Slingshot spiders (Theridiosoma gemmosum) are fascinating arachnids known for their unique hunting technique. Instead of chasing prey or waiting for them to stumble into a web, these spiders launch themselves and their web towards their meals. New research reveals how these tiny hunters know precisely when to strike: they listen.
Scientists at the University of Akron have confirmed a long-held suspicion that slingshot spiders use air vibrations, essentially sound, to trigger their attacks. This discovery not only sheds light on these intriguing creatures but also suggests that sound plays a more significant role in spider hunting than previously thought.
Spiders employ various hunting strategies, from ambushing prey to even fishing. Slingshot spiders, also called ray spiders, stand out with their dramatic hunting method. These tiny arachnids (less than a centimeter in size) construct webs that initially resemble typical orb webs. However, they also create a tension line connecting the web’s center to a nearby anchor point. When hunting, the spider pulls this line taut, creating a cone shape, and then releases it, propelling the web and itself forward with remarkable speed.
Although these spiders have been known for over a century, the mechanics of their hunting technique remained largely a mystery. Unlike other catapulting spiders, slingshot spiders don’t require physical contact with their prey to initiate an attack. Researchers Sarah Han and Todd Blackledge investigated this unique hunting strategy.
Previous research, including studies co-authored by Blackledge, showed that slingshot spiders would release their webs in response to nearby sounds like finger snaps. However, the specific role of sound in prey capture hadn’t been thoroughly examined. “Based on this observation we set out to explore if sound figured into the spider’s web release and prey capture,” explained Han, a biologist studying spider web mechanics.
The researchers collected wild slingshot spiders (commonly found in the northern hemisphere) and housed them in terrariums replicating their natural humid environment. Once the spiders settled and built webs, they were presented with two stimuli: wing-flapping mosquitoes attached to paper strips and tuning forks vibrating at frequencies mimicking insect prey.
Across nearly 100 trials, a clear pattern emerged: the spiders primarily relied on sound to time their attacks. They demonstrated impressive speed, accelerating up to 50g and reaching speeds of nearly one meter per second. The tuning forks also triggered web releases, further supporting the importance of sound in their hunting strategy.
The spiders’ vision likely plays a minimal role, as they face away from their webs and lack the advanced eyes of some other spider species. Instead, they “hear” using specialized hairs on their legs called trichobothria. The spiders strategically release their webs when prey are within striking distance, ensuring a successful capture.
This research, published in the Journal of Experimental Biology, highlights the importance of sound in the slingshot spider’s hunting strategy. While this study has answered a key question, further research could explore whether the spiders also utilize web-borne vibrations to fine-tune their attacks.
Furthermore, slingshot spiders may not be the only arachnids primarily using sound to hunt. This raises the possibility that sound is a more critical factor in spider hunting than currently recognized. “A broader implication of this work is that sound may be a very important and understudied factor in how spiders perceive their environment,” Han noted. Future studies could investigate how spider webs detect sounds and how web construction is influenced by the sounds of potential prey.
The intricate hunting techniques of the slingshot spider demonstrate the remarkable adaptations found in the natural world. This research underscores the importance of continued exploration into the sensory world of spiders and the role of sound in their survival.
