Both male and female spiders produce silk, but their reasons for doing so and the resulting structures are fundamentally different. A spider web is defined as a silk structure built specifically to capture prey, and in this context, female spiders are the primary builders. The large, permanent, and complex webs people typically notice are almost always the work of a female, serving as a combination of hunting ground and long-term residence. Male spiders, in contrast, engage in temporary, specialized silk production focused mainly on reproduction and safe movement, rather than daily sustenance.
The Primary Web Builders
Female spiders are the engineers of the largest and most complex silk structures, such as orb webs and sheet webs, which they use as passive traps for prey. This investment is linked to their reproductive role, as they require a constant, high-volume food source. The massive energy demand of producing a large egg sac necessitates a reliable, expansive hunting tool.
A female orb-weaver dedicates substantial resources to constructing and often rebuilding her sticky spiral capture web daily. These structures are designed to intercept flying insects, providing the necessary calories for the female to sustain herself and mature her eggs. Other females, such as those that build funnel webs, create long-term silken homes that serve both as a retreat and a large trap to ensnare passing insects.
Silk spinning is also necessary for protecting her offspring. She uses dense, specialized silk to construct a durable egg sac, which is a protective casing for hundreds of eggs. This structure shields the developing embryos from predators and environmental threats. The female’s life cycle is intrinsically tied to the construction and maintenance of these large, permanent silk structures for both feeding and maternal care.
Specialized Web Uses for Males
Male spiders, particularly once they reach maturity, largely abandon large capture webs to focus on finding a mate. They continue to produce silk for highly specialized, temporary uses that facilitate reproduction. The most distinct of these is the creation of a “sperm web,” which is a small, simple silk pad or sheet.
Before mating, the male deposits seminal fluid onto this specialized silk structure from his abdominal genital opening. He then draws the fluid into his pedipalps, specialized appendages on his head, for later transfer to the female.
Male spiders also use silk during courtship. They may build small, temporary signaling lines near a female’s web to vibrate and communicate their non-prey identity, reducing the risk of being mistaken for a meal. Males continuously lay down a single strand of silk, known as a dragline, as they move. This dragline acts as a safety tether, allowing them to quickly drop out of danger or climb back up, which is important when navigating a larger female’s territory.
Spiders That Hunt Without Webs
The distinction between male and female web-spinning roles primarily applies to species that rely on sticky silk for prey capture. A significant number of spider families, known as active hunters, do not construct capture webs at all. In these species, neither sex spins a web for hunting purposes, relying instead on speed, camouflage, or ambush tactics.
Wolf spiders and jumping spiders are common examples of active hunters that pursue or pounce on their prey. These spiders have excellent vision and do not need a stationary silk trap to secure a meal. While they do not build traditional webs, they retain the innate ability to produce silk for non-hunting functions.
Silk is used defensively and for shelter by these species. Both sexes use draglines as safety lines, particularly when making long leaps or retreating from a threat. They may also spin small, dense silk retreats for molting, overwintering, or resting. Female wolf spiders still employ silk to construct the round, tough egg sac, which she then carries with her until the spiderlings hatch.