The adult chigger is 1/20” long.
Chiggers are mites that develop through complete metamorphosis, the four stages of which are the egg, larva, nymph, and adult. It is important to understand the lifecycle of the chigger because it is not the adult chigger that requires a host to feed, but the larva.
Chigger Adult Chigger
Size: The adult chigger is approximately 1/20” long. That’s nearly three times smaller than a sesame seed.
Female chigger mites lay as many as 15 eggs per day as soon as the temperatures reach above 60°F. One female can lay up to 400 eggs in her lifetime. The female adult can live up to one year.
Chigger Larval Stage
Size: The chigger larva is 1/150” long. They are so small you can’t see them with the naked eye.
The larval stage of the chigger’s lifecycle is the only time that chiggers are parasitic. The larva will attach itself to a host and feed until it is engorged. It will then drop off, bury itself in the soil, and progress to the nymph stage.
Chigger Nymph Stage
Size: The nymph will grow from 1/150”-1/20” during this stage.
The nymph resembles a smaller version of the adult. No longer a parasite, it will remain beneath the soil feeding on isopods, springtails, and mosquitoes just as it will when it emerges as an adult.
“chigger.” FCPS Home Page Redirect Page. N.p., n.d. Web. 10 July 2012. http://www.fcps.edu/islandcreekes/ecology/chigger.htm
“Chiggers, HYG-2100-98.” Ohioline. N.p., n.d. Web. 10 July 2012. <http://ohioline.osu.edu/hyg-fact/2000/2100.html>.