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.
