USE OF A TEMPERATURE-SENSITIVE LETHAL MUTATION STRAIN OF MEDFLY (CERATITIS-CAPITATA) FOR THE SUPPRESSION OF PEST POPULATIONS

Before the Sterile Insect Technique can be applied successfully, the size of the target population has to be reduced to a manageable level. At present this reduction is achieved by the use of insecticides. Computer simulations have been performed to examine the possibility of achieving this initial population suppression by genetic control strategies; in particular, the effect of releasing fertile males carrying a recessive temperature-sensitive lethal mutation and a Y-autosome translocation has been simulated. The results show that the release of such males is most effective when applied under permissive conditions, i.e. those which allow flies homozygous for the temperature-sensitive lethal mutation to survive and spread the mutation through the population. However, combining this population replacement with a population-suppression strategy is even more effective. If the released males are partially sterile, e.g. due to the presence of a Y-autosome translocation, the population size is reduced before the restrictive conditions for the temperature-sensitive lethal mutation are reached, i.e. before the increase of temperatures in the target area eliminates all flies homozygous for this mutation. By combining these two strategies the resulting population should be low enough to apply the Sterile Insect Technique for eradication.