THE ECOLOGY OF ENGINA-ARMILLATA (GASTROPODA, BUCCINIDAE) IN THE CAPE-DAGUILAR-MARINE-RESERVE, HONG-KONG, WITH PARTICULAR REFERENCE TO ITS PREFERRED PREY (POLYCHAETA, SERPULIDAE)

The egg capsules and larvae of Engina armillata (Reeve) (Gastropoda: B uccinidae) are described for the first time. Its general ecology in th e Cape d'Arguilar Marine Reserve, Hong Kong, is also described, the sp ecies occurring under stable boulders with a community of encrusting s pecies, notably sedentary tubicolous polychaetes. The diet of E. armil lata at Cape d'Aguilar consists of serpulid and spirobid polychaetes. Of the four commonest such species, Hydroides elegans was preferred to Pomatoleios kraussi, Simplicaria pseudomilitaris and Spirorbis forami nosus. Consumption rates by E. armillata varied considerably amongst i ndividuals, but generally ranged between 1.2 and 6.5% of predator dry weight day(-1) during conditions wherein prey quantity was maintained. Such a figure is low when compared to other boring naticid and murici d predatory gastropods which spend much time and energy accessing thei r prey. The ready availability of easily accessible prey may account f or the low consumption rate of E. armillata (as also seen in other non -boring predatory gastropods) and explain its apparent specialist feed ing habits.