PARENT SESSION
Oral Session #28: Plant-Animal Interactions. Presiding: S. Louda.
Tuesday, August 7, 2001. 8:00 AM to 12:00 PM. Hall of Ideas J.
Does human scent bias seed predation studies?
Wenny, Daniel1,2, Duncan, R1, Spritzer, Mark1,3, Whelan, Christopher4, 1 2 3 4
ABSTRACT- Experiments on post-dispersal seed predation involving seeds placed into the environment by researchers may unintentionally provide seed predators with olfactory cues. We tested for differences in the rate and extent of seed predation for seeds having direct contact with human skin (scented) versus seeds having no direct contact (unscented). Experiments were conducted at four sites in Florida, and two sites in Illinois, USA. At each of three Florida sites in 1997-1998, 400 stations with five seeds each were monitored for 30 days. Seed removal tended to be greater for scented than unscented seeds but differences were significant only when all species and sites were combined. At each of two Illinois sites and one Florida site in 1999-2000, 400 stations with one seed each were monitored for 30 days. Scented seeds were removed at significantly greater rates than unscented seeds at the Illinois sites (14% scented vs 4.5% unscented removed after one day), but not at the Florida site. In all trials, any effect of artificial olfactory cues on removal was most pronounced during the first week and disappeared by the end of the experiment. These results suggest that human handling of seeds for seed predation experiments slightly increases seed predation rates, but the effect is weak and short-lived. Potential biases associated with seed predation experiments, including artificial visual and olfactory cues, need further evaluation.
KEY WORDS: seed predation, post-dispersal seed removal, rodents, experimental protocol