Habitat-based intraguild predation by Caribbean reef octopus Octopus briareus on juvenile Caribbean spiny lobster Panulirus argus

Abstract

Intraguild predation occurs when species simultaneously compete for resources and interact as predator and prey, which describes the interaction between juvenile Caribbean spiny lobster Panulirus argus and Caribbean reef octopus Octopus briareus in the Florida Keys, USA. Octopuses are notorious predators of decapod crustaceans, and their use of crevice shelters suggests that they may also compete for shelter with their lobster prey. Lobsters use mainly chemical cues to detect and avoid octopus, so we hypothesized that the negative association between these species may be as much the consequence of avoidance of a superior competitor as it is of direct predation. Surveys of lobsters and octopuses occupying artificial shelters at 19 hard-bottom sites confirmed that lobsters do not share dens with octopuses, and also show that lobster and octopus abundances are negatively correlated. Tethering experiments on a subset of those sites revealed that predation on lobster was indeed higher on sites with more octopuses. Results from mesocosm studies indicated that although juvenile lobsters do not attain a size refuge from octopus predation, the presence of alternative prey and lobster conspecifics reduces the risk of predation on lobster by octopus. Mesocosm experiments also showed that octopuses were the competitive dominants when shelter was limited. Thus, the negative association between lobster and octopus in the field appears to be driven by both predation and avoidance of octopus-rich sites by lobsters, rather than competition per se. However, crevice shelters suitable for juvenile lobster are limited in many hard-bottom areas in the Florida Keys, so areas where octopuses are abundant may further limit the local accessibility of shelters for juvenile spiny lobsters even if the direct effects of predation by octopus are minimal.

In situ swimming and orientation behavior of spiny lobster (Panulirus argus) postlarvae

“…4 & 5). Also, lobster adults and postlarvae have been successfully used in a variety of tethering experiments examining predation (Acosta & Butler 1999, Mills et al 2008, Behringer & Butler 2009, Butler & Lear 2009 and orientation (Lohmann et al 1995, Jeffs & Holland 2000, Lozano-Alvarez et al 2002, Boles & Lohmann 2003. This body of work suggests that tethering is a valid option for assessing lobster ecology and behavior.…”

Defensive strategies of European spiny lobster Palinurus elephas during predator attack

“…Both common octopus and European conger eel co-occur with common lobster in the same coastal, rocky habitat, sheltering in natural holes during the day and mainly active at night (Morato et al 1999). Many octopuses are natural predators of spiny lobsters (Joll 1977, Harrington et al 2006, Bouwma & Herrnkind 2009, Butler & Lear 2009 and O. vulgaris preys on the common spiny lobster P. elephas (Quetglas et al 2001, Goñi & Latrouite 2005. When threatened by octopus in the open, lobsters attempt to escape by using tailflips, darting backwards away from the attacker.…”

White Spot Syndrome Virus and the Caribbean Spiny Lobster, Panulirus argus: Susceptibility and Behavioral Immunity

“…Panulirus argus avoids direct predation or injury through avoidance of chemosensory cues from predators or aggressive competitors and indirectly avoids predation through avoidance of injured conspecifics [46–50]. Injuries leak hemolymph, and alarm cues contained in that hemolymph signal shelters that need to be avoided by unharmed P. argus [46, 48]. Panulirus argus also reduces its foraging activity after detecting the presence of injured conspecifics [51].…”