Earwig: Friend or Foe?

17 May, 2009

A native Common Brown Earwig <I>Labidura truncate</>
A native Common Brown Earwig Labidura truncate
Image: Alan Henderson
Source: Minibeast Wildlife

Question: I have an abundance of earwigs living amongst the leaves of the lettuces in my garden. I originally thought they were eating the lettuce and was keen to be rid of them. However, a friend recently told me that earwigs are carnivorous and eat other garden pests. Is this true? I would also like to know if they sting.

Answer: Earwigs like to live in damp, protected places such as in leaf litter, under loose bark, under stones and between leaves. Lettuces therefore provide the perfect habitat for earwigs. They particularly like lettuce varieties with closely growing leaves, such as Cos.

Whether your earwigs are feeding on your lettuces or on other bugs will depend on what species of earwig they are. Most earwig species are omnivorous, feeding on both plant and animal matter. Many feed on decaying material, however some will attack living plants and others prey on slow-moving invertebrates such as moth larvae.

There are about 1200 earwig species worldwide. At least 85 species of earwig have been described so far in Australia, but it is thought that there are perhaps as many again that are still to be described. One of the most common earwig species found in urban gardens is the introduced European Earwig, Forficula auricularia. This is a significant garden pest, particularly in vegetable gardens. It feeds on both petals and fruit, but may also eat some pest insects. The native earwig, Labidura truncate, is considered to be a beneficial insect to have in one’s garden; it feeds on soft-bodies caterpillars such as the larvae of the codling moth which attacks fruit trees.
 
Earwigs do have a nasty looking pair of pincers on their rear ends. These pincers serve a multitude of functions. Earwigs use them to catch and hold their prey, to cling to their partners during mating and to open their hind wings. Earwigs also use their pincers in self-defence; they may attempt to pinch your finger if you poke them, but they do not sting and will cause you no harm. Some species can emit and squirt a nasty-smelling liquid when threatened, but this too is harmless to humans.

The Discovery Centre at the Melbourne Museum has a free identification service. If you would like to bring in or post us a specimen, we would be very happy to identify it for you. We can then advise you as to what it may be eating in your garden.

Comments (2)

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Mona Bagh 16 October, 2009 16:32
how long can a earwig survive in a vaccumed sealed jar filled with olives and (jar) half filled with salt brine solution kept in room temperature?
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Frederika von Staade 18 April, 2014 15:16
It depends on how you define "survive." About 5 seconds, if you expect the animal to live on after the experience. Beyond 5 minutes, the insect stops all motion, having died. Within an hour, all cells of the insect will be dead.
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