Attack intensity by two species of territorial dam

Authors: A Black V Imhoff J Leese S Weimann J Gumm M Richter M Itzkowitz

Publish Date: 2013/12/28

Volume: 32, Issue: 2, Pages: 63-68

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Abstract

The intensity of interspecific territorial defense should be based upon the degree of competitive overlap We tested this relationship in two territorial Caribbean damselfish dusky Stegastes adustus and longfin S diencaeous with intruders being the bluehead wrasse Thalassoma bifascatus and the slippery dick wrasse Halichoeres bivittatus Based on food habits the slippery dick and the bluehead wrasse should have the same degree of competitive overlap to the two damselfish species We also predicted that the larger slippery dick wrasse intruder would receive more aggression than the smaller bluehead wrasse intruder Neither damselfish species distinguished between the two wrasses suggesting that they were ecologically equivalent We also tested size differences within both species of wrasse and found that size had no influence on the aggression in the dusky damselfish The longfin also did not show a size preference for the bluehead but did prefer to attack the larger slippery dick wrasse In spite of the similarities between the dusky and the longfin damselfish and the similar food habits of the bluehead and the slippery dick wrasse our results suggest that using intensity of interspecific territorial defense alone may not be an adequate measure of competitive overlap

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