A Synergism Between Dimethyl Trisulfide And Methyl Thiolacetate In Attracting Carrion-Frequenting Beetles Demonstrated By Use Of A Chemically-Supplemented Minimal Trap

Microbially-derived volatile organic compounds recruit insects to carrion, shaping community assembly and ecological succession. The importance of individual volatiles and interactions between volatiles are difficult to assess in the field because of (1) the myriad compounds from decomposing animals, and (2) the likelihood that complex component blends are important for the final approach to carrion. On the assumption that searching insects may use simpler volatile cues to orient at a distance, we employed a chemically-supplemented minimal trap that uses test chemicals to attract from a distance and a minimal carrion bait to induce trap entry. Traps supplemented with dimethyl trisulfide (DMTS) attracted more individuals than controls, while traps supplemented only with methyl thiolacetate (MeSAc) did not. Traps supplemented with both chemicals, however, attracted statistically greater numbers of adult silphids (Necrophila americana and Oiceoptoma noveboracense), and the histerid Euspilotus assimilis than the combined totals of DMTS-only and MeSAc-only traps, demonstrating a synergism. The attraction of Necrophila americana larvae to traps left in the field for less than 24 h suggests that this species sometimes moves between carrion sources; a follow-up experiment in the laboratory demonstrated that larvae have the ability to feed on non-carrion insects and to survive without food while moving between carcasses. The use of such species for forensic applications requires caution.