Tube morphology and activity patterns related to feeding and tube building in the polychaeteMesochaetopterus tayloriPotts

Abstract

Tube morphology and activity patterns related to feeding and tube building in Mesochaetopterus taylori Potts were examined using entire specimens and tubes. Tube orientation in situ at Patricia Bay, Vancouver Island, British Columbia, Canada, was typically L-shaped, and tubes were buried to and rarely coursing deeper than 30 cm, with only 1–2 cm of tube aperture exposed at the sand surface. Perforations were found in a distinctive thin-walled region at the buried apex of the tube, and were absent in the much thicker remaining tube length. Filter feeding using one or two mucus bags was observed, while posteriorly directed peristalsis in the abdominal segments generated a current from the exposed tube opening towards the buried tube apex. Thermistor-probe recordings of laboratory-held specimens showed feeding activity to be most prevalent during the day, one mucus bag, on average, being produced every 5.5 min. Mucus bags were also utilized to transport sand during excavation. Tube construction was noted to take place at the buried end of the tube, where old perforations were covered over and new perforations made as the tube was extended. The production of one sand casting per hour was noted in worms undertaking tube construction in laboratory aquaria. Our findings are compared with data available on other members of the Chaetopteridae.