Bug Blog

Common House Centipedes Are Largely Harmless, But Desert Centipedes Are Known To Be Dangerous

Centipedes are among the most ancient of terrestrial arthropods, and their appearance has changed little since they first appeared on earth hundreds of millions of years ago. Along with insects and arachnids, centipedes belong to the phylum Arthropoda, as well as the subphylum Myriapoda, which does not include insects and arachnids. More than 16,000 species belonging to the subphylum Myriapoda have been documented worldwide, and all of these species are characterized by the “myriad” number of legs they possess. While all insect species possess six legs, and all arachnid species possess eight legs, the number of legs possessed by Myriapod species varies between fewer than 10 and as many as 750.

The most frequently encountered centipede species is the house centipede (Scutigera coleoptrata), which is a very common pest of homes throughout the US. Although house centipedes prey on insects within homes, they are widely considered pests due to their unsightly appearance and their tendency to  become an indoor nuisance, especially when multiple specimens become trapped within tubs and sinks. While house centipedes have been known to bite humans on very rare occasions, their mouthparts are too small to cause serious pain or injury, making them harmless to humans. However, the same cannot be said about two other centipede species that are occasionally found around homes and buildings in Arizona. These species are known as the giant desert centipede (Scolopendra heros) and the banded desert centipede (S. polymorpha).

Centipedes avoid sunlight and are reliant on high moisture conditions. All centipede species in Arizona are frequently found on the surface of moist soil beneath objects like stones, wood piles, plant litter, landscaping ornaments, and flower pots. Unlike house centipedes, desert centipedes are not often found in homes, but they may become prevalent in poorly ventilated crawl spaces and occasionally within basements and cellars. Desert centipedes hide in stacks of moist firewood, and homeowners may unknowingly transport them indoors when retrieving outdoor firewood.

The giant desert centipede is between 6 and 8 inches in length, while the banded desert centipede is between 4 and 5 inches. Not only do these two centipede species possess massive pincer-like mouthparts that deliver extremely painful and highly toxic venomous bites, but the National Center for Health Statistics states that five individuals may have died in response to bites from these species in between 1991 and 2001. Medical case reports describe instances in which individuals suffered kidney failure and an acute heart attack in response to a single sting inflicted by the giant desert centipede.

Have you ever encountered a desert centipede?