Chemical and structural defensive external strategies in six sabellid worms (Annelida)

Authors

  • Adriana Giangrande,

    Corresponding author
    1. Dipartimento di Scienze e Tecnologie Biologiche ed Ambientali, Università del Salento, Lecce, Italy
    • Correspondence

      Adriana Giangrande, Dipartimento di Scienze e Tecnologie Biologiche ed Ambientali, Università del Salento, via Prov.le Lecce Monteroni, 73100 Lecce, Italy.

      E-mail: adriana.giangrande@unisalento.it

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  • Margherita Licciano,

    1. Dipartimento di Scienze e Tecnologie Biologiche ed Ambientali, Università del Salento, Lecce, Italy
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  • Roberto Schirosi,

    1. Dipartimento di Scienze e Tecnologie Biologiche ed Ambientali, Università del Salento, Lecce, Italy
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  • Luigi Musco,

    1. Laboratorio di Ecologia Marina, Istituto per l'Ambiente Marino Costiero, CNR, Castellammare del Golfo, Trapani, Italy
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  • Loredana Stabili

    1. Dipartimento di Scienze e Tecnologie Biologiche ed Ambientali, Università del Salento, Lecce, Italy
    2. Istituto per l'Ambiente Marino Costiero, Sezione di Taranto, CNR, Taranto, Italy
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Abstract

In the marine environment, sessile invertebrates have developed an impressive array of mechanisms to avoid predation, bacterial exploitation, and epibiotic overgrowth. In the present study we investigated several defensive strategies adopted by six sabellids: the hard bottom species Sabella spallanzanii (Gmelin, 1791), Branchiomma luctuosum Grube, 1869, Branchiomma bairdi (McIntosh, 1885), and Sabellastarte spectabilis (Grube, 1878), and the soft bottom species Myxicola infundibulum (Renier, 1804), and Megalomma lanigera (Grube, 1846), which have different morphological characteristics and geographical distribution. We examined and compared some defensive features such as branchial crown toughness, tube structure and strength, amount of released mucus, and antibacterial lysozyme-activity in the mucus. The investigated species utilize a combination of defence and deterrence strategies that seems to be related to the colonized habitat. Tube strength was, higher in the hard bottom species compared with the soft bottom ones, where the tubes are generally buried and protected within the sediment. Branchial crown appeared stronger and resistant in hard bottom species, except for S. spallanzanii, which is the species showing the strongest tube. Sabella spallanzanii, M. infundibulum and S. spectabilis secreted high amount of mucus with high lysozyme-like activity. By contrast, B. luctuosum, B. bairdi, and M. lanigera produced low amounts of mucus exerting lower antibacterial activity.

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