A DUAL EFFECT OF CARBON DIOXIDE ON INSECTS POISONED BY OXYGEN

¹ Botany Department, Yale University, New Haven, Conn.
² Department of Biology, Western Reserve University, Cleveland, Ohio

1. The activity of adults of Mormoniella vitripennis and Drosophila melanogaster during and after compression in 10 atms. of oxygen plus small amounts of carbon dioxide (0.1, 0.2, and 0.5 atm.) was studied. Addition of carbon dioxide at pressures above 0.2 atm. to the atmosphere of air in the compression chamber anesthetized Mormoniella adults; on decompression all adults rapidly regained normal activity. The effects of carbon dioxide administered along with 10 atms. of nitrogen were similar except that with 0.5 atm. carbon dioxide, anesthesia occurred more rapidly.

2. Although in some experiments with adults of Mormoniella the presence of carbon dioxide during exposure to oxygen accelerated the onset of paralysis, carbon dioxide actually protected the adults from permanent injury caused by exposure to oxygen. After 2 hours at 10 atms. about half of the adult wasps which had been in oxygen plus 0.5 atm. carbon dioxide completely recovered while none which had been in oxygen without carbon dioxide survived. The number of wasps which recovered increased as the amount of carbon dioxide present during oxygen exposure increased from 0.1 to 0.5 atm.

3. Although the presence of carbon dioxide did not totally prevent oxygen poisoning, permanent injury to "black stage" and "pink stage" developing adults. as well as adult Mormoniella was significantly reduced.

4. In the presence of 10 atms. oxygen, adult Drosophila became motionless more quickly when 0.2 atm. of carbon dioxide was also present. These motionless flies recovered fully when decompressed. Furthermore, significantly fewer flies recovered following paralyzing exposures to oxygen without carbon dioxide.