Chemical Signaling In An Inducible Offense

Abstract

Inducible phenotypic plasticity is the ability of an organism’s genotype to express different observable traits or phenotypes, such as morphology, over and individual’s lifespan. The snails Lacuna vincta and L. variegata produce two different tooth morphologies, blunt or pointed, depending on their diet. They are found in two habitats, eelgrass and macroalgae. We tested whether there are different chemical cues from macroalgae, a kelp in this case, diatoms, or Zostra marina, eelgrass, that trigger different tooth morphologies in these two species of Lacuna to understand what induces the change in phenotype. Changes in tooth morphology during the experiment was different for snails from two source locations, False Bay, an eelgrass bed, and Pile Point, which is dominated by macroalgae, which may reflect different prior environmental variability or stability. Most animals of both species produced pointed teeth on the neutral diet of lettuce, as well as when fed kelp or eelgrass, suggesting this is a default morphology, and blunt tooth production requires a cue for production. Our data suggest that alginate is not a neutral carrier for food, and affected the rate of tooth change. Further experimentation is needed to determine if diatoms produce chemical cues that trigger blunt teeth.