Deimatic behaviour

Spirama helicina resembling the face of a snake in a deimatic or bluffing display

Deimatic behaviour or startle display[1] means any pattern of bluffing behaviour in an animal that lacks strong defences, such as suddenly displaying conspicuous eyespots, to scare off or momentarily distract a predator, thus giving the prey animal an opportunity to escape.[2][3] The term deimatic or dymantic originates from the Greek δειματόω (deimatóo), meaning "to frighten".[4][5]

Deimatic display occurs in widely separated groups of animals, including moths, butterflies, mantises and phasmids among the insects. In the cephalopods, different species of octopuses,[6] squids, cuttlefish and the paper nautilus are deimatic.

Displays are classified as deimatic or aposematic by the responses of the animals that see them. Where predators are initially startled but learn to eat the displaying prey, the display is classed as deimatic, and the prey is bluffing; where they continue to avoid the prey after tasting it, the display is taken as aposematic, meaning the prey is genuinely distasteful. However, these categories are not necessarily mutually exclusive. It is possible for a behaviour to be both deimatic and aposematic, if it both startles a predator and indicates the presence of anti-predator adaptations.

Vertebrates including several species of frog put on warning displays; some of these species have poison glands. Among the mammals, such displays are often found in species with strong defences, such as in foul-smelling skunks and spiny porcupines. Thus these displays in both frogs and mammals are at least in part aposematic.

  1. ^ Startle Display. Elsevier. Retrieved 17 December 2016
  2. ^ Stevens, Martin (2005). "The role of eyespots as anti-predator mechanisms, principally demonstrated in the Lepidoptera". Biological Reviews. 80 (4): 573–588. doi:10.1017/S1464793105006810. PMID 16221330. S2CID 24868603.
  3. ^ Edmunds, Malcolm (2012). "Deimatic Behavior". Springer. Retrieved 31 December 2012.
  4. ^ Umbers, Kate D.L.; Lehtonen, Jussi; Mappes, Johanna (2015). "Deimatic displays". Current Biology. 25 (2): R58–59. Bibcode:2015CBio...25..R58U. doi:10.1016/j.cub.2014.11.011. PMID 25602301.
  5. ^ "δειματόω frighten". Greek Word Study Tool. Retrieved 5 June 2016.
  6. ^ Smith, Ian (3 December 2012). "Octopus vulgaris. Dymantic display". The Conchological Society of Great Britain and Ireland. Retrieved 1 January 2013.