BERKE, SK; WOODIN, SA; University of South Carolina; University of South Carolina: Self-decoration: An Onuphid polychaete example

Behaviors with analogues across phyla suggest the existence of fundamental processes which drive behavioral evolution. Knowledge of such processes allows us to develop a theoretical framework in which to consider behavioral evolution in diverse systems. Behaviors spanning taxa thus warrant close investigation. One such behavior is self-decoration. Self-decoration is observed in a variety of terrestrial, freshwater and marine invertebrates including several insect species as well as some crustaceans, gastropods, anthozoans, echinoderms and polychaetes. A polychaete system which lends itself to study is the tube-building marine worm Diopatra cuprea. Diopatra tubes terminate in large tube caps decorated with pieces of debris from the water column. Several hypotheses have been offered to explain why Diopatra decorate their tubes, but few rigorous tests have been attempted. A series of experiments were conducted to investigate two such hypotheses: 1) that decoration makes the cap cryptic and 2) that decoration enhances the worm’s ability to discriminate among physical disturbances applied to the cap. If decoration makes the cap more cryptic, one expects undecorated caps to experience fewer predation attacks than decorated caps. This prediction was tested using field and laboratory predation experiments. If decoration enhances the worm’s ability to discriminate among disturbances, then one expects worms in undecorated caps to respond differently to disturbances than worms in decorated caps. Diopatra with and without decoration were disturbed in the field and their behavioral responses were measured. These data, combined with data from other systems, suggest commonality among the suite of factors that can give rise to self-decorating behaviors.