Interpopulation and context-related differences in responses of a marine gastropod to predation risk

We conducted laboratory experiments to investigate interpopulation differen ces in the behavioural responses of the whelk Buccinum undatum to the preda tory lobster Homarus americanus and the asteroid Leptasterias Polaris, both in the absence and presence of feeding opportunities. Whelks from three po pulations in the eastern North Atlantic (1) responded to lobsters by displa ying avoidance behaviours (burrowing in the sediments or retreating inside their shell), (2) responded to asteroids by displaying escape responses (ra pid crawling, shell rocking behaviour or foot contortions), and (3) more of ten refrained from feeding in the presence of a lobster than in the presenc e of an asteroid. Although whelks from the three populations responded simi larly to lobsters and asteroids, interpopulation differences were evident. Thus, whelks from populations sympatric with a given predator more frequent ly displayed 'appropriate' antipredator behaviours (i.e. avoidance in the p resence of a lobster, and escape in the presence of an asteroid) than did w helks allopatric with that predator. Also, whelks from a population sympatr ic with both predators fed less readily in the presence of a given predator than did whelks allopatric with that predator. However, the presence of a lobster or an asteroid had the same impact on the feeding response of whelk s from two populations with contrasting predator fields, one sympatric with lobsters, but allopatric with asteroids, and one sympatric with asteroids, but allopatric with lobsters. The results of our study indicate that coexi stence (over evolutionary or ecological time) with lobsters and asteroids i ncreases the propensity of the whelk to display avoidance and escape behavi ours in the presence of lobsters and asteroids, respectively, but has a les s predictable effect on how whelks trade off predation risk and food acquis ition. Studies are needed to investigate the roles of nheritance and experi ence on the development of antipredator behaviours and decision making by p rey animals when predation risk conflicts with other fitness-related activi ties such as the acquisition of food or reproductive opportunities. (C) 199 9 The Association for the Study of Animal Behaviour.