Inter-specific associations of coral reef organisms
An important key to the species-richness of coral reefs is formed by the complex of species interdependencies. Host-symbiont relationships appear very specific. This implies that in order to study the evolutionary history of species associations (phylogenetic ecology or phylo-ecology) for a better understanding of species-rich ecosystems, a good knowledge of both host and symbiont species groups is required. Such studies usually require the application of molecular (DNA) techniques in order to reveal sibling species and to indicate evolutionary inter-relationships.
Since one host species may be responsible for housing feeding many others, the loss of a single host species (coral, sponge or tunicate) may also result in the disappearance of dependent species, such as parasitic snails, commensal shrimps, gall crabs, boring mussels, etc. By systematic inventories of associated species and molecular studies on their phylogenies and those of the associated host organisms, more insight is obtained on the evolution of species interdependencies, their species richness and their risk of extinction.
Selected references 
Reijnen, B.T., B.W. Hoeksema & E. Gittenberger, 2010. Host specificity and phylogenetic relationships among Atlantic Ovulidae (Mollusca: Gastropoda). Contributions to Zoology 79: 57-66.
Samini Namin, K., M.J. Risk, B.W. Hoeksema, Z. Zohari, H. Rezai, 2010. Coral mortality and serpulid infestations associated with red tide, in the Persian Gulf. Coral Reefs 29: 509.
Hoeksema, B.W. & A. Gittenberger, 2008. Records of some marine parasitic molluscs from Nha Trang, Vietnam. Basteria 72: 129-133
Hoeksema, B.W. & S.E.T van der Meij (eds.), 2008. Cryptic marine biota of the Raja Ampat Islands group, pp. 1-74. Naturalis, Leiden.
Gittenberger, A. & E. Gittenberger, 2005. A hitherto unnoticed adaptive radiation: epitoniid species (Gastropoda: Epitoniidae) associated with corals (Scleractinia). Contributions to Zoology 74: 125-204.
Goud, J. & B.W. Hoeksema, 2001. Pedicularia vanderlandi spec. nov. (Gastropoda: Ovulidae), a symbiotic snail on the hydrocoral Distichopora vervoorti Cairns & Hoeksema, 1998 (Hydrozoa: Stylasteridae) from Bali, Indonesia. Zoologische Verhandelingen, Leiden 334: 77-97.
Hoeksema, B.W. & Achituv, Y., 1993. First Indonesian record of Fungiacava eilatensis Goreau et al., 1968 (Bivalvia: Mytilidae), endosymbiont of Fungia spp. (Scleractinia: Fungiidae). Basteria 57: 131-138.
Hoeksema, B.W. & M.B. Best, 1991. New observations on scleractinian corals from Indonesia: 2. Sipunculan-associated species belonging to the genera Heterocyathus and Heteropsammia. Zoologische Mededelingen, Leiden 65: 221-245.
Hoeksema, B.W. & K. Kleemann, 2002. New records of Fungiacava eilatensis Goreau et al., 1968 (Bivalvia: Mytilidae) boring in Indonesian mushroom corals (Scleractinia: Fungiidae). Basteria 66: 25-30.
Kleemann, K. & B.W. Hoeksema, 2002. Lithophaga (Bivalvia: Mytilidae), including a new species, boring in mushroom corals (Scleractinia: Fungiidae) at South Sulawesi, Indonesia. Basteria 66: 11-24.
Wednesday, June 2, 2010