web to stretch and form into a more cone-like appearance. Then, when the spiders spot a possible meal, they release the line, flinging—or slingshotting—the web and itself directly at their prey. It’s a unique hunting style for spiders, and for years, scientists thought maybe the spiders were waiting for their prey to actually touch the web to pounce.
However, after meticulously watching slingshot spiders as they were approached by possible meals, the researchers discovered that the prey rarely—if ever—actually touches the web. Instead, the spiders seem to rely on the sounds that the prey creates. More specifically, they rely on the vibrations those sounds send through the air.
Scientists have had this hunch for a while, though. In fact, we’ve seen these spiders react and release their webs in response to people snapping their fingers close by. This research shed some light on the spiders, but nobody ever really dug into the minute details of how important sound is to the way these spiders hunt.
The researchers used two different methods to test how the spiders react to their prey. First, they placed wing-flapping mosquitos stuck to thin black construction paper into the terrariums they’d created for the slingshot spiders they collected. They then tested their response to how the vibrations from a tuning form caused the spiders to react, too.
Over the course of 100 different experiments, they discovered a very clear pattern of attack for the spiders. Even when a mosquito was placed directly into the cone of a spider’s web, the spider did not react until the mosquito began to flap its wings. This research proves that sound is vital to how these spiders hunt.
Slingshot spiders aren’t the only unique hunters in the spider world, though. We’ve also seen spiders that create elaborate traps for their prey, as well as spiders that hunt in packs.
