Leaf litter consumption and diet breadth expansion in the broad-ranged carnivorous plant, Sarracenia purpurea: a preliminary study

Premise: Diet breadth is an important component of life history that
impacts range size, evolutionary outcomes, and ecosystem functioning.
While studies of diet breadth have traditionally been confined to animals,
carnivorous plants provide an exciting conceptual extension to existing
theory. Here, we examine the possibility of diet breadth expansion in
Sarracenia purpurea, a wide-ranged carnivorous pitcher plant. Methods: We
integrate observational, greenhouse, and manipulative field experiments
with nitrogen combustion analysis to quantify the consumption of leaf
litter by S. purpurea.  Results: Our quantification of captured
biomass in wild S. purpurea demonstrates that trap leaves collect leaf
detritus in situ, and the captured plant biomass is comparable to that of
insect prey. S. purpurea pitchers fed leaf biomass in the field exhibited
increased foliar nitrogen, while a follow up greenhouse experiment did not
support this finding. Conclusions: S. purpurea pitchers collect a
substantial amount of leaf litter, which may represent an additional
nitrogen source beyond insect prey, though the extent of nutrient
assimilation from leaf litter remains uncertain.