Montana Field Guide

The following is taken from Wallis (1961), Kippenhan (1994), Knisley and Schultz (1997), Leonard and Bell (1999), Acorn (2001), Pearson et al (2015). Body length is 11-13 mm; reddish to bronzy-brown above with a short shoulder maculation connecting or nearly connecting with other maculations along the elytra margin, the front (shoulder) maculation shaped like the letter “C.” The underside of the abdomen is purplish to blue-green, undersides of thorax coppery, and covered with short white hairs. Constrictions at front and back of thorax are similar in width. Forehead hairy, labrum white with a single dark anterior tooth. The most widespread of three subspecies, and the only one occurring in Montana.

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 repanda repanda a spring-fall species, in the southeastern US January to June then August to November with stragglers in summer, in the northeast March to June then August to late September, in the west and northwest mid-March to early July then mid-August to early October (Carter 1989, Kippenhan 1994, Acorn 2001, Larochelle and Larivière 2001, Pearson et al. 2015). In Montana, adults present at least mid-May to late September (Nate Kohler personal communication).

The following comes largely from Kippenhan (1994), Acorn (2001), Pearson et al. (2015). This species is most similar in the west to the Twelve-spotted Tiger Beetle (C. duodecimguttata) and Western Tiger Beetle (C. oregona). Distinguished by possessing a front (shoulder) maculation usually complete and connected (or only slightly separated) from white line along the outer edge of the elytra, the pronotum (thorax) about the same width in front and back. In C. duodecimguttata, front maculation is usually broken and widely separated from outer edge of elytra, white marginal line along this edge usually absent, pronotum trapezoidal in shape (front wider than back). Pronotum of C. oregona also trapezoidal in shape (wider at front than back), the front (shoulder) maculation consistently reduced to two spots, not in the shape of the letter “C” as with C. repanda repanda. The other subspecies of C. repanda restricted to parts of the Maritime Provinces of Canada (C. repanda novascotiae) and the Green River Valley of eastern Utah (C. repanda tanneri). (C. repanda novascotiae is more reddish above with maculations reduced to dots and discontinuous lines, C. repanda tanneri similar to C. repanda repanda except the ivory maculations are extremely broad and connected to each other.

Non-migratory but capable of dispersal. When wings fully developed (macropterous), it is a good flier, fast runner, and early to colonize disturbed sites (Larochelle and Larivière 2001).

Adult and larval tiger beetle habitat essentially identical, the larvae live in soil burrows (Knisley and Schultz 1997). Across the range Cicindela repanda repanda is usually found near water, prefers sandy and muddy river banks, lake shores, stream banks, sand bars, sandy roads and sand dunes near water, wet fields, road and railroad cuts, coastal beaches, and open saline ground (Vaurie 1950, Wallis 1961, Hooper 1969, Kippenhan 1994, Knisley and Schultz 1997, Leonard and Bell 1999, Acorn 2001, Larochelle and Larivière 2001, Kritsky and Smith 2005). In Montana, habitat is poorly described but includes lake and river shores, fishing access sites, sand hills, blowouts, river sandbars, and creek banks, to at least 4320 ft (1317 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). Diet of adult Cicindela repanda repanda in the field includes ants, beetles (carabids, staphylinids, weevils, halictids), acridid grasshoppers, caterpillars, flies (sarcophagids, tipulids), springtails, worms, spiders, sassafras and pokeweed fruits. Items in captivity include crushed snails, tadpoles, dead fish, lean meat, and fruit (Larochelle and Larivière 2001). One of the few tiger beetle species documented to be an opportunistic frugivore (Hill and Knisley 1992, Knisley and Schultz 1997). Larval foods include acridid grasshoppers in the field and lean meat in captivity (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). Cicindela repanda repanda has a broad range of ecological tolerance (eurytopic). Larval burrows often in high densities, excavated in moist soil or sand (sometimes clay or mud), sometimes mixed with humus. Leaves burrow for a moister locality when burrow gets too hot or dry. Larvae commonly attacked by a parasitoid fly (Anthrax) (Larochelle and Larivière 2001, Pearson et al. 2015). Adults are diurnal and crepuscular, often gregarious, and hide a short distance from the water’s edge during night and on rainy, cloudy or cool days, in excavated holes 1.2-2.5 cm deep in sand or grass often close to edge of stone, wood, and under dead leaves. Predators across range include toads, frogs, and various birds (bluebirds, gulls, European Starling, American Kestrel, owls, flycatchers), moles, asilid (robber) flies, aeshnid dragonflies, lycosid spiders, and sundews (Drosera). Other associated tiger beetle species include C. duodecimguttata, C. hirticollis, C.[= Ellipsoptera] nevadica, C. oregona, C.[= Cicindelidia] punctulate, C. sexgutta, and C. tranquebarica (Kippenhan 1994, Larochelle and Larivière 2001).

The life cycle of Cicindela repanda repanda is mostly 2 years, 1 year in southeastern US (Knisley and Schultz 1997, Leonard and Bell 1999, Acorn 2001, Pearson et al. 2015). Mating occurs from May to July; copulation lasts about 3 minutes. Adult females oviposit from the surface during the day to depths of 5-10 mm. Eggs yellow, 2 mm in length. Oviposition occurs in May and June in Illinois (Shelford 1908). Larval burrows 7.5-15.0 cm in length at right angle to sloping surfaces, oblique to horizontal surfaces. Fresh adults (tenerals) emerge in July to October then overwinter and reach sexual maturity the following spring after hibernation. Interspecific copulations reported with C. duodecimguttata, C. oregona, and C. sexgutta (Larochelle and Larivière 2001, Brust et al. 2012). No information for Montana.

Not considered rare or in need of special conservation management (Knisley et al. 2014). River and lakeshore habitats benefit from disturbance that retains open conditions. C. repanda repanda benefits in particular from the creation of dredge spoils following operations to maintain or clear ditch or canal channels. Exotic grasses, such as cheatgrass, could become a problem at local scales where they invade moist open habitats. Larval burrows could be impacted by trampling through livestock overgrazing or concentrations at water sources, but grazing at appropriate times and stocking levels could also be beneficial by keeping vegetation cover more open (Knisley 2011).