Earwigs (Labidura riparia) mimic rotting-flesh odor to deceive vertebrate predators
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Many insects repel predators with caustic chemicals, while insects mimicking odors of wastes/dead insects to fool predators have not been documented. We found that the shore earwig, Labidura riparia (Dermaptera: Labiduridae) when bitten by anole lizards, Anolis carolinenesus, spits a rotting-flesh odor that deceives these insectivores into rejecting prey. Once a lizard attacked and rejected an earwig, the lizard did not attack another earwig during several weeks despite consuming other prey, indicating associative learning after one trial. The fetid odor was found in the head-prothorax containing salivary glands of both male and female earwigs and was comprised of ∼100 ng dimethyl disulfide and ∼600 ng dimethyl trisulfide. Nymphs had <5 ng of either compound. Adults also spit odorous sulfides after prolonged attacks by harvester ants, Pogonomyrmex rugosus, who were only deterred by the earwig’s forceps. Sulfides released by the earwig are similar to odors of carrion/feces, which may be innately repulsive to some vertebrate predators. The mean initial discharge percentage (IDP) of sulfides from a cohort of earwigs was 62 %; however, IDPs of individuals were highly variable (3–99 %; mean 57 %). The discharge refill time (DRT) to refill 50 % of the earwig’s allomone reservoir was estimated at 13 h. A positive relationship in sulfide amounts with body weight was found only in females in 2009, suggesting metabolic cost tradeoffs were revealed when sulfide content was half that in 2010. This is the first report of insects releasing sulfur-containing compounds that may mimic carrion-fecal odors as a deceptive defense against vertebrate predators.
KeywordsAssociative learning Defensive allomones Innate aversion Mimicry Predators Vertebrate learning
I thank Le Anne Elhoff for technical assistance. Mention of trade names or commercial products in this article is solely for providing specific information and does not imply recommendation or endorsement by the US Department of Agriculture. USDA is an equal opportunity provider and employer.
Data deposited in figshare repository: http://figshare.com/preview/_preview/1308556
All applicable international, national, and/or institutional guidelines for the care and use of animals were followed.
- Armstrong DM, Jones JK Jr (1972) Notiosorex crawfordi. Mamm Species 17:1–5Google Scholar
- Berg JM, Tymoczko JL, Stryer L (2002) Biochemistry. WH Freeman, New YorkGoogle Scholar
- Brennan TC, Holycross AT (2006) A field guide to amphibians and reptiles in Arizona. Arizona Game and Fish Department, Phoenix, AZGoogle Scholar
- Garber JC, Barbee RW, Bielitzki JT, Clayton LA, Donovan JC, Hendriksen CFM et al (2011) Guide for care and use of laboratory animals. National Academies Press, Washington, DCGoogle Scholar
- Hoffmeister DF (1986) Mammals of Arizona. Univ Arizona Press and Arizona Game Fish Depart 602 ppGoogle Scholar
- Johri PK, Johri R (2012) The description of internal anatomy of Indian earwigs, Labidura riparia form bengalensis (Dohrn), Euborellia annulipes (Lucas) and Nala Lividipes (Dufour): Dermaptera with special reference to digestive, nervous, respiratory, circulatory and reproductive systems. J Exp Zool India 15:309–334Google Scholar
- Langston RL, Powell JA (1975) The Earwigs of California (Order Dermaptera). Bull Calif Insect Survey 20:1-25 Univ Calif PressGoogle Scholar
- Pudil F, Uvira R, Janda V (2014) Volatile compounds in stinkhorn (Phallus impudicus L. ex Pers.) at different stages of growth. Eur Sci J 10:163–171Google Scholar
- Radi RC, Linsenmair KE (1991) Maternal behavior and nest recognition in the subsocial earwig Labidura riparia Pallas (Dermaptera: Labiduridae). Ethology 89:287–296Google Scholar
- Reed TM, Rocke TE (1992) The role of avian carcasses in botulism epizootics. Wildl Soc Bull 20:175–182Google Scholar
- Roggenbuck M, Schnell IB, Blom N, Baelum J, Bertelsen MF, Pontén TS, Sørensen SJ, Gilbert MTP, Graves GR, Hansen LH (2014) The microbiome of new world vultures. Nat Commun 5(5498):1–7Google Scholar
- Symonds MRE, Johnson TL, Elgar MA (2011) Pheromone production, male abundance, body size, and the evolution of elaborate antennae in moths. Ecol Evol 1:227–246Google Scholar