FEEDING AND GROWTH OF THE ISOPOD ASELLUS-AQUATICUS ON ACTINOMYCETES, CONSIDERED AS MODEL FILAMENTOUS BACTERIA

SUMMARY. Asellus aquaticus was fed for 49 days at 15°C on aquatic actinomycetes in the laboratory. Specific growth rates (wet weight) of animals initially 2.5mm in length ranged from 0.85 to 2.33% day−1 on Micromonospora and Streptomyces S2 respectively. Asellus newly released from the brood‐pouch (1.0 mm length) had a similar growth rate (2.74% day−1) on Streptomyces S2. The growth rates of animals fed on actinomycetes were lower than those of animals feeding on macroscopic foods such as Elodea and decaying oak leaves, regardless of the initial size of the animal. However, it was concluded that actinomycetes, and by inference bacteria also, could maintain a population, albeit a slow‐growing one, in a situation where macroscopic foods are largely absent. The possible significance of hyphal diameter of micro‐organisms in relation to assimilation from them is discussed. In this connection actinomycetes are considered as model filamentous bacteria. Copyright © 1979, Wiley Blackwell. All rights reserved