Cicindelinae | uk beetles

CICINDELINAE Latreille, 1802

Tiger Beetles

These impressive beetles are often active in bright sunshine, both terrestrial and in flight. The Green tiger beetle, C. campestris, is the most widespread species, being found throughout the UK.

Introduction

This subfamily was formerly treated as a distinct family of the Adephaga but is now regarded-if not universally accepted-as a highly specialized subfamily of the Carabidae. Some recent classifications have regarded the group as a monophyletic subgroup of the Carabinae but there is, so far, no universally accepted system. The group is a large one with more than 2500 species and subspecies divided among 4 tribes:

Megacephalini Laporte, 1834 includes 16 species of Omus Eschscholz, 1829. Commonly known as Night Stalking Tiger Beetles, they are all black in colour, flightless and nocturnal in habits. All occur along the west coast of North America. The 60 or so species of Tatracha Hope, 1838 are commonly known as Metallic Tiger Beetles and were formerly included as a subgenus of Megacephala Latreille, 1802. They are mostly large, around 20mm, and metallic green species that hunt nocturnally and hide by day. They are poor fliers and are attracted to light. All species occur in the southern U.S.A. and Central America.
Collyridini Brulle, 1834. Includes 7 genera of very varied forms. They are most diverse in South America where some species are very elongate, long legged and colourful. The genus Amblycheila Say, 1830 includes 7 species from the southwest U.S.A. and Mexico. They are all dark, flightless and nocturnal. The usual habitat is arid desert regions and they are mostly found after wet spells in the spring and autumn. The larva of A. hoversoni Gage, 1990 (The South Texas Giant Tiger Beetle) has been found in the ceilings of badger and armadillo burrows. Some species reach 36mm in length. Platychile pallida (Fabricius, 1801), the only member of the genus, is a very atypical cicindelid; entirely pale brown with a large pronotum, relatively small elytra and long appendages. It is a nocturnal predator inhabiting the sandy beaches of Namibia and South Africa, by day it hides under kelp or retreats into burrows along the high tide line.
Manticorini Csiki, 1907. Includes the very impressive genus Manticora Fabricius, 1792 which are the largest species of the subfamily, reaching 65mm. All are drab coloured, flightless and nocturnal. They are sexually dimorphic with the males having greatly enlarged mandibles which are used for grasping the female during mating. All occur in Africa.

ADEPHAGA Clairville, 1806

CARABIDAE Latreille, 1802

9-18mm

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Cicindelini Latreille, 1802. This tribe includes the majority of the species with more than 2000 worldwide. Most species were formerly included in the genus Cicindela Linnaeus, 1758 but this has been split and many former subgenera have been raised to generic rank. Even so, Cicindela remains a large genus with a worldwide distribution. A former subgenus, Cylindera Westwood, 1831 also occurs worldwide and contains over 200 species. They are most diverse in the Oriental region followed by the Neotropics. The species typically have extremely well developed eyes, long legs adapted for running and long, curved and toothed mandibles. The tribe represents what most people think of as Tiger Beetles. Adults are diurnal and generally very active insects adapted to running, flying and snatching prey; their usual form of pursuit is to sprint towards moving prey, stop to reorient themselves, and then sprint again. While in pursuit of prey the antennae are held forward in order to receive tactile stimulation from the environment. The fastest have been recorded sprinting at 9km/h. Both the adults and larvae of all species are predatory. The vast majority of the tribe are terrestrial but a few tropical species are arboreal. The highly modified larvae are typical of all the tribes of the Cicindelinae; they excavate vertical burrows in the soil and lie at the entrance to prey on passing insects. The head is broad and flattened so as to close the burrow entrance, the mandibles are large and well developed and there are specialized hooks on the body surface to grip the sides. They grab passing insects by rapidly flipping backwards out of the burrow.

Description

They are very distinctive insects; 10-15mm and, as a rule, beautifully coloured and often metallic. The elytra are almost parallel, or weakly dilated towards the apex. The head, with its hugely developed eyes, is usually wider than the pronotum, and the pronotum is narrower than the elytra. Most species are rather flattened. The clypeus is wider than the distance between the antennal insertions. Most species have well developed and prominent mandibles which are sickle-shaped and strongly toothed along the inner margin. The hind wings are usually well developed and most species fly readily and powerfully. The legs are long and slender, and most species are rapid and agile on the ground. Males generally have the basal pro-tarsal segments dilated and densely pubescent on the ventral surface. These beetles are unlikely to be confused with any other group; they are strikingly and often beautifully marked so that many can be identified with little effort, and many are widespread and common e.g. there are more than 40 species of Cicindela in Europe, and so they are, inevitably, popular with a certain type of collector. Having written that, there are many closely similar species that need to be identified very carefully, sometimes by dissection.

Ecology

Typical habitats are open and dry or moist, but not wet, soils often near streams or ponds etc. Other species prefer woodland and wooded clearings and parkland, pathways and roadside verges, moorlands, dunes and beaches. Some, e.g. our own C. campestris Linnaeus, 1758, occur to relatively high latitudes.

The group as a whole generally have a similar lifestyle. After mating the males generally remain with the females in order to prevent further mating with other males. An oviposition site is chosen by the female where she digs a shallow depression and lays a single egg, she then buries it. Females are very fussy about choosing this site and will often choose a damp area on otherwise dry soil. The newly hatched larva digs a vertical cylindrical burrow in which it will live and feed. They usually have 3 instars and take 2 or 3 years to develop, depending on the food source and climate. Larvae typically occur in the same habitat as the adults. They are S-shaped and equipped with curved spines on the fifth segment with which to anchor to the burrow walls. Tiger beetle larvae throughout Europe, including the UK, are parasitized by wasps of the genus Methocha Latreille, 1804. For more information, click HERE. Pupation occurs within the burrow. In temperate zones there are two basic strategies:

Spring and autumn species. Adults eclose in the autumn and are active for a few weeks before the weather turns cold, then they overwinter. They emerge in early spring, mate and lay eggs and die off in late spring or early summer. Larvae dig burrows and overwinter once or twice. Mature larvae pupate in the burrow during the summer.
Summer species. Adults eclose in early summer and are active until the autumn. They mate and oviposit in the summer and larvae burrow in late summer or autumn and overwinter once or twice.

A key to the UK species can be found HERE.