Meeting Abstract
Many gastropod species have inducible defenses when exposed to chemical cues from predators. This plasticity is known to manifest in traits like shell growth, thickness, and shape. However, only a few studies have examined shell microstructural responses to predators and these only quantified microstructure at or near the aperture, ignoring remodeling or thickening of the body and apical whorls. The various types of molluscan shell microstructures are known to have different biomechanical properties and could alter the role of the shell as a defense against predators. I experimentally tested if there are inducible microstructural differences in Littorina littorea in response to the invasive predatory crab Hemigrapsus sanguineus and in response to a lower growth rate. Snails from three Long Island Sound populations were used in the experiment to detect differences in response to the predator and reduced growth, as well as overall differences in thickness of microstructural layers among these populations. L. littorea shells are composed of two types of microstructure: 1) an outer irregular prismatic layer composed of calcite, and 2) an inner crossed lamellar microstructure made of aragonite. Microstructure was quantified using sections through the aperture and through the columella, allowing me to determine microstructural plasticity throughout the entire shell. Preliminary results suggest differences in thickness of layers among populations with one population with a thinner crossed lamellar layer, especially near the apex.
