For
example, conditioned leaf litter from Appalachian
(U.S.A.) headwater streams had average C : P and
N : P ratios of 5360 : 1 and 75 : 1 (Cross et al., 2003).
Insects from these heterotrophic streams had correspondingly
high C : P and N : P ratios compared with
terrestrial and lake invertebrates (Cross et al., 2003),
especially among the shredders, a functional feeding
group capable of consuming intact leaf litter