The Crown-of-Thorns Starfish (Acanthaster spp.), a native inhabitant of the Indo-Pacific coral reefs, has long been recognized for its pivotal and paradoxical role in reef ecosystems. Under normal population levels, CoTS contribute to reef health by regulating coral species composition, yet their periodic outbreaks—where populations explode to destructive densities—pose one of the greatest threats to coral reef resilience worldwide. These massive swarms consume vast tracts of coral, undermining the reef’s structural integrity and its ability to withstand escalating stressors such as global warming and ocean acidification. Understanding and managing these outbreaks is therefore critical to preserving reef ecosystems in the Anthropocene.
Directly addressing the challenge of controlling CoTS outbreaks, a groundbreaking multidisciplinary study has revealed the starfish’s ability to detect chemical peptides through their spiny appendages—a sensory modality never before fully understood in this species. This discovery was led by research groups from the Australian Institute of Marine Science (AIMS), the University of the Sunshine Coast, and the Okinawa Institute of Science and Technology (OIST). They identified that CoTS spines not only serve as defensive structures but are also specialized organs for both sensing and secreting a complex array of bioactive peptides, some of which act as chemical cues that influence conspecific behavior beyond reproductive contexts.
Building upon this insight, the researchers synthesized peptides that mimic these naturally occurring chemical signals—termed Acanthaster attractins—that are capable of enticing CoTS at minute concentrations without eliciting toxic effects. In meticulously designed experimental assays, including toxicity tests with Artemia salina larvae, the synthetic peptide mixtures showed negligible lethality, confirming their safety for broader ecological applications. Behavioral assays in controlled flume tanks further demonstrated that CoTS are strongly attracted to streams infused with these synthetic peptides, spending significantly more time and exhibiting enhanced searching behaviors within these chemical gradients.
The implications of these findings for marine conservation and pest management are substantial. Currently, attempts to control CoTS populations primarily involve labor-intensive manual culling, which has limited efficacy across the vast and often inaccessible reef structures. The potential to lure aggregations of starfish using synthetic attractins could revolutionize management strategies by enabling coordinated removal of large groups, thus amplifying the impact of control efforts while reducing required human labor and associated costs.
At the molecular level, the research team employed advanced genomic and proteomic analyses to elucidate the range of peptides expressed and secreted by CoTS spines. Surprisingly, these peptides extend far beyond previously characterized defensive toxins, suggesting a sophisticated chemosensory communication system akin to pheromonal signaling found in other invertebrate taxa. This communication likely underpins behaviors critical to survival and reproduction, including swarming and aggregation, which until now remained poorly understood.
Experimental data from swim-tank assays showed that when exposed to the synthetic peptide cues, CoTS not only altered spatial distribution but also demonstrated increased meandering—a foraging-related movement pattern facilitating source localization. This nuanced behavioral modulation underscores the potential utility of synthetic peptides as behavioral modifiers in ecological interventions. Furthermore, the biophysical properties of the flume tanks ensured minimal turbulence and diffusion, validating the specificity of the peptide’s chemotactic effect and reinforcing the findings’ ecological relevance.
The translational prospects of this research extend into the realm of ecological chemistry and marine biotechnology, as the development of non-toxic, peptide-based attractants could complement or even replace traditional chemical deterrents and manual removal methods. Importantly, these peptides’ specificity to CoTS reduces risks to non-target species, addressing a crucial conservation consideration.
Looking ahead, scalable synthesis and field trials of Acanthaster attractins will be pivotal to determine their efficacy across diverse reef environments and CoTS population dynamics. Such developments could align with integrated pest management frameworks, combining chemical ecology insights with ecological monitoring and localized intervention to restore coral reef balance more effectively.
Marine scientists have long grappled with controlling CoTS outbreaks due to the starfish’s complex life cycle, wide dispersal, and cryptic behavior. This seminal work offers a novel avenue by leveraging intraspecific chemical communication pathways, thereby expanding the toolkit available to reef managers. The ability to manipulate CoTS behavior through peptide signaling reflects an emerging trend in pest ecology: targeting communication systems to disrupt or redirect harmful species without ecological collateral damage.
Professor Noriyuki Satoh, leading the Marine Genomics Unit at OIST, emphasized the innovative nature of this research: “Our findings challenge the traditional view of CoTS spines as purely defensive structures. Instead, we reveal their dual role as both sensory and secretory organs mediating complex behavioral outcomes through peptide signaling. Such insights open transformative potentials for developing targeted, ecologically harmonious control measures.”
This research not only deepens fundamental understanding of starfish biology but also exemplifies how molecular and behavioral ecology can converge to address pressing conservation challenges. The synthesis of bioactive peptides based on naturally occurring chemical cues represents a promising frontier for managing marine pest outbreaks, with applications that may extend to other ecologically impactful invertebrate species.
In terms of practical application, deploying peptide attractants on reefs could facilitate coordinated removal efforts during early outbreak detection, potentially preventing the wide-scale destruction that has plagued Indo-Pacific coral ecosystems. By concentrating CoTS populations, these attractins could also enable more efficient monitoring and rapid response actions, minimizing the ecological and economic consequences of CoTS outbreaks.
In conclusion, this pioneering study heralds a new era of bio-inspired intervention strategies, transforming a nuanced understanding of crown-of-thorns starfish chemical ecology into tangible, sustainable solutions for reef conservation. As marine ecosystems face unprecedented threats, innovations such as synthetic peptide attractants offer hope for preserving the vibrant biodiversity and ecological functions of coral reefs worldwide.
Subject of Research: Animals
Article Title: A family of crown-of-thorns starfish spine-secreted proteins modify adult conspecific behavior
News Publication Date: 18-Apr-2025
Web References:
– https://www.sciencedirect.com/science/article/pii/S2589004225004225?via%3Dihub
– http://dx.doi.org/10.1016/j.isci.2025.112161
Image Credits: Harris et al., 2025
Keywords: Marine conservation, Coral reefs, Reef building corals, Pheromones, Conservation genetics, Peptide hormones, Synthetic peptides, Chemical signals, Pest control, Invertebrates
