The world of spiders is far more varied than the typical image of a creature hanging in an orb-shaped web suggests. This massive group of arachnids includes over 50,000 species identified worldwide. The common assumption that all spiders spin a web to catch food is a misconception that overlooks their incredible range of survival strategies. Focusing only on passive web-builders ignores their diverse hunting behaviors and the many uses they have for silk.
The Direct Answer: Not All Spiders Spin Webs
The definitive answer is that while every known species of spider produces silk, less than half use it to construct a web for capturing prey. All spiders possess specialized organs called spinnerets, located on their abdomen, which extrude the liquid protein that hardens into silk upon contact with air.
Spiders generally fall into two broad categories based on hunting method. Passive hunters, such as Orb Weavers (family Araneidae), rely on stationary, sticky silk structures to ensnare flying insects. In contrast, active hunters, including Wolf Spiders (Lycosidae) and Jumping Spiders (Salticidae), forego a large capture web entirely and actively pursue their meals.
Active Hunting Methods of Non-Web Spiders
Spiders that do not build capture webs have evolved specialized techniques and physical adaptations for direct predation. Jumping Spiders, for instance, have the best eyesight among all arthropods, which they use to stalk and calculate the distance to their prey. They utilize a rapid internal hydraulic pressure system to propel themselves up to 50 times their body length in a targeted pounce.
Wolf Spiders are robust, ground-dwelling hunters that rely on speed and sensitivity to vibrations. They chase down prey through grass and leaf litter, using a burst of speed to overwhelm insects like crickets and beetles. Their hunting strategy is relentless pursuit, often occurring at night when their reflective eye structure helps them spot potential meals.
Other active hunters employ ambush tactics. Crab Spiders (Thomisidae) hide motionless on flowers, often camouflaged to match the petals, waiting for feeding pollinators. Certain species, such as Misumena vatia, can even change their body color over several days to better blend with their surroundings. A specialized technique is seen in Spitting Spiders (Scytodes), which eject a sticky, venomous silk-and-venom mixture from their fangs, accurately pinning down prey from a short distance.
Beyond the Orb: The Diverse Functions of Spider Silk
All spiders use silk in complex, multifunctional ways. A single spider can produce up to seven chemically distinct types of silk, each derived from a different set of silk glands and optimized for a specific purpose. For example, the silk used for the sticky spiral of an orb web is chemically distinct from the silk used for the web’s structural frame.
One fundamental use of silk is the dragline, a non-sticky thread every spider trails behind itself as it moves. This safety line functions like a mountain climber’s rope, allowing the spider to quickly drop or backtrack if threatened. Active hunters, like jumping spiders, rely on this dragline to anchor themselves before making a leap.
Silk is also indispensable in reproduction and transportation. Female spiders use specialized, tough silk to construct thick, protective egg sacs for their offspring. Wolf Spiders carry their spherical egg sacs attached to their spinnerets until the spiderlings hatch. In a process called ballooning, young or small spiders use a fine silk thread to catch air currents, allowing them to travel long distances and colonize new habitats.
Silk is also used to construct retreats or shelters. Examples include the silk-lined burrows of Trapdoor Spiders or the small silk tents some Jumping Spiders use for resting. When prey is successfully captured, a different type of silk is quickly wrapped around the meal to immobilize it.