Olfactory discrimination between chemical cues from coastal vegetation in two palaemonid shrimps,Palaemon vulgarisSay, 1818 andP. affinisH. Milne Edwards, 1837 (Decapoda: Caridea: Palaemonidae)

Abstract

Many decapod crustaceans have highly developed chemosensory systems, with naturally occurring waterborne chemicals used to inform movement and other behavioural processes. I show that two species of intertidal palaemonid shrimps from geographically disparate locations, the North American grass shrimp Palaemon vulgaris (Say, 1818) and the New Zealand tide pool shrimp P. affinis H. Milne Edwards, 1837, possess the ability to discriminate between chemical cues produced by intertidal plants. Both species displayed a variable, but broadly comparable, response to plant odours, showing an attraction to aquatic, emergent species irrespective of taxonomy, and either showing no response or an avoidance to non-aquatic coastal species. While the chemical basis for an attraction or avoidance to these plant species is unclear, the ability to differentiate between plant species could have important implications for the behaviour of these shrimps, assisting them to locate and orient towards structurally complex habitats when visual acuity is limited.