Abstract.1Food demands of the predatory carabidNotiophilus biguttatusF. and their fulfilment were studied in the laboratory and field.2In the laboratory, larval consumption, growth, adult body size and egg production were established for different regimes of temperature and food, the springtailOrchesella cincta.3Temperature strongly influenced feeding rate of larvae and adults and consequently growth and oviposition rates. Accordingly, growth rate and ovi‐position rate increased with prey supply.4Prey supply also had an effect on fat content, but the number of ripe eggs in the ovaries was related neither to temperature nor to prey supply.5Adult body size was affected by temperature during the larval period but more so by food supply.6Dissection of field fresh females showed them to bear eggs for the whole year, except in late winter/early spring and in July.7Fat content was low in spring and, from July on, high in summer and autumn. Survivorship during starvation differed widely between samples and seemed to be related to reproductive status rather than to fat content.8Samples of beetles and springtails from eleven pine plantations revealed for the beetles significant differences in fat content and body size, the latter ranging between the maximum and minimum value obtained in the laboratory.9Conclusions about food limitation based on body size and fat content were not corroborated by a relationship of these indices with springtail densit