Empirical data from the retention period assay described in Dubern [2].

The investigator recorded two components of data: the ‘number of inoculated plants’ (which we describe as the number of replicate cohorts having live insects)(Ej row 1), and the ‘number of infected plants’ (Ij, row 2). Both components were recorded for the jth day-long IAP for each of a total of 13 consecutive IAPs (header row) and with each component corresponding to a total of 30 replicates. The setup involved consecutive daily transfers of insect cohorts for each experimental replicate. Throughout the text, we accordingly refer to either the jth daily transfer or IAP, as appropriate. Note that if the presence of infected insects was not limited by mortality, then the final transfer day for which plant inoculation occurred (row 2, bold) would reflect retention period of the pathogen to some degree. Since insect survival was an important factor, however, it is possible that the same measure reflects mainly the tendency for infected insects to be lost from the experiment due to manual transfer associated mortality.