Hopkins Marine Station Student Paper

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(full paper is archived in the Miller Library)

Title: The natural history of the tube-dwelling polychaete, Diopatra ornata.
Student Author(s): Josling, Catherine
Faculty Advisor(s): Watanabe, Jim
Pages: 26
Location: Final papers Biology 175H
Date: June 2002
Abstract: Diopatra ornata is a tube-dwelling polychaete commonly found in sandy subtidal regions from Mexico to California. Despite their abundance, little information has been published about D. ornata. This study examined tube construction, locomotion, feeding habits, and activity patterns of D. ornata, and its ability to regenerate lost or damaged regions of its body. D. ornata construct elaborate sand and mucus tube caps that are anchored in the sand and arch over with the aperture ~1 cm above the sand and facing downward. Worms attach pieces of shell and drift kelp to the tube cap and can add on as much as 6 cm of new tube in one day. The portion of the tube that extends down into the substratum is more fragile and runs ~ horizontally at a depth of ~10 cm below the surface of the sand. The worms move up and down inside their tubes using parapodia and can turn around completely inside it. They can extend their bodies up to approximately 8 cm from the aperture of the their tube to retrieve food or tube building material, but can quickly withdraw by sudden muscle contraction. They were never observed to leave their tubes completely. When foraging, D. ornata sit at the aperture of their tube cap and undulate their 5 cephalic cirri rapidly. They appear to sense the presence of food nearby using chemoreception or touch. Time lapse video showed that the worms have distinct day-night patterns of activity, with feeding or working on the buried portion of their tubes as the primary diurnal activity, and repair or addition to the tube cap at night. Regeneration of a head appears to require anterior segments with gills; more posterior sections of the body died and deteriorated within 2 days. Sections maintained in natural or artificial tubes (plastic straws) appeared to survive longer, but did not show any signs of regeneration in 22 days. Further study is needed to more fully understand some of these behaviors and examine other behaviors, such as their reproduction.