Responses of freshwater shrimp on alarm cues from injured-conspecific

Many aquatic animals can release signal pheromones when attacked by predator. This chemical cue can be recognized by the conspecifics, and then the conspecifics will respond with anti-predator behaviour. In our experiment, we used freshwater shrimp (Macrobrachium nipponense) as research objection and studied whether it could recognized the chemical cues coming from injured-conspecific. Tub water of raising injured freshwater shrimp was used as stimulus in stimulating treatment while clean water was used in blank treatment. Compared with the control treatment, the number of freshwater shrimp under the shelter increased significantly (Repeated measures ANOVA, F_1.116=14.49 , p<;0.01) in the stimulating treatment, and the number of freshwater shrimp crossing the midline decreased significantly (initial stage: t₁₉= 4.992, p<;0.01; final stage: t₂₉=5.783, p<;0.01). In addition, the number of freshwater shrimp crossing the midline of the final stage in the stimulus treatment was decreased significantly than that in the initial stage (t₅₈=2.700, p=0.009). The results indicate that freshwater shrimp can recognize the chemical alarm cues which is released by injured-conspecific. Freshwater shrimp can use this kind of recognition mechanism to escape predation.