Sm. Lindsay et Sa. Woodin, TISSUE LOSS INDUCES SWITCHING OF FEEDING MODE IN SPIONID POLYCHAETES, Marine ecology. Progress series, 125(1-3), 1995, pp. 159-169
For many animals, foraging is a complex activity involving decisions o
f when, where, and how to feed, as well as what to feed upon. Flexibil
ity in foraging (i.e. switches among activities, habitats, or food ite
ms) is presumed to contribute to overall fitness, and is an important
component of theoretical models of animal feeding behavior. The import
ance of switching among feeding methods is less well described, but ma
y be very important for marine sediment dwellers (infauna). For exampl
e, many infauna switch between suspension and surface-deposit feeding
depending on water flow. However, infauna often lose feeding appendage
s to browsing predators, and the ability to switch to alternative feed
ing methods which are not dependent on those appendages should be adva
ntageous after such tissue losses. Laboratory experiments examined the
effect of feeding appendage loss on 2 species of spionid polychaetes
which have different alternative feeding modes when intact. Behavior o
f individual worms with 0, 1 or 2 palps removed was videotaped for 2 h
within 3 to 4 d of palp removal. Loss of both feeding palps induced s
witches to alternative feeding modes involving mouth-feeding: Rhynchos
pio glutaeus fed on the surface, Pseudopolydora kempi japonica fed bel
ow the surface. As measured by time spent feeding and by fecal product
ion, the alternative was effective for R. glutaeus but not for P. k. j
aponica. The results emphasize the potential importance of injury and
subsequent switching as factors determining feeding behavior.