A new study provides a mechanistic understanding of the food size spectra of the copepod Temora longicornis using an integrated approach including traditional feeding experiments, high-speed videography and flow visualization techniques.
While zooplankton feed on a range of sizes, they are most efficient (ie highest clearance rate) within a more limited, optimum range. Copepods have different feeding modes and are not filter-feeders, therefore this optimum range can not be accurately predicted from “mesh size” calculations.
We studied the marine copepod Temora longicornis, which creates a feeding current and captures particles entrained in the flow. In order to provide an explanation of the food size range, we considered the detection distance (and hence capture area) together with the flow through the capture area (both from video observations) to calculate the theoretical maximum clearance rates. Then we compared this to clearance rates from feeding experiments, and found a reasonable match. Thus the clearance rates observed in bottle incubations with different prey sizes could be explained based on morphological, behavioral and functional traits.
Full reference:
Gonçalves, R. J., H. van Someren Gréve, D. Couespel and T. Kiørboe. 2014. Mechanisms of prey size selection in a suspension-feeding copepod, Temora longicornis. Marine Ecology Progress Series 517: 61–74
The paper can be found here