With a body length of around 5cm, the Great Capricorn Beetle, one of the so-called Long-Horned beetles, is one of the largest native beetle species.
Depending on the availability of food during the larval stage, the adult insect may reach a body length between 24 and 53mm. The Great Capricorn Beetle is completely black except for the light brown end of its elytra. Female Cerambyx cerdo have antennae as long as their body, while males may have ones up to twice as long as their body! The first section of the antennae (beginning from the body) is thickened.
Cerambyx cerdo is native to Central Europe. It thrives in dying or aged English oak trees found in sunny patches. Less often, beech, elm or Sessile oaks are used both as depository for eggs and as food for adult individuals. Deadwood and healthy trees are avoided. Its natural occurrence is limited to non-managed forests with English oaks, national parks, old parks as well as aged trees which have not been removed by humans.
Endangerment and Conservation Status
In Austria, Cerambyx cerdo is one of the most highly protected species and is critically endangered. After it was believed to have become extinct, the Great Capricorn Beetle was recently sighted on the grounds of the Eckartsau Castle and Schlosspark in the Donau-Auen National Park! The species is being promoted with special efforts.
From May to August, these beetles are active during the night, dusk and dawn. Because English oaks only start to become attractive to these beetles after they are 80 to 150 years old, and because the development of larvae takes from three to five years, these animals have become quite rare and are not often seen. Females lay their eggs on trees. The larvae first eat through the bark, then into the wood; the core of the tree is also not spared. Yet trees which have been eaten through by these beetles still sprout new branches and are thus used by future generations as food. The burrows created by older larvae (larval galleries) are as thick as a finger. Adult animals remain loyal to "their" tree.
Male animals carry out territorial battles without harming their rivals with a song-like chirping. Adult beetles may also find nourishment in the sap of injured oaks, and from fruit.