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

Abstract

This study shows that, as with its intertidal counterpart, Nassarius festivus, the rate at which subtidal Nassarius siquijorensis moves towards food bait is similar for starved and well-fed individuals. This study also investigates another facet of nassariid nutrition related to the degree of hunger, i.e. the effect of simulated predation upon a feeding assemblage. Individuals which fed within 7 days, cease feeding and depart palatable food if crushed conspecifics are added. Between 7 and 13 days since its last meal, however, N. siquijorensis will feed when food is available, despite the possibility 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 difference between subtidal and intertidal species may be due to a difference, in terms of days, that a meal can provide for their energy expenditure, particularly with regard to respiration. The bigger, subtidal, N. siquijorensis needs to feed more frequently than the smaller, intertidal, N. festivus.