Tetracha virginica

(Linnaeus, 1767)

Virginia Metallic Tiger Beetle, Virginia Big-headed Tiger Beetle

Tetracha virginica is a large, tiger with metallic green lacking markings. It is the most widely distributed Tetracha in the United States, occurring across the southern two-thirds of the eastern U.S. in diverse including agricultural fields, bottomland forests, and barren clay soils. The species is strictly nocturnal and frequently encountered at building and street lights. Larvae are notable for their large size, white-margined pronotum, and simple thorn-like hooks on the fifth abdominal segment.

Pronunciation

How to pronounce Tetracha virginica: /tɛˈtraka vɜrˈdʒɪnɪkə/

These audio files are automatically generated. While they are not always 100% accurate, they are a good starting point.

Identification

distinguished from other U.S. Tetracha by solid green without lunules or purple reflections (T. carolina has purple basal reflections and expanded apical lunules; T. floridana has divergent lobes of apical lunules and lacks violet/coppery reflections in anteriolateral regions but occurs only in Florida salt marshes). Larvae distinguished from other eastern tiger by simple thorn-like outer hooks on fifth abdominal segment (other genera have curved outer hooks or different hook arrangements). Distinguished from T. carolina larvae by presence of numerous setae on membranous areas around abdominal plates (T. carolina lacks these setae). Burrow diameter approximately 8 mm, larger than most sympatric tiger beetles.

Habitat

Occurs in diverse including barren clay soils, agricultural fields (especially under irrigation pipes), bottomland forests, and sparsely vegetated areas near water. In Missouri, found in wet bottomland forest in southeastern lowlands and throughout the state in various open habitats. Avoids densely vegetated areas; prefer sparsely vegetated ground slightly elevated above moister barren areas for oviposition.

Distribution

Widespread throughout the southern two-thirds of the eastern United States. Occurs from the Atlantic coast westward through the Mississippi Valley. In Missouri, found statewide but especially common in southeastern Bootheel region. Reaches northern limit in the central Mississippi Alluvial Plain. Also occurs in Mexico and Central America.

Seasonality

active nocturnally during warmer months. Larvae present year-round in burrows. In Missouri, adults observed from late spring through summer; in Florida, observed in August. activity peaks after dark, with adults frequently attracted to artificial lights.

Diet

are fluid-feeding that subdue prey with long, sharp mandibular teeth, then use and to masticate tissues into a bolus while extruding proteolytic to liquify digestible components, which are then ingested via pharyngeal pump. Prey includes small insects and other arthropods. Larvae are sit-and-wait predators that seize prey from burrow entrances.

Host Associations

Anthrax analis - Bee fly larvae attach externally to of tiger larvae; represents first reported of Tetracha by bee flies. females oviposit near burrow entrances when larvae are not at surface.

Life Cycle

Larvae construct vertical burrows in soil, reaching depths of approximately 35 cm in third instar. Larvae sit at burrow entrance to ambush prey, dropping down when disturbed. occurs after third instar. emerge from pupal in soil. Females oviposit in soil using eversible ovipositor, digging small holes in sparsely vegetated areas.

Behavior

Strictly ; not active during daylight. Adults are fast runners and difficult to approach; when disturbed, they dash rapidly into vegetation. Frequently attracted to building lights and street lamps. Larvae are sit-and-wait that can be extracted from burrows by inserting a grass stem to depth and jerking upward when the larva bites. Larvae seal burrow entrance using and pronotum when not hunting.

Ecological Role

of small insects and arthropods in soil and ground surface . Serves as for bee flies (Anthrax analis). Larval burrowing activity contributes to soil aeration and structure in clay and agricultural soils.

Human Relevance

Occasionally enters buildings, where it may be encountered by homeowners. Frequently observed by entomologists and photographers at light traps. Sometimes found in agricultural fields, where it may contribute to pest insect . Not considered a pest .

Similar Taxa

Tetracha carolinaOverlaps in southeastern U.S.; distinguished by purple reflections on basal half of , expanded lunules, and association with treeless rather than bottomland forest.
Tetracha floridanaFlorida restricted to salt marsh and mud flat ; distinguished by divergent lobes of lunules and lack of violet/coppery reflections in anteriolateral regions of .
Cicindelidia obsoletaOnly other Missouri tiger approaching similar larval burrow size; restricted to dry rocky dolomite glades in extreme southwestern Missouri, mutually exclusive with T. virginica.

More Details

Feeding mechanics

Despite large, toothed , are strictly fluid feeders. The mandibles function in prey subdual and tissue shredding, while the maxillary and form an oral mill that masticates prey into a bolus. Proteolytic from the liquify the bolus, which is then sucked into the mouth via pharyngeal pump action.

Larval identification significance

Larvae of T. virginica and T. carolina are the only described larvae among four North American Tetracha . The larva of T. floridana was undescribed until collected and preserved in 2011; T. impressa larva remains undescribed.