Feeding effects of postlarval red abalone, Haliotis rufescens (Mollusca: Gastropoda) on encrusting coralline algae

Abstract

Detailed examinations of an algal-microherbivore symbiosis have revealed mutualistic components of such herbivore-plant interactions. High-resolution photomicroscopy and experimental analyses in the field and laboratory were used to evaluate effects of foraging by Haliotis rufescens (red abalone) postlarvae ˜ 200 μm in length, on their encrusting red algal hosts, Lithothamnion (=Lithothamnium) californicum, Lithophyllum lichenare, and Hildenbrandia rubra (=H. prototypus). We have quantified the microscopic food availability, postlarval foraging behaviour, changes in stomach and faecal contents, growth, and mutualistic effects of grazing. Host algae were found to benefit both from a reduction in coverage by epiphytic algae, and from enhancement of vegetative growth.

Keywords:

• Haliotis rufescens
• symbiosis
• grazing
• herbivore-plant interaction
• crustose algae
• epiphytic algae
• larval settlement