Abstract

Chemical cues are commonly used by aquatic vertebrates to assess local threats and facilitate behavioural decision-making. Disturbance cues are ‘early warning signals’ common among aquatic vertebrates, that warn conspecific and heterospecific prey guild members of potential risks. Recent studies suggest that disturbance cues may play an important role in the predation sequence, providing prey with valuable information that affords the opportunity to interrupt the predation sequence and successfully avoid predator encounters. However, little is known about the informational content of disturbance cues and what factors influence the response patterns to these cues. Therefore, we assessed the role of species-specificity and prior experience with predation risk on the information content conveyed by disturbance cues. First, we tested whether receivers exhibit graded antipredator responses to cues from either 10 or 20 conspecific and heterospecific senders. Receivers increased the intensity of their antipredator response to cues from 20 compared to 10 conspecific donors. However, we found that while receivers respond to heterospecific disturbance cues, there was no effect of donor group size, suggesting that there may be a degree of species-specificity of disturbance cues. Second, using wild-caught and laboratory-reared fish, we tested whether senders and receiver responded differentially to disturbance cues if they had prior experience with predation risk. The response of high-risk fish was dependent upon the source of disturbance cue senders (high vs. low risk). However, guppies collected from a low-risk site exhibited similar responses to disturbance cues, regardless of the sender population. Combined, our results demonstrate that disturbance cues may serve as a more elaborate form of risk assessment information than previously thought, and that the response to these cues is, at least in part, dependent upon both the sender’s and receiver’s recent experience with predation.