Field Identification for the Siuslaw Hairy-Necked Tiger Beetle: Cicindela Hirticollis Siuslawensis
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Field identification for the Siuslaw hairy-necked tiger beetle: Cicindela hirticollis siuslawensis Left: Adult Cicindela hirticollis siuslawensis. Right: larval tiger beetle, presumed to be C. h. siuslawensis, showing the top of the head. Photos by Ron Lyons. The best way to identify and differentiate between species or subspecies of tiger beetles in North America is to purchase this book: Pearson, D. L., C. B. Knisley, and C. J. Kazilek. 2006. A Field Guide to the Tiger Beetles of the United States and Canada: Identification, Natural History, and Distribution of the Cicindelidae. Oxford University Press. 227 pp. Generalized tiger beetle illustration from Pearson et al. 2006 C. h. siuslawensis and similar-looking species with overlapping ranges Cicindela hirticollis Cicindela repanda Cicindela oregona Cicindela bellissima Cicindela tranquebarica siuslawensis © Ron Lyons © Chris Wirth, [email protected] © Will Chatfield Taylor © Scott Nelson © Chris Wirth, [email protected] Subspecies Cicindela Subspecies C. repanda repanda: Subspecies Cicindela Species Cicindela bellissima: Subspecies Cicindela hirticollis siuslawensis: “Bronze-brown above with thin but oregona oregona: “Length 12-13 mm; above tranquebarica vibex: “Above it is brownish green complete maculations on the elytra that “The undersides are brown with coppery reflections. “Above brown, green, or dull to green, the maculations are usually not connected to each other. metallic blue or purple The maculations are heavy but coppery green with thin are thin, and the rear hook However, a few individuals in most and the upperside of the separated into three distinct maculations in which the first on the front maculation is populations exhibit an incomplete head, thorax and elytra lines. The middle line has a one is often reduced to a short absent or quite small.” white connection along the outer elytra are the same color, curved bend toward the rear but line; metallic purple to green (Pearson et al. 2006) edge.” (Pearson et al. 2006) usually dark brown but lacks the sharp “elbow” of other below.” (Pearson et al. 2006) with some individuals species, such as [C. oregona], Species Cicindela Species Cicindela repanda: “Length showing green, blue, or with which it occasionally Species Cicindela hirticollis: 11-13 mm; reddish to bronze-brown rarely purple. The occurs… The brown upperparts tranquebarica: “Length 10-15 mm… a above, with three distinct maculations maculations are thin.” of the thorax and head are more “Length 11-15 mm… lack of large tuft of long white hairs on each elytron that are connected to (Pearson et al. 2006) greenish in southern Oregon. extended white line running on the side of the thorax and each other along the outer edge in some Individuals that have completely along the outer edge of the the front maculation shaped individuals and populations. The front Species Cicindela green or blue above are present elytra, and, if present, the rear of roughly in the form of a G, maculation is in the shape of the letter oregona: “Length 11-13 in small numbers at most the front maculation is a long, with a forward hook on its C. Some populations have their mm.” Lacks a “distinct or locations.” (Pearson et al. 2006) straight line angled away from bottom end…is only likely maculations reduced to dots and thin remnant short white line the outer edge of the elytron and to be confused with [C. lines. The underside is metallic blue running along the middle Range: “Occurring only in with a rear tip that is not repanda], which lacks the green to coppery and covered with of the outer edge of each coastal Washington to extreme expanded. The width of the large tuft of white hairs on short white hairs. The constrictions at elytron and at right angles northern California, this species maculations ranges from thick to the side of the thorax and the front and back of the thorax are to the middle band…” is restricted to a narrow band of thin or even absent in individuals has its front maculation in similar in width…Another similar Middle band on the elytra discontinuous sand dunes. The of some populations. Its color the shape of a C. Also, the species, [C. hirticollis], has the front “has a sharp bend toward adults are most common in the below ranges from copper, mandibles of [C. hirticollis] maculation with a distinctive hook at its the rear that forms what is dune swales and actively shifting metallic green, blue, and purple are noticeably longer and rear end forming the letter G. [C. often referred to as an dunes from the shoreline inland to almost black.” (Pearson et al. thinner than those of [C. hirticollis] also has large tufts of white “elbow.”” (Pearson et al. up to 2 km. Only dunes that are 2006) repanda].” (Pearson et al. hairs on the side of the thorax that are 2006) lightly vegetated or devoid of 2006) absent or less obvious on [C. vegetation are occupied. Where Range: “C. t. vibex occurs from repanda].” (Pearson et al. 2006) Range: C. oregona the dunes are relatively close to western BC south to Range: “Occurring only on oregona: “occurs from the the ocean shoreline, adults can California… [Specimens west of the Pacific Ocean beaches at Range: C. repanda repanda: “From the Pacific Ocean inland to also be found along the water’s the Cascades] occur in habitats the mouths of rivers from Atlantic Coast almost to the Pacific the Rocky Mountains.” edge. Growth of extensive such as: sea beaches, mud flats the central Washington Ocean in Oregon, Washington and (Pearson et al. 2006) vegetation and planting for dune along lakes, ponds, streams, and coast south to Eureka, British Columbia.” (Pearson et al. stabilization produces unsuitable irrigated pastures.” (Pearson et California.” (Pearson et al. 2006) habitat for [C. bellissima].” al. 2006) 2006) (Pearson et al. 2006) C. h. siuslawensis paratype specimens at Oregon State Arthropod Collection. Photo by Sarah Foltz. Seasonality of C. h. siuslawensis Active from April to October, peaking from April to late June and early August to September. The species overwinters in both the adult and larval form. (Pearson et al. 2006). In 2008, Ron Lyons observed adult C. h. siuslawensis from mid-April to mid-September on the Oregon Coast, but they started to be more abundant in late May. Larval biology of C. hirticollis “Burrows are restricted to sandy soils near surface water or where the subsurface soil is constantly moist. The density of these typically shallow burrows (8-20 cm) is often high along flood plains, overwash areas, and other low-lying water edge sites. The larvae of this species are unusual in that they are regularly found crawling across the soil surface to relocate their burrow in response to changing soil moisture levels.” (Pearson et al. 2006) Side view and cross section of a tiger beetle larva in its burrow (left), photo from arkive.org, and top view of tiger beetle larval burrows (right), photo from: http://flickr.com/photos/24608578@N00/2349008658. .