Meeting Abstract

52.2  Saturday, Jan. 5  Feeding patterns and their implications for energy budgets in tropical limpets BURNETT, NP*; HELMUTH, B; VILLARTA, K; WILLIAMS, GA; Univ. of California, Berkeley; Univ. of South Carolina; Hong Kong Univ.; Hong Kong Univ.

Energy budget models are often used to understand and predict the metabolic responses of species to environmental variation, such as global warming. The robustness of these models is based on an understanding of patterns of energy gain and expenditure of the modeled organisms, but such measurements can be imprecise for species with complex or poorly understood behavior patterns. Applying these models to keystone species can help predict community-wide responses to environmental variation, especially in the intertidal zone, where many species live near lethal limits of stress. Limpets (Cellana spp.) are keystone grazers in the high intertidal zones of the tropics. Most intertidal grazers forage while submerged or splashed, so their activity patterns are closely limited by the tidal cycle. These constraints have been incorporated into behavior models of Cellana, but little is known of their feeding rates and ingestion, remaining a ‘blackbox’ in the models. Using an accelerometer-based contact microphone, we recorded the feeding patterns (rasping sounds) of Cellana on the shore over several tidal cycles. Limpets fed at a rate of 80 – 100 rasps per minute (rpm) while moving up with the flooding tide, became inactive near slack tide, and then fed again at 80 – 100 rpm while moving down the shore with the ebbing tide. These data are consistent with the prediction of a model of digestion mechanics that limpets are volume-limited grazers, rather than energy-limited foragers. Refining estimates of energy intake using field-based measurements of foraging can help tailor energy budget models, such as Dynamic Energy Budget Models (DEBM), to specific species and improve our ability to forecast energetic consequences of environmental change.