Cicindela denikei Brown, 1934
Laurentian Tiger Beetle
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Basis for Listing
The Laurentian Tiger Beetle (Cicindela denikei) has a limited range globally and is known only from Ontario, Manitoba, and Minnesota. Until recently, this species was only known to occur northwest of Lake Superior, but recently this species was discovered on Manitoulin Island in southeast Ontario (Pearson et al. 2015). This species was first discovered in Minnesota in Lake County in 1958. By 1979, it was known from five locations, four of them in St. Louis County. Given this restricted distribution in the state, the Laurentian Tiger Beetle was listed as a threatened species in Minnesota in 1996. Concerted survey efforts since 2000 have discovered the species in an additional 50 or more locations in Cook, Lake, St. Louis, Koochiching, and Lake of the Woods counties (Steffens 2000, 2001; R. Huber, personal communication). Despite being documented in many new locations in the state, this species apparently occurs in Minnesota only north of the Laurentian Divide (Border Lakes, Littlefork-Vermilion Uplands, and Agassiz Lowlands subsections). Because it is now known to be more widespread in Minnesota than previously thought, the species’ status was changed to special concern in 2013.
Adult Laurentian Tiger Beetles are bright metallic green to blueish green (Pearson et al. 2015). They average 13-15 mm (0.51-0.59 in.) long and have quick escape flight capabilities. There are no other tiger beetles that live in this species' northern Minnesota habitat that resemble it. However, the closely related Six-spotted Tiger Beetle (Cicindela sexguttata) looks nearly identical and occurs in the southern two-thirds of the state.
The Laurentian Tiger Beetle prefers openings in northern coniferous forest; these include in abandoned gravel and sand pits, undisturbed corners of active gravel and sand pits, sand and gravel roads, and sparsely vegetated rock outcrops. This species has also been observed along power line corridors.
Biology / Life History
Adult Laurentian Tiger Beetles emerge in early summer (sometimes as early as late May) and begin feeding, mating, and laying eggs. By mid-summer (late July, sometimes mid-August), the adults begin to die-off. Tiger beetles prey on small insects and other arthropods and are visual hunters. Adults will actively chase down their prey but will also wait in a shaded area and pounce on prey as it wanders by (Pearson et al. 2015). They often chase their prey in short, fast bursts with brief stops in between runs. These stops are necessary for orientation as tiger beetles can run so fast that they cannot see the prey they are pursuing.
Conservation / Management
Given that limited disturbance may actually create habitat for the Laurentian Tiger Beetle, the only threat to this species may be clearcutting large areas. Constant vehicular traffic along roads that act as corridors for this species may reduce local populations (dead, crushed adults have been found along such roads).
Conservation Efforts in Minnesota
Surveys have resulted in over 50 new locations for this species in Minnesota, some of which are protected on state lands.
Ronald L. Huber, 1988 and 2008; Christopher E. Smith, 2017
Brown, W. J. 1934. New species of Coleoptera V. The Canadian Entomologist 66(1):22-24.
Coffin, B., and L. Pfannmuller, editors. 1988. Minnesota's endangered flora and fauna. University of Minnesota Press, Minneapolis. 473 pp.
Freitag, R. 1999. Catalogue of the tiger beetles of Canada and the United States. NRC Research Press, Ottawa, Ontario, Canada. E-book.
Pearson, D. L., C. B. Knisley, D. P. Duran, and C. J. Kazilek. 2015. A field guide to the tiger beetles of the United States and Canada: identification, natural history, and distribution of the Cicindelinae. Second edition. Oxford University Press, New York, New York. 251 pp. + plates.
Steffens, W. P. 2000. Status surveys for the sensitive species Cicindela denikei and other tiger beetles of the Superior National Forest. Report to Superior National Forest, Duluth, Minnesota. 24 pp.
Steffens, W. P. 2001. Status surveys for the sensitive species Cicindela denikei and other tiger beetles of the Superior National Forest. Report to Superior National Forest, Duluth, Minnesota. 13 pp. + figures.
Wallis, J. B. 1961. The Cicindelidae of Canada. University of Toronto Press, Toronto, Ontario, Canada. 94 pp.