Does a spider need a web to catch its prey? Front view of a trap-jaw spider head (family Mecysmaucheniidae) showing pinching mouthparts that snap shut to capture prey the same size or even larger than itself. (Hannah Wood, Smithsonian/Stephanie Stone)
Does a spider need a web to catch its prey?
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What sort of spider can capture its prey without a web?
 
We think of spiders as web-makers. But about half of all known spider species do not make webs. Still, they have organs called spinnerets. Those spin out silk for other uses. Silk can help a spider wrap up its eggs to make an egg case. Or it can line its burrow. Or it can allow the spider to swing to the ground from a branch.
 
All spiders are predators. They sport a huge variety of tactics for capturing their prey. Spiders that do not make webs have other ways to get their meals. A wolf spider hunts down prey and pounces. Then it may use its long legs to straight-jacket it. A fishing spider gets its meal by scurrying over water towards vibrations made by prey. A bolas spider dangles sticky balls made of silk and mucus. The balls are scented to lure in moths. A spitting spider launches a sticky fluid to immobilize its victims.
 
Regardless of their capture technique, nearly all spiders use venom. Once a spider has its prey in hand (actually in its grasping appendages called "chelicerae"), it pierces it with sharp fangs. Then it injects the venom. Spider venom can damage nervous systems or other body tissues. It all depends on the species. But the vast majority of spider venom does not cause harm to humans.
 
One group of spiders with a long name (Palpimanoids) tends to specialize on eating other spiders. What's odd is that the way these spiders capture prey. It may be as complex as their long scientific name. The pelican spider plucks at other spiders' webs. Then it swings its super-long chelicerae outward to pierce them after attracting them over. Another spider in the same group has vice-like chelicerae. These snap shut on its prey with an acceleration that can exceed 1,000 times the acceleration of a space shuttle. Dubbed the trap-jaw spider by Smithsonian entomologist Dr. Hannah Wood, its jaw-like parts look like they are doing splits while they wait in the open position for prey.

Learn more about how spiders capture prey in a live "Smithsonian Science How" webcast on Thursday, January 12, 2017. In "Powerful Predators: Adaptations of Trap-Jaw Spiders" (11 a.m. and 2 p.m. EST on the Q?rius website), Smithsonian scientist Hannah Wood will show you the technology she uses to analyze spider predator adaptations while answering your questions live. You can also get teaching resources to use with the webcast.

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CRITICAL THINKING QUESTION
How do vibrations help a fishing spider?
Write your answers in the comments section below


COMMENTS (160)
  • kmadison-dav
    1/02/2017 - 04:26 p.m.

    A fishing spider gets its meal by scurrying over water towards vibrations made by prey. Once a spider has its prey in hand, it pierces it with sharp fangs. One group of spiders with a long name tends to specialize on eating other spiders. What's odd is that the way these spiders capture prey. The pelican spider plucks at other spiders' webs.

  • irisp-ste
    1/03/2017 - 08:52 a.m.

    Vibrations in the water help a fishing spider by contributing to the location of the creature's prey. By feeling for the vibrations left along as trails in the water, the spider can easily hunt down its food by chasing after the vibrations.

    • aaliyahv-hei
      1/10/2017 - 03:54 p.m.

      I agree spiders can feel vibrations do to their scenes that let them know somethings their.

  • aleahs-kul
    1/04/2017 - 12:31 p.m.

    I’ve never known there are so many different kinds and types of spiders. I HATE SPIDERS because they are like hairy and gross and they crawl everywhere!! That is kind of cool that the spiders eat their prey in different ways, and some actually depend on eating other spiders in order to survive. (53 words)

    • abigailo-kul
      1/05/2017 - 01:41 p.m.

      I agree with Aleah I HATE SPIDERS too!! But it is really interesting on how many ways there are to catch there pray. I thought the only way spiders catch prays are with spider webs. I never knew that spiders eat there pray in different ways. I also didn’t know some spiders depend on other spiders to survive.

    • matthewm-kul
      1/05/2017 - 01:58 p.m.

      I also didn't know that there were that many kinds of spiders either and they if they really need to they will eat each other. I agree that it is cool that they eat their prey in different ways.

    • kayleeb-kul
      1/06/2017 - 10:12 a.m.

      They hate you too. It is really cool that they have so many different ways to capture prey, and it's definitely not a bad thing that they eat other spiders. It helps control the population of the gross, furry beasts.

    • sydney-kul
      1/06/2017 - 12:01 p.m.

      I think everyone will agree with Aleah. I don't understand how someone can LIKE spiders. They are so gross!! Honestly learning about spiders has kinda freaked me out, but at the same time, it's really interesting to finally shine some light on the topic.

  • abigailo-kul
    1/04/2017 - 12:34 p.m.

    I hate spiders!!! I can’t stand them even when they are the little ones. Some of the ways that spiders catch there prays are disgusting! A bolas spider dangles sticky balls of mucus and silk to catch there pray. The balls are even scented to attract pray. Another disgusting way that spiders catch pray is when launch sticky fluid. I never knew some spiders could do that though until I read this. But I still hate spiders and always will.

  • brookeg-kul
    1/04/2017 - 12:37 p.m.

    I never really thought about learning how spiders make webs. I did know that the spiders use venom. It is interesting that they make silk to make their webs. It is gross that some spit their silk thing to catch their prey instead of using their prey. Now I know more.

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