Earwigs are insects belonging to the order of the Dermaptera widely distributed in America, Eurasia, Australia and New Zealand, with more diversity in tropical and subtropical areas. The only continent they are missing from is Antarctica, but with about 2.000 species part of 12 families, they are spread all over the rest of the world. They are mostly nocturnal animals which hide in crevices during the day and are highly active at night. They are recognised as pests due to the damage they cause to foliage, flowers and other crops. They might also invade your house, especially during colder seasons, so being able to prevent such an infestation is quite important.
Description and distribution
They are mostly found in the Americas and Eurasia, but tends to be more common in the hotter regions. Some species are found in North America, or even as far north as Canada, however few earwigs survive winter in cold climates. This is also why when winter comes, they retreat to warmer places such as your house.
Their shape and size also helps them to easily access any small crevice that might give them entry into your home. Depending on the species, adults range in size from 5-25 mm. With a flattened and elongated body, the earwigs are characterised by their cerci, which is the pair of forceps they have on their abdomen. These pincers are normally used to catch their prey or to defend themselves from predators. Males have the more developed and larger forceps which are flexible for multiple uses, as they also play a role in the mating ritual of males and females.
Also, earwigs also have a set of antennas with 10 or more sections and they also have two sets of wings. The first set consists of two oblique and short wings, covering their second set of wings, which are composed of a very thin membrane which expands radically when the earwig takes flight. Thus, most species are capable of flight, although they are rarely seen doing so.
Breeding and dietary information
When it comes to their reproduction, Females typically lay between 30 and 50 but actual numbers depend on species. After hatching, the nymphs undergo four to five moults until they become adults. Clutches of creamy white eggs are laid in protected burrows, with their size being up to 2 mm in length in larger species. Once the nymphs hatch, they generally resemble adults, but can be distinguished from them by their lighter colour and shorter antennae.
After mating, the sperm can be kept in the female for months before the eggs are fertilised. But once they are, she will lay the eggs in two days, will pay close attention to the needs of her eggs, giving them warmth and protection, as the earwigs are among the few non-social species that do show maternal care. She will clean the eggs to protect them from fungi and will defend them from predators. The eggs normally hatch within 7 days, and the nymphs are known to eat the eggs shell and then to feed on food regurgitated by their mother and on their own moults. There are parasitic earwig suborders which are viviparous, and give birth to live young. They most common is the Arixenina family, which are ectoparasites of bats. After around 6 instars, the nymphs moult into adults, they develop a darker colour, and their forewings harden, in order to protect their membranous hindwings.
As most earwigs are nocturnal, they spend their days hidden inside crevices, logs, bark, and various types of debris. Those are places where they can also find food, as they consume a wide array of dead plants or animal matter. Their diet is quite diverse, as they can also eat small insects, such as mites, fleas or other insect eggs. They can also consume fruits and flowers, but are also known scavengers. The plants you need to protect from these insects are Dahlias, zinnias, carnations, butterfly bush, hollyhocks and sunflowers, and when it comes to vegetables, the most affected are lettuce, strawberries, peaches, pears, cabbage, chard, potatoes, lettuce, cucumber, pea and beets. They typically feed at night, and the best way of controlling them will be not planting the type of flowers or vegetables they like to eat. However, due to their omnivorous diet, earwigs can also be considered beneficial to a garden. They can also consume beetle larvae, maggots, scale insects and aphids, being thus beneficial to your plants.
Earwigs as pests
Their interaction with humans is mostly felt in cooler seasons, when earwigs tend to search for a warmer place to live. They can be normally seen on exterior walls, looking for a crevice that could lead it to the inside. If they do reach the inside of your house, you will most likely see them on walls or on the ceiling. Should you disturb them at this point, they will free-fall to the ground and hide in the nearest crevice. They can also gather near damp areas, such as near the sinks or in the bathroom or laundry. However, it is important to note that earwigs do not damage actual property, are not attracted to human food (and thus there is little risk of contamination), and do not reproduce, or live for very long, indoors.
When dealing with earwigs, the best action you can take is to try and eradicate them from your yard, avoiding thus their entrance in your house. It is easier to prevent an infestation from happening, than eradicating it. This is especially due to the fact that the earwigs are excellent at hiding, and reaching them with insecticides will prove to be quite challenging. You are better off checking your yard and keeping it clear of debris such as logs, decorative stones or firewood piles, as those are places where earwigs normally like to hide. Free your yard from mulch, dead leaves and other organic material that can act as food and try to keep a dry zone between your house and the rest of your yard, as earwigs will prefer to stay in damp areas. To do this, you can trim the bushes and trees near your house, in order not to offer them a shady area where they can thrive. Also make sure you are not over watering your yard, as this can also cause the earwig population to flourish.
There is no evidence that they could spread disease to humans or other animals around your yard, as the most damage they can cause is to the plants in your garden. If in large numbers, they are able to cause economic losses in fruits and vegetables, so applying methods of pest control against them from early on, can get you out of a lot of trouble later, when a possible infestation has already developed. It would generally take a large population to do considerable economic damage to fruit or vegetable crops, but this has happened in the past. Some examples include flowers, hops, red raspberries, and corn crops in Germany, and peaches and apricots in the south of France, which have been highly affected.
For more details on how to keep earwigs at bay, follow the steps presented in the ‘Prevent infestation with earwigs’ article, and should you already be dealing with an infestation with these critters, take a look at our article about ‘How to get rid of an earwig infestation’ and find out what type of methods you can use to get deter these creatures from your home, yard and garden.