Meeting Abstract

10.4  Monday, Jan. 4  Feeding metabolics and prey capture in newly emerged tarantula spiderings (Theraphosa leblondi). SHILLINGTON, Cara; Eastern Michigan University cshilling@emich.edu

For most animals, an integral portion of their energy budget is associated with foraging and the metabolic response that accompanies digestion and food assimilation (=specific dynamic action (SDA)). Previous studies have shown that the magnitude and duration of SDA is influenced by many factors including meal size and composition as well as various environmental factors and body size of the predator. In this study, I examined the SDAs of naïve predators feeding for the first time. Model animals for this study were tarantula spiders (Theraphosa leblondi) that had just emerged from their eggsac. I measured resting metabolic rates (RMRs) over three successive molts as well as SDAs after their first feeding and again after their next molt. Spiderlings were divided into three groups that received prey that varied in proportion to tarantula body mass (Group 1: 5-15%, Group 2: 25-35%, Group 3: 45-55%). In addition, I compared prey capture times over successive feedings trials to determine the role of experience in hunting success. Few differences were found between the two higher feeding groups in either metabolic rates or body mass. However, Group 1 had significantly lower body mass after their second molt post-emergence and had lower RMRs and thus a higher scope. Among all three groups, prey capture times were faster at their second feeding compared to their first feeding.