False Markings utilised for Aggressive Mimicry

This week we will explore the use of false markings utilised by predators for aggressive purposes. We will describe how predators share visual characteristics of a harmless species in order to avoid detection or appear harmless to their prey. The most iconic example of aggressive mimicry is utilised by anglerfish and their method of predation. Anglerfish have long filaments, called the illicium, protruding above their eyes from the middle of the head. At the tip of the illicium is a growth of flesh called the esca. The illicium and esca can be moved and wiggled in all directions, creating the illusion of a prey animal. The smaller fish’s response to the anglerfish’s false markings or signal appears straightforward, as the signals appear to resemble the stimulus the small fish would normally get from its own prey (Wilson, 1937). The anglerfish has evolved to be able to deceive their prey and manipulate what the prey is seeing. Some deep-sea anglerfish have even utilised a symbiosis relationship with bacteria in order to emit light from their escas to attract prey but these will be explored in the future.

Figure 1: Deep sea anglerfish Melanocetus johnsonii. Photographer: Anonymous (2015).

Much like the anglerfish; several snakes, lizards and even a shark have evolved to utilise aggressive mimicry in order to attract prey. The method these animals utilise is called Caudal luring. This is the use of tail movements by the predator to attract prey. Acanthophis antarcticus (death adder) is such a species that utilises caudal luring. The death adder will display caudal movements is such a position that the tip of the tail is right above its head, so close to the mouth that a prey item would almost certainly be within striking range (Hagman et al, 2008).

Figure 2: Death adder Acanthophis antarcticus displaying caudal luring. Photographer: R. Hoser (1989).

Next week we will explore false behaviour and its exploits.

References

Anonymous. (2015). Deep sea anglerfish Melanocetus johnsonii. http://www.montereybayaquarium.org/animal-guide/fishes/deep-sea-anglerfish; retrieved 29/03/2015.

Hagman, M., Phillips, B. L., & Shine, R. (2008). Tails of enticement: caudal luring by an ambush-foraging snake (<i>Acanthophis praelongus</i>, Elapidae). Functional Ecology. 22, 1134-1139

Hoser, R. (1989). Northern death adder Acanthophis antarcticus displaying caudal luring. http://www.smuggled.com/addtax2.htm; retrieved 29/03/2015

Wilson, D.P. (1937). The habits of the angler-fish, Lophius piscatorius L., in the Plymouth Aquarium. J. Mar. Biolog. Assoc. 21,477–497.