Hunger, partial consumption of prey and prey size preference in a carabid beetle

Partial consumption of prey and prey size preference were studied in females of the carabid Notiophilus biguttatus F., using different size‐classes of the springtail Orchesella cincta (L.) as prey. Time to ingest a prey increases disproportionately with prey size, mainly as a consequence of satiation. During consumption of a prey the predator's rate of ingestion decreases, partly because of diminishing returns from the prey over feeding time. The hypothesis that the diminishing returns from the prey induce partial consumption was refuted. Partial consumption in the beetle is due to gut limitation; its occurrence depends on prey size. Average weight of prey remains in four prey size classes were close to weights expected from average intercatch intervals and estimates of hunger. Prey choice depends on level of food deprivation. Partial consumption of prey, prey size preference and profitability of prey in relation to hunger of the beetle are discussed.