Sandra Caldwell Marine and Estuarine Science Program Department of Biology MSc. Completed 2001 BSc.  Evergreen State College, 1999

Project

Title: Energetics of crawling and swimming in the hooded nudibranch Melibe leonina.
   
Abstract: The opisthobranch Melibe leonina both swims and crawls.  Elective response between these two modes make M. leonina a model organism for studies of gastropod locomotion.  The effect of activity on the metabolic rate of M. leonina was investigated in three phases: 1) oxygen consumption rates were measured during alert, crawling, and swimming states, 2) anaerobic energy output was investigated by measuring whole-body levels of anaerobic enzymes, and 3) estimates of net cost of transport (COT_net) for swimming and crawling were established.  Melibe leonina exhibited a two-fold increase in oxygen consumption between alert (234 ml O₂ h^-1 for a 10 g animal) and crawling (477 ml O₂ h^-1) states, and a six-fold increase in oxygen consumption between alert and swimming (1380 ml O₂ h^-1) states.  Opine dehydrogenases were not detected in whole body tissue and only low levels of lactate dehydrogenase (0.23 IU g wet tissue^-1 min^-1) were found.  This indicates that both swimming and crawling are supported aerobically in M. leonina.  Swimming COT_net (6 ml O₂ kg^-1 m^-1) and crawling COT_net (5 ml O₂ kg^-1 m^-1) were similar to each other.  However, when these values were compared to other swimming and crawling invertebrates, it was found that M. leonina displayed the typically high cost of gastropod crawling but swimming COT fell above the 95% confidence interval for energy costs associated with invertebrate swimming.