http://www.robertosozzani.it/Utila/gorgon.html
Quote from
Sweeper Tentacles in a Gorgonian Octocoral:
Morphological Modifications for
Interference Competition
KENNETH P. SEBENS AND JULIA S. MILES
Northeastern University, Marine Science Center, Nahant, Massachusetts 01908
The encrusting gorgonian Erythropodium caribaeorum
Pallas (Octocorallia: Gorgonacea) is abundant on shal
low reefs in the Caribbean, and competes for space with
numerous coral species, sea anemones, and other cnid
arians. Zones ofcontact between this gorgonian and sev
eral coral species were observed and recent damage to
the coral colonies was noted. Furthermore, the gorgo
nian develops fields of modified polyps along such bor
ders. These polyps have elongate tentacles termed
‘¿sweetpeenrtacles,' as in scleractinian corals. Such tenta
des lack the side branches (pinnules) characteristic of oc
tocorals in general, and bear a bulbous tip (acrosphere)
densely packed with nematocysts. Transplant experi
ments showed damage to corals placed in contact with
the gorgonian's sweeper tentacles and sweeper tentacles
were induced when scleractinian corals contacted Ery
thropodium colony borders having exclusively normal
tentacles. Thus, sweeper tentacles may contribute to the
competitive success of this species in habitats where
space is limiting and where there are a number of
competing species, many with agonistic mechanisms of
their own.