Hunger rapidly overrides the risk of predation in the subtidal scavenger Nassarius siquijorensis (Gastropoda : Nassariidae): an energy budget and a comparison with the intertidal Nassarius festivus in Hong Kong

This study shows that, as with its intertidal counterpart, Nassarius festiv us, the rate at which subtidal Nassarius siquijorensis moves towards food b ait is similar for starved and well-fed individuals. This study also invest igates another facet of nassariid nutrition related to the degree of hunger , i.e. the effect of simulated predation upon a feeding assemblage. Individ uals which fed within 7 days, cease feeding and depart palatable food if cr ushed conspecifics are added. Between 7 and 13 days since its last meal, ho wever, N. siquijorensis will feed when food is available, despite the possi bility of predation. For the intertidal N. festivus, the critical time for hunger to override the risk of predation is between 14 and 21 days. The dif ference between subtidal and intertidal species may be due to a difference, in terms of days, that a meal can provide for their energy expenditure, pa rticularly with regard to respiration. The bigger, subtidal, N. siquijorens is needs to feed more frequently than the smaller, intertidal, N. festivus. (C) 1999 Elsevier Science BN. All rights reserved.