none. Fourteen genetically different populations of the almond moth Ephestia cautella (Walker) were maintained for 12 months with a regular weekly replacement of the old food cups by fresh ones. Two unplanned factors affected population size: 1) Low humidity caused it to decrease. The populations recovered when humidity was increased. 2) Infestation by two parasitoids. Nemeritis canescens co-existed with the moths and did not affect population sizes significantly; Bracon hebetor spread to all populations and within 3 months reduced them to extinction.