Synonyms and other taxonomic changes
formerly placed in their own family (Cicindelidae), now regarded by most experts as a subfamily or supertribe of Carabidae.
Numbers
109 species in North America.
(1)
Twelve genera of tiger beetles are native to North America. Several genera in the tribe Cicindelini were historically considered subgenera of the genus Cicindela but have been elevated to genus rank by Erwin and Pearson (2008) - these include Brasiella, Cylindera, Dromochorus, Ellipsoptera, Eunota, Habroscelimorpha, Microthylax, and Opilidia. The other North American genera are Amblycheila, Omus, and Tetracha, all three of which are placed in the tribe Megacephalini. Classification modified from Erwin and Pearson (2008).
Size
body length about 10-21 mm
Identification
Shape is distinctive. Elytra nearly straight-sided or somewhat wider apically; pronotum narrower than forewings (elytra). Head at eyes wider than pronotum.
The clypeus is wider than distance between sockets of antennae (See this photo) Legs are long and slender. Coloration is brownish, black, or green. Many species are brightly patterned; some are iridescent and very colorful.
The larvae are elongate, cylindrical, and somewhat grub-like with powerful, upward–curving mandibles.
Habitat
Most species are restricted to open habitats such as stream edges, seashores, dirt roads, and sand dunes.
The larvae typically occur in the same habitat as the adults. The S-shaped larvae construct vertical burrows in the soil and anchor themselves with hooks located on the fifth abdominal segment (See
photo)
Food
Larvae and adults feed on other insects.
Life Cycle
The adult female selects a site, excavates a small hole up to one centimetre deep, deposits one egg, then fills in the hole (Fig. 1). Females are extremely specific about choosing an oviposition (egg–laying) site, and they appear to favor damp soil.
After hatching, the larva (Fig. 2) digs a cylindrical burrow at the site. There are three instars, and the larva expands the burrow as it grows. The development of the larva is dependent on the climate, usually requiring 2-3 years for completion depending on food availability.
Tiger beetles exhibit two general life cycles: There are spring - fall species and summer species.
In spring - fall species, adults emerge from pupae in the autumn and are active for a few weeks or longer, depending on the weather conditions. As frosts occur and the weather cools, the adults hibernate for the winter. They emerge from hibernation during the spring and mate (Fig. 3) and the females then lay eggs (Fig. 1). The adults then usually die off, and the newly hatched larvae develop burrows and hibernate for one or more winters. When the larvae are mature, they pupate during the summer and emerge as adults in the fall. Depending on the species, the spring - fall life cycle generally takes 2 to 4 years to complete.
In summer species, the adults emerge from pupae in the early summer and are active during the summer months. They mate (Fig. 3) and the females lay eggs (Fig. 1) during this time. Note that male and female may couple for extended periods of mate guarding in which the male stays in contact with the female after actual mating in order to prevent further matings. Larvae hatch in fall, develop burrows, and hibernate for the winter. This summer life cycle generally takes 1 or 2 years to complete.
Fig. 1: Female ovipositing
Fig. 2: Larvae (removed from its burrow)
Fig. 3: Mating pair
Remarks
Two species of cicindelids found in the United States are endangered (
Cicindela ohlone and
Ellipsoptera nevadica lincolniana) and two species are threatened (
Habroscelimorpha dorsalis dorsalis and
Ellipsoptera puritana).
See Also
Marsh Ground Beetles (
Elaphrus species) resemble miniature tiger beetles with coalesced iridescent spots on their elytra
Print References
Erwin, T. L. and D. L. Pearson. 2008. A Treatise on the Western Hemisphere Caraboidea (Coleoptera): Their classification, distributions, and ways of life. Volume II (Carabidae-Nebriiformes 2-Cicindelitae). Pensoft Series Faunistica 84. Pensoft Publishers, Sofia, 400 pp.
Pearson et al.,
A Field Guide To The Tiger Beetles Of The United States And Canada (1)
Borror and White, page 151
(2)
Internet References
Tiger Beetle Morphology (Patrick Beauzay, North Dakota State U.)
Tiger Beetles of Canada pinned adult images of 19 species (CBIF)
