3.6.2.2.1. Mites used in the bioassay

To study the factors that affect oogenesis, mites that have not yet been stimulated to start oogenesis must be used. Indeed, if a mite has been in contact with a L5 larva for 0-6 h, oogenesis is initiated (Garrido et al., 2000). Phoretic mites must therefore be used. However, not all phoretic mites will initiate reproduction and oogenesis since they are of various age and physiological status. To study factors triggering oviposition once mite oogenesis has been activated and completed, mites must be collected at least 24 h after capping, but no later than 132 h (after which they stop reproducing, Nazzi unpublished) and introduced in cells containing pupa young enough to allow the normal reproductive cycle. See section 3.1.4.2.1. ‘Opening each cell’ for methods to obtain mites from their cells. For these studies, the different phases of the mite´s ontogenetic development, the time-dependent course of the gonocycle must be considered (Steiner et al., 1994).