Preparing for escape: anti-predator posture and fast-start performance in gobies

Area of Science:

• Animal Behavior
• Biomechanics
• Ecology

Background:

• Anti-predator postures are typically viewed as vigilance or defense displays.
• The role of postures in enhancing subsequent escape responses remains largely unexplored.

Purpose of the Study:

• To investigate if postural curvature in black gobies (Gobius niger) influences escape responses.
• To test the hypothesis that pre-escape postures can enhance escape performance.

Main Methods:

• Three experiments were conducted on black gobies using weak stimuli (WS) to induce postural bending.
• Fish were startled with lateral or overhead mechanical stimuli to assess escape direction and performance.
• Field observations were used to correlate natural escape behaviors with postural C-shapes.

Main Results:

• Locomotor performance increased with postural curvature.
• Fish showed a preference for escaping away from lateral stimuli, prioritizing direction over performance.
• When startled from above, WS-stimulated fish favored escaping from positively curved postures, enhancing performance.
• Field observations confirmed escapes predominantly occurred towards the convex side of the C-shape.

Conclusions:

• Anti-predator C-shaped postures in black gobies can prepare them for escape, especially from overhead threats.
• This postural adaptation provides an advantage by directing thrust effectively.
• A trade-off exists between escape direction and performance, with direction favored during horizontal threats.