Copepod grazing in turbulent flow: elevated foraging behavior and habituation of escape responses

When exposed to non-turbulent followed by turbulent conditions, the copepod Centropages hamatus initially responded with numerous escape reactions and increased foraging behavior. However, when the cycle of non-turbulent followed by turbulent flow was repeated for several consecutive cycles, the two behaviors followed distinctly different patterns. Foraging effort increased during the first two cycles, and then remained at high levels during both turbulent and non-turbulent periods (period durations of 12.5 and 25 min). In contrast, escape behavior habituated rapidly during each turbulent period and dishabituated during each non-turbulent period. These response patterns are suited to the strongly intermittent nature of oceanic turbulence and allow C.hamatus to utilize the benefits of enhanced encounter rate, while minimizing the expense of unnecessary escape responses.