Macroalgae and interspecific alarm cues regulate behavioral interactions between sea urchins and sea cucumbers

Abstract

Sea urchins and sea cucumbers are mutually beneficial organisms in kelp ecosystem. As herbivores, sea urchins process kelp through feeding and egestion, providing inaccessible food for benthic consumers such as sea cucumbers. Sea urchins in turn profit from the sediment cleaned by sea cucumbers. However, behavioral interactions between them remain poorly understood, which greatly hampers our understanding on the relationship between ecologically important benthic species in marine ecosystems and the regulating mechanism. The present study investigated behavioral interactions between sea urchins Strongylocentrotus intermedius and sea cucumbers Apostichopus japonicus in laboratory conditions. We revealed that the presence of sea urchins caused significant higher speed movement of A. japonicus. Interestingly, the negative effects of S. intermedius on A. japonicus were significantly reduced in the shared macroalgal area. For the first time, we found the interspecific responses to alarm cues between sea cucumbers and sea urchins. Conspecific responses were significantly larger than the interspecific responses in both sea urchins and sea cucumbers. This indicates that interspecific response to alarm cues is an efficient approach to anti-predation and coexistence in mutually beneficial organisms. The present study shed light on the interspecific relationships and coexistence between sea urchins and sea cucumbers in kelp ecosystem.

Artificial Reefs Reduce Morbidity and Mortality of Small Cultured Sea Cucumbers Apostichopus japonicus at High Temperature

“…Lobsters use chemical cues from diseased individuals to determine whether the shelter is safe, and healthy lobsters rarely share the shelters with diseased lobsters [34]. Diseased sea cucumbers emit certain chemical cues for warning [33,35]. Sea cucumbers show escaping behavior after receiving alarm cues from diseased individuals [35,36].…”

“…Diseased sea cucumbers emit certain chemical cues for warning [33,35]. Sea cucumbers show escaping behavior after receiving alarm cues from diseased individuals [35,36]. Artificial reefs are possible places for escape due to their attraction to sea cucumbers [20,37].…”

Metabolome and Transcriptome Association Analysis Reveals the Link Between Pigmentation and Nutrition Utilization in the Juveniles of Sea Cucumber Holothuria leucospilota

“…As essential sweepers of the environment, sea cucumbers make signi cant contributions to the marine ecosystems through their feeding, excretion, and bioturbation processes, thereby maintaining the ecological balance in the recirculation and remineralization of organic matter in reef sands (Purcell et al, 2016, MacTavish et al, 2012. Sea cucumbers ful ll their role within the intricate food web as symbiotic, parasitic, and predatory organisms, enhancing species diversity and facilitating the cycling of nutrients (Larson et al, 2013, Purcell and Eriksson, 2015, Sun et al, 2022. Sea cucumbers are highly valued for their commercial value.…”