It is preferred that the composition comprises a carrier, suitable for providing a porous medium, and a food substance for the factitious host species and that the factitious host species is maintained as a three dimensional culture on the carrier. In such a three dimensional culture members of the factitious host species are free to move in three dimensions . In this way they may infest a larger volume of the carrier and utilise the food substance more optimally. Considering the size of the mobile stages of Amblyseius swirskii relative to individuals of the factitious host, this organism will in general also infest the total volume of the carrier, when foraging for the factitious host. Preferably the three dimensional culture is obtained by providing the carrier in a three dimensional layer, i.e. a layer having three dimensions, of which two dimensions are larger then one dimension. Exemplary is a horizontal layer with a length and breadth in the order of metres and a certain thickness in the order of centimetres. A three dimensional layer is preferred because it will allow sufficient exchange of metabolic heat and gasses and will provide a larger production volume compared to a two dimensional layer.