Montana Field Guide

The following is taken from Wallis (1961), Graves and Brzoska (1991), Kippenhan (1994), Knisley and Schultz (1997), Leonard and Bell (1999), Acorn (2001), and Pearson et al (2015). Body length is 10-15 mm, variable across the range. The forms in Montana are usually dark brown to purple or reddish-brown above. Maculations are heavy, complete, and usually connected along the elytra margins. Middle maculation is perpendicular or nearly so to margin before turning posterior at a right angle, often with a slight anterior bump at the bend. The shoulder (humeral) maculation is coat-hook or G-shaped (left) or inverted G-shape (right). There is a distinctive tuft of long white hairs (setae) on the side of the thorax. Below, purple to blue-green on the abdomen, sides of thorax coppery. The body, legs, and forehead are hairy. Labrum is medium, mandible with 1 tooth.

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, and Pearson et al. 2015). Adult Cicindela hirticollis a spring-fall species although some individuals can be found April to October throughout the range. Active period in the north typically April to late June and early August to September, in the south typically February to June and August to November (Larochelle and Larivière 2001, and Pearson et al. 2015). April to October in Nebraska and South Dakota (Kirk and Balsbaugh 1975, and Carter 1989), early April to late September in Colorado, to late September in Alberta (Kippenhan 1994, Acorn 2001). Poorly described for Montana but probably similar to Alberta and South Dakota, with records from early September (Nate Kohler personal communication).

The following come largely from Kippenhan (1994), Acorn (2001), and Pearson et al. (2015). Most similar in appearance to the Bronze Tiger Beetle, (Cicindela repanda), which is smaller (11-13 mm) and has a shoulder (humeral) maculation that is elongate C-shaped not G-shaped. Also the long dense tufts of hairs (setae) on the side of the thorax in C. hirticollis are absent or less obvious in C. repanda. Subspecies validity is questionable, based on recent range-wide mDNA analysis, although western forms showed some differentiation (Pearson et al. 2015).

Non-migratory but capable of dispersal. When wings fully developed (macropterous), it is a strong flier, fast runner, and very active (Larochelle and Larivière 2001).

Adult and larval tiger beetle habitat is essentially identical. The larvae live in soil burrows (Knisley and Schultz 1997). Across the range Cicindela hirticollis is usually found in open ground associated with sandy edges of rivers, streams and creeks, lakes, coasts, sandy beaches and sand bars, moist pans in dune fields, less often sand dunes, and saline flats. Sandy habitats tend to be moist rather than dry (Shelford 1907, Vaurie 1950, Wallis 1961, Knisley 1979, 1984, Carter 1989, Graves and Brzoska 1991, Kippenhan 1994, Acorn 2001, Larochelle and Larivière 2001, and Pearson et al. 2015). In Montana, the habitat is poorly described but probably similar to elsewhere across the range and includes riverbanks and riverine sand bars (Nate Kohler personal communication).

Larval and adult tiger beetles are predaceous. In general, both feed considerably on ants (Wallis 1961, and Knisley and Schultz 1997). The diet of adult Cicindela hirticollis in the field includes small amphipods, adult and larval beetles (carabids, heterocerids), flies, insects washed up as beach drift, and other small insects. In captivity ants, worms, flies, and lean meat. Diet of larvae in the field includes small amphipods; in captivity lean meat (Larochelle and Larivière 2001).

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 are 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, and Pearson et al. 2015). Cicindela hirticollis has a narrow range (stenotopic) or broad range (eurytopic) of ecological tolerance, depending on the subspecies. Of the subspecies occurring in Montana, C. h. couleensis is stenotopic, C. h. shelfordi is eurytopic (Larochelle and Larivière 2001). Adults are mostly diurnal but are sometimes attracted to lights at night, gregarious, and sometimes occurring in swarms. They occupy self-made burrows in late afternoon and at night, are active during the hottest times of the day, hides under sparse vegetation or near downed wood during cloudy, cool or rainy conditions. They are very wary, very cryptic when motionless, and when pursued often escapes by rapid flight (Vaurie 1950, Kippenhan 1994, Larochelle and Larivière 2001, and Pearson et al. 2015). Third-instar larvae prefer 7-50% soil surface moisture in which to burrow, abandon burrows within 96 hours of flooding or rains but create new burrows only during daylight when more exposed to predators (Shelford 1908, and Brust et al. 2006). Predators of adults include birds (gulls, robins), frogs, and robber flies (asilids); of larvae, bee flies (bombyliids) and tiphiid wasps. Emits the defensive secretion benzaldehyde when attacked and captured (Knisley and Schultz 1997, Leonard and Bell 1999, and Larochelle and Larivière 2001). Associated tiger beetle species include, among others, Cicindela (=Ellipsoptera) cuprascens, C. (= Ellipsoptera) nevadica, C. oregona, C. (= Cicindelidia) punctulate, C. repanda, and C. tranquebarica (Carter 1989, Kippenhan 1994, Knisley and Schultz 1997, and Larochelle and Larivière 2001).

The life cycle of Cicindela hirticollis is 2 years in the north, possibly 1 year farther south. Mating is reported in July. Females oviposit in level moist sandy areas. Larval burrows are straight, vertical, 8-20 cm deep in moist sand, second-instar burrows are 13.5 cm deep. The duration of larval life in southern populations is 4 months. They overwinter as third-instar larvae, reemerge in spring then pupate in June-July. Sexually immature adults (fresh tenerals) emerge in July-August then overwinter before reemerging the following spring to mate. Adults sometimes present in overlapping generations (Shelford 1908, Vaurie 1950, Kirk and Balsbaugh 1975, Knisley and Schultz 1997, Larochelle and Larivière 2001, and Pearson et al. 2015). No information on reproductive characteristics for Montana.

Not considered rare or in need of special conservation management as a species but several currently-recognized subspecies are in decline or extirpated (Leonard and Bell 1999, Knisley et al. 2014, and Pearson et al. 2015). Cicindela hirticollis is especially sensitive to drought, pollution, pesticides, river damming, channelization, shoreline development, and destruction of larval habitat by vehicles and other human-caused disturbances (Graves and Brzoska 1991, Knisley and Schultz 1997, and Pearson et al. 2015). Early-succession sandy habitats near water favored by this species experience vegetation encroachment and stabilization as succession proceeds for whatever reason (Shelford 1907, and Knisley 1979), and benefit from disturbance that retains a mosaic of successional conditions. Absence in Theodore Roosevelt National Park, North Dakota (near the Montana state line) in early 21st century attributed during recent decades to lack of preferred riverine sand habitat (Kritsky and Smith 2005). Some colonies (particularly the larval burrows) could be impacted by trampling through livestock overgrazing or access to water sources at lakes, streams and rivers, but grazing at appropriate times and stocking levels could also be beneficial by keeping vegetation cover more open. Creation of dredge spoils from channelization could benefit this species (Knisley 2011). Retention and restoration of natural stream and river sediment-deposition processes (especially of sand, not silt) will also benefit this species, as will controlled burns to reduce vegetation cover and encroachment.