Spiders frequently remove their webs, most often by systematically ingesting the silk to reclaim the valuable materials it contains. This behavior is a highly efficient survival strategy employed by many web-building species. Instead of discarding damaged or ineffective traps, the spider turns the old web into a reusable resource. Recycling and rebuilding allows the spider to conserve energy and nutrients, especially where resources are scarce.
Recycling Valuable Silk
The primary incentive for a spider to eat its web is the reclamation of protein. Producing silk requires the spider to synthesize specialized proteins called fibroins. By ingesting the old web, the spider’s digestive system breaks down the silk proteins, allowing up to 90% of the raw material to be absorbed and repurposed for spinning new threads.
Recycling is important when a spider has not recently captured prey, allowing for continuous silk production without steady dietary intake. Web ingestion also provides a mechanism for water conservation. The viscid silk used in the capture spiral is coated with hygroscopic glue droplets that actively absorb atmospheric moisture.
When the spider consumes the web, it collects this moisture, providing a net gain of water. For some species, like the orb-weaver Argiope trifasciata, the water gained is equivalent to nearly 30% of their daily water lost through evaporation. This dual benefit of nutrient retrieval and hydration is a necessary biological economy for survival.
Web Maintenance and Relocation
Spiders remove and rebuild webs due to functional and environmental pressures that compromise efficiency. The sticky coating on the capture spiral degrades over time, causing the web to lose effectiveness. Contaminants like dust, pollen, and fungal spores adhere to the glue droplets, reducing the web’s ability to ensnare prey.
Environmental factors such as strong winds, heavy rain, or the impact of non-prey debris can cause significant structural damage to the web’s threads. While minor repairs are possible, extensive damage often requires the entire structure to be dismantled and rebuilt to ensure a high capture rate. A damaged web is less effective for hunting and can draw attention from predators.
Lack of hunting success also triggers web removal and relocation. Spiders assess the web’s performance by sensing vibrations and monitoring prey capture frequency. If the energy spent maintaining the web outweighs the nutritional gain, the spider consumes the old web to recover protein and moves to a better location.
Varies by Species: Different Web Architectures
The frequency and method of web removal depend heavily on the spider species and the web’s architecture. Orb-weaving spiders, such as those in the family Araneidae, are the most well-known recyclers. Many species dismantle and consume their large, two-dimensional, wheel-shaped webs daily.
This daily rebuild, often performed at dawn or dusk, is necessary because their exposed, planar webs are highly susceptible to damage and contamination. In contrast, spiders that construct three-dimensional structures maintain their webs for much longer periods.
Tangle web spiders (cobweb spiders) build messy, irregular structures that are continually expanded and repaired instead of being torn down completely. These webs are often built in sheltered locations, protecting them from environmental damage and reducing the need for frequent reconstruction.
Funnel web spiders and sheet web weavers construct dense, non-sticky sheet-like structures with a retreat tunnel that can remain in place for months or years. These spiders primarily repair and reinforce their existing silk, adding new layers as they grow or as the web is damaged.
The difference in behavior is tied directly to the web’s design. The fragile, temporary nature of the orb web necessitates daily recycling, while the robust, complex architecture of 3D webs allows for long-term maintenance.