103.4 Saturday, Jan. 7 Zebrafish larvae evade predators by sensing water flow STEWART, WJ*; CARDENAS, GS; MCHENRY, MJ; University of California, Irvine; University of California, Irvine; University of California, Irvine firstname.lastname@example.org
The ability of prey fish to evade predators is central to the ecology and evolution for a diversity of fishes. However, it is largely unclear what sensory systems mediate predator-prey interactions in fishes and what kinematic variables matter most to predator evasion. We evaluated the role of flow sensing by exposing larval zebrafish (Danio rerio) to adult predators of the same species in a cylindrical arena. Larvae were able to escape predators in almost three-quarters of encounters (probability of escape=0.77, N=53). However, when we pharmacologically ablated the lateral line system of larvae, evasion was rarely successful (probability of escape=0.090, N=11). In order to investigate the detailed kinematics of these interactions, we recorded freely-swimming predators and prey at high speed with high spatial resolution using a custom-built camera dolly. This device permitted two-dimensional camera motion to manually track prey as they moved through the experimental arena. Using this device, we found that prey responding with an escape maneuver before the predator’s suction-feeding strike were more than three times more likely to escape than prey responding after the start of a strike. In addition, we found that prey were most successful at escape when responding to an approaching predator from an intermediate distance (probability of escape =0.88 when responding 0.5–0.8 cm from the predator, N=8). These results suggest that successful larvae are responding from a strategically optimum distance after sensing water flows produced by an approaching predator.