Nature and perception of barnacle settlement pheromones

Area of Science:

• Marine Biology
• Chemical Ecology
• Larval Biology

Background:

• Gregarious settlement in barnacles, crucial for marine invertebrate life cycles, has been studied for nearly 50 years.
• Mechanistic studies primarily focus on Semibalanus balanoides and Balanus amphitrite, with B. amphitrite gaining importance due to its fouling impact.

Purpose of the Study:

• To provide an overview of research on barnacle settlement pheromones and their perception.
• To explore the chemical communication mechanisms underlying barnacle larval settlement.

Main Methods:

• Review of existing literature on barnacle settlement induction.
• Immunological comparison of larval adhesive proteins with adult settlement-inducing protein complex (SIPC).

Main Results:

• Initially, arthropodin (settlement-inducing protein complex or SIPC) was considered the sole settlement pheromone.
• At least two additional pheromones are now recognized: an adult-released waterborne cue and a cypris temporary adhesive.
• The cypris temporary adhesive shows immunological relation to SIPC.

Conclusions:

• Barnacle settlement involves complex chemical communication, likely mediated by receptor-ligand interactions and signal transduction pathways.
• These findings suggest a conserved mechanism for chemical communication in marine invertebrate larval settlement.
• Understanding these pathways has implications for developing novel antifouling strategies.