Don’t Pinch Me With Those Pincers

The last few weeks brought an influx of a curious insect pest described by some as a cross between an ant-cockroach-beetle with pointy pincers extending from the rear end. The pest in question is none other than the European earwig. and judging from the lack of literature in our Extension files, it hasn’t been a common pest inside houses in Nebraska.

Male European earwig measures 5/8"

European earwig is occasionally found inside homes, not in ears. Photo by Jody Green, Nebraska Extension in Lancaster County.

When I tell people their specimen is an earwig, they immediately touch their ears, and shutter in despair. Earwigs do not crawl into ears, bore into brains and cause death to humans. This was an urban legend or myth. After doing a bit more digging, I found this interesting paper by entomologist, May Berenbaum (2007) about the entomology and etymology of earwigs.

What do earwigs look like?

Earwigs are their own order, Dermaptera, and they are quite unique looking. They are long, flattened, and a dark reddish-brown color with pale legs, wings and antennae. They are often about 5/8” long, which includes their forceps-like, pincer appendages called cerci. Cerci are used in mating rituals, defense against predators and to hunt prey. Earwigs have two pairs of wings but seldom fly. Their hindwings are larger than they appear, membranous, folded and tucked origami-style underneath short, leathery forewings. Immature earwigs resemble smaller versions of the adult, but lack wings.

Comparison of male and female earwigs. Males have curved cerci and females cerci are straight

The size and shape of the cerci can be used to distinguish the sex of the earwig. Male earwigs have large, curved cerci (lower earwig) compared to the cerci of the female (upper earwig), which are short and straight. (Photo: Jim Kalisch, UNL Department of Entomology)

Where do earwigs live?

Although they are not considered social insects, they aggregate in large groups in the same harborage areas. Moist summers will favor higher populations of earwigs. They lay eggs in soil in the garden beds, under mulch, stones, boards, concrete structures and other debris.

What do earwigs eat? 

Earwigs are not pests that will harm or bite humans. They are omnivorous scavengers that eat both living and dead plants and animals. Outdoors they are known to damage fruits, flowers, vegetables, shrubs, and trees by chewing irregular holes in leaves and roots. They can survive on any type of organic material.

Why are they inside my house?

Occasionally they will enter a structure in search of moisture. They are most active at night and attracted to lights, which in periods of dry weather, draws earwig populations to the exterior of the structure. Earwigs will get in through openings and gaps around doors, windows, cracks in the foundation and utility line/cable openings. Indoors, they are often found in basements, bathrooms and laundry rooms, seeking shelter under rugs, mats, baseboards, and other materials that hold moisture.

How can I reduce the number of earwigs outside?

The key to managing earwigs outdoors is to eliminate the damp, cool dark places around the foundation. This would include cleaning the gutters, fixing the grade, adjusting the downspouts, removing leaf litter and organic matter, reducing vegetation adjacent to the structure, and avoiding unnecessary mulch or boards in gardens. It may be a good idea to consider the altering the watering schedule so that it is not later in the day or evening, when earwigs are most active. Trapping can be effective to reduce the number of earwigs in the garden. Homeowners can make simple pit fall trap using a shallow tuna fish can and a little oil as bait to catch foraging earwigs. Another trap can be made by leaving a rolled up newspaper in the garden. Putting the captured earwigs in a solution of soapy water will kill them. If an insecticide treatment is warranted, there are a variety of products sold in hardware stores with earwigs listed on the label. Always read the instructions and follow the safety precautions.

How do I get earwigs out of my house? 

To remove earwigs from inside the home, scoop them up (they will not hurt you), use sticky glueboards and a vacuum. Consider remedies to decrease the moisture and increase the ventilation in the area where earwigs are found. This can be done using fans, air conditioners, dehumidifiers, fixing plumbing leaks, hanging up wet bath mats, and squeegeeing standing water in tubs/showers to drains. Insecticide treatments are not recommended indoors.

How can I stop earwigs from getting inside the house in the future?

To prevent earwigs from getting inside in the future, use caulk, sealant or weather stripping to eliminate pest entry into the building. Reduce the lighting close to garage doors, entry doors and windows. On occasion, humans will accidentally bring a hitchhiking earwig inside on materials, so shake out line-dried laundry and inspect objects and flowers before bringing them in from outside.

Earwigs hiding in the petals of marigolds

Earwigs hiding in and damaging marigold flowers in the garden. Damage resembles slug damage without the shiny secretions  (Photo: Jim Kalisch, UNL Department of Entomology)

 

Confessions of an Extension Entomologist: My personal relationship with earwigs. Growing up in Southwestern Ontario, the earwig was my insect nemesis. They only showed up in a below-grade bathroom in the middle of my cousin’s house, but they were there each and every night to spook us and drive us into a complete teenage frenzy. A night didn’t go by without us seeing one crawl across the countertop or floor, fall out of the towel, run up the shower curtain, squeeze under a bath mat, or appear on our bodies during a shower. One night, we decided to take a stand against earwigs, and we started collecting them. What we suspected were one or two indestructible critters, ended up being approximately 25-30 earwigs of varying sizes, cannibalizing one another, in a glass jar that remained on the counter. We collected every single earwig until the problem was gone. Who would have known I was practicing IPM (Integrated Pest Management)! As a matter of fact, the earwig may be the pest responsible for my interest in pest management and career in urban entomology.

Keep calm and respect the critters,

Jody

Here is where you can find Earwigs in the Pest Section of the August 2016 NebLine:

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