Feeding Preferences and Growth of Tallaperla spp. (Plecoptera: Peltoperlidae): A Cross-Site Comparison using Tropical and Temperate Leaves

Shredders can be important consumers of leaf detritus in headwater streams, where they influence decomposition and facilitate other consumers. Leaf quality can also be a major controlling factor of the leaf decay process, as consumers tend to show preference for higher quality resources. Although many studies have examined the importance of shredders to leaf decay, only a handful of studies have addressed consumer feeding preferences and differences in resource quality using tropical vs. temperate leaf types. We examined growth rates of nymphs of the stonefly Tallaperla, a common temperate-zone shredder, in laboratory feeding trials using individual and mixed treatments of temperate (Liriodendron tulipifera) and tropical (Cecropia schreberiana) leaves. We also estimated percent leaf mass loss semi-weekly over a 56 d period. We found no significant differences in Tallaperla growth rates between treatments, however, growth rates differed over time. There were significant differences in leaf mass loss between leaf types, with tulip leaves exhibiting faster breakdown rates. Our results suggest that during the initial stages of decomposition, leaf quality (i.e. chemistry) may have a greater influence on decomposition than consumer activities.