Selecting for Conspecific Alarm Cues in Planaria Using Electric Stimuli

Abstract

Studies conducted by Wisenden and Millard (2001) indicate that planarian species, a clade of platyhelminthes, posses a conspecific chemical alarm cue mechanism much like those of other aquatic organisms. Their methods and protocol, however, involved use of an entire crushed planarian as their alarm cue. This could lead to noxious overstimulation of olfactory receptors. The purpose of my experiment was to determine if an alarm cue is released by planarians when they are subjected to stress without physical injury. Test solutions were obtained by electrically stimulating planarians and then collecting the surrounding medium. The planarian's preference between the test solutions and a control solution was determined with a single sample t-test. My results showed no statistical preference toward the test or control solution(t= 1.98, df=19, 0.10 > P > 0.05) These results prevent us from rejecting our null hypothesis, yet they do not rule out the possible presence of a conspecific alarm cue mechanism in planarian species.