Handling of coarse and fine particulate organic matter by the aquatic insects Paraleptophlebia gregalis and P. temporalis(Ephemeroptera: Leptophlebiidae)

SUMMARY 1. Paraleptophlehia gregalis and P. temporalis were abundant throughout a flow‐controlled section of stream that contained large quantities of fine particulate organic matter (FPOM; 0.45 μm to 1 mm in diameter), and in upstream and downstream areas. 2. In laboratory studies, Paraleptophlebia spp. fed and grew on FPOM and CPOM (coarse particulate organic matter; greater than 1 mm in diameter); growth rate was not related to the particle size of food. In addition, these animals were able to survive and grow on various sizes of faecal material produced by shredders. 3. Paraleptopblehia spp. consumed relatively large amounts (0.16±0.09 mg per mg animal dry mass) of detrital material daily. 4. The mayflies had short gut content passage times (2–3 h) and low efficiencies of conversion of ingested food to body substance (0.08±0.07%). They egested relatively small, amorphous faeces, 5. The overall pattern exhibited by Paraleptophlebia spp. involved rapid processing and partial recycling, through relatively simple alimentary tracts, of large amounts of detrital material from a wide range of sources.