Invasion History

First Non-native North American Tidal Record: 1853
First Non-native West Coast Tidal Record: 1920
First Non-native East/Gulf Coast Tidal Record: 1853

General Invasion History:

Anisolabis maritima, (Seaside Earwig) was first described from the Mediterranean (Italy) in 1832 (Scudder 1876a; Langston 1974). Its native region is somewhat uncertain because this species was probably transported widely by shipping before its description (Hincks 1947). The Mediterranean region, from which it was described, seems a likely choice (Carlton 1979; Cohen and Carlton 1995). It was subsequently found widely distributed in temperate to tropical coastal habitats (Scudder 1876a), on all continents and many islands, including the West Indies (Rehn and Hebard 1917), Mauritius (Hincks 1947), Hawaii (Carlton and Eldredge 2009), the Canary Islands, and New Zealand (Langston 1974). This insect, because of its preference for shoreline debris, has high potential for transport by shipping (Carlton 1979) and has probably been transported by humans over most of its present range (Scudder 1876a; Hincks 1947).  This earwig is often abundant in crevices in marinas and docks, and can occur on small boats and ships (Fofonoff, personal observations).

North American Invasion History:

Invasion History on the West Coast:

The Seaside Earwig (Anisolabis maritima) was collected on Vacouver Island in 1920 (Vickery and Kevan 1985), San Francisco Bay in 1933 (Cohen and Carlton 1995), and Laguna Beach, southern California by 1922. This insect's distribution on the Pacific Coast of North America appears to be spotty, rather than continuous (Carlton 1979; Cohen and Carlton 1995; GBIF 2022). This insect was probably introduced with dry ballast and cargo.

Invasion History on the East Coast:

Anisolabis maritima was first collected in North America in South Carolina in 1853 (Langston 1974). It has been considered to be most likely introduced (Morse 1920; Scudder 1876b), though Scudder noted that 'This may be indigenous, but it occurs over nearly the whole world.' On the Atlantic coast, it was known from Key West (Florida) to North Carolina by 1876 (Scudder 1876b), and reported from the shore of Long Island Sound (Cold Spring Harbor, New York; Bennett 1904). Bennett considered these insects to be rare in New England, but by 1924, they were known from Maine to Connecticut (Morse 1920). The fact that the early records of this species came from the southeast, suggests that this earwig may have extended its range northward, considering the high frequency of collectors in the Northeast. However, records of the Global Biodiversity Information Facility (GBIF 2023) indicates that likely this species has few records in the Carolinas, but many in the Atlantic Coast of Florida.  It was collected along the Indian River Lagoon (1896, Rehn and Hebard 1916). Likely vectors of introduction are dry ballast and cargo.  


Invasion History on the Gulf Coast:

Anisolabis maritima was reported on Key West by by Scudder (1876a) and found at several Florida Gulf coast sites, and in Galveston, Texas in 1910 (U.S. National Museum of Natural History Entomology Collections 2020).  Reported records in the Global Biodiversity Information Facility are spotty outside of the Gulf Coast of Florida (GBIF 2023).


Invasion History in Hawaii:

Kaalaea Beach, Oahu/HI/Pacific Ocean (1953, Brindle 1980); Oahu/HI/West Loch, Pearl Harbor (1974, Brindle 1980); Midway Atoll/Pacific Ocean; Laysan Island/HI/Pacific Ocean (1914, Fullaway 1914, cited by Brindle 1980)

Invasion History Elsewhere in the World:

Anisolabis maritima, (Seaside Earwig) was first described from the Mediterranean (Italy) in 1832 (Scudder 1876a; Langston 1974). Its native region is somewhat uncertain because this species was probably transported widely by shipping before its description (Hincks 1947). It has been introduced to the Azores, the Canary Islands, Bermuda, and the eastern Antilles  )Global Biodiversity Facility  2023).  In the Indo-Pacific, it is widespread in coastal China Korea, and Japan (Global Biodiversity Facility 2023), and from Mauritius, and New Zealand  (Hincks 1947).

In the Eastern Pacific, it is known from the Galapagos Islands (1905, Carlton et al. 2019), Cocos Island, Costa Rica, (Hogue and Miller 1981) and the Isla Secas Islands, Panama (GBIF 2023).


Anisolabis maritima is a large earwig, usually associated with the littoral zone of marine and estuarine habitats, often under logs and rocks and in wrack-piles along the upper tideline. It was described from the Mediterranean Sea and is now widespread on temperate and tropical shores. Adults are 16–26 mm long. Males have strongly curved forceps (‘pincers’ at the end of the abdomen) compared to females. Females are larger than males. The body is dark brown with yellowish legs (Bennett 1904: Blatchley 1920; Vickery and Kevan 1975).


