The earwig, my dear, is nothing to fear. Despite what you heard; it won’t climb in your ear. Those pinchers you see at the end of its tail are for picking up groceries, garbage, and mail. From “26 Things that Bug Me” by M.J. Raupp
Earwigs almost always surprise me. Whether it’s when I inspect my flowers at night, look behind a tree face on my American elm, or open a hatch on my kayak, there they are, a kind of creepy scrum of wiggly, pincher-tailed insects. Earwigs belong to an order of insects called Dermaptera, derived from the Greek meaning “skin wing”. This derivation refers to the hind wings of the earwig that are not often seen, as they are folded beneath and hidden by the forewings. The common name of earwig is thought to refer to the shape of the hindwing which, when unfolded, resembles a human ear, according to Wikipedia. An old urban legend has it that earwigs crawl into human ears to lay eggs. While this legend has been largely debunked, there are actually two documented accounts of earwigs entering people’s ears, much to the consternation of the human and presumably the earwig.
Clusters of earwigs are often found on flowers or foliage where they munch blossoms and leaves.
During a recent question and answer interlude following a presentation, one clever listener wanted to know a bit more about earwigs and what roles they played. Well, I can’t speak about all earwigs, but with our common non-native earwig, Forficula auricularia, I do have some relevant experience. Several years ago, I had a wonderful bed full of marigolds with glorious blossoms. Little by little I noticed ever increasing levels of defoliation on the leaves of many plants. I carefully inspected the plants each day to see who the culprit might be. This mysterious mandibulate leaf-muncher remained a mystery until one midnight I crept out to the garden and discovered legions of European earwigs feasting on my marigolds. Undoubtedly, earwigs are herbivores. Several years later while studying misery levied on azaleas by azalea lace bug, one of my students discovered European earwigs snacking on azalea lace bug nymphs. So, clearly European earwigs are omnivores leading a Dr. Jekyll and Mr. Hyde existence as beneficial predators of plant pests and pests in their own right when they eat our ornamental plants and vegetables. These strange insects do have some admirable traits shared even with ourselves. Mother earwigs tend their eggs in an egg nest, cleaning them and moving them about to keep them free of pathogens and in proper ranges of temperature and humidity. Following egg hatch, nymphs are guarded and fed by their mother.
Earwigs almost always surprise me. Whether it’s a nighttime raid on my flowers, when I peek behind a tree face on my American elm, or when I open a hatch on my kayak, there they are, a kind of creepy scrum of wiggly, pincher-tailed insects.
As alluded to above, earwigs are most active at night and seek dark moist places to hide during daylight hours. Perhaps their most notable and unique attributes are the intimidating pinchers, aka cerci, found at the tips of the earwig’s abdomen. These formidable appendages are used in defense, mating, and prey capture. However, pinches delivered by the cerci tend to be more surprising than painful. In addition to scary pinchers, abdominal glands produce irritating benzoquinones that can be sprayed on attackers while held fast by its pinchers. So, hail the earwig for their beneficial activities as predators, but reserve a modicum of blame for their sneaky nocturnal attacks on plants.
Acknowledgements
Bug of the Week thanks an avid listener to a presentation on climate change who inquired about earwigs and provided the inspiration for this episode. The short communication “Earwig in the ear” by J. R. Fisher, the fact-filled Featured Creature bulletin “Common name: European earwig scientific name: Forficula auricularia Linnaeus (Insecta: Dermaptera: Forficulidae)” by John Capinera, and the wonderful “Secret weapons” by Thomas Eisner, Maria Eisner, and Melody Siegler were used as references for this episode.
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