There is a tantalising footnote on Maria Fremlin's wonderful website about the European Stag Beetle Lucanus cervus. She says:
Large horse chestnut tree felled on October 2011, one emergence hole on 1 June 2014. This stump soon developed fruiting bodies of turkey tail Trametes versicolor, which is strongly associated with the presence of stag beetles (unpublished).Turkeytail is a very common, easy to recognise fungus and I encounter it frequently in the forest, growing from fallen wood and the stumps of felled trees.
Turkeytail on a stump in the Forest of Loches.Lesser Stag Beetle Dorcus parallelipipedus also prefers wood infected with Turkeytail. It seems likely however, based on Maria and others' observations of various stag beetle species, that they eat the mycelia of certain fungi as both larvae and adults. This probably provides the beetles with important nutrients that the fungi makes available through its own 'feeding' on the wood.
A male Stag Beetle on a wall in Preuilly.
Turkeytail Trametes versicolor fungus.
A female Stag Beetle in the Forest of Loches.Stanley...his last year by our friend Tim, who writes Aigronne Valley Wildlife.