ASSOCIATION OF BENTHIC FORAMINIFERA WITH A GAMMARID AMPHIPOD ON TIDALFLATS OF SAN-FRANCISCO BAY, CALIFORNIA

The gammarid amphipod Oligochinus lighti Barnard is an abundant and co nspicuous component of the intertidal benthic fauna in San francisco B ay, California. This crustacean lives protected in an agglutinated tub e, feeding mainly on diatoms and smaller metazoans. Five foraminiferal species were observed as epizoans either attached or free-living at t he outer surface of the host's tube. The epizoic association of benthi c foraminifera with a filter-feeding invertebrate is considered advant ageous in terms of access to increased trophic resources, provision of otherwise limited hard substrates, and possibly shelter. Host selecti on, benefits and constraints of foraminifera/invertebrate associations are reviewed briefly.