Common to warm, dry inland climates, black house spiders are increasingly being found in houses and other residential structures. Concerned you might have a black house spider problem? This article will tell you everything you need to know to safely and effectively address the issue.
Unfortunately, black house spider identification can be challenging. Often mistaken for funnel spiders due to their distinctive funnel-shaped web, black house spiders have few distinguishing physical characteristics. Black house spiders are black or very dark brown in color, with slightly lighter legs and appendages. Often, the spider will have a row of barely-visible white or grey V's on their abdomens; however, this is not always the case. The male black house spider measures around 9mm in length, while the female is significantly larger, up to around 18mm long.
The black house spider's web are usually quite thickly embroidered, and are made up of radiating circular threads held together with sideways cross-threads. When freshly constructed, the spider's web often has a blue hue, although once aged the web takes on the characteristic milk-white hue of other spider webs. At the center of the web, the spider typically creates a small covered area, accessed by a number of separate entrances. This structure provides shelter and cool during the heat of the day.
In the wild, the black house spider prefers a habitat similar to that of other spiders. The spiders can usually be found in rock crevices, or the loose bark of unhealthy trees. When nesting in human-built structures, black house spiders typically prefer vents, cracks in masonry walls, and other similarly protected areas. Indoors, the spider shows a particular predilection for nesting in the top corners of windows, where prey is plentiful - this propensity has lead to the spider being nicknamed the "black 'window' spider."
Bites from black house spiders are quite rare. Because of the black house spider's generally reclusive personality, bites typically occur as a defense of last resort, when the spider cannot hide or flee. Although not lethal, black house spider bites can be quite painful, and result in localized redness and swelling, nausea, vomiting, sweating and limited airway restriction. If you are bitten by a black house spider, professional medical attention is suggested, although not strictly required.
Identification and Control
While black house spiders do not pose a significant general risk, it's important to address a suspected spider infestation as quickly as possible, particularly if pets or young children use the space. Because black house spiders can be difficult to identify, it's important to have a professional exterminator confirm As with other spider species, home remedies are rarely effective.