Insects as a significant source of nitrogen for the purple pitcher plant Sarracenia purpurea.

Abstract

Since nitrogen is a limiting factor for most plants, those that grow in nitrogen deficient environments should have adaptations that make up for the lack of nutrients from the soil. This is found to be the case in the purple pitcher plant, Sarracenia purpurea. S. purpurea is a carnivorous plant that supplements its nutrient poor root uptake by digesting the insects captured in its modified leaf. In this study we sampled 27 plants, 28 insect contents, and 6 leaf litters from two locations, which were called wet and upland, in an interdunal swale in northern Michigan. We analyzed these in a mass spectrometer using stable ntirogen isotopes 14N and 15N to determine the proportion of the plants total nitrogen is received from the insects and found that 65% +-3% of the nitrogen came from the insect prey. Using statistical analysis, we found this to be significantly different from 50% with a p-value of 0.0001 which suggests that insects are an important source of nitrogen in a nitrogen deficient environment.