Un tubo per due: associazione simbiotica tra i policheti Harmothoe spinifera (Polynoidae) e Eunice vittata (Eunicidae)

Abstract

Symbiosis indicates diversified interactions between organisms of different species living together in close association. In marine benthos, polychaetes are involved in symbiotic several associations, due to their abundance and distribution on the seabed. Here, we report the first observation of a commensalism association between the Polynoidae Harmothoe spinifera and the Eunicidae Eunice vittata in the southern Adriatic Sea, off the Apulian coast. The specimens of the two species were found inside the same single parchment tube, encrusted with sedimentary debris and produced by E. vittata. This finding can be considered a case of recently occurring commensalism as it has never been observed before, although they are both common species; moreover, it improved knowledge on the pattern of symbiotic interactions as commensalism of polynoids also extends to vagile polychaetes as hosts.