Starting from the parental individuals, at every 3–4 generations,
RecR individuals were submitted to temephos multiple concentrationconcentration
bioassays according to WHO protocol (1981), in order to
estimate the lethal concentrations for 50% (LC50) and 90% (LC90)
of larvae. Estimated LC50 was used to expose larvae in the selection
process, however, as the bioassays were not performed in all
generations, the same temephos concentration was used in at least
3–4 consecutive generations. Table 1 shows the number of exposed
larvae in generations utilized in bioassays.