Montana Field Guide

The following is taken from Kippenhan (1994) and Pearson et al. (2015). Body length is 12-15 mm. Above dull black, dark purplish brown, copper, olive or bright green, underside dark metallic purplish-blue to green sometimes with copper on lateral portions of thorax. Forehead without hairs, upper lip (labrum) of both sexes and all forms longer than wide and is unique, except for C. nebraskana [but see Diagnostic Characteristics]. Elytra maculations vary from three heavy whitish lines to a single thin middle line only.

Tiger beetle life cycles fit two general categories based on adult activity periods. “Spring-fall” beetles emerge as adults in late summer and fall, then overwinter in burrows before emerging again in spring when mature and ready to mate and lay eggs. The life cycle may take 1-4 years. “Summer” beetles emerge as adults in early summer, then mate and lay eggs before dying. The life cycle may take 1-2 years, possibly longer depending on latitude and elevation (Kippenhan 1994, Knisley and Schultz 1997, Leonard and Bell 1999). Adult Cicindela longilabris laurentii a spring-fall species, April to September but mostly late May to early July and again August to September, with stragglers in between except at higher elevations where adults emerge later (Spanton 1983, Kippenhan 1994, Acorn 2001, Larochelle and Larivière 2001). In Montana, adults present at least April to mid-September with peaks in May and August (Nate Kohler personal communication).

The following largely comes from Acorn (2001) and Spomer (2009). Most similar to the Prairie Long-lipped Tiger Beetle (Cicindela nebraskana), which some authors consider conspecific withC. longilabris based on molecular evidence (Spomer 2009, Pearson et al. 2015). Underside of C. nebraskana is black, elytra smooth and shiny with only a thin middle band if any maculations present, labrum of female dark or only partially white. C. nebraskana occupies clay soils in open grassland instead of sandy/gravelly soils in grassy openings of conifer forests, but widespread areas of intergradation exist between C. nebraskana, C. longilabris longilabris, and C. longilabris laurentii, including in western Montana (Spanton 1983). All morphs (including black) of Cow Path Tiger Beetle (C. purpurea auduboni) have hairy forehead, elytra always with white tip.

Non-migratory but capable of dispersal. When wings fully developed (macropterous), generally a strong flier and fast runner, although C. l. laurentii is considered a weak flier (Larochelle and Larivière 2001, Pearson et al. 2015).

Adult and larval tiger beetle habitat is essentially identical, the larvae live in soil burrows (Knisley and Schultz 1997). Across the range Cicindela longilabris laurentii prefers open grassy spaces within conifer forests, pocket gopher mounds, paths, roadsides, blowouts, usually with sandy or gravelly areas, often not associated with water or moisture, also above treeline in tundra meadows, to 12,000 feet (3678 m) in Colorado (Vaurie 1950, Wallis 1961, Kippenhan 1994, Acorn 2001, Larochelle and Larivière 2001, Pearson et al. 2015). In Montana, found in blowouts, sand pits, sparsely-vegetated areas near creeks, two tracks, unpaved roads, road cuts, trails, usually in or near conifer forests, to at least 7600 feet (2316 m) elevation (Nate Kohler personal communication).

Larval and adult tiger beetles are predaceous. In general, both feed considerably on ants (Wallis 1961, Knisley and Schultz 1997). Adult C. longilabris laurentii diet not reported (Larochelle and Larivière 2001), but probably small insects and spiders.

Larval tiger beetles live in burrows and molt through three instars to pupation, which also occurs in the larval burrow. Adults make shallow burrows in soil for overnight protection, deeper burrows for overwintering. Adults sensitive to heat and light and are most active during sunny conditions. Excessive heat during midday on sunny days drives adults to seek shelter among vegetation or in burrows (Wallis 1961, Knisley and Schultz 1997). Cicindela longilabris laurentii has a broad range of ecological tolerance (eurytopic). Larval burrows often scattered among open patches near sparse vegetation, average 8-20 cm deep with funnel shaped opening (Pearson et al. 2015). Adults are diurnal and nocturnal (attracted to artificial nightlights), solitary or gregarious, wary and difficult to approach, prefers to run when pursued, flight slow and heavy, in straight line, emits musky scent when captured. Predators include asilid (robber) flies and frogs. Other associated tiger beetle species include C. lengi, C. limbalis, C. purpurea, C. terricola (= Parvindela terricola) (Vaurie 1950, Kippenhan 1994, Acorn 2001, Larochelle and Larivière 2001).

Life cycle of Cicindela longolabris laurentii probably 3-4 years, 2-3 years as larvae (Acorn 2001, Larochelle and Larivière 2001, Pearson et al. 2015). Reproductive cycle not reported but probably similar to full species; mating: May to July, oviposition: May to June, pupation: June to July, fresh emerged adults: August to September, then overwinters emerging in spring as sexually mature adults (Larochelle and Larivière 2001). No information for Montana.

Not considered rare or in need of special conservation management (Knisley et al. 2014). Grassy openings and meadows in coniferous forest habitats, and the sandy/gravelly or clayish loamy soils favored by this species, experience vegetation encroachment and stabilization as succession proceeds, and benefit from disturbance that retains a mosaic of successional conditions. Larval burrows could be impacted by trampling through livestock overgrazing, but grazing at appropriate times and stocking levels could also be beneficial by keeping vegetation cover more open (Knisley 2011). Prescribed burning in late autumn could also be a useful tool for sustaining habitat once larvae and adults are in overwinter burrows.