Appearance
The adult beetle is 8 to 13 millimeters long. It is metallic green in color with a black or yellow cast. There is a pair of white spots on the inner edges of the elytra. The larva is a creamy white color and measures up to 43 millimeters in length. The first thoracic segment is enlarged. The grub is legless and has a pair of horns on its last abdominal segment. Female beetles have an average lifespan of 2 months, but some may live upwards of 5 months.Behavior
The adult beetle can fly several kilometers. It can also be transported to new areas with shipments of wood.Food
The main hosts of this insect are oak species, including English oak, sessile oak, downy oak, evergreen oak, cork oak and turkey oak. The beetle can also be found on European beech and chestnut.The beetle develops under the bark of the tree and produces damage to the wood during pupation. The female lays clusters of eggs in cracks in the bark and the larvae feed on the inner bark and outermost layer of wood. They produce long, zig-zag galleries in the tissues of the tree as they dig. This action causes girdling of the tree, preventing the circulation of nutrients through its tissues. The following spring, the adults emerge through holes in the bark and feed on the leaves of the tree.
This species typically attacks trees that are stressed by insect damage, frost, or drought. It kills trees by the girdling action of the larvae. It contributes to oak dieback, large-scale losses of stands of oak trees caused by several factors. The beetle favors mature oaks with trunks over 30 centimeters in diameter.
Predators
Natural enemies of the beetle include woodpeckers, which dig the larvae from the bark. A number of parasitoid wasps utilize the larvae, including ''Spathius curvicaudus'', ''S. ligniarius'', ''S. radzayanus'', ''Atanycolus neesii'', and ''Deuteroxorides elevator''.References:
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