Taxonomic Tree

Kingdom:   Animalia
Phylum:   Arthropoda
Subphylum:   Hexapoda
Class:   Insecta
Subclass:   Pterygota
Superorder:   Neoptera
Order:   Dermaptera
Family:   Carcinophoridae
Genus:   Anisolabis
Species:   maritima


Anisolabis maritima (Fieber, 1853)
Brachylabis maritima (Dohrn, 1864)
Forficesila maritima (Serville, 1853)
Forficula maritima (Bonelli, in Gene, 1832)

Potentially Misidentified Species

Euborellia annulipes

A cosmopolitan introduced species, known mainly from terrestrial habitats, Massachusetts to Florida, and California (Arnett 1993), but also from strandlines and elsewhere (Blatchley 1920; Langston 1974; Vickery and Kevan 1985).

Labidura riparia

A cosmopolitan introduced species known from the shores of rivers and oceans (Arnett 1993; Blatchley 1920; Hincks 1947)



In Europe, North America, and throughout most of its range, the Maritime Earwig tends to favor littoral habitats near the sea. It is often found on beaches and on the banks of rivers under pieces of timber and ‘rejectamenta of all kinds ' (Hincks 1947). On the shores of Vancouver Island, British Columbia, they were found 'in trash at the high-water level and well above this mark, and under the bark of logs on the shore' (Vickery and Kevan 1985). In California, 'Many of the areas where this earwig was found were rocky with considerable drift and debris, but very little noticeable plant life' (Langston 1974). However, in Maryland (Kent Island) it was collected from a brackish marsh, dominated by Spartina alterniflora (Smooth Cordgrass), Phragmites australis (Common Reed), and Iva frutescens (Marsh Elder) (Bickley and Seek 1975).  At temperatures near freezing, these insects retreat to sites well above the high-tide mark, where they become dormant. While A. maritima is most frequently found on marine and estuarine strandlines, it has also been collected from the shores of the St. Lawrence River near Montreal and Lake Ontario (Vickery and Kevan 1985), and in mountains in France, Burma, and Lebanon (Hincks 1947). Most reports are from the upper strandline of tidal shores. However, 'It is probable that A. maritima moves up and down from the high tide level to feed. (Langston 1974). 'When disturbed, they frequently enter the water' (Bennett 1904). 



amphipods, fly larvae, crickets, drowned insects

Trophic Status:




General HabitatCoarse Woody DebrisNone
General HabitatUnstructured BottomNone
General HabitatMarinas & DocksNone
General HabitatRockyNone
Salinity RangeOligohaline0.5-5 PSU
Salinity RangeMesohaline5-18 PSU
Salinity RangePolyhaline18-30 PSU
Salinity RangeEuhaline30-40 PSU
Tidal RangeMid IntertidalNone
Tidal RangeHigh IntertidalNone
Tidal RangeSupratidalNone
Tidal RangeTerrestrialNone
Vertical HabitatEndobenthicNone
Vertical HabitatEpibenthicNone

Life History

Reproduction: Sexes are separate. Males tend to be larger than females. Fertilization is internal. Females dig burrows in sand or nest in crevices in rotten logs and lay the eggs there, later guarding the eggs and young (Vickery and Kevan 1985).

Tolerances and Life History Parameters

Minimum Salinity (‰)0Tolerates seasonal exposure to freshwater, but apparently rarely established in permanently freshwater habitats in San Francisco Bay (Langston 1974) and Chesapeake Bay (Fofonoff, personal observation)
Maximum Salinity (‰)37Typical Mediterranean salinity
Broad Temperature RangeNoneCold temperate-Tropical
Broad Salinity RangeNoneMesohaline-Euhaline

General Impacts

Economic impacts of Anisolabis maritima (Seaside Earwig) have not been noted. Most people find them unattractive, but economic impacts are likely insignificant.

