Trophic niche partitioning in marine wood-borers revealed by stable isotope analysis

Marine wood-borers often live in sympatry, sharing deadwood scattered at sea, both as food and habitat. In this study, carbon and nitrogen isotope compositions were determined to test the hypothesis that the trophic niches of Chelura terebrans, Limnoria quadripunctata, and Nototeredo norvagica obtained from softwood boards maintained in running, unfiltered seawater are different. Comparison of isotope compositions supports niche partitioning, with N. norvagica foraging primarily on wood, and crustaceans foraging on decaying wood. Needs and acquisition routes for nitrogen determine the trophic behavior of the species. Results presented here are valuable for assessing the impact of wood-boring species on each other, but also for evaluating the effect of the separation of carbon and nitrogen sources on the diversity of the interactions between co-existing species belonging to the same trophic guild.