Abstract
The crown-of-thorns starfish (CoTS, Acanthaster spp.), is responsible for a considerable amount of coral loss in the tropical Indo-Pacific region. After decimating coral populations through predation, it is expected that CoTS will face food scarcity before coral recovery. It is unclear how CoTS respond to starvation stress. Therefore, we conducted a four-month starvation stress experiment on CoTS, and analyzed the response characteristics of its stomach bacterial communities using high-throughput 16S rRNA sequencing. The results showed no significant differences in the α-diversity of the stomach bacterial community, but the β-diversity differed significantly between fed and starved CoTS. The bacterial community composition in the CoTS stomach changed dramatically, manifesting mainly from Tenericutes to Proteobacteria at the phylum level, and from a community dominated by digestive bacteria (Mycoplasma) to beneficial bacteria (Endozoicomonas) at the genus level. Furthermore, co-occurrence network analysis revealed that starvation reduced the network stability of the bacteria community, but improved network modularity, which may have contributed to the CoTS adaptation to chronic starvation. This study provides a basis for elucidating the mechanism of starvation resistance in the crown-of-thorns starfish.