Regional Distribution Map

Bioregion Region Name Year Invasion Status Population Status
MED-II None 1832 Native Estab
MED-VII None 1832 Native Estab
CAR-VII Cape Hatteras to Mid-East Florida 1853 Def Estab
NA-ET3 Cape Cod to Cape Hatteras 1901 Def Estab
NA-ET2 Bay of Fundy to Cape Cod 1911 Def Estab
CAR-I Northern Yucatan, Gulf of Mexico, Florida Straits, to Middle Eastern Florida 1876 Def Estab
GL-III Lake Ontario 1985 Def Unk
GL-I Lakes Huron, Superior and Michigan 1985 Def Unk
NEP-III Alaskan panhandle to N. of Puget Sound 1920 Def Estab
NEP-V Northern California to Mid Channel Islands 1935 Def Estab
NWP-2 None 0 Def Estab
NWP-3a None 0 Def Estab
NWP-4a None 0 Def Estab
NWP-4b None 0 Def Estab
NWP-3b None 1926 Def Estab
NA-ET4 Bermuda 1902 Def Estab
NZ-IV None 1922 Def Estab
CAR-IV None 1917 Def Estab
CAR-III None 1968 Def Estab
EA-V None 1947 Def Estab
MED-IX None 0 Native Estab
NEA-V None 0 Native Estab
MED-III None 0 Native Estab
MED-IV None 0 Native Estab
SP-XXI None 1914 Def Estab
SA-IV None 1968 Def Estab
NEA-II None 1850 Def Extinct
SP-IV None 1976 Def Estab
MED-V None 0 Native Estab
WA-I None 0 Crypto Estab
M040 Long Island Sound 1901 Def Estab
M020 Narragansett Bay 1920 Def Estab
M130 Chesapeake Bay 1916 Def Estab
S190 Indian River 1896 Def Estab
G070 Tampa Bay 1930 Def Estab
G260 Galveston Bay 1908 Def Estab
G310 Corpus Christi Bay 1910 Def Estab
M010 Buzzards Bay 1970 Def Estab
S180 St. Johns River 1916 Def Estab
S080 Charleston Harbor 1853 Def Estab
P090 San Francisco Bay 1935 Def Estab
P297 _CDA_P297 (Strait of Georgia) 1990 Def Unk
N100 Casco Bay 1985 Def Estab
N170 Massachusetts Bay 1911 Def Estab
NEP-VI Pt. Conception to Southern Baja California 1921 Def Failed
P027 _CDA_P027 (Aliso-San Onofre) 1921 Def Failed
P093 _CDA_P093 (San Pablo Bay) 1935 Def Estab
N050 Penobscot Bay 1985 Def Estab
S206 _CDA_S206 (Vero Beach) 1876 Def Estab
G020 South Ten Thousand Islands 0 Def Estab
G080 Suwannee River 1916 Def Estab
S020 Pamlico Sound 1916 Def Estab
S175 _CDA_S175 (Nassau) 1916 Def Estab
S160 St. Andrew/St. Simons Sounds 1916 Def Estab
SEP-H None 1981 Def Estab
CIO-VI None 1965 Def Unk
GAden Gulf of Aden 1900 Def Unk
NEA-VI None 1979 Def Estab
WA-VI None 0 Crypto Estab
WA-VI None 0 Crypto Estab
N130 Great Bay 1975 Def Estab
WA-V None 2015 Def Estab
SEP-Z None 1905 Def Estab
M060 Hudson River/Raritan Bay 2013 Def Estab
PAN_PAC Panama Pacific Coast 2020 Def Estab
CMAR1 Isla del Coco / Cocos Island 1981 Def Estab

Occurrence Map

OCC_ID Author Year Date Locality Status Latitude Longitude


Arnett, Ross H., Jr. (1993) American Insects: A Handbook of the Insects of America North of Mexico., In: (Eds.) . , Gainesville, FL. Pp. <missing location>

Bebehani. Manaf I.; Croker, Robert A. (1982) Ecology of beach wrack in northern New England, with special reference to Orchestia platensis, Estuarine and Coastal Marine Science 15: 611-620

Bennett, Charles B. (1904) Earwigs (Anisolabis maritima Bon.), Psyche 11(3): 47-53

Bickley, William E.; Seek, Timothy R. (1975) Insects in four Maryland marshes., Agricultural Experiment Station University of Maryland, College Park, Maryland: Miscellaneous Publications 870: 1-27

Blatchley, W. S. (1920) Orthoptera of Northeastern America, In: (Eds.) . , Indianapolis. Pp. <missing location>

Brindle, A. (1968) The earwigs (Dermaptera) of the Galapagos Islands, Entomologists Record and Journal of Variation <missing volume>: <missing location>

Brindle, A. (1980) The cavernicolous fauna of Hawaiian lava tubes. 12. A new species of blind troglobitic earwig (Dermaptera: Carcinophoridae), with a revision of the related surface-living earwigs of the Hawaiian islands., Pacific Insects 21(4): 261-274

