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How Do Black Widow Spiders Catch Their Prey?

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Black widow spiders are infamous for their potent venom and the females’ tendency to sometimes mistake their male counterparts for prey after mating. When they aren’t eating each other, black widow spiders harness their web-weaving skills to capture and consume their next meal.


The black widow diet consists primarily of insects like flies, mosquitoes, moths, crickets, beetles, grasshoppers and caterpillars. Occasionally, black widow spiders will also eat reptiles, small mammals and other spiders that venture into their webs. Fortunately, humans are not on the black widow menu.


Dark, sheltered areas are prime real estate for black widows to build their webs. In natural habitats, black widow spiders assemble their tangled traps under loose bark or stones, under bushes, in small trees or inside hollow logs. City-dwelling black widows spin their snares in crawl spaces beneath houses, underneath furniture or floorboards, and in a variety of other nooks and crannies with limited human traffic.


A black widow’s web is her best hunting tool. With limited sight capabilities, black widows rely on sensing movement within the web to help identify the presence of a potential meal. Typical black widow web design includes an asymmetrical network of mesh including a funnel-like or dome-shaped retreat where the spider waits for the next victim’s arrival.


The black widow spider rushes over to secure her prey immediately after a prize gets trapped in the web. Using silk spun from bristles on her hind legs, the black widow wraps her victim up tightly. Since spiders must drink their meals for lack of teeth, the black widow first must convert her meal to liquid form. The spider uses fangs to inject her victim with venom and digestive enzymes that will first kill then liquefy the body. The black widow waits in her retreat while the venom and enzymes work their magic, but will return shortly to drink up the fruits of her labor.


Despite its notorious reputation for being a killer, the black widow spider is not a major threat to humans that stay out of her way. Most black widow spiders try to avoid people and will only bite if they feel threatened or cornered. Though the black widow spider runs to investigate most movement on her web, she will typically run away from the web if she senses that the disturbance is caused by something as large as a bird or human finger.