Just the mention of chiggers is enough to make any outdoors-loving person tremble in fear. These tiny bugs can be difficult to see when they're on you, but once you've suffered chigger bites, you'll never forget them. I once endured chigger bites so itchy I would have given state secrets to the enemy to make the itching stop. So what are chiggers, and where do they hang out?
Chiggers are nothing more than young mites, specifically the parasitic larvae of mites in the genus Trombicula. Mites belong to the class Arachnida, along with ticks and spiders. Like other arachnids, chigger mites go through four developmental stages: egg, larva, nymph, and adult. Nymphs and adults have four pairs of legs, while the larvae have just three pairs.
Adult mites and nymphs don't bother people at all. They feed on small organisms (including insects) they find on decaying plant matter, as well as on insect eggs. The adult chigger mites spend the winter in the soil, under leaf litter, or in other protected places. When soil temperatures warm up in the spring, the females deposit eggs on vegetation, most often in areas where it's slightly damp and the vegetation is thick.
When the eggs hatch, the trouble begins. Hungry larvae crawl up the vegetation and wait for unsuspecting hosts – people, pets, or other wildlife – to wander past. Should you brush against chigger-infested vegetation, or worse, sit down to rest in shady grass full of chiggers, the tiny bugs will immediately crawl up your body, looking for a place to hide. Because chiggers measure just 1⁄150 inch in diameter, they're so tiny, you are unlikely to see or feel them.
Chiggers like to settle under tight-fitting clothing, so they'll often wind up in your socks or waistband. Other favorite chigger feasting spots include the backs of your knees, your armpits, or your crotch. Once the chiggers find a good location on your body, they pierce your skin with their mouthparts and inject you with a digestive enzyme that breaks down your body tissues. Chiggers then feed on your liquefied tissues. They don't suck your blood, like mosquitoes or ticks.
The chigger will remain attached to the host for several days, feeding on dissolved tissues. Once it has an adequate meal, it detaches and drops to the ground, where it continues its development into a nymph. For most people, however, the intense itching caused by the chigger bite leads to equally intense scratching, and the chigger is dislodged by frantic fingers before finishing its meal.