Littorina irrorate (common name marsh periwinkle snails) perform a vertical migration on Spartina alterniflora (salt marsh cordgrass) during high tides. This could be a result in trying to avoid predators such as Callinectes sapidus (common name blue crab). Field studies have shown that the result of climbing up vegetation provides protection from predators. The comparison that is to be made, is the Littorina irrorates response to the presence of the Callinectes sapidus pheromones by vertical migration. The alternate hypothesis is that there will be a difference in how the Littorina irrorate react with the Callinectes sapidus pheromones, by the vertical movement the snails make to avoid the crabs compared to being in a non-pheromone seawater. …show more content…
One Littorina irrorate was put into the non-pheromone graduated cylinder, setting with the foot of the snail on the bottom and timed with a stopwatch for 120 seconds. The Littorina irrorate was measured with a ruler on how high it moved up the side of the graduated cylinder, vertically in millimeters and recorded into an Excel spreadsheet. The used seawater was drained into a discard tank and the snail was fished out. That same graduated cylinder was then refilled with 125 mL of new non-pheromone seawater for a new Littorina irrorate. The same Littorina irrorate that was just tested in the non-pheromone seawater is then put into the graduated cylinder with 125 mL of the pheromone seawater, setting with the foot of the snail on the bottom and timed with the stopwatch for 120 seconds. The Littorina irrorate was measured with a ruler on how high it moved up the side of the graduated cylinder, vertically in millimeters and recorded into an Excel spreadsheet. The used pheromone seawater was drained into the discard tank and the snail was fished out and went into a discard bowl to be held until the experiment was done, and to not reuse the same snail. That same graduated cylinder was then refilled with 125 mL of new pheromone seawater for a new Littorina irrorate