These fast, agile predators are common and widespread throughout Britain and are frequently seen on brownfield sites. Green tiger beetles (Cicindela campestris) are easily recognised with their iridescent green colouring and the yellowish spots on their back.
Green tiger beetle (Cicindela campestris) © Greg Hitchcock
Green tiger beetles are ground beetles (family Carabidae) from the order Coleoptera. There are over 40,000 species of ground beetle worldwide and Britain has over 350 species.
The striking colouration of the Green tiger beetle makes them easily recognisable. The adults of the Green tiger beetle can be seen from April to September and are 10.5-14.5mm in length. Long legs that make them agile when hunting for prey and large eyes make them the perfect predator. If disturbed they will fly for short distances very fast and they make a buzzing sound in flight. Green tiger beetles have strong sickle shaped jaws (mandibles) that have several teeth. Adults feed on any small invertebrates they can catch including spiders, caterpillars and ants.
Green tiger beetles breed in the summer and their eggs are laid separately in small burrows in the ground. When the egg hatches the larvae stay in the burrow over the winter feeding and growing.
|Green tiger beetle larva (Cicindela campestris) © Greg Hitchcock|
The larvae have strong jaws (mandibles) that they use when hunting. The small burrow in which the larvae lives acts like a pitfall trap and they actively wait for passing prey to fall into their burrow which they then grab with their mandibles. The larvae feed on spiders, ants and anything else they can drag down their burrow. The larvae have a spine on their back that anchors it to the side of the burrow. Green tiger beetle larvae go through three larval instars and before each molt they need to enlarge their burrow.
Larvae of the Green tiger beetle are parasitized by the solitary wasp Methoca ichneumonoides. This means that the wasp lays its eggs inside the Green tiger beetles body. The female wasp is smooth and slender in shape and this enables it to survive being gripped by the larva’s strong mandibles. The wasp then stings the Green tiger beetle larvae to paralyse it and she then inserts an egg into the larva’s burrow. When this egg hatches the wasp larva can feed off the beetle larva in the safety of its own burrow.
|Green tiger beetle habitat (bare ground with little vegetation)|
Green tiger beetles are often found at ground level and prefer areas of bare ground with little vegetation. They are most commonly seen in warm and sandy habitats in heaths, hillsides and dunes, and they are also seen regularly at Brownfield sites. Bare ground warms up rapidly in sunshine and this is perfect for both the larvae and adults of the Ground tiger beetle. Warmth is extremely important as a warm animal is a faster one and they can then hunt and avoid being preyed on more efficiently. Soil under bare ground is significantly warmer than the soil under vegetation and eggs and larvae of the Green tiger beetle will be able to develop more rapidly.
Brownfield sites are excellent habitats for Green tiger beetles as they have been left undisturbed and many have a good mixture of different types of habitats such as with bare ground and little vegetation within a small area.
There are five species of tiger beetle in Britain that include the Heath tiger beetle (Cicindela sylvatica) and the Cliff tiger beetle (Cicinedela germanica) and both of these species are UK BAP species (this means they are species of conservation concern and action is being taken to protect and conserve them and their habitats).