Standard Presentation Australian Marine Sciences Association Annual Meeting 2023

Responsive and Reactive: Access to Nutrients Drives Coral Larval Behaviour (#206)

Colleen Rodd 1
  1. Southern Cross University, East Lismore, NSW, Australia

Nutritional mode is a fundamental biological trait that defines the planktonic larval phase of marine invertebrates with complex life cycles. An important historical theme in marine ecology has been the tendency to underestimate the capacity of larvae during this phase. Coral larvae are considered non-feeding, passive propagules with little control over their behaviour. The strict classification of coral larvae as non-feeding and passive masks the wide variation in life history strategies across species. Recent evidence indicates that some coral larvae can supplement their energy budgets by feeding on exogenous nutrients. Broadcast-spawning corals have biological characteristics and developmental patterns consistent with feeding marine invertebrate larvae, which begs the question: Can coral larvae feed? If so, under what conditions? And at what scale? This talk will present results that quantify the behavioural response of coral larvae to food. Preference for food was dictated by a dynamic interplay between rearing conditions, food concentration, and competency to settle. Directed swimming towards food-rich environments demonstrates that coral larvae are responsive to their environment and capable of purposeful behaviour over small spatial scales. Detailed knowledge of these behavioural patterns provides valuable insight into the links between nutritional mode, development, dispersal, and recruitment.