House spiders, such as common cobweb spiders and funnel weavers, are frequent inhabitants of homes. While their presence is often known, fewer understand the natural forces that regulate their indoor populations. Exploring these predators offers insight into the complex, often hidden, ecosystems within our living spaces, clarifying indoor pest control dynamics.
Arthropod Predators of House Spiders
Other spiders commonly prey on house spiders. Cellar spiders, often known as “daddy long-legs,” hunt other spiders, even larger species. They vibrate webs to mimic trapped prey, then attack. Jumping spiders also actively hunt and consume smaller arachnids. Cannibalism can occur among spiders, particularly when food is scarce or females consume males after mating.
House centipedes (Scutigera coleoptrata) are efficient, multi-legged predators frequently found indoors, known for rapid movements. These nocturnal hunters pursue a diverse diet including spiders, cockroaches, silverfish, and other small arthropods. They use venomous fangs to immobilize prey, making them effective in controlling household pests. While their appearance may be unsettling, they are beneficial for reducing insect populations.
Certain insect species also prey on house spiders. Predatory wasps, such as spider wasps and mud daubers, paralyze spiders and lay eggs on or within them; the larvae then consume the spider. Mantispid lacewing larvae target and consume spider egg sacs. Some beetles, including ground beetles, also prey on spiders.
Other Natural Enemies
Small reptiles can be opportunistic predators of spiders, particularly in warmer climates where they may enter homes. House geckos and anoles are insectivorous lizards that consume spiders. Geckos hunt at night, while anoles are active during the day, ambushing prey. These lizards help manage indoor insect and spider populations where they are present.
Amphibians like frogs and toads are generalist predators that eat spiders if the opportunity arises. However, their presence indoors is typically rare, making them less common house spider predators. They are more likely to encounter spiders in outdoor or damp, secluded areas.
Birds, known for consuming insects, also include spiders in their diet. Wrens, sparrows, bluebirds, and blackbirds may prey on spiders if they find their way into a home. Some birds, like the great-tit, specifically hunt spiders to feed their young. However, birds are not a primary or reliable method for controlling established indoor spider populations.
Small mammals, though not typically associated with spider hunting, can occasionally consume them. Shrews are aggressive insectivores that hunt and eat spiders. Mice and rats, being omnivores, also opportunistically eat spiders, particularly when other food sources are scarce. Spiders are not a preferred or significant part of their diet, but they will be consumed if encountered.
Considering the Presence of Spider Predators Indoors
While natural predators can contribute to controlling house spider populations, their presence indoors might not always be desirable. These predators are part of a natural ecosystem that extends into homes, consuming other arthropods. However, many, such as house centipedes or mice, are often considered pests due to their appearance, potential for property damage, or indication of a larger pest issue. Their presence can suggest an existing food source of other insects.
It is not advisable to intentionally introduce these predators into a home for pest control. Doing so can lead to new challenges, such as establishing another unwanted animal population, potential bites, or introducing parasites if wild specimens are used. Effective methods for managing house spiders involve preventative measures: limiting their access and food sources. Strategies include sealing cracks and entry points, reducing clutter, and maintaining cleanliness. Removing other insects, a spider food source, also deters them from settling indoors.