Right on cue: Fire ant attraction to vertebrate carrion-related compounds

Insects are amongst the most important facilitators of vertebrate carrion decomposition. The most studied decomposers are flies and beetles since they are prolific biomass consumers, some can be primary colonizers, and they play obvious roles in decomposition ecology and forensic entomology. Though not considered as vertebrate carrion decomposers, ants have been observed recruiting to carrion, actively removing tissue and consuming exuded liquids. In previous experiments on laboratory-maintained colonies of the red imported fire ant (Solenopsis invicta), we showed that a dietary supplement of vertebrate carrion was very attractive to foragers but had no influence on overall colony performance. As a follow-up, the present study was designed to characterize the mechanisms underlying ant attraction to vertebrate carrion. Under laboratory conditions, the attraction of blow flies to carrion has been shown to be mediated by various volatiles emitted by the decomposing tissues. We conducted field experiments to examine the attraction of fire ants to previously identified “death cues”: indole and dimethyl disulfide (DMDS). Our results show a positive influence of DMDS on ant recruitment, suggesting that fire ant recruitment to vertebrate carrion may be facilitated by the emission of DMDS during decay.