Widespread Occurrence of a Rarely Known Association between the Hydrocorals <i>Stylaster roseus</i> and <i>Millepora alcicornis</i> at Bonaire, Southern Caribbean

• Main Authors: Simone Montano, James D. Reimer, Viatcheslav N. Ivanenko, Jaaziel E. García-Hernández, Godfried W.N.M. van Moorsel, Paolo Galli, Bert W. Hoeksema
• Format: Article
• Language: English
• Published: MDPI AG 2020-05-01
• Series: Diversity
• Subjects: Caribbean Netherlands; fire corals; Hydrozoa; pseudo-auto-epizoism; stony corals; substrate
• Online Access: https://www.mdpi.com/1424-2818/12/6/218

Among symbiotic associations, cases of pseudo-auto-epizoism, in which a species uses a resembling but not directly related species as substrate, are poorly documented in coral reef ecosystems. In the present study, we assessed the distribution of an association between the hydrocorals <i>Stylaster roseus</i> and <i>Millepora alcicornis</i> on about 50% of coral reef sites studied in Bonaire, southern Caribbean. Although previously thought to be uncommon, associations between the lace coral <i>S. roseus</i> and the fire coral <i>M. alcicornis</i> were observed at both the windward and leeward sides of Bonaire, mainly between 15 and 25 m depth, reaching a maximum occupation of 47 <i>S. roseus</i> colonies on a single <i>M. alcicornis</i> colony. Both species’ tissues did not show any signs of injuries, while an in-depth inspection of the contact points of their skeletons revealed that both partners can partially overgrow each other. How it is possible that <i>S. roseus</i> is able to settle on the stinging tissue of <i>Millepora</i> as well as how, by contrast, the latter may facilitate the lace coral by offering a certain degree of protection are questions that deserve further investigations.