All invertebrate organisms that have a segmented body contained within an exoskeleton belong to the phylum Arthropoda. The phylum Arthropoda is made up of all extinct and extant species of insects, arachnids, crustaceans, and myriapods (centipedes and millipedes). More than one million living arthropod species have been documented, and arthropods account for more than 80 percent of all living animal species. Fossil evidence and taxonomic studies involving cutting edge genetic sequencing technology indicate that millipedes were the first organisms to successfully transition from a marine to a terrestrial habitat nearly half a billion years ago.

Today, more than 7,000 millipede species have been documented worldwide, 1,400 of which occur in the United States and Canada. Millipedes are ecologically important organisms, as they break down organic waste and enhance soil fertility. Millipedes are ubiquitous on residential and commercial landscapes where they thrive in moist soil. Due to their nocturnal nature, millipedes remain hidden in dark and moist spaces beneath leaf litter, stones, and logs during the daytime. Unfortunately, a few millipede species are known to be occasional nuisance pests within homes and buildings in Maine.

The most commonly encountered millipede species within and around homes are black to brown in color and between 1/16 to 4½ inches in length. Millipedes are highly dependent on moisture in order to survive, and studies have shown that millipedes must remain within conditions where the relative humidity is at least 80, or possibly, 75 percent in order to avoid dessication. Millipede pests prefer temperatures ranging from 70 to 80 degrees, but they can tolerate much cooler temperatures. Millipedes frequently enter homes in order to escape from bouts of dry weather and excessive rainfall between April and September in Maine.

Every few years, millipedes become overabundant on residential and commercial properties where they often migrate indoors to escape from overcrowded outdoor conditions where food sources have been depleted. These indoor migrations occur most frequently during the spring and fall following mild winters and particularly wet and rainy spring and summer seasons. Due to their need for high moisture conditions, millipedes often die shortly after gaining indoor access, but large numbers can survive indoors by securing humid shelter in basements, bathrooms, and kitchens. Reducing indoor moisture will make indoor conditions inhospitable to millipede pests, but professional pest control intervention is often necessary to fully eliminate infestations.

Have you ever found live or dead millipedes in your home?