Multimodal signalling, the use of a combination of signals along different sensory modalities (e.g. visual, olfactory etc.) has attracted a lot of research in the past 10+ years. A number of empirical studies across a variety of taxa have started to pick apart the functions of different aspects of multimodal signals, by examining a range of functional hypotheses. Our study examined a novel form of multimodal warning signals whereby an entomopathogenic nematode (Heterorhabditis bacteriophora) induces a visual, olfactory and gustatory cue in the host it infects which deters predation. Infected hosts, in this case waxworms (Galleria mellonella) are red, produce a foul-smelling odour and have a chemical defence.

Utilising both avian predators, Great Tits (Parus major) and arthropod predators, Black Clock Beetle (Pterostichus madidus), we examined the role of the visual, olfactory and gustatory cues alone and in concert. Data will be presented showing that the two predators relied on different cues for avoidance of infected hosts. This suggests that the signals in this system support the ‘perceptual variability’ hypothesis whereby prey may need to produce multiple signal components in different sensory modalities to be effective against a range of predators. Additionally, these signals may be acting in a sequential manner, with the visual signal acting at a longer range than the olfactory signal, to minimise the risk of predation. It is hugely beneficial for prey that the predator notices a signal and that it stops an attack at the earliest stage; the quicker this happens, the less damage is likely to occur to the prey. Within this system, the parasite in an infected host utilises a visual, olfactory and gustatory cue in a multimodal signalling context to avoid predation, which would result in parasite death.