INVESTIGADORES
GONÇALVES Rodrigo Javier
artículos
Título:
Mechanisms of prey size selecon in a suspension feeding copepod, Temora longicornis
Autor/es:
R. J. GONÇALVES; H. VAN SOMEREN GRÉVE; D. COUESPEL; KIØRBOE, THOMAS
Revista:
MARINE ECOLOGY PROGRESS SERIES
Editorial:
INTER-RESEARCH
Referencias:
Lugar: Oldendorf/Luhe; Año: 2014 vol. 517 p. 61 - 74
ISSN:
0171-8630
Resumen:
We
examined size-dependent prey detection and prey capture in
free-swimming Temora
longicornis using
video observations, particle image velocimetry (PIV), and bottle
incubations with phytoplankton prey sizes within the range 6−60 µm
equivalent spherical diameter (ESD). T.
longicornis generates
feeding currents by oscillating its appendages at about 25 Hz. Prey
cells >10 µm ESD are perceived and captured individually. A
capture response was elicited when prey was touched by (or within a
few cell radii from) the setae on the feeding appendages. The
extension of the setae defines the prey encounter cross section,
which is therefore independent of prey size. The flux of water
through the encounter area, estimated from PIV, was ca. 150 ml ind−1
d−1,
which represents the maximum possible clearance rates and was similar
to that estimated in incubation experiments. However, while the
detection probability was nearly 100% for cells >10−15 µm, it
declined rapidly for smaller cells. Conversely, the probability that
a cell which elicited a capture response was actually ingested
declined with increased cell size, from nearly 100% for small cells,
to ~0% for the largest cells examined. The resulting prey size
spectrum, predicted as the product of the cell-size-specific
encounter rates and capture probabilities, was dome-shaped, with a
maximum around 20−30 µm ESD. The prey size spectrum from
incubation experiments had a similar shape and an optimum range of
30−50 µm ESD. The mechanistic underpinning of the prey size
spectrum suggested here deviates from previous descriptions mainly in
the mechanism and range of prey detection.