DISTRIBUTION OF SWEEPER TENTACLES ON MONTASTRAEA CAVERNOSA 



Elizabeth A. Chornesky 

 Division of Biological Sciences, The Univ. of Texas, Austin 78712 



Susan L . Willi ams 

 Mar. Sci. Res. Ctr., State Univ. of New York, Stony Brook, NY 11794 



ABSTRACT 



I 

 spac 

 cni d 

 desc 

 but 

 the 

 swee 

 whic 

 enco 

 cong 

 both 

 of s 

 enco 



n d i 

 e, s 

 ae, 

 ri be 

 deve 

 Cari 

 per 

 h do 

 unte 

 ener 

 the 

 weep 

 unte 



rect 

 ome s 



r sw 

 d thu 



1 op a 

 bbean 

 tenta 



not 

 rs . 

 i c sp 



numb 

 er te 

 r . 



com pet i 

 p e c i e s 

 eeper t 

 s f ar , 

 s compe 

 reef c 

 c 1 e s d i 

 necessa 

 Neverth 

 eci es M 

 er of p 

 ntacl es 



ase 



INTRODUCTION 



Reef corals are known to use a variety of mechanisms to compete 

 for limited substrate space in crowded reef environments. Two of 

 the best described are the use of mesenterial filaments (Lang, 

 1971, 1973; Sheppard, 1979) or of "sweeper tentacles" (Richardson, 

 et al., 1979; Wellington, 1980; Bak , _et _al_., 1982; Chornesky, 

 1983~J by some corals to damage the tissues of neighboring corals. 



Mesenterial filaments are normally present in all polyps of 

 every coral. When corals of different species are placed into 

 direct contact, these digestive filaments are deployed rapidly 

 and extracoel enteri c digestion of opponent tissues may take place 

 within hours (Lang, 1971, 1973; Sheppard, 1979). The immediate 

 "winner" (i.e., the animal remaining undamaged) in such interactions 

 is generally predictable among various species pairs. Unlike 

 mesenterial filaments, sweeper tentacles (elongate tentacles with 

 specialized cnidae) are found only on certain species of coral 

 (see Lewis and Price, 1975; Bak and Elgershuizen, 1976). Moreover, 

 within these species, sweepers may not be present on all colonies, 

 and, when present, may be erratically distributed over the colony 

 surface. On some corals, sweeper tentacles develop specifically 

 after damage by mesenterial filaments (Wellington, 1980; Bak, e_t 

 al., 1982; Chornesky, 1983) or after contact with recognition 

 XChornesky, 1983) of other corals. In natural interactions, this 

 delayed development, and thus the ability of the coral to utilize 

 sweepers against a neighbor, occurs some time after the interaction 

 has begun (on the order of a month--Wel 1 i ngton , 1980; Bak, ejt 

 al . , 1982; Chornesky, 1983). However, on at least one species of 



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