Stag beetle larvae are saproxylic (dependent on dead or dying wood).
They are large, c-shaped, and can grow up to 80mm. They are creamy-white with an orange head containing sharp jaws enabling them to tear through fibrous wood. They have 3 pairs of prolegs and due to their tunnelling life-style have no need for sight.
Larval development is protracted due to the lack of nourishment gained from the larval foodstuff, and development can take as long as 6 years in unfavourable circumstances. Adult size differentiation may be dependent on the food available to the larval stage.
The larvae feed on the decomposing wood by scraping the surface of the wood for splinters. They are particularly fond of wood infested with white rot. The more decomposed the wood, the less energy is expended on breaking up the wood fibre, thereby the larvae develop at a favourable rate.
Pupation takes approximately 6 weeks and begins in the final autumn of the beetle’s life cycle. Once emerged, the adult will remain under ground throughout the winter, until it comes to the surface the following spring.