Effects of DDT Upon the Respiration of Susceptible and Resistant House Flies1

Abstract

Two strains of houseflies which differ greatly in their response to DDT normally respire at equal rates; respiration reaches equally high rates after treatment with 1,1-bis-p-chlorophenyl.2.nitropropane (-butane) mixture. Application of DDT to susceptible flies causes the rate to increase after delays of about 4 hours, with small doses to a few mins. with very large doses. Thereafter the rate decreases and reaches zero after a period of several hrs. to about one day. DDT-resistant flies increase the rate after exposure much less and comparatively low maxima are reached. Addition of piperonyl cyclonene to DDT causes the respiration curves for the resistant flies to resemble those for the susceptible ones but somewhat lower maxima are reached. The total respiration from time of treatment till death is the same at 25[degree]C for the 2 strains but is considerably less than that for the untreated flies. At 35[degree]C treated and untreated flies of both strains have the same total respiration and DDT appears to have less influence in causing death than the environmental conditions.