Abundance of Hemlock Looper Moths (Lambdina fiscellaria)

Katie Bauder wrote:

During the first week of September 2019, I noticed tons of small white and brown moths plastered along the sides of buildings and on the sidewalks in North Burnaby in the early morning. I also saw hundreds at night in the same areas flying around parking lot lights and landing on windows.

I then found two separate posts (1, 2) in the Vancouver subreddit about the number of moths people are seeing. A colleague who heard me talking about it then sent this news article about an outbreak of Hemlock Looper Moths.

A google search turned up the following passage in a book by Kuhnlein and Turner (1991) about the value of Western Hemlock to coastal indigenous communities:

"Western hemlock was apparently little used as food by Interior peoples of British Columbia, but for the Coastal peoples, the inner bark was formerly an important dietary component. The tree also has other food uses. Almost everywhere along the British Columbia coast where herring are known to spawn—from Coast Tsimshian territory in the north to the Nuu-chah-nulth territory on the coast of Vancouver Island, hemlock boughs, or sometimes entire trees, are immersed in the waters of inlets and river estuaries, or tied onto floating logs anchored close to the shore, to collect herring spawn, which was and still is a valued food."

It makes me wonder about other impacts that could arise from this unusual outbreak, or what it could signal more generally.

Greg Pohl of Natural Resources Canada wrote:

There has indeed been a big infestation of this species in the Lower Mainland, and these two news stories (1, 2) cover it very accurately.

This is a native species that occasionally outbreaks but the massive populations don't generally last that long so they aren't typically controlled by the province. This is a very different species from gypsy moths. In the comments on the thread, people talked about lots of other moths, including tiny ones in homes. While most of the big ones on windows right now are probably the Hemlock Looper, the ones in homes are something else entirely. At last count, there were 2,666 species of moths known in British Columbia (see Pohl et al. 2015 and Pohl et al. 2018), so people shouldn't jump to conclusions that any moth they see is a Hemlock Looper.

The BC LEO Coordinator, Tom Okey, wrote:

Regarding the cultural importance of Western Hemlock (Tsuga heterophylla), Emeritus Professor Nancy Turner and colleagues have written extensively since the early 1970s about traditional ethnobotany of the indigenous peoples of British Columbia, including numerous discussions of Western Hemlock. Adding to the Kuhnlein and Turner (1991) quote that Katie shared, Professor Turner commented on the present observation of Hemlock Looper Moths:

"Hemlock is also valued medicinally, and in technology as a source of dark brown dye, for making eelgrass-twisting poles, for the Kwakwaka’wakw."

She added that there is "So much more" information about traditional uses of Western Hemlock, referring to five fascinating and well documented excerpts from her work that included descriptions of traditional uses. The following tallies of described uses should be considered a minimum estimate of the number of uses of Western Hemlock by these cultural groups of people:

• 9 uses by the Coast Salish people (Turner and Bell 1971);
• 12 uses by the people of Bella Coola (Nuxalk) (Turner 1973);
• 24 uses by the Southern Kwakiutl (Kwakwaka’wakw) people (Turner and Bell 1973);
• 17 uses by Nitinaht (Ditidaht) people (Turner et al. 1983);
• 7 uses by the Thompson people (Turner et al. 1990).

It is clear, even from studies of just four indigenous groups, that Western Hemlock has significant cultural importance in British Columbia, and by extension outbreaks of Hemlock Looper Moths, drought, and other stressors that may combine to negatively affect this unique tree species.

Literature Cited

Kuhnlein, H.V. and Turner, N.J., 1991. Traditional plant foods of Canadian indigenous peoples: nutrition, botany, and use (Vol. 8). Taylor & Francis.

Pohl, G.R., Cannings, R.A., Landry, J.F., Holden, D.G. and Scudder, G.G., 2015. Checklist of the Lepidoptera of British Columbia, Canada: Entomological Society of British Columbia Occasional Paper (No. 3). Lulu Press, Inc.

Pohl, G.R., Landry, J.F., Schmidt, B.C., Lafontaine, J.D., Troubridge, J.T., Macaulay, A.D., van Nieukerken, E.J., DeWaard, J.R., Dombroskie, J.J., Klymko, J. and Nazari, V., 2018. Annotated checklist of the moths and butterflies (Lepidoptera) of Canada and Alaska. Pensoft Publishers, Sofia, Bulgaria. 580 p.

Turner, Nancy J. (1973). Ethnobotany of the Bella Coola Indians of British Columbia. Syesis, 6, 193-220.

Turner, Nancy J. and Marcus A.M. Bell. (1973). The ethnobotany of the Southern Kwakiutl Indians of British Columbia. Economic Botany, 27(3), 257-310.

Turner, Nancy J. and M. A.M. Bell. (1971). The ethnobotany of the Coast Salish Indians of Vancouver Island. Economic Botany, 25(1), 63-104; 25(3), 335-339.

Turner, Nancy J., John Thomas, Barry F. Carlson and Robert T. Ogilvie. (1983). Ethnobotany of the Nitinaht Indians of Vancouver Island. Victoria: British Columbia Provincial Museum Occasional Paper No. 24

Turner, Nancy J., Laurence C. Thompson, M. Terry Thompson and Annie Z. York. (1990). Thompson Ethnobotany. Knowledge and Usage of Plants by the Thompson Indians of British Columbia. Victoria: Royal British Columbia Museum, Memoir No. 3 and Vancouver: University of British Columbia Press.