Grrlscientist: If eyespots, famously used in a butterfly's "startle display", are good enough to scare off hungry birds, why then does the peacock butterfly hiss too?
« [...] Since the non-hissing peacock butterflies were nearly as good at defending themselves against hungry birds, three of the original four scientists decided that hissing may work better as a defence against nocturnal predators -- mice and other small rodents. They designed a series of studies and found that, even in total darkness, peacock butterflies' wing-flicking has an anti-predator function against mice; 75% of the mice ran away, but mice ran further away from butterflies that could also hiss. For this reason, the Swedish team suggests that intense predation pressure from rodents during the butterflies' hibernation has been the driver of the evolution of hissing in the peacock butterfly [...] »
Vallin A., Jakobsson S., Lind J. & Wiklund C. (2005). Prey survival by predator intimidation: an experimental study of peacock butterfly defence against blue tits, Proceedings of the Royal Society B: Biological Sciences, 272 (1569) 1203-1207. doi:10.1098/rspb.2004.3034
Olofsson M., Jakobsson S. & Wiklund C. (2012). Auditory defence in the peacock butterfly (Inachis io) against mice (Apodemus flavicollis and A. sylvaticus), Behavioral Ecology and Sociobiology, 66 (2) 209-215. doi:10.1007/s00265-011-1268-1
Via Bourdoncle, Bernadette Cassel