Mar Biol DOI 10.1007/s00227-009-1264-4

ORIGINAL PAPER

Octopus insularis (), evidences of a specialized predator and a time-minimizing hunter

Tatiana Silva Leite · Manuel Haimovici · Jennifer Mather

Received: 1 June 2009 / Accepted: 16 July 2009 © Springer-Verlag 2009

Abstract Shallow-water have been reported as foraging behavior, habitat variables, and body size. major predators of motile in benthonic marine com- Mottle was the most frequent pattern, especially during munities, capturing their prey by diVerent foraging tech- poke and crawl, in shallower depths. Dorsal light–ventral niques. This study assessed for the Wrst time the feeding blue green was more frequent during swimming at mid- ecology, foraging behavior, and defensive strategy during water, and Blotch was the normal pattern during web-over foraging, including the use of body patterns, to construct a by large . The large proportion of two species of general octopus foraging strategy in a shallow water-reef small crabs in den remains, the intense search for food dur- system. Octopus insularis was studied in situ using visual ing short hunting trips, and the intense use of cryptic body observations and video recordings. The diet included at patterns during foraging trips, suggest that this species is a least 55 species of (70%), bivalves (17.5%), ‘time-minimizing’ forager instead of a ‘rate-maximizer’. and gastropods (12.5%); however, only four species accounted for half of the occurrences: the small crabs Pitho sp. (26.8%) and Mithrax forceps (23.9%), the bivalve Lima Introduction lima (5.3%), and the gastropod pusio (4.9%). Poke and crawl were most frequent foraging behaviors observed Shallow-water octopuses have been reported as major pre- in the video recordings. The foraging behaviors were asso- dators of motile species in benthonic marine communities, ciated with environmental variables and octopus body size. feeding on a large number of species of crabs and mollusks, The sequences of foraging behavior showed characteristics which can be captured by several foraging techniques of a tactile saltatory searching predator, as well as a visual (Ambrose 1983; Mather 1991a; Hanlon and Messenger opportunist. Body patterns showed a relationship with 1996). Despite the intensive research on octopus feeding diet, especially that of Octopus vulgaris (Mather 1991a) and Enteroctopus doXeini (Vincent et al. 1998; Scheel et al. Communicated by X. Irigoien. 2007), evidence is mostly indirect, that is, prey remains (Mather 1991a; Vincent et al. 1998) or stomach contents T. S. Leite (&) (Ibáñes and Chonge 2008). Little is known about individual Departamento de OceanograWa e Limnologia, Universidade Federal do Rio Grande do Norte, hunting tactics and overall feeding and foraging strategy Via Costeira sn, Mãe Luiza, Natal, Brazil (Mather 1991a; Forsythe and Hanlon 1997; Anderson et al. e-mail: [email protected] 2008), owing to the diYculty of observing these animals in the Weld. M. Haimovici Departamento de OceanograWa, The widely accepted classic foraging models (Stephens Laboratório de Recursos Demersais e Cefalópodes (FURG), and Krebs 1986) are based on maximizing the net rate of Rio Grande, Brazil energy gain while foraging (time minimizers or energy maximizers). The animals are faced with two basic prob- J. Mather Psychology Department, lems: prey choice and the optimal time to leave a food University of Lethbridge, Lethbridge, AB, Canada patch (Shoener 1971; Stephens and Krebs 1986). Fryxell 123 Mar Biol and Lundberg (1998) and Stephens et al. (2007) argue that saltatory searchers, with the stop -and -go pattern (O’Brien Weld applications of the theories probably call for mor