Characteristics of the high frequency escape reactions of Oithona SP.

The cyclopoid copepod Oithona was found to exhibit multiple escape reactions when entrained within quantified flow fields. The distance of the escape from the flow‐producing predator mimic (a siphon) decreased with a concurrent decrease in escape distance and speed. Although individuals became behaviorally more sensitive to fluid motion with each successive escape reaction, the lower thresholds were not manifested as more distant escape reactions. Overall, the escape distance and speed decreased significantly with decreased signal strength. The decrease may result from the high cost of the escape reaction, which was calculated to account for 36% of the normal metabolic rate and 500 times the cost of normal swimming.