An Energy Budget for a Deposit‐feeding Amphipod1

An energy budget, with the parameters determined independently, was constructed for Hyalella azteca (Amphipoda) feeding on surface sediment from Marion Lake. At 15C, adult amphipods ingested 0.0525 cal as sediment and microflora per hour. Egested sediment represented a loss of 0.043 cal/hr. Of the calories assimilated, 49% were respired, 36% were lost as soluble excretory products, and 15% were accumulated as growth, egg production, and moults. The assimilation efficiency (15%) is comparable to that calculated for Hyalelta from a previous study. Production respiration and production : assimilation ratios were 0.31 and 0.15.