Food Web of Spiders

Many spiders use webs to trap their prey.

Love them or hate them, spiders are a vital part of our natural ecosystem. Not only do they help keep insect populations in check, but they are food for a wide variety of creatures. Though spider prey and predators vary widely depending on the spider species, spiders have an important place in the food web.

Web Builders

Spiders that build webs between tree branches (or any other vertical supports) generally do so to catch flying insects. Houseflies, mosquitoes, moths and gnats are all common prey. In fact, without spiders, we probably would be overrun with pests.

Spiders are not picky eaters. Anything that happens to wander into a spider web is fair game. Ants and beetles have been known to crawl in unaware. In very rare cases, spiders have been documented feeding on small birds that get stuck in their webs.

Ground Dwellers

Spiders don't just make their webs above ground. Some of them like to make nests and trapdoors that they can jump out of to ambush nearby prey. Ground-dwelling spiders eat just about any kind of insect, as well as baby frogs and snakes.

Tarantulas

Tarantulas, the biggest of spiders, do not use webs at all. They live in burrows from which they jump at their prey. Big spiders need big food, such as grasshoppers, beetles, crickets, small lizards and baby rodents. The largest tarantula is accurately named the Goliath bird-eating spider because it has been documented eating small birds, such as hummingbirds, and bats.

Feeding Habits

Spiders are efficient predators and do not need to eat very often. If many insects are stuck in one spider's web, it will eat until it is full then wrap up the remaining insects to eat later. Active hunters such as trapdoor spiders and tarantulas use more energy than other spiders to catch their prey, and so they eat whenever food is available. In cases when no food is available, or none comes close enough to catch, most spiders can survive for months without eating.

Spiders as Food

Though predators themselves, spiders are relied on as food by many creatures. Birds, lizards, frogs and even fish have been known to enjoy a high-protein spider meal. Spiders also are eaten by spiders larger than themselves--even within their own species.

Even tarantulas are not at the top of the food chain. Several species of parasitic wasp rely on tarantulas to incubate their young. These wasps lay their eggs on the tarantula's body, and once the eggs hatch, the larvae devour their host.

References

• Animal Corner: Trapdoor Spiders
• Telegraph.co.uk: Giant Spider Eating a Bird Caught on Camera; Bonnie Malkin; Oct. 22, 2008
• San Diego Zoo: Insects and Spiders: Tarantulas
• Blue Planet Biomes: Goliath Bird-Eating Spider