Meeting Abstract

9.0  Jan. 4  Energy maximization strategies of two surface deposit-feeding gastropods. MAHON, H. K. *; DAUER, D. M.; Old Dominion University; Old Dominion University hmahon@odu.edu

Surface deposit-feeders rely on a poor food source; therefore, many have evolved strategies to increase sediment processing efficiency and to maximize net energy gain. Two strategies are patch selection and particle selection. This study looked at patch and particle selection of two common gastropods, Littoraria irrorata and Ilyanassa obsolete, which feed upon deposited sediments. For patch selection, time spent on each patch was recorded for a total time of 10 minutes. The results show both gastropods spent more time on organically-coated patches over uncoated patches and more time on large-particle patches over small-particle patches. For particle selection, gastropods were allowed to feed on a mixture of particles for 3 hours. Afterwards, their guts were dissected into four parts (i.e. esophagus, stomach, digestive gland, and intestine) and the ratio of beads was determined. The results demonstrate L. irrorata showed no difference in particle ratio between the esophagus, stomach, intestine, and ambient sediment. However, the digestive gland showed more coated particles and also more small particles, indicating internal particle selection. Ilyanassa obsoleta showed no difference in particle ratio between the gut and the ambient sediment. The differences seen may be attributed to both ecological and phylogenetic differences between the gastropods.