Meeting Abstract

P1-116   -   Using Natural Intraspecific Variation to Determine the Functional Relationship Between Larval Phenotypes and Predation Rate in Streblospio benedicti Rios, C*; Rockman, M; New York University ; New York University cr2663@nyu.edu

Marine invertebrates undergo either planktotrophic or lecithotrophic development. Planktotrophic larvae are born in large numbers from small eggs, requiring relatively little energy investment from the parent per larva, and they feed in the water column until metamorphosis. Lecithotrophic larvae are born in small numbers from larger eggs, requiring a greater energy investment per larva, and settle directly into the benthos. Beyond body size, planktotrophic larvae also have distinct morphological features lost during metamorphosis that differ from the lecithotrophic larvae. One such feature is the presence of chaetae. This has been proposed to function in larval defense against size-selective predators by increasing the size of the larvae. Streblospio benedicti is a marine polychaete that occurs naturally in populations of either planktotrophic or lecithotrophic larval developmental modes. Previous studies have determined that larval size is dependent on the maternal genotype and have mapped the maternal loci that affect this trait. Unlinked, zygotically acting loci that influence aspects of larval morphologies have also been identified. The unique genetic components of larval size and morphology in S. benedicti allow us to investigate the effect of larval phenotypes on the rate of predation independent of larval size. We are testing whether the presence, length, and number of larval chaetae influence the survivorship of S. benedicti larvae exposed to predation. Larvae are imaged and measured using a modified Planktoscope, a flow-through microscope system. In addition, we are testing whether predation pressure results in changes in allelic frequencies at loci found in previous studies to be associated with chaetae morphologies. The aim of this research is to test the influence of the different larval phenotypes of benthic marine invertebrates on ecological fitness.