Meeting Abstract

23.3  Wednesday, Jan. 4  Group shooting behavior in archerfishes BURNETTE, M.F.*; ASHLEY-ROSS, M.A.; Wake Forest University; Wake Forest University

The archerfish (Toxotidae) are a small family of brackish-water fish native to Asia and Australia. All seven species of archerfish demonstrate a unique hunting strategy: traveling in small groups, individuals forcibly shoot jets of water from their mouth at prey located above the surface of the water on twigs or leaves. These streams of water dislodge the prey and cause it to fall into the water where it is then consumed, either by the shooter or another member of the group. In order to aim this jet, the fish must rotate its body so that the tip of the mouth breaks the surface of the water. Researchers have demonstrated a wide range of body angles that individual archerfish use during spitting; it is thought that body rotation serves as a cue to group members who seek to steal prey from the shooter. A recent report indicates that as group size increases, archerfishes become less accurate when shooting. We sought to test the relationship between accuracy, body rotation and group size. We hypothesize that as group size increases, competition for the prey item as it impacts the water will lead shooting archerfishes to take less preferred shooting positions below the prey, choose shallower shooting angles and perform the rotation maneuver more rapidly. High-speed lateral and overhead video will be used to track the shooter during free-feeding on crickets suspended over the aquarium. Group sizes will vary from 1 to 4 individuals. Time to shooting position, time to maximum dorsal rotation, magnitude of dorsal rotation, horizontal distance to prey and time to ventral rotation after the shot will be quantified from video sequences. Individual variation in these parameters and the effect of group size will be determined.