Laboratory studies on the behaviouristic resistance of Anopheles albimanus in Panama

The behaviouristic resistance of A. albimanus to DDT observed in populations on the Rio Chagres by Trapido in 1952 was re-investigated in 1958. Measurement of the excitatory effect of DDT in inducing flight showed that the mean excitation times for engorged adults from the Chagres populations of Gatuncillo and Santa Rosa were respectively significantly and almost significantly less than those for a population from an untreated area or for a laboratory population which had never encountered DDT. There was no difference in the susceptibility levels between the Gatuncillo, the untreated and the laboratory strains when they were confined to DDT deposits for one hour.