Ontogenetic changes in chemical alarm cue recognition and fast-start performance in guppies (Poecilia reticulata)

Risk recognition and fast-start performance are critical to fish survival when faced with predators. Many fish species have been shown to recognize risks associated with chemical cues released by injured conspecifics. However, little is known about the ontogeny of risk recognition via damage-released chemical alarm cues and fast-start performance in prey fishes. The objectives of this study were to determine whether risk recognition and fast-start performance in guppies (Poecilia reticulata) exhibit ontogenetic variation, and whether there is a trade-off between risk recognition and fast-start performance. To achieve these objectives, individual guppies from replicate groups were assayed on one of the 1st, 7th, 14th, 21st, or 28th day after their birth. We found that both the risk recognition and fast-start performance in guppies exhibited ontogenetic variation, as on days 1 and 7, fish did not exhibit risk recognition when exposed to alarm cues from conspecifics, but by day 14, such recognition was evident. Noticeable increases in maximum linear velocity (V-max), maximum linear acceleration (A(max)), and escape distance (S-120ms) were concurrent with progressive ontogenetic stage, and no significant correlations were found between risk recognition and fast-start performance at any ontogenetic stage. Our findings reveal ontogenetic variation in damage-released chemical cue recognition and fast-start performance in guppies.