The larvae of ambrosia beetles feed on specialised fungi that develop in galleries made by the maternal insect in the sapwood (rarely the hardwood) of a branch. Generally the host plant is already dead, but some species live in healthy or weakened trees. Ambrosia beetles do not comprise a taxonomic entity, but rather an ecological guild. Often the fungi cause a bluish-black discolouration of the wood.
Gebhardt, Begerow & Oberwinkler (2004a).