Carlton, James T. (1979) History, biogeography, and ecology of the introduced marine and estuarine invertebrates of the Pacific Coast of North America., Ph.D. dissertation, University of California, Davis. Pp. 1-904

Carlton, James T.; Eldredge, Lucius (2009) Marine bioinvasions of Hawaii: The introduced and cryptogenic marine and estuarine animals and plants of the Hawaiian archipelago., Bishop Museum Bulletin in Cultural and Environmental Studies 4: 1-202

Carlton, James T.; Keith, Inti; Ruiz, Gregory M. (2019) Assessing marine bioinvasions in the Galápagos Islands: implications for conservation biology and marine protected areas, Aquatic Invasions 14(1): 1-20

Charles Darwin Foundation 2021 Galapagos Species Checklist. <missing URL>

Cohen, Andrew N.; Carlton, James T. (1995) Nonindigenous aquatic species in a United States estuary: a case study of the biological invasions of the San Francisco Bay and Delta, U.S. Fish and Wildlife Service and National Sea Grant College Program (Connecticut Sea Grant), Washington DC, Silver Spring MD.. Pp. <missing location>

Davis, Luckett V. (1978) An Annotated Checklist of the Biota of the Coastal Zone of South Carolina, In: Zingmark, Richard G.(Eds.) . , Columbia, South Carolina. Pp. <missing location>

de Sousa, A. Bivar; Sakai, Seiroku (1997) [Earwigs (Insecta, Dermaptera) of Macaronesia, faunistics and zoogeography], Boletim de faculdade de Sociedade de Portuguesa de Entomologia 171(VI-21): 289-308

GBIF (Global Biodiversity Information Facility) 2017-2023 GBIF (Global Biodiversity Information Facility).

Hincks, W. D. (1947) Preliminary notes on Mauritian Earwigs (Dermaptera), Annals and Magazine of Natural History <missing volume>: 518-540

Hogue, Charles L.; Miller, Scott E. (1981) Entomofauna of Cocos Island, Costa Rica , Atoll Research Bulletin 250: 1-29

Langston, Robert L. (1974) The maritime earwig in California (Dermaptera: Carcinophoridae), Pan-Pacific Entomologist 50(1): 28-34

Miranda, Ricardo J. de Anchieta. José Nunes, C. C. Mariano-Neto, Eduardo Sippo, James Z. Barros, Francisco (2018) Do invasive corals alter coral reef processes? An empirical approach evaluating reef fish trophic interactions, None <missing volume>: <missing location>

MIT Sea Grant 2003-2008 Introduced and cryptogenic species of the North Atlantic. <missing URL>

Morse, Albert P. (1920) Manual of the Orthoptera of New England, Proceedings of the Boston Society of Natural History 35(6): 197-556

Quintanilla, Elena; Thomas Wilke; Ramırez-Portilla, Catalina; Sarmiento, Adriana; Sanchez, Juan A.2017 (2017) Taking a detour: invasion of an octocoral into the Tropical Eastern Pacific, Biological Invasions <missing volume>(17): 2583–2597
DOI 10.1007/s10530-017-1469-2

Rehn, James A. G.; Hebard, Morgan (1916) Studies in the Dermaptera and Orthoptera of the Coastal Plain and Piedmont region of the southeastern United States, Proceedings of the Academy of Natural Sciences of Philadelphia 68: 87-314

Rehn, James A. G.; Hebard, Morgan (1917) Studies in West Indian Earwigs (Dermaptera), Bulletin of the American Museum of Natural History 37: 635-651

Reichardt, Hans (1968) Catalogue of New World Dermaptera (Insecta) Part II: Labiodea, Carcinophoriidae, Papeis Avulsos Zoologia de Sao Paolo 22: 35-46

Scudder, Samuel H. (1876) A synopsis of North American earwigs, with an appendix on the fossil species, Bulletin of the United States Geological Survey 2: 249-260

Scudder, Samuel H. (1876) Critical and historical notes on Forficulariae, including descriptions of new generic forms and an alphanumeric synonymic list of the described species., Proceedings of the Boston Society of Natural History 18: 287-332

Scudder, Samuel H. (1876) A synopsis of North American earwigs, with an appendix on the fossil species, Bulletin of the United States Geological Survey 2: 249-260

Vickery, Vernon R.; Kevan, D. K. M. (1985) <missing title>, Research Branch, Agriculture Canada, Ottawa. Pp. <missing location>

Walden, Benjamin Hovey (1911) The Euplexoptera and Orthoptera of Connecticut, Bulletin of the State Geological and Natural History Survey of Connecticut 6: 41-169