Reply to Sitters and Olde Venterink: Untangling the relative importance of processes that influence fecal nutrient stoichiometry

Sitters and Olde Venterink (1) question the generality of the positive relationship that we show between herbivore body size and fecal N:P stoichiometry (2). Their data show different and at times opposite patterns. They highlight dietary composition and metabolic requirement as two additional size-related mechanisms determining fecal nutrient ratios and argue that the increased skeletal phosphorus requirements of larger animals that we suggest may not be the primary determinant of fecal P concentrations.We fully agree that dietary nutrients strongly determine fecal nutrients, and the latter often serves as a proxy for the former (3, 4). This is particularly clear when comparing grazers and browsers. However, in … ↵1To whom correspondence may be addressed. Email: elizabeth.liza.le.roux{at}gmail.com