Bug Blog

A Few Home-Invading Arthropod Pests In Arizona Pose A Medical Threat To Humans, But Not All Are Well Known To Residents Of The State

Numerous creepy crawlies that many people hope to never encounter can be found in the southwest desert regions, including several tarantula species, potentially deadly scorpions, as well as species of both wasps and ants that are notorious for inflicting the most painful stings known to mankind. While Arizona is home to several arthropod pest species that are well known for either invading homes or inflicting medically significant bites or stings, there are few arthropod species in the state that are capable of pulling off both of these tasks. For example, the western black widow is one of the few spider species in the country that is capable of inflicting deadly bites to humans.

Luckily, due to the advent of several medical treatments, such as antivenom, black widow fatalities are nearly unheard of in all areas of the country these days, but they do invade homes and they can send residents to the emergency room. While red-imported fire ants were successfully eradicated from southeastern Arizona after their short stay in the area several years ago, three native fire ant species can be found in the state. The most notable of these three species, the southern fire ant, invades homes often, and while fatalities rarely result from their stings, a baby died in response to southern fire ant stings a little more than a decade ago.

The most notable home-invader in Arizona that produces potentially deadly venom, the Arizona bark scorpion, very rarely inflicts stings that require medical intervention. Surprisingly, a little known spider species that commonly invades homes in the state where they bite humans without provocation has been gaining a reputation as a medically harmful house pest in recent years. This species is commonly known as the agrarian sac spider, and one recent case report describes an incident in which dozens of these arachnids invaded a home in the southwest before inflicting bites that hospitalized a man.

Several other case reports describe bites from this species that have caused necrotizing skin wounds. Research shows that agrarian sac spider venom is also neurotoxic, and many bite victims have experienced symptoms that may have been fatal without medical intervention. Medical professionals well versed in this spider species’ danger to humans strongly recommend that all bites be examined by a doctor.

Have you ever noticed a group of spiders congregating in your home?