Understanding and managing earwigs

Ringlegged earwig (Euborellia annulipes). PHOTO: BRETT_HONDOW / ISTOCK / GETTY IMAGES PLUS / GETTY IMAGES

Earwigs (Dermaptera) are commonly found in outdoor gardens and occasionally indoors during the summer months, often raising concern due to their unique appearance. Anecdotally, our technical team at Adam’s Pest Control has seen an increase in earwig populations at residential accounts. Understanding their biology, habits and habitat is crucial for implementing effective management and control strategies.

Identification

Earwigs are elongated insects, ranging from 0.16 to 0.87 of an inch in length, characterized by forceps-like appendages known as cerci. They possess short, veinless front wings and folded hindwings, with only the tips exposed. The term “earwig” originates from an ancient English myth falsely claiming these insects enter sleeping individuals’ ears to burrow into their brains¹.

Globally, there are approximately 2,000 species of earwigs², with about 25 species found in North America³.

Biology and behavior

Earwigs, exemplified by the ringlegged earwig (Euborellia annulipes), undergo gradual metamorphosis through three stages: egg, nymph and adult. Females lay eggs in underground burrows, with nymphs typically hatching within seven to 10 days. Nymphs molt several times over weeks to months, influenced by temperature and food availability. Adults ensure species continuity by laying multiple clutches of eggs⁴.

Life cycle dynamics, including mating behaviors, nesting phases and seasonal activities, vary significantly among earwig species because of their evolutionary adaptations and ecological preferences. Earwigs primarily feed on plant material and decaying organic matter, occasionally preying on small insects. They exhibit defensive behaviors such as secreting foul-smelling fluids when threatened. Ecologically, earwigs contribute to decomposition processes and serve as prey for various organisms.

Earwigs are distributed globally, with species preferences tied to climatic conditions and habitat availability. They can have an impact on agriculture and gardens by feeding on seedling plants, soft fruit and flowers, potentially causing economic losses⁵. Human interactions with earwigs often involve nuisance issues and traditional perceptions about their presence.

Management

Managing earwig infestations requires prioritizing monitoring, identification and elimination of key hiding spots and entryways. Implementing targeted treatments and exclusion methods around these areas is essential for effective control, ensuring proactive management of earwig populations and promoting pest-free environments. Earwigs typically hide and lay eggs outdoors in sheltered locations such as under tree bark, in soil and mulch, and beneath rocks and debris. Occasionally, they enter indoor environments at night, attracted by light filtering through gaps, cracks and crevices in foundations, doors and windows. During the day indoors, they seek shelter in potted plants and dark, moist, cool crevices.

Long-term strategies should focus on removing or altering daytime shelters — boards, stones, paper, mulch, etc. — and sealing points of entry such as cracks, crevices in the house exterior and gaps under doors. Reducing lighting and damp conditions around potential entry sites will also deter them. Creating a clean, dry border directly around the foundation wall reduces earwig presence near structures. Modifying exterior lighting, such as using sodium vapor or yellow “bug lights” can further discourage them.

If these measures prove insufficient, apply an appropriately labeled residual pyrethroid-based pesticide around perimeter areas to manage earwigs attempting to enter structures. Using granular bait insecticides in known earwig harborage sites, like rocks, mulch, foundation walls, crawlspaces, unfinished basements and uninhabited attics, can also be effective. Indoor infestations benefit from residual insecticide treatments targeting earwig hiding and entry sites, such as baseboards, doors, windowsills, beneath cabinets and other hiding places.

Post-treatment monitoring involves placing sticky traps or pitfall traps in typical hiding places, particularly damp, dark areas, to assess earwig infestation levels. Regular monitoring around common entryways, while ensuring safety considerations, helps manage and adjust interventions based on findings.

Conclusion

In summary, a comprehensive approach to earwig management involves proactive monitoring, targeted treatment and habitat modification. This ensures effective control, contributing to environments free from pest disturbances.

References:

1. Bland, R.G. and Jacques, H.E. (1978). How to Know the Insects. 3rd Edition, WCB/McGraw-Hill, Dubuque.
2. Zhang, Z.-Q. (2011). Phylum Arthropoda von Siebold, 1848 In: Zhang, Z.-Q. (Ed.) “Animal biodiversity: An outline of higher-level classification and survey of taxonomic richness.” Zootaxa. 3148: 99–103.
3. Gillott, Cedric (2005). Entomology (3rd ed.). Dordrecht: Springer, pp. 175–179. ISBN 978-1-4020-3184-7.
4. Rankin S.M., Palmer J.O., Larocque L., Risser A.L. (1995). “Life history characteristics of ringlegged earwig (Dermaptera: Labiduridae): emphasis on ovarian development.” Ann. Entomol. Soc. Am. 88:6887–93.
5. Moore, W. S., C. S. Koehler and P. Svihra. Aug. (1994). HortScript #7. “Earwigs and Their Control.” Univ. Calif. Coop. Ext. Marin County.