Almost all spiders possess venom for the purpose of subduing their prey – normally insects. This makes spiders one of the most beneficial of invertebrate groups. Spider venom is occasionally used against humans. This usually happens when the spider is trying to defend itself. Many spiders are not able to penetrate human skin with their fangs. Those that can occasionally inflict painful and, in rare cases, dangerous bites.
Keeping spiders off and out of a building for a long period of time is almost impossible without a professional pest control program. Spiders do not congregate in a single large nest, so the population cannot be destroyed by targeting one site. New spiders will quickly recolonize an area once the old spiders are killed off. In many species, young spiders disperse by “ballooning”. They spin silk strands that are taken by the wind, carrying the spiders over potentially long distances.
Although keeping an area free of spiders is difficult, there are many precautions that can be taken to avoid bites. Avoid walking outside with bare feet, especially at night. When gardening, wear shoes, long pants and gloves to guard against any spiders, scorpions, centipedes or stinging insects.
Wandering spiders can enter houses at ground level, often under a door. Although they will die after crawling over the treated door sweep, fitting weather strips or using draft excluders can block this entry route in the first place, keeping them outside. Fitting fly-screens to windows and wall ventilators will prevent any climbing spiders from obtaining access. A cleared area around the house and keeping foliage well away from building surfaces will discourage spiders from gaining access to the sides of the building.
It is a good idea to educate children to “look but don’t touch” when they find any spiders and for adults to obey the same rule. It is sensible to be respectful of spiders, rather than frightened of them.