Observation: I grew up in the Fairfield/James Bay/Beacon Hill park area of Victoria circa 1965. Earwigs were present in large numbers during this time frame. I moved away for a prolonged period and I've only seen one earwig since returning to live in the same area in 2009. Was this species deliberately and knowingly eradicated en mass? If so, what was the reason? I know it was always decried as a garden pest but was not an invasive or commercially "dangerous" species (eg pine beetle). I've been doing a bit of research online and this seems to be a more global occurrence with scarcity of earwigs being noted in other areas where they used to be found in large numbers (eg Sussex, England). Found the question asked many times but no clear answer. Is their die off just another result of the overuse of pesticide by home gardeners or are they yet another bellweather indicating some profound environmental change? I know they're "just earwigs" so I'm not sure if their presence or absence is of any particular interest scientifically. Just wanted to make the observation and am curious to obtain any information that may have been collected. - Nance Schrader, Victoria, BC
LEO BC Coordinator: Earwigs (Order: Dermaptera) are a diverse group and broadly distributed, and can be an important part of the ecology within their distributions. Their diet is also broad, but they are recognized as important arthropod predators in some settings, such as orchards and other agricultural settings, providing important ecosystem services. There appears to be very little known about the causes of some observed declines in earwigs, but there is some evidence that they are indeed vulnerable to some insecticides (Malagnoux et al. 2015). I am forwarding this observation to Dr. Rob Cannings of the Royal BC Museum. - Tom Okey, Ocean Integrity Research and the University of Victoria.
Consult from Dr. Rob Cannings: I still see lots of European Earwigs (Forficula auricularia) in my garden near Gonzalez Hill, Victoria, and they were abundant in the South Okanagan when I was growing up there in the 1950s, 60s and 70s. I remember commonly finding them in apricots, which they had chewed their way into! But I agree that today, in many areas, they are less abundant than they were then. Now I don’t see the great congregations under boards or in other sheltered places that were common in the 1960s and 1970s.
There has been no concerted effort to eradicate Forficula here and I’m sure they’re not considered a consequential pest anymore. They mainly damage flowers (they love chewing Dahlia petals), so perhaps in places where cut flowers are grown, they are still a nuisance. In general, they are probably more beneficial (as insect predators) than they are a problem.
My best guess concerning their decline in most areas is that the normal and characteristic rapid increase of populations of an introduced species is over. New colonies tend to increase to very high levels during the initial decades after introduction (lack of disease, competition, etc in the new environment) and then gradually decline to a sustainable level after some time. As far as I can tell, they have been in BC for a century or so, first appearing in Vancouver and then showing up on Vancouver Island. Lamb and Wellington (1975) noted that initial large populations in Vancouver have substantially declined. As Vickery and Kevan state (1985) the population change in Forficula “is a prime example of this type of population behaviour.”
The Maritime Earwig, Anisolabis maritima is a cosmopolitan species (perhaps originally from Africa) of beaches. It’s been known in BC for decades and is still common under beach logs and other debris along much of coastal BC. It’s larger than the European Earwig and is completely wingless. The two other earwig species once recorded in BC (Euborellia annulipes and Labia minor) might not be still around. They haven’t been seen for ages, as far as I know. Anyway, apparently all earwig species in BC are aliens. - Dr. Rob Cannings, Royal British Columbia Museum
Resources:
Entomologist studies role of insecticides in earwig population decline
Researching earwig decline
References:
Cannings, R. A. and G. G. E. Scudder. 2005. THE EARWIGS (DERMAPTERA) OF BRITISH COLUMBIA in: Klinkenberg, Brian. (Editor) 2017. E-Fauna BC: Electronic Atlas of the Fauna of British Columbia [www.efauna.bc.ca]. Lab for Advanced Spatial Analysis, Department of Geography, University of British Columbia, Vancouver. [Accessed: 5 June 2017]
Lamb, R.J. and W.G. Wellington. 1975. Life history and population characteristics of the European Earwig, Forficula auricularia (Dermaptera: Forficulidae), at Vancouver, British Columbia. Canadian Entomologist 107: 819-824.
Malagnoux, L., Capowiez, Y. and Rault, M., 2015. Impact of insecticide exposure on the predation activity of the European earwig Forficula auricularia. Environmental Science and Pollution Research, 22(18), pp.14116-14126.
Vickery. V.R. and D.K.McE. Kevan. 1985. The Insects and Arachnids of Canada. Part 14. The Grasshoppers, Crickets, and related Insects of Canada and Adjacent Regions. Agriculture Canada Research Branch Publication 1777. Ottawa. 918 pp.
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Observations From Members 