- August 28, 2024 - Insectarium : Champions of nature
Written on December 27, 2013
Spiders demonstrate an astonishing imagination in terms of capturing their prey. When we think of the traps they use, the first one that comes to mind is the orb web. But even though that type of construction is the one we most easily notice, that beautiful spiral is used as a capture method by less than 10 percent of the world’s spider species. Québec’s arachnological wildlife includes, at this date, 677 species of spider, with the existence of a number of others suspected on our territory. How do these exceptional hunters go about capturing their prey? Here are some examples of the traps used by these fascinating and indispensable animals.
A 108 km/h spit
Spiders in the Scytodidae family can be compared to Spider-Man in their method of catching prey. What happens is, these spiders spit a mix of sticky and venomous fluid that allows them to immobilize prey located several centimeters away. Once in contact with the prey, the sticky substance shrinks by 50 percent, quickly immobilizing the capture. Another spectacular fact: the substance in question is spat at close to 30 m/s, equivalent to 108 km/h. At this point in time, we still don’t know whether the venom portion of the mixture has any effect besides immobilizing the prey. Although no specimens from this family have been collected in Québec, the presence of one species (Scytodes thoracica) is more than likely, according to Québec arachnologists.
Champions of imposture
The Mimetidae family (pirate spiders) includes spiders that specialize in catching…other spiders! Various tactics are used by pirate spiders. Some of them will very quickly bite one of the extremities of another spider and wait for a few seconds, long enough for the prey to be paralyzed. Then they’ll feed through the hole originally caused by the bite. Some pirate spiders will simply set another spider’s web vibrating, leading it to believe that there’s prey in its trap. But when it leaves its retreat to fetch its meal, the predator becomes prey!
Spiders that go fishing
The Dolomedes, the biggest spiders here in Québec, sometimes use a stratagem that’s earned them the name “fishing spider.” These spiders remain motionless, firmly attached to some substrate, with their front legs on the water. The legs move slightly to create little vibrations, something like what an insect disturbing the water’s surface would do. This draws little fish close enough that the spider can catch them. (That said, tadpoles and aquatic insects are believed to be on the menu more often than fish.) These spiders are also capable of diving in pursuit of prey, and remaining submerged for many minutes. The record on file is impressive: individuals have been observed underwater for longer than half an hour! Being well adapted to life close to waterways, Dolomedes are also able to run short distances on the water’s surface. There are four species in Québec, mostly found near bodies of water.
The lasso or fake-perfume technique
The American Bolas spider (Mastophora hutchinsoni) for its part uses a technique similar to the lasso. The female of this species of spider produces a blob of sticky silk at the end of a thread it holds with its legs; that ball is used to capture its prey, but not just any prey… What the Bolas spider does is coat the sticky sphere with a pheromone (scent) that imitates the smell of the females of certain moth species. Males, drawn by the smell, make their way unsuspectingly towards the trap. In a fraction of a second, the spider swings the bolas directly at its prey and captures it, a bit the way a cowboy throws a lasso. A few test runs are sometimes necessary… Incidentally, it was Maxim Larrivée, the director of the Insectarium, who discovered this spider species in Québec in 2005.
