Changes in the feeding behaviour of a malaria vector, Anopheles farauti Lav., following use of DDT as a residual spray in houses in the British Solomon Islands Protectorate



  • 1To investigate the failure of DDT to interrupt malaria transmission in parts of the British Solomon Islands Protectorate, regular all-night man-biting catches of malaria vectors were made before and after DDT house spraying on San Cristobal Island.
  • 2Changes were observed in the man-biting behaviour of Anopheles farauti. There was a reduction in the degree of entry into houses and a shifting of the times of peak biting. Whereas before spraying the indoor and outdoor biting cycles differed, after spraying there was no difference although both the indoor and outdoor cycles had altered.
  • 3DDT was found to have a deterrent effect on An.farauti but this effect decreased with time.
  • 4DDT also appears to eliminate a dominant indoor feeding fraction of the farauti population. Following this there can be an increase in an outdoor feeding fraction which can be responsible for a resumption of malaria transmission.
  • 5Biting cycles obtained before spraying are also shown for An.koliensis and An.punctulatus.