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Interindividual Variation in Prey Selection by the Snail Nucella (= Thais) Emarginata
Author(s) -
West Lani
Publication year - 1986
Publication title -
ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.144
H-Index - 294
eISSN - 1939-9170
pISSN - 0012-9658
DOI - 10.2307/1937702
Subject(s) - nucella , predation , biology , snail , littorina , intertidal zone , ecology , foraging , population , gastropoda , predator , range (aeronautics) , zoology , demography , sociology , materials science , composite material
Variation in diet among individuals of a population of carnivorous marine snails in a rocky intertidal environment of central California was analyzed. Nucella emarginata drills and eats barnacles, mussels, and limpets. Out of 128 marked snails, 104 were observed through two or more feeding attacks in the field during the 4—mo study. Fifty—one of these snails were observed through five or more sequential feeding attacks. Three major points are illustrated. (1) Within each study site, individuals close to the same size often chose strikingly different diets. (2) There was a range of dietary specialization and generalization among individuals foraging in the same habitat. Individuals showed a high degree of consistency in their diets. While the population of N. emarginata attacked seven prey species at site A and four prey species at site B, no individual snail observed in this study ate more than three species of prey. (3) Food choices made by each individual were not a simple reflection of the relative abundance of the surrounding prey species or the differences in microhabitat prey distribution that each predator encountered. These conclusions remained the same for several different methods of measuring prey availability. I suggest that Nucella emarginata diet patterns have a variety of causes, which may include ingestive conditioning, learning, and genetic variability.