Note
In rocky subtidal habitats of the Sanjuan Islands, Washington, the solitary ascidian Boltenia villosa
occurs primarily as an epizooite on two other ascidians, Pyura haustor and Halocynthia igaboja, where
it obtains refuge from the abundant predatory gastropod Fusitriton oregonensis. To investigate the
prediction that larvae of this species should prefer refuge habitats as settlement sites, l offered
choices among various "safe" and "unsafe" substrata to the tadpole larvae ofB. villosa in laboratory
experiments. Tadpoles selected tunic of the refuge ascidians significantly more often than subtidal
rocks or other substrata, but did not distinguish between refuge ascidians and conspecific adults.