Juvenile age and available coral species modulate transition probability from herbivory to corallivory in Acanthaster cf. solaris (Crown-of-Thorns Seastar)

Prior to transitioning to a coral diet, juvenile Acanthaster cf. solaris, the Crown-of-Thorns Seastar (COTS), feed on crustose coralline algae. Although a detailed understanding of juvenile ecology is crucial to predict and prevent outbreaks, the exact timing of the transition is unresolved. Two experiments were conducted to measure time and size of COTS at the transition, and investigate potential modulating effects of different coral species. COTS began early transitions at similar sizes (7.5-8.5 mm), and these first transitions were observed around 136-145 d. Between 175 and 191 d, a 50% transition in the presence of Acropora tenuis was measured. After 175d, the percentage of COTS cohorts that had transitioned was significantly lower in A. millepora (38%) and Stylophora pistillata (7%) compared to A. tenuis (51%). These data fill important knowledge gaps in juvenile ecology, and the influence of coral species on transition suggests an undescribed feedback mechanism between prey and predator.

Automated summary

Two experiments were conducted to investigate the timing and size of transition from crustose coralline algae to coral diet in juvenile Crown-of-Thorns Seastar (COTS), as well as the potential modulating effects of different coral species. The results filled important knowledge gaps in understanding juvenile ecology and revealed an undescribed feedback mechanism between prey and predator.