Smelling Danger – Alarm Cue Responses in the Polychaete Nereis (Hediste) diversicolor (Müller, 1776) to Potential Fish Predation

C Elisa Schaum,Robert Batty,Kim S Last,Roberto Pronzato

doi:10.1371/journal.pone.0077431

Abstract

The harbour ragworm, Nereis (Hediste) diversicolor is a common intertidal marine polychaete that lives in burrows from which it has to partially emerge in order to forage. In doing so, it is exposed to a variety of predators. One way in which predation risk can be minimised is through chemical detection from within the relative safety of the burrows. Using CCTV and motion capture software, we show that H. diversicolor is able to detect chemical cues associated with the presence of juvenile flounder (Platichthys flesus). Number of emergences, emergence duration and distance from burrow entrance are all significantly reduced during exposure to flounder conditioned seawater and flounder mucous spiked seawater above a threshold with no evidence of behavioural habituation. Mucous from bottom-dwelling juvenile plaice (Pleuronectes platessa) and pelagic adult herring (Clupea harengus) elicit similar responses, suggesting that the behavioural reactions are species independent. The data implies that H. diversicolor must have well developed chemosensory mechanisms for predator detection and is consequently able to effectively minimize risk.

Highlights

Predation is an important force that affects evolution, behaviour, life history and phenotypic traits in prey animals [1], [2] and animals in both the aquatic and the terrestrial environment have evolved predator evasion and avoidance mechanisms, which are not the result of direct attack
Many marine polychaete worms are involved in interesting predator-prey interactions as they have to expose themselves to a relatively high level of risk every time they emerge from their sea-bed burrows [3]
Either has been described to have profound impact on prey behaviour in many invertebrate taxa, e.g. flatworms [14], brittle stars [15], zooplankton [16], [17] and gastropods [18], [19], but the exact pathways in which the recognition of these cues eventually leads to a behavioural response in marine polychaetes are not yet fully understood, despite the functional and ecological importance of this group [20,21]

Summary

Introduction

Predation is an important force that affects evolution, behaviour, life history and phenotypic traits in prey animals [1], [2] and animals in both the aquatic and the terrestrial environment have evolved predator evasion and avoidance mechanisms, which are not the result of direct attack. Many marine polychaete worms are involved in interesting predator-prey interactions as they have to expose themselves to a relatively high level of risk every time they emerge from their sea-bed burrows [3]. At such times the energetic costs of not emerging to feed are outweighed by the costs of not being eaten by a predator [4]. Either has been described to have profound impact on prey behaviour in many invertebrate taxa, e.g. flatworms [14], brittle stars [15], zooplankton [16], [17] and gastropods [18], [19], but the exact pathways in which the recognition of these cues eventually leads to a behavioural response in marine polychaetes are not yet fully understood, despite the functional and ecological importance of this group [20,21]

Methods

Results

Conclusion