MEPS 545:135-145 (2016)  -  DOI: https://doi.org/10.3354/meps11602

Invasive décor: an association between a native decorator worm and a non-native seaweed can be mutualistic

Nicole M. Kollars1,2,4,*, James E. Byers3, Erik E. Sotka1,2

1Grice Marine Laboratory and the 2Department of Biology, College of Charleston, 205 Fort Johnson Road, Charleston, SC 29412, USA
3Odum School of Ecology, University of Georgia, 140 East Green Street, Athens, Georgia 30602, USA
4Present address: Center for Population Biology, University of California Davis, One Shields Avenue, Davis, CA 95616, USA
*Corresponding author:

ABSTRACT: The likelihood of invasion success increases when non-native species engage in mutualisms with a native or non-native species. Mutualisms formed between native and non-native species have been termed ’novel mutualisms’, and research in terrestrial systems has advanced our understanding of the ecological processes involved in their formation and persistence. However, documentation of novel mutualisms in marine systems is rare. In Atlantic estuaries of the southeastern USA, the native polychaete worm Diopatra cuprea actively decorates its tube with the non-native red seaweed Gracilaria vermiculophylla. We used field and laboratory experiments to test whether the Diopatra-Gracilaria interaction is mutualistic. We found that Diopatra facilitates Gracilaria by securing the seaweed onto the soft-sediment benthos within a favorable tidal elevation for growth and where hard substrata for attachment are otherwise rare. A combination of laboratory and field experiments also suggests that Gracilaria can enhance the growth of Diopatra by increasing access to epifaunal crustacean prey. However, field removal experiments showed that the benefits of Gracilaria to Diopatra only occurred in some sites and years. We found no evidence that this invader has a significant negative effect on Diopatra, and it appears in some instances to even benefit the worms, which suggests that Gracilaria (and its associated impacts on ecosystems) are likely to remain an important component of southeastern USA estuaries for the foreseeable future.


KEY WORDS: Biological invasion · Decoration association · Novel mutualism · Diopatra cuprea · Gracilaria vermiculophylla


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Cite this article as: Kollars NM, Byers JE, Sotka EE (2016) Invasive décor: an association between a native decorator worm and a non-native seaweed can be mutualistic. Mar Ecol Prog Ser 545:135-145. https://doi.org/10.3354/meps11602

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