Microbial volatiles provide essential information for animals, which compete to detect, respond to and perhaps control this information. Burying beetle parents have the opportunity to influence microbially-derived semiochemicals because they monopolize a small carcass for their family, repairing feeding holes and applying exudates that alter the microbial community. To study adaptive manipulation of microbial cues we integrated mechanistic and functional approaches. We contrasted Gas Chromatography, Mass Spectrometry (GC-MS) volatile profiles from carcasses that were or were not prepared by a resident pair of Nicrophorus orbicollis. Methyl thiocyanate (MeSCN), the primary attractant for burying beetles seeking a fresh carcass, was reduced 20-fold by carcass preparation, while dimethyl trisulfide (DMTS), which deters beetles, was increased 20-fold. These results suggest that parental care serves to make previously public information more private (crypsis, MeSCN) and to disinform rivals with a deterrent (DMTS). Functional tests in the field demonstrated that carcass preparation reduced discovery and use by congeners (three-fold) as well as by dipteran rivals. Because microbes and their chemicals influence nearly every aspect of animal ecology, animal manipulation of microbial cues may be as widespread as manipulation of their own signals.