Dust mites are found in homes all over the world, most commonly in rooms like bedrooms and living rooms where it finds the most food -- particles of skin shed by you and your pets. Dust mites have no eyes and no antennae, and females are slightly larger than males. Dust mites go through five life stages.
Bundles of Joy
Dust mite eggs are cream-colored and covered in a sticky substance so they are able to attach to substrates. The number of eggs laid by dust mites depends on the species. For example, American house dust mites produce around 30 eggs over one month, while European house dust mites lay 80 eggs over 45 days. Either one single egg or groups of three to five eggs are laid each day. Eggs hatch after two to eight days.
After hatching from their eggs, dust mites go through several stages of development. During these periods of development they are called larva, protonymph and tritonymph, respectively. The larval stage lasts for one to 10 days, as the larvae feed and prepare to shed their outer skin. After their first shed, the developing dust mites are now in their protonymph stage. After two to seven days the protonymph sheds again. Now in the tritonymph stage, these growing dust mites consume dead skin and other dead dust mites for two to eight days until they are fully developed adults. Although adult and nymph dust mites have eight legs, dust mite larvae have only six legs, developing their final pair as they shed into protonymphs.
The individual growth of a dust mite, as well as the growth of the population, is dependent on temperature and humidity. Since dust mites live in temperature-controlled indoor environments, they are found in different parts of their life cycle year-round. Dust mites thrive in environments with high humidity, since these enable them to take in water from the air around them. Population and individual growth slows down, or even stops completely, when humidity falls below 60 percent, since dust mites cannot survive in dry conditions.
All Grown Up
The total time from egg to adult is less than one month. Adults feed on human skin and animal dander on surfaces like mattresses, pillows, carpets and stuffed toys. Adults are ready to mate and start a new generation a mere 24 hours after becoming fully developed adults -- unsurprising, as the life expectancy of a dust mite is no more than two months. If you are having trouble with dust mites, which cause allergic reactions in some people, you can control them by keeping the humidity in your home below 50 percent, lowering the temperature to below 70 degrees Fahrenheit, replacing old pillows or using dust covers and cleaning your home often to remove dust and dander.
- Alabama Cooperative Extension System: Dust Mites [PDF]
- University of Kentucky: House Dust Mites
- University of Florida: House Dust Mites
- Environmental Health and Safety Online: Dust Mites: Everything You Might Not Want to Know!
- University of Michican Museum of Zoology: Life Cycle of House Dust Mite Dermatophagoides pteronyssinus Under Laboratory Conditions in Kolkata Metropolis [PDF]
- Consumer Specialty Products Association: House Dust Mites
- Comstock/Stockbyte/Getty Images