Zoological Studies

Vol. 51 No. 2, 2012

Diverse Interactions between Corals and the Coral-Killing Sponge, Terpios hoshinota (Suberitidae: Hadromerida)

Jih-Terng Wang1,*, Yi-Yun Chen1, Pei-Jie Meng2,3, Yu-Hsuan Sune3, Chia-Min Hsu4, Kuo-Yen Wei1, and Chaolun Allen Chen4,5,6

1Graduate Institute of Biotechnology, Tajen Univ., Pingtung 907, Taiwan
2National Museum of Marine Biology and Aquarium, Pingtung 944, Taiwan
3Institute of Marine Biodiversity and Evolution, National Dong Hwa Univ., Checheng, Pingtung 944, Taiwan
4Institute of Oceanography, National Taiwan Univ., Taipei 108, Taiwan
5Biodiversity Research Center, Academia Sinica, Nangang, Taipei 115, Taiwan
6Taiwan International Graduate Program (TIGP)- Biodiversity, Academia Sinica, Nangang, Taipei 115, Tawian

Jih-Terng Wang, Yi-Yun Chen, Pei-Jie Meng, Yu-Hsuan Sune, Chia-Min Hsu, Kuo-Yen Wei, and Chaolun Allen Chen (2012) Terpios hoshinota is an encrusting sponge which can kill corals by overgrowing them. However, little is known about interactions between sponges and corals. Using visual observations and scanning electron microscopy (SEM), 4 features, including hairy tips, thick tissue threads, compact edges, and disintegrated tissues, displayed at the coral-facing front of Terpios were summarized from examining 20 species of corals. Hairy tips, found on 13 species of coral victims, were occupied by cyanobacteria, sponge tissues, and spicules. Thick tissue threads, found on only 7 coral species, were obviously an extension of Terpios tissues. Twelve coral species displayed a compact edge at the Terpioscoral border, in which some Terpios fronts had extruding spicules. Disintegrated tissue was only found on the coral side in 5 species of coral, but that on the sponge side was only found on 1 coral species. Only a few disintegrated tissues being found at the Terpios-coral border suggests that allelochemicals are not the major player in Terpios-coral interactions. The interactions also did not display species specificity, except in the case of Terpios having been retrogressively grown over by a coral, which was only found in Millepora exaesa. Under SEM examination, coral nematocysts were usually found on the surface of the invading Terpios, but they did not seem to retard the growth of the sponge. In summary, exploitation of the substratum by T. hoshinota on coral does not move forward in a consistent manner. The performance of Terpios, such as when overgrowing a coral, building a clear border, or being retrogressively overgrown by a coral, may rely on the viability status of both organisms.

Key words: Terpios, Cyanobacteria, Coral-killing sponge, Substrata competition.

*Correspondence: Tel: 886-8-7624002. Fax: 886-8-7621645. E-mail:jtw@mail.tajen.edu.tw