Widow spiders are known worldwide for their ability to cause pain and suffering in humans. The black widows found in the Okanagan have a strikingly beautiful colour combination of shiny black body with bright red markings, which adds to the apprehension people have for the spider. The red markings often involve an hourglass on the underside of the abdomen, but variations include a dorsal red stripe and dorsal spots.
Black widows produce about 300 eggs per egg sac and can store sperm from the original mating to produce more than 10 egg sacs over many months.
Aside from detriment to human health, the desire to control populations of black widows and other spiders often erupts out of a need based on psychology (arachnophobia), nuisance (disgust, symbols of poor housekeeping), commerce (transport of goods), or even litigation (prevention of lawsuits).
Because black widow spiders can potentially cause severe envenomation symptoms, rigorous control efforts are necessary when the spider is found inside a home or other building:
- Sanitation – removal of potential hiding places outside the building such as lumber, debris, heavy vegetation touching the structure, covering holes in brick and stucco with mortar or stucco putty, improving storage practices to reduc4e available harbourages.
- Removal – vacuum, vacuum, vacuum! This is a simple technique to immediately remove existing spiders, webs and egg sacs as they are discovered during inspection. Black widows are generally easy to find because their webs are found in accessible areas under furniture, in corners and in, on or under stored items. Remember to remove the vacuum bag soon after finishing and seal in a plastic bag before disposing.
- Exclusion and Lighting – seal all cracks in the exterior of buildings, ensure weather stripping and screens are tight, exterior lighting should have dim lights to attract fewer insects which are prey for black widows.
- Treatment – call your pest professional!
- Colour: black body with bright red markings
- Shape: roundish body
- Size: 3-10 mm