A Brief Introduction to Lily Beetles:
It is perhaps because I grew up with a plant enthusiast as a mother, that I learned a lot about gardening and developed an awareness of the invasive lily leaf beetle (Lilioceris lilii). Previously unknown in the Province of Saskatchewan, the lily leaf beetle is the nighttime terror that would invade my mothers dreams. This herbivorous insect invades and consumes “every possible kind of lily from native to exotic” (Regina Horticultural Society, 2020), including native species such as the Saskatchewan official floral emblem, the Prairie Lily. “These little red demons can devastate your lily bed, seemingly overnight. They eat every part of the plant: stem, leaf bud,” (University of Saskatchewan, 2018). With a garden over 100 types of lilies, as seen in figure 1 and 2, my mother has a lot to lose if these insects migrated to Saskatchewan. While she has been an avid gardener in Regina for over 35 years, she has yet to come across the lily beetle.
Observation: A Horrifying Discovery
While gardening in August 2020 at our home in Regina, Saskatchewan, I was admiring the heirloom orange lilies we inherited when we moved into our home in 2018. I spotted a brightly coloured red beetle and thought it an attractive bug, as seen in Figure 3, before I realized, this was perhaps the dreaded lily beetle in my yard. My neighbour indicated they had lily beetles in their yard the previous summer. Prior to this conversation, I had only heard of whisperings that, given the lily beetle was already in Alberta, and Manitoba, our neighboring provinces, it was only time before they moved into Saskatchewan. While perusing gardening forums online, I saw that many other gardeners were finding these beetles in their yards in 2020.
Discussion & Interpretation:
My interpretation of the causal factors responsible for the appearance of the lily beetle in 2020 is, that this invasive species has migrated to new areas, due to human actions. This could include the transport of infected lilies sold to customers, and additionally, the local flora and fauna could be more sensitive to invaders because of climate change and possibly the varying temperatures equates to a better habitat for the beetles. This invasive species is not only detrimental to our hobbies, but also to the native, sometimes at-risk lilies.
Expert Consultation:
While researching the lily beetle for this assignment, I came across a few sources for expert consultation, including:
- Regina Horticultural Society Inc. which is group is a local group “for avid growers in Regina to come together to learn, share and interact”, (Regina Horticultural Society Inc., n.d.), and organized lily beetle educational seminars,
- James Tansey, and entomologist and the provincial specialist in Saskatchewan for insect and vertebrate pest management, who is often quoted in news stories concerning the lily beetle,
- Dr. Naomi Cappuccino, an associate professor at Carleton University, who specializes in research surrounding biological control of invasive species, in particular the lily beetle.
Research
All three experts above were emailed for the purpose of this assignment, and there was no response given at the time of submitting this assignment. However, I conducted a research into the lily beetle in order to understand the observation of a lily beetle in my garden in 2020, an otherwise lily beetle free garden up to that point.
There are over 2000 species of insects that have been introduced into North America in the last 500 years (Bouchard, et al., 2008), including the lily beetle. The beetle’s introduction into North America originally occurred twice from Europe. Once in 1943 in Montreal and once in Massachusetts in the 1990s and has spread east to 8 southern provinces, not including B.C. (Dieni et al., 2016). The beetles were introduced by the importation of Asiatic lilies (Bouchard, et al., 2008).
According to the University of Saskatchewan, the lily beetle “has recently been found in Saskatchewan” (2018) with other sources indicating the beetle was first observed in Saskatchewan in 2015, (Williams, 2016). While my observation of the beetle in 2020 was not the first sighting of the beetle in Saskatchewan, it is relatively a newly observed invasive species to my area.
I was not able to find specific information about the effects of climate change on the lily beetle, however the Invasive Species Centre (n.d.), indicates that climate change could accelerate the spread of invasive species due to several factors. This includes, increased extreme weather events that stress native species, changing temperatures can increase favorable conditions for the invasive species and the change in climate can effect the species life cycle and possibly their adaptation to other locations.
The beetle has been successful at persisting and spreading within North America. The beetle has no natural enemies in North America, however there is evidence that a parasitic wasp that was released in eastern Canada, is helping to control the population (Williams, 2016). It is interesting that the solution to removing an alien species is to introduce another alien species to the ecosystem.
Conclusion
We are now starting into the sixth gardening season since the first documented sighting of a lily beetle in Saskatchewan occurred in 2015. Although, the beetle has not yet made a sighting in my mother’s garden, located a few blocks from my home, it is relatively close and I am sure there will be many beetle inspections this summer.
Cardinal beetle
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