Document: JAC-3-48-14

Common deciduous tree seed characteristics influence seed removal by lab-reared Peromyscus maniculatus.

SCHNURR, J.L.*

Idaho State University, Pocatello, Idaho 83209 USA ¹

Abstract:
Tree seeds differ in chemical composition and physical characteristics that may influence their susceptibility to predation. I tested if lab-reared Peromyscus maniculatus displayed preferences for tree seeds (red oak, red maple, sugar maple, white pine and black cherry) that differed in size, water content, percent carbon, percent nitrogen, and C/N ratio. I used a modified Giving-Up Density technique that assumes quitting harvest rate is a function of the metabolic costs of foraging (C), the predation risk experienced by foraging (P) and the missed opportunity costs of feeding versus other activities (MOC). If all environmental factors (C, P and MOC) are held equal (e.g., lab conditions), differences in the number of seeds remaining after foraging should reflect different preferences for food items. Seeds with the lowest C/N ratios had consistently higher removal rates than red oak, which had the highest C/N ratio. Water content and seed size were not correlated with removal rate. These results indicate that small mammals can change seed preferences in response to the nutritional value of seeds. However, I also found that familiarity with seed type changed preference between trials: most seed types displayed higher removal rates in the second trial. These results aid in explaining the results from field seed removal experiments.

Keywords: seed predation, Peromyscus maniculatus

This abstract is being presented at: 3:30 PM in session:
PLANT-ANIMAL INTERACTIONS