I would be interested in any published information about volatiles emitted by insects used as cues by insect predators to locate they prey. Best would be studies focusing on belowground systems, but any information will be welcomed.
The information about volatiles involved in below-ground prey location is scarce. Nevertheless, there is some information about kairomones released from grub frass that are used by insects parasitoids for host location. In addition, some papers deal with herbivore-induced plant volatiles released from damaged roots that are involved in the recruitment of entomopathogenic nematodes.
Here are some papers dealing with olfactory cues in below-ground prey location in insect parasitoids, mites and nematods:
Rogers & Potter (2002) Entomol Exp Appl 102: 307-314.
Aratchige et al. (2004) Exp Appl Acarol 33: 21-30.