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University
of Rhode Island GreenShare Factsheets
Earwigs Forficula
auricdularia
Dermaptera: Forficulidae
The name earwig
comes from a European superstition that these insects entered the
ears of a sleeping person and bored into the
brain. This belief is totally unfounded. Earwigs do often cause
alarm to homeowners when discovered indoors, despite the fact that
they are harmless to humans. They have a frightful appearance, move
rapidly around baseboards at the ground level and may emit a foul-smelling,
yellowish-brown liquid from their scent glands. Active at night
and hiding during the daytime, earwigs normally live outdoors and
do not establish themselves indoors. They are harmless to humans
and animals, although if handled carelessly, the earwig can give
a slight pinch with the forceps. Earwigs can be responsible for
serious feeding damage on flowers, vegetables, fruits and other
plants, giving the leaves a ragged appearance with numerous, small,
irregular holes. Earwigs
are elongate, flattened insects, ranging from light red-brown to
black and are easily recognized by their forcep-like appendages
(pincers) on the end of the abdomen. The forceps (cerci) are unequal
in length in the males. Earwig female forceps are straight-sided,
whereas male forceps are strongly curved (caliper-like) and larger.
They have chewing mouthparts and long, slender antennae. Some species
are wingless but others have a pair of leathery forewings covering
a few segments of the abdomen and the membranous hind wings, which
have the tips protruding. There are many species of earwigs: the
European earwig ranges from 13-20 mm (1/2 to 3/4 inch) in length,
with banded legs and reddish head; the ringlegged earwig ranges
from 13-18 mm (1/2 to 3/5 inch) in length and is black-yellowish
underneath with legs having dark crossbands. Young earwigs (nymphs)
are similar in appearance to adults. They are white to olive-green
and lack wings. An
earwigÁs forceps are used to defend the nest, capture prey, probe
narrow crevices and fold or unfold wings. Earwigs are primarily
scavengers on dead insects and rotted plant materials. Some species
are predators, feeding on aphids. Only a few of the winged species
are good fliers. They are often transported great distances in
plant
materials and occasionally in other freight. Earwigs require moist,
cool places and are found in damp crawl spaces, flower gardens
near
the home, in mulches, compost piles, trash, under boards and in
wood piles. After entering houses, they feed on sweet, oily or
greasy
foods or houseplants. They are attracted to lights.
Earwigs develop from egg to adult through gradual metamorphosis
with four to five nymphal instars or stages. During the spring or
autumn, females lay 20 to 50 smooth, oval, pearly-white or cream-colored
eggs in a below-ground chamber (upper two to three inches of soil).
The female moves, cleans and provides maternal care by protecting
the eggs and new young until the first molt. Young then leave the
nest, fend for themselves and mature in one season. Most species
in this country have one generation per year, overwintering as eggs
or adults in the soil. Earwigs may dig as deep as six feet below
ground to escape the cold temperatures.
Some feed on living plants and often become pests in greenhouses
and field crops. Prevention:
For best control indoors, one must first control earwigs outdoors.
Since they are attracted to lights, reduce lighting around doors,
windows and other potential entry sites. Use good night light discipline
and special sodium vapor yellow lights (less attractive to insects)
instead of white, neon or mercury vapor lights. Earwigs need
and are very attracted to moisture. High populations, practically
invisible during the day, may be present around foundations, in
landscaped yards, in mulch, under boards, etc. Be sure to eliminate
damp, moist conditions in crawl spaces under houses, around faucets,
around air-conditioning units and along house foundations. Rain
gutters and spouts should carry water away from the house foundation.
Use caulking compound, putty and weather stripping around doors,
windows, pipes and other entry sites, especially at the ground level.
Change landscaping by creating a clean, dry border immediately around
the foundation wall. Gravel or ornamental stones can make an attractive
barrier against earwigs and other pest invaders. Trapping:
Earwigs can be trapped outdoors in cardboard boxes baited with
oatmeal or bran with pencil hole size entry sites punched in the
sides near the bottom. Place burlap bags, canvass, boards, newspapers
or other cover material in mulch, shrubbery and similar habitats
to collect individuals the following day. The adults can be squashed
by hand or vacuumed with a "shop vac." Indoors, remove with broom
and dustpan or by vacuum cleaner. Adapted
from the Virginia Cooperative Extension and the Ohio State University
Extension, 1999
Pesticides
are poisonous! Read and follow all safety precautions on labels.
Handle carefully and store in original containers out of reach
of children, pets or livestock. Dispose of empty containers
immediately, in a safe manner and place. Pesticides should never
be stored with foods or in areas where people eat.
When trade names are used for identification, no product endorsement
is implied, nor is discrimination intended against similar materials.
Be sure that the pesticide you intend to use is registered for
the state of use.
The user of this information assumes all risk for personal injury
or property damage.
For more
information, call the URI CE Gardening and Food Safety Hotline
at 1-800-448-1011 or (401)874-2929 from outside Rhode Island;
Monday-Thursday between 9 am and 2 pm.
University
of Rhode Island Cooperative Extension provides equal program
opportunities.
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