Dangerous Spiders: Black Widow and


There are thousands of species of spiders, of which only a fraction pose any real threat to humans. The most infamous species in the United States are the black widow and the brown recluse. Both of these spiders are known to bite humans when provoked and inject their venom, which can be very harmful and sometimes fatal.


Female black widow spiders are easily identified by the colored hourglass shaped mark on the underside of their abdomen. The females are significantly larger than the males and can measure up to 13 millimeters in length. In contrast, male black widow spiders are significantly smaller, at between 3 and 10 millimeters, and are often more brown than black.

The black widow earned its name from its chilling mating ritual. Upon mating with a male, the female black widow will often kill and eat their mate.

 Dr. Killigan's Black Widow SpiderInsects are the most at-risk of being bit by a black widow spider. When black widows feed on other insects, they inject digestive enzymes into their prey. Once the body of their prey is liquified, the black widow will suck up the remaining fluid.I

The spider’s bite is feared by humans because it is estimated to be 15 times stronger than that of a rattlesnake. Most people who are bitten by a black widow suffer no serious damage, but side effects of a bite can include nausea, muscle aches, and difficulty breathing. The bites can be fatal to children, the elderly, or those with an already weakened immune system.


Brown recluse spiders are brown in color, about ¼ inch to ½ inch long – about the size of a U.S. quarter, and have a violin-shaped marking on their dorsum, the space between their mouth and abdomen. They do not have stripes or any other designs or colors on their abdomen or legs, which is one thing that helps to identify brown recluses from other brown spiders.  Unlike the black widow, there is no significant difference between the male and female spiders of this species.

Dr. Killigan's Brown Recluse SpiderBeing bit by a brown recluse tends to be a rare occurrence, but the situation is not to be taken lightly as the bite can be very serious.

A small blister will usually appear at the site of the bite and the area will become swollen. Necrosis, or dead tissue, may then form where the venom was injected. The dead tissue will gradually slough away within the next two weeks, leaving an open ulcer that in extreme cases can expose underlying muscles and bone.


First of all, if a child is bit by a black widow, seek medical attention for the child right away.  In severe cases, a black widow’s bite can cause death to small children.

If you have been bitten by either a black widow or a brown recluse spider, the directions are mostly the same.  Wash the area of the bite with soap and water.  Take a pain killer such as Tylenol.  Ice the bite, keep it elevated, and apply an antibiotic ointment or cream.  It is recommended to seek medical attention after these steps are taken.  While the bites from black widows and brown recluses rarely kill, the symptoms can be very painful and the bites can make you very sick.  Be intentional about taking care of the bite in order to ease the symptoms and prevent infection.


Ultimately, the best way to protect yourself from an infestation of either one of these dangerous spiders is to prevent them from entering your home in the first place.

Avoid leaving untouched debris, such as firewood, inside or outside of your home. Both the black widow and the brown recluse are attracted to areas that have plenty of space to hide and to build webs that will not be disturbed.  Ward off these dangerous spiders by keeping the inside and outside of your home well-maintained.

Since both species of spiders also feed on insects, homes that are already suffering from insect infestations are more likely to attract them. Keeping any insect infestations under control will also help to protect your home from spiders.

Dr. Killigan's Insect Buster / Bulb DusterFinally, the black widow and brown recluse will often enter the home through small cracks. Be sure that these cracks are sealed tight.


If you are interested in some extra peace of mind, Dr. Killigan’s Insect Buster can be used to spread Diatomaceous Earth powder in or near cracks.  The powder will dry up any spiders or insects that try to enter your home.


Small Insect Buster 

Large Insect Buster