Chigger

Trombicula alfreddugesi

ATW from Kountry Life

Chiggers are animals that many people have heard of, or have been bitten by, but don't know what they are. Chiggers are actually mites, cousins of spiders and ticks. They have a life cycle very much like insects, even though they are not insects. There are several species of mites called "chigger," but Trombicula alfreddugesi is probably the most common.

Chiggers spend most of their lives living in moist soil, and prefer edges. Examples of edges include where forests become meadows, streambanks, shores of marshes, and boundaries of yards and parks. Adult chiggers are tiny and you can barely see them if you look closely. They are red, about 1/20 inch long, and have 8 legs. The adults do not bite, though, so if you see one it can't do you any harm.

Female chigger laying eggs. Home and Garden Information Center, University of Maryland

Chigger eggs. Home and Garden Information Center, University of Maryland

Female chiggers lay eggs in early Spring, when the first warm weather comes. One female can lay up to 400 eggs. She lays them in damp soil.

Larvae hatch from the eggs and immediately find plants to climb onto while they wait for a host. The larva stage of a chigger is a parasite. It must find a host to feed on. Hosts include mammals, birds, reptiles, and some amphibians. When a potential host brushes against a plant, the chigger larva jumps on. A larva is microscopic, so you can't see it with your eye. They also have only six legs in this stage.

The larva finds a place to feed and attaches itself to the skin of the host. It feeds by using its saliva, which has a special chemical in it. This chemical turns skin cells into liquid, which the larva then drinks.

The larva will feed for about 3 days if nothing bothers it, and then it drops off. Hosts are not harmed, though they may feel itchy.

Chigger larva. Home and Garden Information Center, University of Maryland

Chigger nymphs. Home and Garden Information Center, University of Maryland

Once a larva has fed and left its host, it returns to the soil where it rests before changing into the next stage of its life cycle, a nymph. Nymphs look a little more like adults, including having 8 legs.

Nymphs eat and grow until they are ready to change into adults. Nymphs and adults both eat small animals in the soil. Their favorite foods are eggs of springtails (tiny soil insects), isopods, and mosquitoes.

Chiggers have two or three generations each year. The adults who are around in the fall overwinter, and start over the following Spring. Chiggers die shortly after mating and/or egg-laying.

Chiggers are most active in the afternoon, especially in May and June. Remember: adults can't hurt you, but if you see adults, there are probably larvae close by.

Predators include animals that feed on mites, such as small salamanders, beetles, ants, centipedes, larger mites, and spiders.

Relationships in Nature:

PREY/FOOD
PREDATORS
SHELTER
OTHER

Snow Flea

Red-backed Salamander

Switchgrass

Human H

Isopod

Black Carpenter Ant

Smooth Crabgrass

Five-lined Skink H

Asian Tiger Mosquito

Common Black Ground Beetle

Kentucky Bluegrass

White-tailed Deer H

Human

Garden Centipede

Common Reed

Red Fox H

Five-lined Skink

Daring Jumping Spider

Greenbrier

Woodchuck H

White-tailed Deer

Harvestman

Black-eyed Susan

Virginia Opossum H

Red Fox

Convergent Ladybug Beetle

Bracken Fern

Striped Skunk H

Woodchuck

Common Ragweed

Wild Turkey H

Virginia Opossum

Devil's Beggar-tick

Northern Bobwhite H

Striped Skunk

English Plantain

American Robin H

Wild Turkey

Goldenrod

Red-winged Blackbird H

Northern Bobwhite

Highbush Blueberry

Eastern Cottontail H

American Robin

Japanese Honeysuckle

Eastern Gray Squirrel H

Red-winged Blackbird

Jimsonweed

Eastern Box Turtle H

Eastern Cottontail

Lamb's Quarters

Eastern Hognose Snake H

Eastern Gray Squirrel

Pokeweed

American Toad H

Eastern Box Turtle

Poison Ivy

Meadow Vole H

Eastern Hognose Snake

Queen Anne's Lace

American Toad

Red Clover

Meadow Vole

Spicebush

Relationship to Humans:

Chiggers are annoying pests to people. When a chigger larvae is feeding on you, it will cause a red welt which can itch for up to two weeks. The most common places they feed are ankles, waistband and armpits. They will only make you uncomfortable; they are not known to carry any dangerous diseases.

SCIENTIFIC CLASSIFICATION

KINGDOM
Animal
PHYLUM
Arthropod
CLASS
Arachnid
ORDER
Acari
FAMILY
Trombiculidae
GENUS
Trombicula
SPECIES
Trombicula alfreddugesi

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