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Spiders are arthropods which have two distinct body parts and four pairs of legs. Spiders prey on insects and help to suppress pest populations. An acre of typical meadow may contain thousands of these beneficial organisms.

The European House Spider (Tegenaria domestica) is a brown spider 11 mm in length with a chevron pattern on the abdomen. It has adapted to live in human habitations, as has its relative, the Giant House Spider (Tegenaria duellica).

The Daddy longlegs (Phalangium opilio) is not actually a true spider in that it does not have a separate cephalothorax and abdomen but belongs to a related family (Opiliones). They also lack the poison producing glands typical of the true spiders.  The myth that the Daddy longlegs is 'the most venomous spider in the world but its fangs are too short to break through human skin' is just that, a myth.

Spider Facts Spider

The majority of spiders only live outdoors where food is plentiful. Common garden and orb spiders (Araneus trifolium) are a good example. In North America only the black widow (Latrodectus mactans) and the brown recluse (Loxosceles recluse) spiders are seriously venomous. Both these spiders live in warmer climates south of Grande Prairie. Spiders only bite humans when they feel threatened and usually people are unaware that they have been bitten.

Spiders travel by foot; however, very small spiders can travel on a breeze by suspending themselves from a silken line. This method of travel is called ballooning and is also utilized by spider mites.

Affected Species

Spiders are one of the most beneficial and perhaps misunderstood arthropods in our urban environment. It is important to remember that arachnids pose little risk to people and help suppress pest populations that do pose a risk to our urban environments.

There are approximately 40,000 thousands species of spiders in the world and 3000 in North America. Only a few of these have venom strong enough to harm a human and are usually not strong enough to kill adults.


  • Keep all weather stripping around doors in good condition and replace as needed. If a draft can get in, so can a spider.
  • Fill cracks in basement foundations.
  • Check your basement for spider webs.

The Royal Alberta Museum provides more information on spiders in Alberta.

Last updated: 10/28/2013 9:49:40 AM