Initially thought to be ectomycorrhizal (symbiotic with plants, like most Boletaceae), "C. piperatus" has not been confirmed as such in multiple synthesis studies or in isotope fractionation studies. There is some speculation that "C. piperatus" is a mycoparasite on the mycorrhiza of "Amanita muscaria". In New Zealand, "A. muscaria" is thought to have been introduced with "Pinus radiata", and has made a host jump to the native "Nothofagus" trees; "C. piperatus" has since been observed fruiting near "Nothofagus" trees with "A. muscaria" associations. "Buchwaldoboletus lignicola" is in the same clade as "C. piperatus" and is thought to be a parasite as well, strengthening the evidence that "C. piperatus" and its relatives may be mycoparasites.