Energy budget of the grain mite, Acarus siro (Acari: Acaridae).

Immature individuals of Acarus siro L. ingest a total of 0.1408 J of food energy, 58.5% of which is consumed by the deutonymph, 27.1% by the protonymph and only 14.1% by the larva. The total ingestion is much greater (2.8169 J +/- 0.0981 SE). Much energy, 0.7031 J +/- 0.0231 SE, is used for egg production, which is concentrated in the first 20 days of adult life. Assimilation efficiency during this period varies from 63 to 71%. Most energy ingested between the 20th and 40th days of adult life is used in biomass production, and biomass increases significantly up to the 30th day. Afterwards, old individuals expend a large amount of assimilated energy on respiration due to the increased cost of maintenance.