Mimicry and foraging behaviour of two tropical sand-flat octopus species off North Sulawesi, Indonesia

Publication Type:Journal Article
Year of Publication:2008
Authors:R. T. Hanlon, Conroy, L. A., Forsythe, J. W.
Journal:Biological Journal of the Linnean SocietyBiological Journal of the Linnean Society
Date Published:Jan
Type of Article:Article
ISBN Number:0024-4066
Accession Number:ISI:000251738300004
Keywords:adaptive coloration, antipredator defense, assemblages, camouflage, Cephalopod, Cephalopoda, color, colour patterns, CONSTRAINTS, cuttlefish, evolution, GUILD STRUCTURE, IMPERFECT MIMICRY, mimic octopus, N.-GEN., Octopodidae

The so-called 'mimic octopuses' of tropical Indonesia are reputed to mimic up to 13 species of other local marine organisms. We tested for mimicry by allowing individuals of two species of octopus to habituate to divers, then observing and filming two species continuously as they foraged daily in the same open, featureless volcanic sand habitat. Mimicry of a local, abundant flounder occurred commonly during 5 days of natural foraging: nearly 500 episodes were analysed. Both octopus species mimicked the shape, swimming actions, speed, duration, and sometimes the coloration of swimming flounders. During flounder mimicry, octopuses were actively moving and conspicuous, whereas immediately before and after flounder mimicry, they were camouflaged and motionless (sitting or very slowly crawling). Furthermore, when motionless, octopuses assumed body patterns and postures that resembled small sponges, tube-worm tubes, or colonial tunicates, which were among the few objects in the open sand habitat. The key finding was that octopuses used flounder mimicry only when their movement would give away camouflage in this open habitat. In all cases, octopuses used mimicry as a primary defense. Several interactions with fishes and stomatopods were filmed and typical secondary defense behaviours, not mimicry, were used by the octopuses. Foraging occurred twice per day and two tactile feeding tactics were used. Dens and food were not limiting; thus, we observed a highly unusual circumstance of a guild of small, long-armed octopus species that shared the same habitat, den sources, food, activity period, and some behaviours. (c) 2008 The Linnean Society of London.

Alternate Journal:Biol. J. Linnean Soc.
Scratchpads developed and conceived by (alphabetical): Ed Baker, Katherine Bouton Alice Heaton Dimitris Koureas, Laurence Livermore, Dave Roberts, Simon Rycroft, Ben Scott, Vince Smith