Orthoporus ornatus

Appearance

The desert millipede is small, long, has many legs and body segments. The head, which is the first body segment, has a paired organ called the Organ of Tömösváry. This is a sensory organ located at the base of each of the antennae. For every body segment there are two pairs of legs. Desert millipedes shed every time they add a new body segment.

Individuals on average are 4 inches in length, but can either be as small as 3 inches, or exceed up to 9 inches in length. They are dark brownish coloured, but can sometimes be yellow. In fact, in every state the species look different. The antennae are located near the organs of Tömösváry.

Behavior

"Orthoporus ornatus" is a slow-moving organism. It is mostly nocturnal; however, it emerges after rainy periods in the early mornings when the soil is moist. It spends most of its time in self-dug burrows. Once the soil is dried up from the desert sun it will go back into the deep soil. Their movement has been documented to be at its peak during the early mornings with some nocturnal activity as well. Soil-surface activity stopped before the surface temperature reached 35 degrees Celsius and began again when the ground resumed to 35 degrees Celsius. During high-temperature periods, it can be found under rocks and sometimes on the aerial portions of shrubs; though this was only observed when the air temperature was 35.5 degree Celsius.

Habitat

"Orthoporus ornatus" inhabits deep, damp soil of desert ecosystems, residing in small channels and voids in the soil. The soil contains abundant food sources as well as acts as protection from above--ground biotic or abiotic effects such as predation, weather, and ultraviolet radiation.

The desert millipede's main food source is bacteria and dead plant material and tissues of dead shrubs such as cholla, creosote bush, and ocotillo. It also eats surface litter and bark of "Mormon tea" and mesquite as well as tiny pieces of sand, rock, and other invertebrate animals. It is incapable of feeding in the absence of moist soil. Feeding behaviors above-ground are not observed year-round, as the millipede only comes to the surface once annually. When emerging, it feeds voraciously in an effort to store sufficient energy for when it returns to the soil. This behavior is thought to contribute to desert nutrient cycling.

Food

The species feed on both living and dead organic material. The species prefer sunshine, but can be seen on summer rainy days as well. A disturbed "Orthoporus ornatus" may curl into a coil and release a toxic substance that is located on all sides of its body. The species can live more than ten years. The species feed on shrubs of "Ephedra", which grows in Jornada del Muerto, and on "Salsola" that grows in Albuquerque.

Defense

The millipede has defenses against predation, though its subterranean habitat offers the greatest protection. There are about thirteen species that have been observed to feed on the millipedes.