Montana Field Guide

The following is taken from Wallis (1961), Kippenhan (1994), Acorn (2001), and Pearson et al (2015). Body length is 8-11 mm. Highly variable above, dull brown to reddish-brown, green, blue or black. Maculations may be absent, thin and unconnected, or thin dorsally but broadly connected along or above the outer margin of the elytra. Body is long and narrow, but relatively small for a tiger beetle, with relatively straight and parallel outer margins of the elytra. Below is metallic blue-green or purplish, with sparse white hair-like setae on sides of thorax and abdomen. Forehead not hairy, labrum medium, with 1 tooth. In Montana, three subspecies reported (C. t. terricola, C. t. cinctipennis, C. t. imperfecta with zones of intergradation between the first two), mostly greenish or brown to dark brown above with complete maculations joined along the margins of the elytra, or the thin anterior two maculations joined above the elytral margin.

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, and Leonard and Bell 1999). Adult Cicindela (=Parvindela) terricola a summer species, is active April to September across its range but most common June to early August (Larochelle and Larivière 2001, and Pearson et al. 2015). May to August in Nebraska (Carter 1989), late June to early September in Colorado (Kippenhan 1994), June to August in South Dakota (Kirk and Balsbaugh 1975), most common June and July in western North Dakota (Kritsky and Smith 2005), July to August in Alberta (Acorn 2001). In Montana, records from early June to late August (Nate Kohler personal communication).

The following largely comes from Kippenhan (1994, 2007), Acorn (2001), and Pearson et al. (2015). This is the smallest tiger beetle in Montana, and not likely to be confused with any other species. Size and the maculations are unique. Of the three subspecies present in the state, C. t. terricola (eastern) is variable in color and maculations, but usually dark brown with more complete maculations in our region, the middle band often reduced to a transverse dash originating on the elytral margin but never with a complete marginal band. Intergrades with the next subspecies and displays intermediate markings. C. t. cinctipennis (eastern) brown, greenish brown to blue above with complete maculations, middle band marginal in origin with an indistinct foot, usually with a complete marginal band. C. t. imperfecta (western) usually dark brown to greenish brown with first two maculations joined above the elytral margin (a submarginal origin of the middle band). There is a lack of consensus on the number and validity of subspecies across the species range (Kippenhan 2007, Woodcock et al. 2007, and Pearson et al. 2006, 2015).

Non-migratory but capable of dispersal. Wings fully developed (macropterous) but normally a weak flier, and fast runner (Larochelle and Larivière 2001, and 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 (=Parvindela) terricola is associated with sparse prairie or grassland vegetation, muddy or dry, sandy clay or muddy alkaline or salty flats, dry creek beds, salt lake margins, irrigation ditches, banks along rivers, river bars, badlands, sagebrush areas, sandy blowouts, gravel pits, wooded fields, agricultural fields, and shaded paths in open forest. Higher elevation populations in moist soils at margins of meadows (Criddle 1907, 1910, Vaurie 1950, Wallis 1961, Kirk and Balsbaugh 1975, Knisley 1984, Carter 1989, Kippenhan 1994, Acorn 2001, Larochelle and Larivière 2001, Kritsky and Smith 2005, and Pearson et al. 2015). In Montana, habitat is poorly described but probably similar to elsewhere across its range. Includes areas of sparse grass or low vegetation with openings, alkaline lake shores, saline spots near roads, reclamation pond areas, and creek banks (Vaurie 1950, 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 Cicindela (=Parvindela) terricola is poorly described, but adult diet in the field includes beetles (curculionids) and halictid wasps, probably various small arthropods. Diet of larvae is not described (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). Cicindela (=Parvindela) terricola has a broad range of ecological tolerance (eurytopic). Adults are diurnal, mostly solitary but may be gregarious. They hide in grass and under plants during the hottest parts of the day. They are very wary, and when pursued often runs or flies erratically 2-5 m then seeks grass cover; remains active late into afternoon or early evening (Vaurie 1950, Kippenhan 1994, Larochelle and Larivière 2001, and Pearson et al. 2015). Predators of adults are not described but probably include birds, spiders, and robber flies (Asilidae). Associated tiger beetle species include Cicindela denverensis, C. decemnotata, C. duodecimgutta, C. fulgida, C. lengi, C. limbalis, C. longilabris, C. nebraskana, C. (=Ellipsoptera) nevadica, C. (=Cicindelidia) nigrocoerulea, C. (=Cicindelidia) punctulate, C. purpurea, C. repanda, C. scutellaris, and C. tranquebarica (Kippenhan 1994, Acorn 2001, Larochelle and Larivière 2001, and Kritsky and Smith 2005).

The life cycle of Cicindela (=Parvindela) terricola is probably 2 years, third instar larvae overwinter (Acorn 2001, Larochelle and Larivière 2001, and Pearson et al. 2015). Little information otherwise. Larval burrows are found among bare patches in open clay soil. Fresh adults (tenerals) emerge April-July, with later emergence at more northern latitudes. No information on reproductive characteristics for Montana.

Cicindela (=Parvindela) terricola not considered rare or in need of special conservation management as a species (Knisley et al. 2014), although the moderately endemic subspecies C. t. continua of southern California is of conservation concern due to threats of water level reductions. In general, the species benefits from the creation or maintenance of certain anthopogenic habitats, such as irrigation ditches (Knisley 2011). Changes in irrigation that affect the creation or occurrence of saline mudflat habitats within grasslands could have a negative impact on some populations. Some colonies (particularly the larval burrows) could be impacted by trampling through livestock overgrazing and attraction to water sources, but grazing at appropriate times and stocking levels could also be beneficial by keeping vegetation cover more open (Knisley 2011).