Data from: Arena size modulates functional responses via behavioral mechanisms
Uiterwaal, Stella F., University of Nebraska - Lincoln
Dell, Anthony I., National Great Rivers Research and Education Center
DeLong, John P., University of Nebraska - Lincoln
Published Nov 20, 2018 on Dryad.
Cite this dataset
Uiterwaal, Stella F.; Dell, Anthony I.; DeLong, John P. (2018). Data from: Arena size modulates functional responses via behavioral mechanisms [Dataset]. Dryad. https://doi.org/10.5061/dryad.4sr5b16
Laboratory-based functional response experiments, in which foraging rates are measured across a range of resource densities, are central for determining trophic interaction strength. Historically these experiments often are performed in arbitrarily sized arenas, with larger sized organisms generally used in larger arenas. However, arena size influences foraging rates and therefore also estimates of the functional response parameters, particularly space clearance rate (attack rate). We hypothesized that non-random movement within arenas by predators and prey may explain this effect. To test this hypothesis, we video-recorded Schizocosa ocreata wolf spiders (predators) and flightless Drosophila melanogaster prey in circular arenas of three different sizes to reveal thigmotactic behavior. We then estimated foraging rates and space clearance rates from feeding trials performed at a single, low prey density in three differently-size arenas in either annular (ring-shaped) or circular arenas. Annular arenas mitigated the effects of predator and prey aggregation and thus controlled the experienced prey density near arena edges. Unlike the circular arenas, annular arenas produced similar foraging rates and space clearance rate estimates across arena sizes, confirming that it is the increased density of prey along edges that generates the previously observed arena size effect. Our results provide a key insight into how animal behavior and experimental design must be considered for the accurate interpretation of foraging rates, both when considering standalone functional responses and when making comparisons across experiments.
Results from foraging trials in two types of arenas (circular and annular).
Movement data of spiders in circular arenas of three sizes, divided into three sheets (tabs). Trial number is given in column A. Spider's location is given in columns B and C. Conversion from pixels to millimeters is given in column D. Location of arena center is given in pixels in columns E and F. Radius of the arena is given in pixels in column G.
Fly movement in circular arenas, presented in matlab data files obtained via ctrax. Data files are labeled with a letter to indicate arena size (S, M, or L) and a number to indicate trial number. X and Y are fly positions in pixels. Note that associated arena centers, radii, and correct pixel to milllimeter conversions are given in Fly Tracking Arena Data.
Fly Tracking Arena Data
Arena data associated with the Fly Tracking data. Arena size is given in column A. Replicate number is given in column B. Arena center in pixels is given in columns C and D. Arena radius is given in pixels in column E. Conversion from pixels to millimeters is given in column F.