Cellulose digestion and metabolism in the freshwater amphipod Gammarus pseudolimnaeus Bousfield

SUMMARY. 1. Weight-specific respiration and feeding rates of Gammarus pseudolimnaeus were inversely related to body weight at 12°C, the temperature of the stream from which they were collected.
2. At this temperature animals could digest about a third of ingested, purified ¹⁴C-cellulose. In animals greater than 20 mg live weight, about 38% of ingested cellulose was metabolized; animals smaller than 20 mg metabolized about 28%.
3. Respired CO₂ from cellulose metabolism was 33–47% of measured uptake of C₂ in animals greater than 20 mg live weight and approximately 25% in smaller animals.
4. Ability to digest cellulose would be of nutritional benefit to Gammarus feeding on any plant material, but would be of particular advantage in the spring/summer period when fine detritus is the main foodstuff.