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), Pearson et al (2015): length 12-15 mm; above, usually reddish-brown; maculations heavy, complete, and connected along the elytra margins, middle maculation 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 coat-hook or G-shaped (left) or inverted G-shape (right); 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. Body, legs, forehead hairy, labrum medium 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 shelfordi, a spring-fall species, active period is April to late June and early August to November (Larochelle and Larivière 2001, and Pearson et al. 2015). April to October in Nebraska (Carter 1989), early April to late September in Colorado, to late September in Alberta (Kippenhan 1994, and Acorn 2001). Poorly described for Montana but probably similar to Colorado and Alberta, with records from early September (Nate Kohler personal communication).

The following largely comes 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-shape. Also the long dense tufts of hairs (setae) on the side of the thorax in C. hirticollis are absent or less obvious in the C. repanda. Differs from C. h. couleensis (the other subspecies possibly in Montana) primarily by range, being east of the continental divide in the eastern prairies (not west of the divide in the Columbia River Basin), and dorsal coloration, maculations, and size. C. h. shelfordi is reddish-brown, not dark brown to purple, the maculations are connected along elytra margins, not with breaks, and it is slightly larger than C. h. couleensis. Subspecies validity 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 are 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 shelfordi is found in open ground associated with sandy river beaches and sand bars, streams and creeks, lakes and reservoirs, coasts, moist pans in dune fields, less often saline areas and flooded fields. Sandy habitats may be dry or moist but near water, sometimes alkaline (Vaurie 1950, Wallis 1961, Knisley 1984, Carter 1989, Kippenhan 1994, Acorn 2001, Larochelle and Larivière 2001, and Pearson et al. 2015). In Montana, habitat is poorly described but probably similar to elsewhere across the range and includes river banks 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 shelfordi in the field includes adult and larval beetles (carabids, heterocerids), flies, and other small insects. Diet of larvae in the field is not described but probably includes a variety of small insects (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 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 shelfordi has a broad range (eurytopic) of ecological tolerance, using a variety of habitats usually associated with sand (Larochelle and Larivière 2001). Adults are mostly diurnal but possibly attracted to lights at night, gregarious, sometimes occurring in swarms. Occupying self-made burrows in late afternoon and at night, active during hottest times of day, hides under sparse vegetation or near downed wood during cloudy, cool or rainy conditions. Very wary, very cryptic when motionless, when pursued often escapes by rapid flight (Vaurie 1950, Kippenhan 1994, Larochelle and Larivière 2001, and Pearson et al. 2015). Third-instar larvae 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) and robber flies (asilids); larval predators not described but probably include 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, and Larochelle and Larivière 2001).

The life cycle of Cicindela hirticollis shelfordi is 2 years in the north, possibly 1 year farther south. Reproductive traits are probably similar among subspecies across the range (Brust et al. 2006). Mating is reported in July. Females oviposit in level moist sandy areas. Larval burrows are straight, vertical, and 8-20 cm deep in moist sand. Second-instar burrows 13.5 cm deep. 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, 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 (Knisley et al. 2014). However, Cicindela hirticollis shelfordi is susceptible to habitat loss from drought, river damming, channelization, shoreline development, and destruction of larval habitat by vehicles and other human-caused disturbances and developments (Acorn 2001, and Pearson et al. 2015). Early-succession sandy habitats near water favored by this subspecies experience vegetation encroachment and stabilization as succession proceeds for whatever reason (Shelford 1907, 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 reservoirs, 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 hydrological sediment-deposition processes (especially of sand, not silt) probably especially beneficial for this subspecies, and controlled burns to reduce vegetation cover and encroachment in specific areas may also be of benefit.