Spiders are one of the most successful predators among invertebrates, and many of them have unique and effective ways of catching their prey. The vast majority of spiders are experts at being ambush predators, relying on sticky webs or hiding spots to allow prey to be easily caught as they get stuck or walk past. Some spiders, on the other hand, use much more aggressive methods to catch their prey and this often includes some kind of special ability that gives them the upper hand.
The net-casting spiders (Deinopidae), also known as ogre-faced spiders because of their huge eyes and jaws, have one of the largest set of eyes of any spider. Net-casting spiders have an extremely unique way of catching prey. They are nocturnal spiders that grow light-sensitive membranes in their giant eyes every night (the membranes are destroyed in the daylight) in order to see their prey in the dark. They also hang from a specialized web where they then build a super-stretchy web between their legs. This web can be stretched out to two or three times its relaxed size and wrapped around an insect that walks by the net-casting spider at night with great precision because of their night vision.
Fishing spiders (Dolomedes sp.) are a genus of spiders with more than 100 species around the world, including a couple that live right here in Hamilton County. These spiders are able to jump on the surface of the water and they can even gallop across the surface to chase after prey. They have specialized hairs on their bodies, which repel water and allow them to dive into the water to capture an insect without getting wet. The film of air that forms on their body can give them a silver glow, and the trapped air allows them to breathe underwater. Most spiders wouldn’t survive falling into water, but fishing spiders dominate the creeks and streams and the large ones sometimes even eat fish!
Jumping spiders have amazing vision compared to other spiders, with a particularly large set of lower eyes that can help them hone in on prey within jumping distance. They can jump distances several times their body length and are usually very accurate. Many species of jumping spiders are considered uniquely intelligent, and the species within the genus Portia are well known for appearing to have learning and problem-solving abilities that are normally only seen in mammals or highly intelligent animals like crows. Jumping spiders seem to use trial and error to come up with the best hunting methods, and may even spend an hour taking detours in order to find the best route to their prey.
The bolas spider (Mastophora sp.) is the fisher of the spider world, and their main specialty is the ability to create the perfect bait for their prey. The bolas that they’re named after is actually a tiny, sticky droplet full of a moth pheromone that is perfectly designed to attract a specific species of moth. This pheromone attracts male moths to the bolas, and the spider, hanging from a horizontal line of web, swings the line allowing the sticky bolas to catch the moth, which is then reeled in and eaten. The bolas spider is nocturnal, and during the day, it stays motionless on a branch disguised as excrement from a bird.
The triangle weaver (Hyptiotes cavatus) is one of my favorite local species, and it creates a very special triangular web, as its name suggests. Their web appears to be just one section of a regular orb web, but, if you examine it more closely, you’ll notice the spider is hanging on the edge of the web instead of sitting in the middle. In fact, triangle weavers tightly wind their webs and hold on to one edge of the web waiting for prey to touch the sticky threads. When they do, the spider loosens its grip and web collapses on the prey causing them to be instantly wrapped up and trapped. These spiders may be tiny and hard to spot, but I highly recommend going out and trying to find one of these in action!
Check out the videos linked below if you want to see these spiders using their special abilities!
- Net-Casting Spider Ensnares Prey | The Dark: Nature’s Nighttime World | BBC Earth
- Galloping spiders – Spiders: how they move and spin | OpenLearn from The Open University
- Spider With Three Super Powers | The Hunt | BBC Earth
- An Alluring Spider | Animal Armory | Nat Geo WILD
- Catapulting spider winds up web to launch at prey | AFP News Agency
- How spiders see the world | The Australian Museum
- Dark Fishing Spider | Macalester College
- Harland, Duane & Jackson, Robert. (2000). ‘Eight-legged cats’ and how they see – A review of recent research on jumping spiders (Araneae: Salticidae). Cimbebasia. 16.
- Haynes, K.F., Yeargan, K.V. & Gemeno, C. (2001).Detection of Prey by a Spider that Aggressively Mimics Pheromone Blends. Journal of Insect Behavior 14, 535–544.
- Han, S. I., Astley, H. C., Maksuta, D. D., & Blackledge, T. A. (2019). External power amplification drives prey capture in a spider web. Proceedings of the National Academy of Sciences, 116(24), 12060–12065.
Nature Interpreter, Nature Center at The Summit