Mucus-net feeding behavior by the sessile gastropod Thylacodes adamsii (Gastropoda: Vermetidae)

Abstract

Vermetid gastropod Thylacodes adamsii secrete a mucus net for feeding. We observed a feeding behavior of T. adamsii in the intertidal zone of Shirahama, the coast facing the Pacific Ocean. Thylacodes adamsii spread its mucus net within 20minutes of submergence. Creating a network of mucus threads immediately after submergence may be important for efficient feeding when T. adamsii is distributed in the intertidal zone. Additionally, we investigated the organisms trapped in the mucus net, because identifying the species from the stomach contents of T. adamsii was difficult. The organisms trapped on T. adamsii mucus nets in Shirahama included Dinophyta, Nematoda, Annelida, Arthropoda, Gastropoda, Chordata, and particles of seaweeds. By contrast, the most frequently trapped organisms in Maizuru, the coast facing the Sea of Japan, were diatoms. The difference between organisms trapped in Shirahama and Maizuru is probably due to the different vertical distribution of T. adamsii at the two locations.