Temporal and spatial sampling strategies maintain tracking success of whelks to prey patches of differing distributions
Publication Type: |
Journal Article |
Year of Publication: |
2012 |
Authors: |
Miranda L. Wilson, Marc J. Weissburg |
Publication/Journal: |
Animal Behaviour |
Keywords: |
busycon carica, knobbed whelk, navigational efficiency, odour plume, odour-mediated predation, prey distribution, sensing strategies, spatial sampling, temporal integration, time averaging |
ISBN: |
0003-3472 |
Abstract:
The ability of predators to navigate efficiently towards prey patches can determine competitive ability, abundance and distribution of predator or prey species. Slowly moving odour-mediated predators that have a high capacity for temporal integration of signals can successfully navigate prey odour plumes in naturally turbulent environments, but their ability to do this in response to different distributions of prey in patches has not been assessed. We challenged knobbed whelk, Busycon carica, predators to detect and navigate to hard clam, Mercenaria mercenaria, prey patches with different distributions of individuals at two densities (three clams/patch: parallel versus perpendicular arrangement relative to the direction of water flow; 10 clams/patch: aggregated versus random distribution) in laboratory assays to better understand how prey-generated mixing impacts time-averaging predators. Whelks decreased navigational efficiency (movement speed and path linearity) and increased spatial sampling (scanning) in perpendicular treatments at low densities, but these did not result in differences in success. No differences in whelk foraging efficiency, incidence of spatial sampling or success were seen at high prey densities. Increased mixing at high and low prey density (parallel treatment only) may have mitigated information about the distribution of prey individuals within patches and accounted for our results. The whelks’ ability to utilize time-averaging strategies effectively to extract information from odour plumes regardless of prey distribution allowed them to maintain foraging success and may enable them to occupy specific sensory niches that could reduce competition with other odour-mediated predators over resources.