Meeting Abstract
The distinction between self and non-self is important for all animals. Certain species of sea anemone live in tightly packed communities, among clonemates and non-clonemates. Competition for space leads to intraspecific and interspecific aggressive interactions among anemones. The initial aggressive interactions appear to involve reciprocal discharge of cnidae triggered by contact with non-self feeding tentacles. In this study, we found that anemone mucus sensitizes cnida discharge. Interspecific mucus significantly enhances nematocyst discharge twofold and spirocyst discharge fourfold relative to baseline values obtained in seawater alone. Conspecific mucus does not enhance cnida discharge relative to baseline values. These data suggest that anemone mucus contains one or more components that specifically are involved in self, non-self recognition as related to cnida discharge. Hence, cnidae in feeding tentacles are employed as weapons among anemones engaged in aggressive interactions. Recognition of non-self begins before the anemones move into direct contact with each other. Surprisingly, the disproportionately larger enhancement of spirocyst discharge as compared to nematocyst discharge suggests that spirocysts may be an effective weapon among anemones despite the commonly held view that spirocysts are most effective when discharged onto hard substrates.
