Relationships Among Potassium, Calcium and Trace Elements in Tree Leaves and Associated Canopy Arthropods

There is a paucity of information that describes the relationship between the suite of nutrient elements in tree foliage and associated arthropod assemblages. Foliage from chestnut oak (Quercus prinus), hickories (Carya spp.), yellow poplar (Liriodendron tulipifera), red maple (Acer rubrum), and flowering dogwood (Cornus florida) and associated canopy arthropods were collected in an undisturbed and a 15 yr-old successional forested watershed and analyzed for K, Ca, Mn, Fe, Cu, Zn, Rb, and Sr. Foliar Mn and Sr were found in higher concentrations in the undisturbed watershed. Foliage from hickories was generally higher in concentrations of metals (Mn, Fe, Cu, Zn) compared with other tree species. Dogwood foliage had significantly higher concentrations of Ca and significantly lower concentrations of Mn than other tree species (P < 0.05). Concentrations of foliar elements in herbivore-damaged and undamaged leaves did not differ significantly (P > 0.05). Concentrations of elements in and among arthropod feeding categories varied substantially such that no trends were apparent among tree species and between watersheds. The most apparent trend among arthropod feeding categories was the relatively large accumulation of K in chewing herbivores (primarily caterpillars). In general, there appeared to be increases in K, Fe, Cu, and Zn concentrations from primary producers to consumers. This study contributes to arthropod nutritional ecology and to defining the role of canopy arthropods in forest ecosystem nutrient cycles.